[Introduction]: Gold CIL process (carbon in leach) is an efficient method of extracting and recovering gold from its ore. By cyaniding and carbon leaching crushed gold ore slurry simultaneously, CIL process lowers the gold mining operation cost and increases gold recovery rate to 99%, which is the first choice of modern gold mining and gold beneficiation plant.
[Application]: CIL mainly applies for the process of above 1g/t grade gold ore and gold ore with large bearing ore volume: silver, platinum, copper, etc. And CIL has a better performance in extracting these minerals at the same time.
After the crushing and grinding stage, add 9 step-arranged high-efficiency cyanidation leaching tanks into the pulp. Gold pulp cyanidation is carried on the first two leaching tanks, countercurrent adsorption operation is carried on the last six or seven leaching tanks (cyanidation and adding activated carbon simultaneously).
Compared with gold CIP process and other traditional gold extraction processes, Xinhai gold CIL process greatly shortens the cyaniding time, reduces the capital backlog in the gold retention stage. Taking the gold cyanidation plant with processing capacity of 100000 tons per year and gold grade of 7.5 g/t as an example, gold CIL process can save the investment cost of $486000 than the CIP process, reduce the capital backlog of $201700, save and recycle capital of $675100 in advance excluding the cost of activated carbon.
In the adding activated carbon step, add the coconut shell activated carbon (small hole, high activity, wear-resisting and renewable) specially selected by Xinhai mineral processing design institute into the pulp, which can dissolve and adsorb the gold and silver ions then form the gold loaded carbon according to the characteristics of gold and silver adsorption.
Compared with the traditional gold extraction process, Xinhai gold CIL process ensures the gold and silver dissolution and the adsorption of activated carbon synchronously, which will not be affected by the excessive ion concentration, greatly improves the recovery rate of the precious metals (such as silver and copper) in the associated metals , and significantly improves the economic benefits.
Vibrating screen and dewatering screen are the key equipment for the reverse movement of pulp and carbon. Filter press and high frequency dewatering screen developed by Xinhai can effectively reduce the carbon wear on the surface of vibrating screen and in the process of continuous slurry pumping, and reduce the cost, facilitate the maintenance and operation.
Air lifter used in the agitation process can make the slurry carry on small minor-cycle. Compared with other agitation tanks, Xinhai air lifter can reduce the power consumption by 70%, making the solid materials uniformly suspended, the activated carbon less worn, and the gold recovery rate higher, which is an important equipment in a modern cyanide plant.
Xinhai desorption electrolysis system implements high-temperature desorption electrolysis on gold in the gold-loaded carbon through the mixed liquor of sodium cyanide and sodium hydroxide. After wood chips and other sundries are removed by washing machine, and the gold desorption is carried out by Xinhai high-temperature and high-pressure desorption method (150 degrees and 0.5Mpa), which can resolve 99% of gold within 2-6 hours.
The pregnant solution obtained by the desorption of gold-loaded carbon contains higher concentration of gold and silver cyanidation complex ions, while the impurity ions are greatly reduced, which provides an ideal solution for the reduction and recovery of gold from the pregnant solution by electrodeposition. Finally, with Xinhai desorption electrolysis system, the solid gold with high purity can be obtained safely and economically.
Gravity beneficiation is refers to separating gold ore according to mineral density and plays an important role in contemporary mineral processing methods. The main gravity separator equipment are chute, shaker table, mineral jig, hydrocyclones, etc.
Whatre the limitations of the flotation method? For the ores with particle size greater than 0.2mm, and the quartz gold-bearing ore containing no sulfide, it is not suitable to use the flotation method.
The amalgamation process is an old gold extraction process, simple and economical, suitable for the recovery of coarse-grained monomer gold, but it has pollution to the environment and is was gradually replaced by gravity separation, flotation and cyanidation process.
Among the gold resources, the amount of low-grade oxidized ore occupies a certain proportion. It is not economical to use the cyanide method to extract gold, and the heap leaching process has economic benefits.
The heap leaching method actually deposits gold-bearing ore on an impervious site and is immersed and leached with a cyanide solution. After dissolving the gold and silver in the ore, the pre-designed grooves along the site flow into the storage tank. The gold-silver-containing liquid is carbon-adsorbed with activated carbon and then desorbed to recover gold and silver.
A PROSPECTOR DIGGING AND PANNING FOR PLACER GOLD IN A STREAM AREA. THE WAY GOLD WAS MINED HUNDREDS OF YEARS AGO. TODAY, MODERN MINING METHODS REQUIRE PRECISE ENGINEERING, DESIGN, MODERN EQUIPMENT AND SKILLED PROFESSIONALS TO PRODUCE PRECIOUS METALS WITHOUT HARMING THE ENVIRONMENT WHILE KEEPING COSTS IN LINE TO MAKE IT A PROFITABLE BUSINESS. PHOTO OF A MODERN GOLD MINE AND PROCESSING PLANT. STATE OF THE ART HEAP LEACH PROCESSING AND OPEN PIT MINING ALLOW MINING COMPANIES TO PROCESS ORE WITH AS LITTLE AS 0.015 OUNCES OF GOLD PER TON OF ROCK (ORE) AND MAKE A PROFIT. TRY THAT WITH A PICK, SHOVEL AND GOLD PAN! Contact Us Copyright 1994-2012 Mine-Engineer.Com All Rights Reserved
PHOTO OF A MODERN GOLD MINE AND PROCESSING PLANT. STATE OF THE ART HEAP LEACH PROCESSING AND OPEN PIT MINING ALLOW MINING COMPANIES TO PROCESS ORE WITH AS LITTLE AS 0.015 OUNCES OF GOLD PER TON OF ROCK (ORE) AND MAKE A PROFIT. TRY THAT WITH A PICK, SHOVEL AND GOLD PAN! Contact Us Copyright 1994-2012 Mine-Engineer.Com All Rights Reserved
Apache Mill Tailings USA, Inc. is a precious metals mining company specializing in gold, silver, copper and high value, rare earth minerals reclamation recovery. To maximize profits, accelerate project success and reduce risk, we work with above ground mine and ore mill tailings deposits. We have developed a business growth and expansion program that we feel is the best way to progress from start-up to major mining company in the shortest time possible while generating the greatest revenues and highest profits.
Our focus is reclaiming the treasures that are easily accessible and readily available in tailings deposits. No traditional mining is necessary. Drilling, blasting and mine tunneling operations are not required. Research shows that the very best profit potential lies in tailings reclamation. We have conducted extensive research and analysis to locate the best, most profitable tailings deposit sites available. In addition to extremely high profit potential, the projects we have selected can be quickly put into production. Normal mining costs are approximately 50% of the income derived. Our processing operations costs are estimated to 2% to 3% of income.
Vast treasures are waiting to be taken from selected properties with already mined tailings piles. Old processing technologies focused only on gold recovery have left behind fortunes which can be easily recovered. These riches are above ground and "shovel ready". Late 1800's and early 1900's Western USA mines and ore processing mills left behind vast treasures of large gold and ultra-fine gold not processed with the lower recovery rates from the technology of the time. These extremely valuable mineral waste tailings were piled up at the mill's and mine's above ground dumping sites. These fortunes are waiting ready to be recovered using simple modern processing technology.
By just recovering the gold at our target project sites we can build a highly profitable company. Certified independent geologist assay reports verify significant deposits of silver, copper, platinum, rhodium, palladium, iridium, osmium and ruthenium in our targeted site tailings piles. The miners digging for gold at these sites and the mills processing that ore did not know of, could not recover and left behind these treasures buried in the piles of dirt and rocks they discarded. Today there is a national security, critical demand to find key components of cell phones, televisions, weapons systems, wind turbines, MRI machines and batteries. These materials are extremely difficult and costly to mine. Because China monopolizes the world's supply, charges a premium and continues to increase prices, other countries around the world are looking for alternative sources. The versatile mineral rare earth elements needed in these components can be found in the tailings piles on our targeted projects. Typically they co-exist together with gold. Modern extraction techniques allow for cost effective and highly profitable recovery. Multiple environment friendly, non-toxic processing technologies are available to quickly and profitably reclaim these precious metals.
Apache has done the research to find the best high profit tailings reclamation projects available. We have had independent geologists conducted in-depth assays of the minerals at our target sites. To accurately identify and determine the recoverable value of our tailings assets, we have used advanced analytical assay technologies including both laboratory and portable X-ray fluorescence (XRF) instruments. Portable XRF analyzers provide fast, accurate analysis of tailings to quickly and easily gauge the efficiency of extraction and enrichment processes. We have used the expertise of top mining consultants to conduct mining project evaluation appraisals. They have presented us with extensive strategies for the fasted and most profitable metallurgy and mineral processing equipment. Tailings and mine waste engineering, environmental, social, permitting and closure compliance has been conducted. After in-depth research and investigations into our initial targeted projects, we had independent geologists conduct detailed valuation assays at the sites. The value of the recoverable precious metals and rare earth minerals at these sites would give Apache Mill Tailings USA, Inc. the assets to be ranked as one of the leading mining companies in the World.
Harvesting Fallen Gold. Specializing in the environment friendly reclamation recovery from above ground, previously mined and milled tailings deposits, we do not have to dig or build mines. Normal mining costs are about 50% of the income derived. Apache's reclamation costs are estimated to about 3% of income.
Advanced Reclamation and Nano Recovery. With several high yield processing processes available to us, we can customized each project operations to deliver maximum profits as fast as possible. Utilizing our specially designed truck mounted systems we can set up production quickly and scale up to multiply production outputs as needed.
Deposits Worth Billions of Dollars. We select the best high grade, sweet spot mining claims in prime areas of historically known successful gold mining districts. The project sites have immense above ground tailings piles that can be readily processed. Large mining projects or major ore mill processing plants, where the best ore from 100's of miles around was shipped, operated on these sites.
Nothing on this site is to be interpreted as a solicitation or offer of any kind for any purpose in any form or content. All contents of this site is for informational purposes only and is intended only to outline the basic information of potential precious metals reclamation projects and Apache Mill Tailings USA, Inc.'s potential acquisitions, ownership and future targets. Upon accessing this site, all visitors hereby acknowledge this Disclaimer.
Notice: The information on this site is presented for Discussion Purposes Only. As there are both distinct regulations, security and privacy issues regarding this industry, the enclosed information is most basic and introductory in nature. The information on this site does not constitute an offer to sell or solicit the purchase of any security, nor does it constitute an obligation to underwrite, place or otherwise distribute any security described herein. The Content is for informational purposes only, you should not construe any such information or other material as legal, tax, investment, financial, or other advice. Nothing contained on this site constitutes a solicitation, recommendation, endorsement, or offer by Apache Mill Tailings USA, Inc. or any third party service provider to buy or sell any securities or other financial instruments in this or in any other jurisdiction in which such solicitation or offer would be unlawful under the securities laws of such jurisdiction.
Here ispractical, timely information on Placer Mining Methods and equipment used in placer gold recovery. Included is detailed information on equipment, practices, recovery factors, efficiency, design, and, where available, costs. Selected gold recovery operations are described in detail. In addition, the reported efficiency and reliability of various types of equipment used today is presented. One notable method not described is the cyanide process, the recovery of gold through leaching with cyanide, a hazardous substance that must be handled with great care.
The information presented herein applies to small as well as large placer mining operations. Recreational and independent miners will find information on available equipment and designs with some suggestions for improving recovery. Those intending to mine small- to medium-sized placer deposits will find detailed descriptions of suitable equipment and recovery methods. Finally, those interested in byproduct gold recovery from sand and gravel operations and other large placer deposits will find descriptions of appropriate equipment and byproduct recovery installations.
Gold has been mined from placer gold deposits up and down the state and in different types of environment. Initially, rich, easily discovered, surface and river placers were mined until about 1864. Hydraulic mines, using powerful water cannons to wash whole hillsides, were the chief sources of gold for the next 20 years. In 1884, Judge Lorenzo Sawyer issued a decree prohibiting the dumping of hydraulic mining debris into the Sacramento River, effectively eliminating large-scale hydraulic operations. For the next 14 years, drift mining placer gold deposits in buried Tertiary channels partially made up for the loss of placer gold production, but overall production declined. Production rose again with the advent of large-scale dredging. The first successful gold dredge was introduced on the lower Feather River near Oroville in 1898. Since then, dredging has contributed a significant part of Californias total gold production. The last dredge to shut down was the Yuba 21 dredge at Hammonton in 1968 (Clark, 1973). It is fitting that the 1981 revival of major placer gold production in California started with the reopening of this same dredge.
Over 64% of the gold produced in California has come from placer deposits. The reason so much of it has been mined from placers is that placer deposits are usually easier to locate than lode deposits. A lone prospector with a gold pan can verify the existence of a placer gold deposit in a short period of time. Small placers are also relatively easy to mine, and the ore usually requires less processing than ore from lode mines. The same holds true for large placers other than drift mines. Today, placer gold production comes from the dredge operating at Hammonton, from large placer mines employing the cyanide process, from byproduct recovery in sand and gravel plants, from small placer mines, and from small dredging operations in rivers and streams.
With placer mining, recovery of the gold from the ore is usually the most expensive phase of the mining operation and can be the most difficult to implement properly. The value of gold deposits is based on the amount of gold that can be recovered by existing technology. Failure to recover a high percentage of the gold contained in thedeposit can affect the value of the deposit.
Gravity separation remains the most widely used recovery method. Gravity recovery equipment, including gold pans, sluice boxes, long toms, jigs, and amalgamation devices, has been used since the time of the California gold rush, and many present day operations still employ the same equipment. The major flaw of the gravity separation method is that very fine gold, referred to as flour, flood, or colloidal gold, is lost in processing. Early miners recovered no more than 60% of assayed gold values, and as late as 1945 recovery of free gold averaged only 70-75% (Spiller, 1983). Moreover, it is likely that most remaining placer deposits have a higher percentage of fine gold than placers worked during the gold rush. It is understandable, then, that today more care is given to the recovery of fine gold.
In recent times a number of changes and new designs in gravity separation equipment have been developed. Most of these were developed outside the United States for the recovery of materials other than gold. Some of the new equipment has been successfully used to recover gold and some older designs have been modified and improved. Today, many types of equipment exist for the efficient recovery of placer gold.
It is important to note that recovery techniques are often very site specific. A recovery system that collects a high percentage of fine gold from one deposit may not perform effectively with ore from a different deposit. Many factors, such as particle size, clay content, gold size distribution, mining methods, and character of wash water, affect the amount of gold recovered. Extensive experimentation and testing is usually required to design an optimum gold recovery system.
The recovery of placer gold involves processing similar to the processing of most ores. First, the valuable material is separated from the valueless waste through concentration. The final concentrate, usually obtained by repeated processing, is smelted or otherwise refined into the final product. This report focuses on the equipment and methods used for initial processing, or concentration. As in other processing applications, many specialized terms are used to describe the phases of mineral concentration. Although these terms are described herein as they relate to the processing of placer gold ores, most of the terms identified apply to mineral processing in general.
The concentration of placer gold ore consists of a combination of the following three stages: roughing, cleaning, and scavenging. The object of concentration is to separate the raw ore into two products. Ideally, in placer gold recovery, all the gold will be in the concentrate, while all other material will be in the tailings. Unfortunately, such separations are never perfect, and in practice some waste material is included in the concentrates and some gold remains in the tailings. Middlings, particles that belong in either the concentrate or the tailings, are also produced, further complicating the situation.
Roughing is the upgrading of the ore (referred to as feed in the concentration process) to produce either a low-grade, preliminary concentrate, or to reject tailings that contain no valuable material at an early stage. The equipment used in this application are referred to as roughers. Roughers may produce a large amount of concentrate, permit the recovery of a very high percentage of feed gold, produce clean tailings, or produce a combination of the above. Roughers include jigs, Reichert cones, sluices, and dry washers.
The next stage of mineral processing is referred to as cleaning. Cleaning is the re-treatment of the rough concentrateto remove impurities. This process may be as simple as washing black sands in a gold pan. Mineral concentrates may go through several stages of cleaning before a final concentrate is produced. Equipment used for cleaning is often the same as that used for roughing. A sluice used for cleaning black sand concentrates is one example of a rougher used as a cleaner. Other devices, such as shaking tables are unsuitable for use as roughers and are used specifically for cleaning. Concentrates are cleaned until the desired grade (ore concentration) is obtained.
The final stage is known as scavenging. Scavenging is the processing of tailings material from the roughing and cleaning steps before discarding. This waste material is run through equipment that removes any remaining valuable product. Scavenging is usually performed only in large operations. Where amalgamation is practiced, scavenging also aids in the removal of mercury and prevents its escape into the environment. Equipment used in both roughing and cleaning may be used for scavenging, depending on the amount of tailings to be processed. Any piece of equipment used in this latter capacity is termed a scavenger.
Specific terms are also used to describe the efficiency of the concentration process. Recovery refers to the percentage of gold in the ore that was collected in the concentrate. A recovery of 90% means that 90% of the gold originally in the ore is in the concentrate and the remaining 10% is in the tailings and/or middlings. The concentrate grade is the percentage of gold in the concentrate. A concentrate grade of 10% indicates the concentrate contains 10% gold by weight. The ratio of concentration (or concentration ratio) is the ratio of the weight of the feed to the weight of the concentrates. For example, if 1,000 pounds of feed are processed and 1 pound of concentrate is recovered, the ration of concentration would be 1,000. The value of the ratio of concentration will generally increase with the concentrate grade.
There is a general inverse relationship between recovery and concentrate grade in mineral concentration. Usually, the higher the concentrate grade, the lower the total recovery. Some valuable material is lost in producing a high grade concentrate. In such cases, the higher grade concentrate is easier to refine than a lower grade concentrate, reducing refinery costs. The savings in refining costs is usually greater than the cost of recovering the small amount of remaining gold from the tailings. For each mining operation, a carefully determined combination of grade and recovery must be achieved to yield maximum profitability. The best recovery systems will collect a maximum amount of placer gold in a minimum amount of concentrate.
Most large-scale and regulated gold mining companies do not use mercury in their mining operations. However, Small-scale and illegal gold mining operations will sometimes use mercury to separate the gold from other materials.
Large mining companies include Barrick Gold, Newmont Mining, and AngloGold Ashanti. Many investors will invest in these companies either directly through owning company shares or through investing in gold exchange-traded funds (ETFs).
First, mercury is mixed with the materials containing gold. A mercury-gold amalgam then is formed because gold will dissolve in the mercury while other impurities will not. The mixture of gold and mercury is then heated to a temperature that will vaporize the mercury, leaving behind the gold. This process does not result in gold that is 100% pure, but it does eliminate the bulk of the impurities.
The problem with this method is the release of the mercury vapor into the environment. Even if the equipment is used to catch the vapor, some still can get into the atmosphere. Mercury also can get into the soil and water if it still is contaminating other waste materials from the mining process that may be discarded.
Mercury first was used to extracting gold as many as 3,000 years ago. The process was prominent in the U.S. up until the 1960s, and the environmental impact on northern California is still felt today, according to sciencing.com.
Mercury vapor negatively impacts the nervous, digestive, and immune systems, and the lungs and kidneys, and it can be fatal, according to the World Health Organization. These health effects can be felt from inhaling, ingesting, or even just physical contact with mercury. Common symptoms include tremors, trouble sleeping, memory loss, headaches, and loss of motor skills.
The Guyana Shield region (Surinam, Guiana and French Guiana), Indonesia, The Philippines and part of Western Africas coast (e.g., Ghana) are particularly impacted by the phenomenon. Under the socio-economic and political conditions found in the small-scale gold mining operation, the use of mercury is often considered as the easiest and most cost-effective solution for gold separation.
Gold is heavier than most other particles, so alternative methods typically use motion or water to separate the gold from lighter particles. Panning involves moving sediment that potentially contains gold in a curved pan with water and moving in such a way that any gold will settle at the bottom while the water and other particles will leave the pan. Sluicing involves sending sediment down a platform with water. The platform has a carpet-like material at the bottom that will catch the heavier gold particles while the water and other particles wash away. Other more complex methods involve magnets, chemical leaching, and smelting.
Found in Bulgaria are some of the oldest gold artifacts known to mankind, in the Varna Necropolis, a collection of graves built between 4700 and 4200 BC. This finding, dating back nearly 7000 years, provides evidence of the first civilization to use gold mining equipment. Some archeologists claim the Sakdrisi site in southern Georgia, which dates to roughly 4000 BC, is the worlds first gold mine.
In the 19th century, gold rushes occurred around the globe and people migrated to different regions hoping to strike it rich. The Victorian Gold Rush took place in Victoria, Australia, between 1851 and the late 1860s, and the Second Boer War took place in South Africa between 1899 and 1902. In America, the famous California Gold Rush took place in 1949, and discovery of Nevada's Carlin Trend,North America's largest gold depository,took placein 1961.
Since the beginning of civilization, humans have mined around 6 billions troy ounces of gold. Today, 2.5 percent of all gold production happens in Nevada, making it one of the primary regions on earth. As of 2017, China produced the most gold per year at 429 metric tons, followed by Australia, and then Russia. However, there's still a lot of gold out there, and you can join in the gold mining industry by investing in basic gold mining equipment.
There are two basic steps to gold mining: prospecting and production. "Prospecting" refers to the actual search in a certain area for valuable minerals, and "production," also known as mining, is the physical act of removing the gold from where you found it. Since different equipment exists for prospecting and mining, this article explores, briefly, equipment used for prospecting, and then focuses, primarily, on gold mining equipment.
How do you find gold? In the gold mining industry, theres a lot of value in learning from others who have gone before you. No one ever gets all the gold out of any one location. So, try going to where gold exists in abundance. Consider this: the California Gold Rush only removed a small percentage of the gold thats out there. That's right.
There are areas in California that are still open to recreational prospecting, including the Auburn State Recreation Area and the South Yuba Recreation lands. Once you get your feet wet in an area proven to have gold, you can move on to other areas closer to home. After mastering prospecting and gold-mining techniques, you might even want to look for gold in your own back yard.
Some people say, Gold is where you find it. What this means is you have to learn what to look for. First, understand that the way water moves in rivers and streams determines where gold deposits might settle. Next, you need to learn why gold concentrates in certain areas, and then search those areas.
Once youve selected a specific waterway for mining, youll want to pick specific points to search. Since it is impractical to search the entire stream or river, there are ways to read a waterway to determine the most likely places to find gold. The following describes how to find those places.
The first thing to know is gold is heavy. Its about 19 times heavier than the same amount of water and 6 times heavier than solid material found in streams and rivers. So, anything that slows the movement of water is likely to trap gold deposits. Things that slow down moving water are:
Water on the downriver side of obstacles will move slower, and this is where heavier gold will settle. When looking at a chosen waterway, begin by searching for natural dams where gold may have collected. Another place that collects heavier objects in a waterway is inside bends, places where water naturally slows down. Heavy objects will often form a bar at these points, and the upside of a bar inside bends is a great place to look for gold.
Once gold has settled in a stream, over time, it works its way down layers of soil and settles in bedrock. A great location for gold is in the material coating bedrock under a stream. Choose a location on the inside a bend where there is an obstruction and then dig to the bedrock. Sifting the soil coating bedrock, usually, will produce gold.
Learn to delay the excitement of seeing gold for the first time and you will have more gold-filled dirt to take home with you. Once you get better at choosing locations, and especially if you find a proven location, its best to spend your time digging and removing dirt, rather than sifting and cleaning it on site. Delay celebrating and get as much dirt as possible to take home. Once you get home, sift and clean the gold youve found.
Another great place to look for gold is in tall grass growing above an inside bend. Grass acts like a sieve and the largest gold pieces end up at the roots of grass. They often call this kind of gold oat gold. The pieces might be smaller than gold found in other places, but there could be a lot.
If you want to invest a little in your endeavor, you can purchase a metal detector designed to find gold. This gold mining equipment can cut down on the time spend hunting, but a mid-level detector can cost about $600.
When considering getting involved in gold prospecting and mining, make sure you learn and follow the rules. There are certain places where prospecting is legal and others where it is not. Many prospecting clubs exist and joining one can help ensure you are following rules. For examples, most sites require that you refill any holes you have dug, and that you do not destroy local plant life. Learn the rules before you head out with your gold mining equipment.
Once youve finished prospecting and have a location where you know there is gold, you will need gold mining equipment. What you use will depend on the size of your operation. If you are working in the gold industry, you will have industrial gold mining equipment. If you are mining on your own as a hobby, youll need smaller, personal gold mining equipment. Lets look at both.
If you want to use industrial mining equipment, make sure you have the proper training. If working for a business, they should provide needed training. However, if you purchased industrial gold mining equipment for a personal claim, be certain you know what you are doing. Safety should always come first.
Miners use drills for underground mining to create access holes for descending underground, or to place explosive charges to bring material to the surface. The drill miners choose depends on how and what is being mined.
Blasting tools create an explosion to blast away chunks of material to access minerals. Blasting can also remove chunks of unwanted materials that are keeping other machines or people from getting to a seam of wanted materials. In underground and open pit mines, miners use both drilling and blasting tools, often together. They use drills to place blasting tools at the right depth and in the right place.
Earth-moving machines move around large amounts of materials. They might haul material after blasting, move other materials allowing access to seams of minerals, dig underground mines, or get down to the bedrock where minerals might exist.
Crushing equipment moves materials around an underground mine. Miners use this equipment to keep the flow of materials going at an efficient rate, and to save money. It is easier to remove crushed rocks rather than heavy chunks, so crushing equipment saves time and effort.
A sluice box is a way to sift through raw material more quickly. Essentially, its automated panning. These machines used to be large and heavy in the early days of panning, but are now lightweight and easier to use. If youre serious about mining, they are worth checking out.
A higher quality sluice box, high banker boxes have a water pump allowing more material to move through faster. These boxes recycle water so you dont have to rely on water flow in the river. They recover more gold than basic models.
If you arent going into the professional gold mining industry, but are looking for a hobby or a part-time job to bring in a little extra money, consider joining a mining club to help you once you begin your prospecting journey. The club will help you learn about personal gold mining equipment, but, for now, lets take a quick look at what you will need.
There are lots of different sizes, colors, and options in gold pans. Essentially, a 14-inch plastic pan is the best size, by far. Color does not matter, however gold shows up better in black. Black sand shows up better in blue or green. There are many new kinds of pans, but a basic pan with sharp, undercut riffles is all you need. Make sure the bottom of the pan is as wide as possible to catch more gold.
You will need a place to store the gold you find. All you need is a waterproof container you can close tightly, such as a 35mm film container. You can purchase containers on the internet, specifically made for holding gold.
The last thing to consider is investing in Gold Lab, a personal system that recovers gold from the concentrate you have refined. A good gold panner can get most of the gold from refined dirt, but a Gold Lab kit will allow you to further refine and recover 100% of your gold.
Once you have your equipment, its time to get in the river to pan for gold. This simple technique mimics what the river does naturally. You recover material, or dirt and place it in the pan, from a river location where you think there might be gold. Then, you shake it in a left-to-right motion underwater to sweep away light materials while causing heavier materials to go to the bottom of the pan.
Take the pan with the riffles on the far side and shake it, vigorously, left and right. This breaks up materials sending heavier items to the bottom. Do not slosh water out of the pan. If you need to, repeat the previous step and break up larger chunks again.
Continue shaking the pan back and forth and keep removing the top layer of lighter materials until you are down to only the heaviest materials, such as coins, BBs, old bullets, buckshot, nails, garnets, black iron rocks and black sand. You should now be able to see gold in the pan when shaking and tilting it forward slightly.
Use a magnet to remove black sand and other metal objects. Keep removing things until only gold remains. Remove the larger gold pieces and save any leftover concentrate. Let it sit for a while so you can recover any remaining pieces of gold that settle.
If you have enjoy the outdoors, and have just a little ambition, you can make a hobby out of gold prospecting and mining. All you need are basic tools that as your gold mining equipment and the willingness to do a little research. Once you decide where to go, or join a mining club to help you find locations, pack up your tools and prospect. It may take practice at panning before you find anything, but once you do, youll love the feeling of satisfaction and discovery. If you find you enjoy the hobby, invest in semi-professional gold mining equipment and see if you can up the amount you discover. Even if you only discover a few flakes, prospecting can be a great way to make new friends, learn about the gold industry, and understand a little about gold prospectors of old. Its an inexpensive hobby, so grab basic gold mining equipment and get started today.
911MPE has for target market what mining professionals consider the pilot-plant scale mining operation or artisanal mining operations with a focus around under 500TPD. Metals you can extract include: gold, silver or other of the precious group as well as the classic base metals; copper, lead, zinc, nickel, molybdenum. Much of our ultra-small scale equipment allows you to process from just a few kilo (pounds) per day and work on your passion for a small budget.
At the time, 1890, the Author said There is, of course, nothing for us to learn from this imperfect and rudimentary gold-extraction process described here, which is doubtless destined to disappear ere long, before the progress of scientific mining, now making itself slowly felt throughout the far East. I think it advisable, however, to put on record all such crude efforts, if only to enable us to trace more completely the evolution of our modern systems of mining, and to teach us by what widely-divergent methods different races of mankind have attempted to solve one, apparently simple, problem.
Their method of mining was then, and is now, the following: A small water-furrow is first brought in at the highest possible level on a suitable hill-side, and the stream is turned down the hill. By means of a heavy long wooden crowbar, shod with a long strongly- made chisel-pointed iron socket, and with the help of the stream of water, which rarely exceeds 50 cubic feet per minute, the surface- soil and weathered country-rock are loosened and sluiced away. No trouble is taken to save any of the gold washed down, except in one or two instances where rude riffles have been inserted in the tail-race; the race is, however, carefully searched for bits of quartz showing visible gold, which are picked out and put on one side. The surface of the shales is thus stripped, and any veins of gold that may be laid bare are then worked. The principal mining- tool is a rough kind of pick, and the use of explosives, or even of wedges, is quite unknown. Neither shovels nor barrows are used ; their places are taken by broad hoes and baskets, a pair of the latter, swung at each end of a stick and holding at least 70 pounds, being easily carried up steep grades by a Chinese miner. The tunnels, small and irregular, usually incline steeply upward ; they are rudely timbered, and as timber decays rapidly in this climate, these workings cannot penetrate far into the hills, but soon have to be abandoned, and the whole series of operations has to be recommenced.
A party of 27 miners, who owned and worked a rich hillside, considered themselves to be doing well when their entire days output (they do not work night-shifts as a rule) was a little over half a ton of quartz. The quartz, as extracted from the reef, is cobbed down with hammers to about pass a 1 J-inch ring, and is then carefully hand-picked, all stone showing visible gold, sulphurets or any other favorable indications being sent to the mill and the restbeing thrown away. From one-eighth to one-half is thus rejected. I have assayed many samples of this refuse rock, which carries from 3 to 10 pennyweights of free milling gold to the ton, so that it is quite worth milling according to our modern ideas.
At first the mode of crushing adopted by the Chinese consisted in heating the rock red-hot, quenching it in water and then pounding it down and rubbing it between two stomps. About 35 years ago atilt-hammer, made entirely without iron and having a stone head, was introduced, and is still much used by individual miners. About twelve years ago the battery of three to six hammers, worked by a water-wheel, was first employed. It is said to have been copied from mills for crushing the materials of joss-sticks. Tilt-hammer rice-mills are also built. Such water-mills are usually the property of a party of miners working together.
The foot-mill shown in Figs. 1 and 2 is of the usual type, from which there are but few unimportant departures. The entire falling weight is about 45 pounds, and the length of drop about 20 inches; as a rule, these mills are worked at 15 to 20 blows per minute.
The mill shown is built entirely without iron; the stone that forms the base of the mortar is a piece of hard quartzite or of barren reef-quartz, the same material being used for the hammer-head, which is firmly held in its socket by wooden wedges, the socket being kept from splitting by a stout hoop of rattan twisted round it. Some of the mills use iron hoops, and some have iron spindles for the hammer to work on; with these exceptions and one or two other very unimportant details, the construction is always the same, though the dimensions may vary a little. There is scarcely a house in the whole district that has not one of these mills.
The Chinese usually work these mills for about eight hours per day. A shovelful of quartz is first thrown into the mortar and the mill is then worked by the foot of the miner, who stands on one or other of the stones shown in the drawings, grasping the uprights or else a cross-bar that is sometimes fastened across them.
When the quartz is supposed to be crushed sufficiently fine, the hammer-head is propped up, and the crushed stone is scraped out and sifted through a circular sieve 15 inches to 20 inches in diameter, and about 1J inches deep. The sieve itself is made of thin strips of rattan about 0.1 inch in width. There are from 36 to 40 holes per square inch, so that the width of mesh varies between 0.04 and 0.06 inch. A man can crush in a working day, with one of these mills, from 70 lbs. to 140 lbs. of stone, according to its hardness.
The number of heads in a power-mill varies between 3 and 6, depending principally on the quantity of water available. As the district is well watered, the large majority are 6-stamp mills; out of 11 power-mills which it contains, 8 are 6-stamp mills. Figs. 3 and 4 show the usual type of the latter mills, from which pattern there is practically no departure. I could not even induce the Chinese to try a curved cam instead of a straight one, as they seemed to consider such innovations dangerous ; and they added that wood and water were both cheap enough. As will be noticed, the construction of the water-wheel is extremely crudethe water, which issometimes brought down very steep hills from considerable heights in small, highly-inclined ditches, strikes the flat buckets with considerable velocity, so that the wheel is partly an impact and partly a pressure wheel; the buckets are never more than half-filled at the best, and the wheel is sometimes allowed to wade in tail-water to the full depth of the shrouding. Much power is accordingly wasted, the amount of water consumed in driving one of these mills beingfrom 80 to 100 cubic feet per minute. The average number of drops of each head varies between 27 and 32 per minute; the length of the drop is about 2 feet, and the effective falling weight of the head is about 70 lbs. Thus only about one-third of the theoretical power of the water is utilized, but of course much of this loss of energy is due to the friction of the whole machine, notably between the straight cam and the tailpiece of the hammer. There are usually 3 men per shift working one of these mills, 2 being engaged in looking after and feeding the machine, while the third sifts thepounded stone as already described, throwing back under one of the hammer-heads whatever will not pass the sieve.
The cost of one of these mills complete, including a substantial shed over it thatched with palm leaves, but excluding the water- furrow, is said to be about very little, and they are supposed to last from 5 to 7 yearsneeding, however, constant repairs.
A stone hammer-head lasts from a week to a month, according to its quality. They are made, as in the foot-mills, from boulders of quartz rock, and it is mostly one mans business to search for these boulders in the bed of the stream, and, when found, to dress them into shape.
I tested the degree of fineness to which these mills reduce the quartz by differential siftings of a number of samples, taken by spoon-sampling the heaps of crushed ore lying at various mills. The results of some of my tests are given in the following table :
It appears from the above table that a great deal of the ore is crushed very fine (too fine, indeed), while some is not fine enough. As about 40 per cent, of the ore will pass through a 6,400 sieve, there must be much over-stamping, resulting, no doubt, in the production of a great deal of float-gold and slimes.
After the mill has been running for a longer or shorter period, according to circumstances, a clean-up takes place. The crushed ore is carried out in large wooden pails to a Chinaman, who washesit, squatting down by the side of a square pit, through which a small stream of clear water is kept running. The implement used for washing is a flat, somewhat conical wooden dish, cut from the spurs of certain hard-wood trees, and fashioned with much care. It is known as the dulang, and much resembles the Spanish-American batea, except that the section of the former is that of a very obtuse rounded cone, while the section of the latter is approximately that of a sphere.
A section of a typical dulang is shown in Fig. 5. Much importance is attached to the correct shape of the conical point, as it is in this that the precious metal is gathered together. The dulang is filled with from 10 to 15 lbs. of crushed stone, according to its size, and this is washed by a curious circular, combined with a slight undulatory motion, by which the particles of light, barren quartz are swept over the edge of the dulang, which is held just dipping below the surface of the water in the pit, while the heavier particles are collected in the rounded apex of the cone. When nearly cleaned, the gold and concentrates are transferred to a smaller, very carefully made and polished dulang, about 1 foot in diameter, in which thequartz is washed off as thoroughly as possible, and the gold, by a skillful jerk, is thrown clear from the sulphurets, and finally collected in a small brass dish. The sulphurets still retain much coarse gold, to which they cling obstinately. They are ground as fine as possible on a stone and re-washed several times, a good deal of the gold being thus separated and added to that previously obtained. Even then the sulphurets still carry much gold, the larger portion of which is free. They are stored away in jars while wet and allowed to rust, and after a time they are sometimes re-crushed and re-washed ; very often, however, they are merely allowed to accumulate and are not treated further. The first tailings are re-washed, and then stacked.
The cleaned gold is dried and melted over a small forge provided with a box-shaped wooden blower of the usual Chinese type. The fuel is charcoal. Tiny, conical crucibles, capable of holding about a couple of ounces of gold are used; the gold-dust is melted in these with borax and niter as fluxes; the slag is lifted off the surface of the gold when the latter is supposed to be clean, by means of an iron rod, and the gold is then granulated by pouring into water. If it is not considered to be sufficiently soft and pure it is re-melted, and the process is repeated until the gold is quite soft. The principal impurities removed seem to be sulphur, arsenic, a little copper, and perhaps traces of lead. Both the granulated gold and the crude gold-dust, as also gold got from river-washing, are used as currency in this district, coined money being scarcely ever seen here, and then only in the form of the old dollar.
In a partial wash-up at one of these mills, during my stay in the district, the following results, considered to be exceptionally good, were obtained, the quantity washed being as nearly as possible 2000 pounds of crushed ore:
As a general rule, there seems to be left in the tailings about one- third of the gold originally present in the ore, while there must be a considerable additional loss of float-gold carried away in the process of washing, due to the original fineness of some of the gold in the ore, and to the over-stamping already referred to.
From the average of these two assays it would appear that nearly one-third of the original proportion of gold is still left in the tailings. I might quote numerous other assays, but the results in all cases were approximately the same; there were no really clean tailings at all, in spite of the fact that they were all the result of handling sur- face-ores, where practically the whole of the gold was free. The losses above indicated appear enormous, but it must be remembered that the thrifty Chinamen throw nothing awaynot even tailings; however completely, in their opinion, these may be exhausted, they still pile them up and keep them. When, for any reason, their mill would otherwise be idle, they re-pound and re-wash their old tailings, and always get some gold out of them. The piles of tailings are, however, left exposed, so that a considerable proportion gets washed down into the streams and rivers by the heavy rains that occur at each change of monsoon ; and there are a good many Chinese of the poorer classes who make a sort of living by washing the sands in the river-beds, the gold they get being principally, to all appearance, that which has been thrown into the rivers by the miners up stream. It is noticeable that there is no gold, or very little, to be found in the rivers above the points where there are mines in operation. A fair days work of one Chinaman in the river-bed (say six hours actual work) was found, as the average of several trials, to produce an output of 7.3 grains of gold about .940 fine, worth say little in localcurrency. This quantity of gold was obtained by washing 22 large dulangs of gravel, each holding about 70 pounds of dirt.From the average of these two assays it would appear that nearly one-third of the original proportion of gold is still left in the tailings. I might quote numerous other assays, but the results in all cases were approximately the same; there were no really clean tailings at all, in spite of the fact that they were all the result of handling surface-ores, where practically the whole of the gold was free. The losses above indicated appear enormous, but it must be remembered that the thrifty Chinamen throw nothing awaynot even tailings; however completely, in their opinion, these may be exhausted, they still pile them up and keep them. When, for any reason, their mill would otherwise be idle, they re-pound and re-wash their old tailings, and always get some gold out of them. The piles of tailings are, however, left exposed, so that a considerable proportion gets washed down into the streams and rivers by the heavy rains that occur at each change of monsoon ; and there are a good many Chinese of the poorer classes who make a sort of living by washing the sands in the river-beds, the gold they get being principally, to all appearance, that which has been thrown into the rivers by the miners up stream. It is noticeable that there is no gold, or very little, to be found in the rivers above the points where there are mines in operation. A fair days work of one Chinaman in the river-bed (say six hours actual work) was found, as the average of several trials, to produce an output of 7.3 grains of gold about .940 fine.
It is interesting to note that in custom-milling, of which there is a good deal done here (many of the fossickers sending all the gold quartz they collect, whether by mining or picking out of the river- gravels, to one of the water-mills for crushing), the charge made is equal to just a few $U. S. per (long) ton of quartz, this payment including the washing of the gold, but not, so far as I can make out, its cleaning and melting.
It is obvious from the above description, that the total quantity of stone crushed by all the mills in the district, supposing them all to be going simultaneously, and including the foot-mills, could not exceed some 12 tons a day at the best, an amount that could be far more economically and efficiently handled in a five-stamp Californian mill of moderate power. Yet the total annual output of gold from this district (including, however, alluvial as well as reef-gold) is said to be 4861 ounces, fully .900 fine. The total number of men engaged in mining, in one way or another, is close upon one thousand.
Removing the gold-bearing rock from the ground is just the first step. To isolate pure gold, mining companies use a complex extraction process. The first step in this process is breaking down large chunks of rock into smaller pieces. At a mill, large machines known as crushers reduce the ore to pieces no larger than road gravel. The gravel-like material then enters rotating drums filled with steel balls. In these drums, the ore is ground to a fine slurry or powder.
Next, mill operators thicken the slurry with water to form pulp and run the pulp through a series of leaching tanks. Leaching dissolves the gold out of the ore using a chemical solvent. The most common solvent is cyanide, which must be combined with oxygen in a process known as carbon-in-pulp. As the cyanide and oxygen react chemically, gold in the pulp dissolves. When workers introduce small carbon grains to the tank, the gold adheres to the carbon. Filtering the pulp through screens separates the gold-bearing carbon.
The carbon moves to a stripping vessel where a hot caustic solution separates the gold from the carbon. Another set of screens filters out the carbon grains, which can be recycled for future processing. Finally, the gold-bearing solution is ready for electrowinning, which recovers the gold from the leaching chemicals. In electrowinning, operators pour the gold-bearing solution into a special container known as a cell. Positive and negative terminals in the cell deliver a strong electric current to the solution. This causes gold to collect on the negative terminals.
Smelting, which results in nearly pure gold, involves melting the negative terminals in a furnace at about 2,100 degrees F (1,149 degrees C). When workers add a chemical mixture known as flux to the molten material, the gold separates from the metal used to make the terminals. Workers pour off the flux and then the gold. Molds are used to transform the liquid gold into solid bars called dor bars. These low-purity bars are then sent to refineries all over the world for further processing.
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Innovation plays a critical role in the mining industry as a tool to improve the efficiency of its processes, to reduce costs, but also to meet the increasing social and environmental concerns among communities and authorities. Technological progress has also been crucial to allow the exploitation of new deposits in more complex scenarios: lower ore grades, extreme weather conditions, deeper deposits, harder rock mass, and high-stress environments. This paper discusses the importance of innovation for the mining industry and describes the mechanisms by which it is carried out. It includes a review of the drivers and actors involved and current trends. The digital transformation process that the industry is going through is analyzed, along with other relevant trends that are likely to shape the mining of the future. Additionally, a case study is presented to illustrate the technical and economic implications of developing a disruptive innovation project.
Over the past decades, the mining industry has had to face a challenging scenario for its operation. Improving productivity to overcome natural factors such as decreasing ore grades, deeper deposits, and harder rock mass, combined with an increasing environmental and social awareness, has boost the industry to constantly work to enhance their processes along the whole value chain. In this, innovation plays a crucial role by providing suitable solutions to surpass these difficulties, ensuring the continuity and sustainability of the mining activity.
There has been a historical debate whether mining is indeed an innovative industry or not. It is often perceived as a conservative sector, where innovation takes only a secondary position in the concerns of companies. But at the same time, many argue that mining is more likely to be comparable with high-tech industries, considering that it utilizes vanguard technologies in its processes, such as automated or remote-controlled machinery, and advanced monitoring systems for the collection and analysis of large amounts of data .
Nowadays, many relevant actors of the industry claim that mining is going through the first stages of a deep changeover from the hand of digital transformation. It is said that this process could change how mining is done, passing from human-run operations to autonomous or semi-autonomous remote-controlled mines. Independent if fully automated operations are achieved in the near future or not, the digital transformation is already impacting the industry and will continue doing so.
It will contribute to improve the understanding of the dynamics and mechanisms involved in the innovation processes, along with analyzing the current status and expected future of the mining industry, in terms of technological advance.
The scope of this paper covers the mining industry in general and its entire value chain (exploration, extraction, processing, and smelting and refining). However, by the nature of the topic, artisanal and small-scale mining have been mostly excluded from the analysis, considering the historical low degree of technological specialization in this sector. Also, for the illustration and exemplification of certain points made in this document, a special focus has been put in the large-scale copper mining sector and the main copper producer countries.
Cambridge Dictionary defines innovation as a new idea, method, design, or product, as well as its development or use . In general, innovation can be understood as a process of change, through which a new idea or solution is applied in a good, service, or productive procedure to create value and meet new requirements from customers and higher safety or environmental standards, among other goals.
In this section, the importance of innovation for the mining industry is discussed. Firstly, the relation between innovation and labor productivity is examined. Then, a general view regarding the innovation dynamics within the industry is provided, exploring the main drivers and actors involved.
A first approach to understand the relevance of innovation within the industry can be made through the analysis of labor productivity. Technological advances usually have an impact on the output, allowing larger production rates while maintaining a similar workforce, or directly reducing the needed personnel by the automation of processes. Nevertheless, changes in labor productivity of a mine may be caused by a series of other reasons. Natural factors, such as decreasing ore grade and deepening of deposits, mean that a larger amount of material in more complex situations must be removed to obtain the same final metallic output, thus impacting negatively on labor productivity, while, in an aggregated view (e.g., when analyzing the mining industry of an specific country), the discovery and exploitation of new and better deposits can also positively impact the overall labor productivity . On the other hand, in a high-price mineral commodities scenario, companies are willing to compromise their costs in order to increase production (because it is profitable) and, therefore, reduce their labor productivity .
Several authors have analyzed the behavior of labor productivity in specific mining industries in an attempt to isolate the effect of innovation. Tilton et al.  first introduced the importance of innovation and new technologies in the growth of labor productivity while studying the decline and recovery of the US copper industry during the 1970s, 1980s, and 1990s. The authors attributed most of the labor productivity increase in this period to the incorporation of the solver extraction and electrowinning technology (SX-EW), along with the use of larger trucks, shovels and drills, in-pit mobile crushers and conveyor belt systems, computerized scheduling of trucks, and real-time process controls.
In a later study, more concrete evidence regarding the previously mentioned was provided . Since the exploitation of new deposits can have an impact on the aggregated labor productivity, the authors built two scenarios to analyze this index between 1975 and 1995: one, considering only the mines operating at the beginning of the studied period, and therefore, excluding the effect of new mines, and two, the actual situation, including both old and new operations. In Fig. 1, the adjusted curve represents what labor productivity would have been if no new mines would have entered in operation in this period of time. As shown, adjusted and actual labor productivity resulted to be not so far different; thus, approximately 75% of the productivity growth in the US copper industry over those years came from productivity improvements at individual mines (i.e., innovation and technological advances), despite the exploitation of new deposits.
Under a similar methodology, the labor productivity growth in the Chilean copper industry during the 19781997 period was analyzed (Fig. 2) . Their findings, though not as dramatic as in the US copper industry, showed that innovation and the introduction of new technologies were responsible for approximately a third of the productivity growth in the total period. Specifically, during the years prior to 1990, this factor accounted for the total growth, while in the 1990s, the development of new world-class mines (e.g., Escondida) turned over the scenario. Nevertheless, these results were coherent with the findings of previous studies on the US copper industry, regarding the role of innovation in improving the competitiveness of the mining industry.
Labor productivity for the Chilean copper industry, actual and constrained (or adjusted) assuming no change in the location of mine output 19781997 (tons of copper contained in mine output per copper company employee). Modified after 
More recent research on the copper industry of Chile and Peru has presented additional supporting evidence that, though not the only factor, innovation, including the adoption of new technologies and managerial changes, remains as a key element for the improvement of labor productivity .
When looking at the following time period (late 1990s to early 2010s), the situation presents a dramatic change. From 2005 onward, the average labor productivity of Chilean mines suffered a sharp decline, as shown in Fig. 3. The same situation can be observed in other main mining countries, like Australia, Canada, and the USA (Fig. 4). Labor productivity in these countries started falling in the first years of the 2000s. This decline can be attributed to a combination of natural and economic factors. On one side, while reserves are depleted, ore grades tend to decrease and the operation advances to deeper locations, increasing hauling distances, stripping ratio, and geotechnical difficulties, all of which have a negative impact on labor productivity. On the other side, in a period of high mineral commodity prices, like the one that the industry went through during the second half of the 2000s and the beginning of the following decade, mining companies will favor production growth despite productivity .
As presented, labor productivity is affected by a series of factors, mainly by natural characteristics of mineral deposits, market conditions, and innovation. While in periods of labor productivity growth it has been possible to isolate the positive effect of innovation, during declining cycles, this task turns more complicated. However, the fall in these periods is attributed mainly to natural and economic factors. In the meantime, innovation remains crucial to maintain the competitiveness of the industry, to the extent possible, providing the methods and tools to overcome the natural challenges faced by modern mines and exploit new and more complex deposits. In other words, while declining labor productivity may be inevitable during certain periods of time, the development and adoption of new technologies, along with innovation at a managerial level, are essential to maintain minings competitiveness through the different cycles.
As discussed in the previous section, innovation constitutes an important factor affecting the productivity of mining operations. Examples of technologies developed to improve the efficiency of processes, reduce costs, and in consequence enhance productivity are easily found. Hydrometallurgical production method SX-EW has been identified as a major contributor for productivity growth in the US copper industry over the last decades of the twentieth century . Likewise, continuous mining equipment in underground coal mining, along with draglines and bucket wheel excavators in surface coal mining, were key advances to reach new levels of productivity in coal production. In smelting processes, the development of flash, and, more recently, bottom blowing furnaces, has had a great impact in reducing energy consumption and OPEX.
Besides boosting productivity, through innovation, it has been possible to unlock the potential of deposits that were technically infeasible to exploit by traditional methods. For example, preconditioning of the rock mass through hydraulic fracturing, confined blasting, or a mix of both has allowed the exploitation of deeper ore bodies, in high-stress environments.
Addressing safety and environmental concerns has been also a major driver for innovation. Over the recent decades, focus has been put on removing workers from critical activities through the automation of processes and the use of autonomous and semi-autonomous (remote-controlled) equipment.
Meeting more rigorous environmental regulations and attending the concerns of local communities are minimal requirements for maintaining the social license to operate. Therefore, innovation has been also aimed at developing cleaner and more environmentally friendly solutions in the whole value chain of the business, and not only to improve the efficiency and reliability of its processes . Examples of these are the new tailings disposal methods that have been implemented to reduce the impact of mining on the environment, such as the thickened and paste tailings disposal. These methods improve water efficiency in their processes, reduce the requirement of surface for their disposition, and minimize risks of collapse, among other advantages over traditional methods.
Regardless, extractive firms have historically shown low levels of expenditure in research and development (R&D), often perceived as the main innovation-related index . During the decades of the 1990s and 2000s, R&D intensity of relevant mining and mineral companies, understood as the R&D expenditure as a percentage of total revenues, was on average only approximately 0.5% .
Figure 5 shows the average R&D intensity for some of the largest mining companies, as revenue level refers, during the 20112018 period. Though presenting variation during the period, on average, this index has remained around 0.4%. These levels of R&D intensity are considerably low compared with other industries. For example, in 2015, pharmaceuticals and information and communications technology (ICT) equipment, the most R&D-intensive industries, reached levels of 25.1% and 24.7%, respectively. Moreover, the average R&D intensity in 2015, across all industries in OECD countries, was 5%, more than ten times the level of the selected mining companies .
R&D intensity of five of the largest mining companies, based on 2018 revenues(companies selected accordingto availability of information i.e.R&D expenditure informed in annual reports, individualized and separated from exploration expenses). R&D intensity calculated as a percentage of total annual revenues for the 20112018 period(in the case of Zijin Mining, R&D intensity was calculated as a percentage of total operating income, according to data reported by the company). Data retrieved from annual reporting of companies Anglo American (available in: https://www.angloamerican.com/investors/annual-reporting), China Shenhua Energy Company (available in: http://www.csec.com/shenhuaChinaEn/ 72/dqbg.shtml), Codelco (available in: https://www.codelco.com/prontus_codelco/site/edic/base/port/memorias.html), Rio Tinto (available in: https://www.riotinto.com/investors/results-and-reports-2146.aspx), and Zijin Mining (available in: http://www.zijinmining.com/investors/Annual-Reports.jsp).
Measuring the level of innovativeness of an industry by only examining R&D intensity, however, can lead to misinterpretation. Some authors argue that R&D expenditure fails to consider other activities that could be related to innovation efforts, such as engineering development, plant experimentation, and exploration of new markets. Also, R&D expenditure in general does not include mineral exploration expenses . While these arguments may be reasonable, it is necessary to analyze in more detail how and by whom innovation is done in mining.
Whereas in the past mining companies would have tended to develop technology solutions in-house, over the last decades of the twentieth century the tendency changed. Economies of scale from using larger loading and hauling equipment had an important impact in improving productivity and reducing costs. Yet, these solutions came from equipment manufacturers, not from mining companies . This is how outsourcing became a tendency among large producer firms, resulting in higher degrees of vertical disintegration . Companies would focus on their core business, while relying on suppliers for the development of technological solutions, therefore avoiding the risks associated with the large investments involved. At the same time, in many cases, suppliers of such are also subcontractors for mining companies, handling construction and mining activities in projects and operations. These include the development of methods, techniques, and technologies to accomplish these tasks and therefore liberating their clients, the mining companies, from the technological concerns.
Leading technology suppliers, such as Sandvik, Epiroc, and Caterpillar, among others, have not only focused in the development of new equipment according to the technological and sustainability trends (currently, on automation and electromobility), but they have also put effort in the development of the proper digital systems for the operation and coordination of these machinery within the operations (e.g., AutoMine from Sandvik).
Though large global suppliers are important actors for the development of new technologies, the outsourcing tendency previously mentioned has also opened the opportunity for the emergence of local knowledge intensive mining suppliers. These firms hold specific local knowledge that allows them to provide customized solutions for mining companies in niches that cannot be covered by the standardized products offered by large global suppliers .
Also, this outsourcing trend has promoted the creation of collaboration initiatives between large mining companies, local suppliers, and governmental and academic institutions for the development of technological solutions. Instances like these can be found in Australia, Chile, and Brazil . In Chile, for example, the World-Class Supplier Program, a public-private partnership between the mining companies BHP, Codelco, and Antofagasta Minerals; Fundacin Chile and other governmental institutions; and more than 75 local suppliers has already developed over a hundred innovation initiatives since it was launched in 2009. Though the program has had a positive impact in the development of the knowledge-intensive mining supplier sector in Chile, certain challenges need to be faced to bring this sector to the next level of progress. Among these challenges, it is necessary to escalate the program, promoting high-impact and long-term innovation projects, despite the usual incremental technological solutions developed until now .
Unlike most mining companies, the supplier sector holds in high priority the innovation agenda. A survey conducted on 432 firms from the Mining Equipment, Technology and Services (METS) sector in Australia, in 2015, revealed that for 63% of these companies innovation was core to their business strategy, driven mainly by a customer-focused vision, the necessity of staying ahead of the competition and direct solutions requirements from their customers .
A similar view is shared by the mining supplier sector in Chile. One hundred five of these companies were surveyed in 2019, revealing a high level of innovation-aimed expenditure. On average, they reported innovation expenses for 14.3% of 2018 revenues, reaching levels of 28.7% and 22.3% in the medium- and small-scale suppliers, respectively. Likewise, their innovation projects were driven mainly by direct solutions requirements from their customers, the necessity of staying ahead of the competition and by having innovation as core to their business strategy .
Besides the dynamics involved in the development of technologies, either by mining companies themselves or their suppliers, the mining industry is also recognized for its capacity to adopt technologies from other industries. ICTs have facilitated the introduction of important improvements in exploration techniques, mining, and processing. Simulations, sensor systems, automation and remote-controlled operations are some examples .
Nowadays, ICTs offer a new level of technological advance from the hand of digital transformation. The extractive industry finds itself in the early stages of adopting these new technologies. The full potential of their applicability for mining processes is yet to be unlocked. The implications of the current trends of Industry 4.0 for the mining industry are discussed and analyzed in the following section.
Defining a future view for an industry is not a simple task. Nowadays, the world is changing faster than ever before. New technologies are developed every day, impacting the way people live. The phrase we live in a different world than the one where our parents grew up does not completely cover the reality of the past few decades. For example, in current days, most people would not conceive their lives without their smartphones, and even though the first ones were commercialized in 1992, the massification of these devices came only a little more than a decade ago (e.g., the first iPhone was developed in 2007).
Nevertheless, in the case of the mining industry, it is possible to identify certain trends that can be of help to outline this future scenario. First and most evident, it is the major technological shift occurring across all industries: the so-called Fourth Industrial Revolution, or simply Industry 4.0, as the transition to the digital era. Then, social and environmental concerns are already compelling mining to look for safer, more efficient, and sustainable ways of conducting the business. Reduction of energy and water consumption, lower emissions, and waste generation are all factors that will be in the core of the mine of the future.
Over recent history and since the beginning of industrialization, several changes in production paradigms have taken place, promoted by the surge and application of novel technologies. As shown in Fig. 6, the world has already seen three paradigm shifts, better known as industrial revolutions. Currently, a new transformation is in progress from the hand of cyber-physical systems and a set of new technology developments, e.g., automation, internet of things, and analytics [16, 17].
The Fourth Industrial Revolution brings a new concept of industry, also called Industry 4.0. This concept is based on an advanced digitization of production processes and the combination of internet-oriented technologies, allowing the connection between smart sensors, machines, and IT systems across the value chain. The implementation of these cyber-physical systems should bring a series of benefits, such as productivity increase by the automation of production and decision-making processes, reduction of waste, improvement of equipment utilization, and maintenance costs reduction. However, Industry 4.0 is not only about the adoption of new technologies, but it will also demand organizational changes, specialized knowledge, and expertise [16, 17].
To achieve the scenario set by Industry 4.0, companies from all sectors, though at different speeds, are implementing the necessary changes at a technological and organization level. These changes constitute the process of digital transformation.
Though the term digital transformation (DT) has been extensively used in recent years, mainly to describe the adaptation process of organizations to new digital technologies, there is not a unique definition for it. On the contrary, there are many. Acknowledging this situation, and after an exhaustive review of DT-related literature,  offers the following definition: a process that aims to improve an entity by triggering significant changes to its properties through combinations of information, computing, communication, and connectivity technologies.
The reason for the existence of various acceptations for DT may lie in the differences among industries: each sector operates in particular ways; therefore, each digital technology will have a different impact, depending on the industrial sector adopting it.
The specific information, computing, communication, and connectivity technologies involved in DT also vary from one industry to another. In the case of mining, however, it is possible to identify a set of tools that will and are already affecting the processes not only at the mine site but across the operational and corporate units within a firm.
DT is a transversal process of change across the complete value chain of the mining industry, from the exploration to the production of final products, their commercialization, and even the closure of operation sites. Experts, companies, and government agencies have been discussing how the digital mine should look like while advancing forward in the DT process. Figure 7 shows how modern digital technologies are and will keep affecting the different areas of the business.
As shown, novel technologies are producing operational changes across the value chain, and their use is not necessarily exclusive for a specific activity. For example, intelligent operation centers are being implemented for both extraction and processing operations. Likewise, augmented and virtual reality, along with digital twinning, are tools that will enhance the design and construction of mining projects (Establish in Fig. 7), and the extraction and processing operations.
While the view of the digital mine may vary among firms and organizations, it is possible to define a set of core technologies that represent the pillars of the DT in the mining industry [19,20,21,22,23,24,25,26,27]. These key elements are described below.
These technologies might hold the highest level of implementation among the tools offered by DT. The first and more clear benefit of the automation of processes, use of robots in critical activities, and remote operation centers (ROC) is the improving of safety, by reducing the number of operators required in hazardous sites .
ROCs can also significantly reduce OPEX and CAPEX of mining operations. Since less workforce is needed at the mine site, fewer or none supporting infrastructure is required, such as housing installations, hospitals, or schools. Also, other expenses are reduced, such as transportation of operators. The impact on costs is larger as the location of the mine is more remote, distant, and isolated .
The use of autonomous equipment, such as hauling trucks, LHDs, and drillers, is expanding rapidly. For example, global equipment manufacturer Caterpillar has already provided more than 239 autonomous trucks for large-scale mining operations in Australia, Brazil, Canada, and the USA .
Similarly, Komatsu holds a total fleet of 141 autonomous trucks distributed in Australia, Canada, Chile, Japan, and the USA. In Chile, these vehicles operate in Codelcos mine Gabriela Mistral. Over the 10 years of operation of the mine, the use of autonomous trucks has allowed a significant collision risk reduction and high levels of productivity and tires performance .
By February 2020, a total of 459 autonomous haul trucks were accounted as active in mining operations around the world . Though these equipment still represent less than 1% compared with the total of manual trucks currently operating,Footnote 1 they are characterized as high year-to-year growth: 32% in the 20192020 period and higher rates are expected for the next years, from the hand of significant investments made by major companies such as BHP, Fortescue Metals Group, Rio Tinto, and Hancock Prospecting in Australia and Suncor Energy and Canadian Natural resources in Canada.
In general terms, besides the benefits in safety, autonomous equipment enhance productivity and reduce operational costs, by increasing equipments utilization (due to the continuous operation), reducing variability in the production outcome, and improving tires and components performances [20, 29].
IoT is understood as a network of physical objects, such as sensors, equipment, machinery, and other sources of data. The elements connected to this network can then interact, exchange information, and act in a coordinated way . Thanks to advances in IoT technology, nowadays, it is possible to establish low-cost networks. Additionally, the development of smart sensors allows real-time capture of data from machines and equipment across the operation. This generation of data is the base to conduct an integrated planning and control, considering the different units within the operation, and support the decision-making process .
Due to the digitization of processes, advances in IoT, and real-time data capture, mining operations have enormous amounts of data available regarding production, processes, and performance of machines, among others. Through advanced analytics methods, it is possible to transform this information allowing its use for a better planning of activities and to support fast and effective decision-making processes for the operation. Predictive models can also be developed to enhance maintenance of equipment, therefore improving productivity .
AI/ML methods are also being applied for mineral prospecting [32,33,34]. It is expected that these methods will optimize the prospection and exploration activities, reducing costs and improving their accuracy.
The concept of digital twinning refers to the construction of a digital model of the physical operation. This is possible using the geological and engineering information of the site, but more importantly, thanks to the real-time data generated from the sensors connected across the operation. With the digital twin of the mine, it is possible to perform simulations and predict potential failures or downturns in equipment performance. Thus, the digital twin constitutes a useful tool to improve operational planning and reduce operational costs, by avoiding unexpected interruption in production processes and optimizing the maintenance of equipment [20, 21].
In its study of 2017, the World Economic Forum and Accenture estimated a potential benefit for the mining industry, as a consequence of DT, of US$ 190 billion over the period 20162025, equivalent to approximately 9% of the industrys profit . Correspondingly, in the USA, the mining industry has been included among the group of sectors with potential to increase productivity from the further digitization of its assets, customer relations processes, and transformations in its workforce . These expectations are aligned with the results of a survey conducted by Accenture in 2014 among executives from 151 mining companies around the world. In this, 85% of the surveyed executives reported that their companies were strongly supporting internal DT initiatives and 90% that the DT programs were already elevated into strategies and high-level decision-making .
However, the level of overall digitization of mining is still low, when compared with other industries. By 2014, though DT was mentioned in six out of ten of some of the largest (by market value) global mining companies annual reports,Footnote 2 qualitative benefits from DT were reported only by three of them and only one presented actual quantitative gains . This confirms that, though DT has claimed a relevant position among mining companies concerns, on average, the industry is still in the early stages of this transformation, and most of the potential benefits are still to be unlocked.
Correspondingly, a survey conducted on 105 companies from the mining supplier sector in Chile in 2019 revealed that 59% of them perceived a medium level of interest from the mining companies to incorporate DT-related technologies and 32% a low level of interest. Only 9% of the surveyed firms perceived a high level of interest from mining companies to incorporate these technologies in their operations(Fig. 8). Regardless, most of these suppliers are already developing or will develop in the next 5 years products or services incorporating technologies 4.0, being remotization, automation, smart sensors, and analytics the most frequent ones 
In general terms, though DT is frequently mentioned as one of the main concerns among most large-scale mining companies, which over the years has generated great expectations regarding its benefits, the overall level of digitization of the industry remains low. Nevertheless, there are several cases of mining operations where a high level of digitization and automation of its processes has been achieved. LKABs iron ore mines, Kiruna and Malmberget, located in northern Sweden, are operated under a combination of remote-controlled and fully automated equipment for drilling, blasting, and hauling processes. Moreover, full automation and electrification are core elements in the future plans for deeper levels, for which development KLAB has been working in close collaboration with high-tech companies, such as ABB, Epiroc, and the Volvo group . Similarly, the Syama underground gold mine in Mali, owned by Resolute, constitutes the first fully automated mine, incorporating an automated haulage system, automated rehandle level, and mine digitization [37, 38].
Likewise, some technologies present a greater level of adoption across the mining industry than others. For example, autonomous and semi-autonomous equipment, such as trucks, LHDs, drills, and trains, started to be tested more than a decade ago (in some cases, even before); some have been successfully operating for several years now and are rapidly spreading [28, 29, 39]. In the same way, many companies have implemented ROCs to control their operations remotely. In Chile, for example, Codelco has a ROC for its mine Ministro Hales and it is developing centers for three more of its divisions . BHP has also implemented its Centre of Integrated Operations (CIO) in Santiago, Chile, from which it will coordinate all its operations in the region.
Smart sensors and monitoring systems are also already generating large amounts of data. However, the wide and successful application of advanced analytics to support and gradually automate the operational decision-making processes is still to come. Today, its use remains mainly in the construction of predictive models for maintenance purposes and the visualization of data to support human decision-making.
For the period 2019-2020, the digital effectiveness has been identified as the second most relevant risk for the mining industry . It highlights the importance of advancing in digitization, as a necessity for companies to remain competitive. The main risk lies then on the fact that DT is often perceived as a task exclusive of the information technology (IT) area. Nonetheless, to achieve a truly effective and value-creative transformation, it must be carried out as a joint task across the organization, with a shared view of the business goals and a strong commitment from the top management. Otherwise, DT initiatives will remain as isolated IT projects, with no significant benefits considering the investments involved [22, 23, 41].
Ensuring the convergence of IT and OT (operational technology) is also key for a successful DT. These areas have traditionally worked by different paths: IT closely to corporate and support systems, while OT running core processes at the operation site. However, the automation of processes requires an integrated IT/OT management .
DT is a process of change that goes beyond technology. As mentioned in the first paragraph of this section, it requires coordination across the whole company. But it is also important to understand what this transformation will mean at an organizational level . Structures will suffer changes by the automation of processes and introduction of new technologies and methods. For example, a recent study revealed that around 80% of the current labor competences in the mining sector in Chile will potentially change in the middle and long term as a consequence of the technological progress. Even more, at least 40% of them have a high probability of being replaced by automated processes . This situation must be considered and evaluated. The new structures must be designed in advance and action must be taken to prepare the employees for these new arrangements. New knowledge and skills will be required, so the firms should also invest in the proper training programs to face DT.
Finally, in an increasing digital environment, a special focus must be put in cybersecurity. DT brings a wider connectivity among equipment and sensors but also between different business units. The company could then be exposed to greater risks of security breaches. For this reason, cybersecurity constitutes a fundamental element in DT [20, 25]. In fact,  also classified this issue as the fourth most important risk for the mining industry in 20192020. To overcome this risk, a solid cybersecurity culture must be promoted in every level of the organization, incorporating new security-related practices in the daily responsibilities of the employees, along with the measurement of relevant KPIs and a periodical revision of the adopted strategies to evaluate their effectiveness and generate improvements, if necessary .
In parallel with the technological wave brought by the digital transformation, a series of other trends have been gaining relevance in the mining industry over recent years. Driven by safety and environmental concerns, cost reduction, enhancement of efficiency, and productivity in the operation, or a mix of these motives, these trends are complementary to the technologies 4.0 and offer an idea of the future paths that mining might follow.
Electromobility, as the development and use of electric-powered vehicles, is a technological trend across industries. From personal-use cars and public transportation vehicles, to heavy machinery, electromobility offers an economical and more environmentally friendly alternative to the use of fossil fuels.
Mining is especially affected by this paradigm change. Most mobile equipment in mining operations has been historically powered by internal combustion engines (ICEs), using diesel fuel. While the impact of the negative aspects of these engines might be bearable in open pit operations, in underground mines, where ventilation can account for up to 2540% of the total energy costs, the situation is different . Diesel ICEs emit exhaust gases containing a series of pollutants, such as unburned hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), and diesel particulate matter (DPM). Additionally, a large amount of heat is also produced. All these elements increase the demand for fresh air flow in order to ensure a proper working environment for operators and equipment, having a significant impact on costs .
Moreover, due to the increasing environmental and safety awareness in the industry, regulations regarding the admissible levels of pollutants have become stricter in the past decades and are likely to become even stricter in the future. At the same time, after exhausting shallow deposits, mining is moving to deeper locations, aggravating the temperature conditions .
Even though some methods to provide electric power have been used for a long time already (e.g., trolley assist), today there are more incentives to look for electric-powered alternatives to replace the mobile equipment that have been predominantly running with diesel ICEs, like LHDs and haul trucks. According to the method used to supply the motor with electric energy, this equipment can be classified into five categories :
In Table 1, a summary of the differences among diesel-powered equipment and the categories mentioned of electric-powered equipment, according to key operational, environmental, and economic parameters, is presented.
In general terms, the main advantages of electric-powered over diesel-powered equipment are higher energy efficiency, higher service life (and, therefore, lower fleet requirements along the life of the mine), lower maintenance requirements, reduced generation of pollutants, heat and noise, and overall lower operating costs. The lower ventilation requirements can also have an impact on the CAPEX of the mining project, by reducing the size of ventilation adits and fans. On the downside, electric-powered equipment usually presents higher CAPEX and, depending on the type, can present some other disadvantages (Table 1). Also, the specific conditions of the operation can affect the preference for one specific technology, e.g., open pit vs. underground, haulage distances, deepness and rock temperature, regulations of the country, and diesel and electricity prices. For these reasons, an integral techno-economic evaluation must be conducted in each case.
Nevertheless, a lot of effort is currently being put in R&D regarding electric-powered equipment, especially battery and hydrogen fuel cell-powered. These show the greater potential to replace diesel equipment, due to their high flexibility, besides the safety and environmental advantages already mentioned .
Main mining equipment manufacturers have already developed several models of battery-powered vehicles. The Epirocs zero-emission fleet for underground operations includes the Minetruck MT42 Battery (articulated low-profile truck), Boomer E2 Battery (drill rig), and the Scooptram ST14 Battery (LHD) . In the meantime, Caterpillar continues to develop its R1700 XE battery-powered LHD  and Sandvik works on its LH514BE battery-assisted LHD (as a combination of battery and tethered cable) .
Though the transition to electric mining equipment has been relatively slow, it is difficult to think of a mining industry of the future still depending on fossil fuels. The shift to cleaner sources of energy is global: industries and governments across the world are implementing renewable energy sources strategies and policies, regulations are becoming stricter and social scrutiny harder. Electromobility has arrived to stay and the mining industry is not excluded from its influence.
The concept of a mining with no impact on the surface is not new. Underground operations have been using their waste material to backfill open cavities left after ore extraction, mainly for stability reasons and as a mean to reduce haulage costs. At the same time, this practice reduces subsidence effect and, therefore, the impact on the surface above the underground mine. However, it is not possible to use all the waste extracted due to interference with the operation (e.g., during early development stages). Also, not every mining method allows backfilling application (e.g., caving operations). Therefore, it is certain that impact on the surface can be significantly reduced, but most of the time it is unavoidable.
In this regard, in situ leaching (ISL), also referred to as in situ recovery (ISR), constitutes an alternative that minimizes the effect on surface and generates practically zero waste. This method is understood as the in-place leaching of the ore, recovery of the enriched solutions, and their transportation to the surface for further processing.
ISL has been mainly applied in uranium mining (since it was first introduced in 1959 in the U.S.). There is also a record of successful cases of ISL applied in copper and gold deposits, though in relatively small scales. Besides typical characteristics of deposits (e.g., shape, dimensions, mineralization, grade distribution), the most critical factors restricting its applicability are permeability, hydrogeological conditions in site, and the possibility of achieving selective leachability of the ore body . Containment of the leaching solutions within the zone of interest to prevent the contamination of groundwater might be the greatest environmental risk regarding ISL .
From an economic point of view, ISL presents obvious advantages over traditional mining methods. Energy consumption is reduced, thus lower OPEX needs to be met. ISL also requires lower CAPEX for infrastructure and mine developments. Additionally, this mining method admits a high production flexibility and can be developed as a modular project, if desired .
Future widespread application of ISL depends greatly on the technological advance regarding permeability enhancement and hydrogeological management. Findings in preconditioning techniques used in caving operations are likely to be adapted and applied in ISL mining for permeability improvement. Pilot tests of in situ bioleaching have shown that it is possible to enhance permeability within the orebody after the application of conditioning methods, such as hydraulic fracturing and water pressure blasting , whereas the use of barriers, such as the gel barriers widely used in the oil and gas industry to control the flow of sweep and production, are also potentially applicable for this mining method as a tool for proper leaching solutions containment . For these reasons, R&D efforts should be mainly aimed at the adaptation and improvement of existing technologies.
Besides environmental benefits of this method, if the restrictions mentioned can be overcome, ISL opens the possibility to exploit very deep low-grade deposits, currently uneconomic or technically infeasible to mine.
Continuous extraction and material handling systems have been used for many years in the coal mining industry. In surface operations, this has been carried out combining the action of bucket wheels excavators for the extraction and conveyor belt systems for the transport of coal and waste. Meanwhile, underground methods such as longwall mining and room and pillar (by using continuous miner equipment) have also offered continuous flows of material. However, due to rock strength, most metallic ore deposits do not allow mechanical extraction methods, making necessary the use of drill and blasting, therefore, impeding continuous operation.
Traditional mining methods combining drill and blasting, excavators for loading and mobile equipment for hauling (or LHD for loading and hauling, in underground mining), have high levels of operational inefficiency and low equipment utilization: significant hauling cycles, in which at least half of the time the mobile equipment is empty, along with queues and waiting times at loading and dumping site, are some of the inefficiencies of these processes.
As discussed in the previous sections, increasing productivity and enhancing efficiency of operations are the main drivers for innovation. Then, the development of continuous extraction and material handling systems, outside the coal sector, are trends that will likely gain importance in the future.
Indeed, efforts in this matter have already been done in recent years. One example is the S11D iron mine of Vale in Brazil. This mine operates in four independent truckless systems. Each system consists of an excavator, a mobile sizer rig (MSR), and a mobile belt wagon (MBW) that connects to a belt conveyor (BC). Due to its continuous truckless design, the project has reported high operating productivity rates (about four times higher than Vales typical rates in the region) and lower operating costs (approximately three times lower than Vales traditional cost levels in the region) .
Initiatives in underground mining have also been developed. Such is the case of the Continuous Mining System (CMS) for caving operations, introduced by Codelco in Chile. This design considered the continuous and simultaneous extraction of broken ore from active drawpoints in a block or panel caving mine, by the combined action of feeders (located at the drawpoints), heavy weight conveyors, and primary crushers .
After almost 20 years of research and testing, the project was finally dismissed as a consequence of difficulties faced in the construction phase for its industrial validation . Thus, the design did not get to be tested at an industrial level, and therefore, its real potential and applicability remained unclear. However, previous tests and studies suggested that great benefits in terms of productivity, costs, workforce requirements, and ramp-up duration can be achieved through the implementation of the CMS .
The Continuous Mining System (CMS) was an innovation project developed by Codelco, in Chile, that intended to create a continuous material handling system for block and panel caving operations. With the objective of illustrating the impacts and implications of implementing a disruptive innovation project, the CMS initiative is below described and analyzed.
Codelco is a Chilean state-owned mining company, first copper and second molybdenum worldwide producer. It is divided into eight operating divisions located in the central and north of Chile. In total, Codelco possesses seven mining operations, four smelters and three refineries .
Divisions Andina, El Teniente, and Salvador include panel caving operations, thus the importance of projects such as CSM for the corporation. Moreover, Chuquicamata Underground Mine has been recently commissioned, a block caving operation that required over US$ 5.5 billion for its construction and will extend the life of Chuquicamata Division for at least 40 years.Footnote 3
The concept of continuous mining for caving operations was first introduced by Codelco and its Institute for Innovation in Mining and Metallurgy, IM2, in 1998. It was conceived as a tool to face the future challenges of underground mining, specifically the necessity of increasing extraction rates and improving safety .
The CMS comprised dozer feeders at the drawpoints, panzers to collect and transport the broken ore from the dozers to the sizer crushers, and finally the sizers themselves. Changing the operation of LHDs for a continuous material handling system also requires a reorganization of the layout of the extraction level. The basic differences between the El Teniente layout (typically used by Codelco in its caving operations) and the CMS layout are presented in Fig. 9.
El Teniente layout (left) vs. CMS layout (right). Modified after . Left layout dedicated to LHD access to drawpoints, whereas right layout with perpendicular arrangement dedicated to continuous material flow with panzers (flow direction indicated by arrows)
The first phase took place in Codelcos Salvador Mine, in 2005. It was focused on the validation at a pilot level of the concept of continuous extraction. For this, the extraction of ore from one drawpoint by a prototype of a dozer feeder was tested.
The test showed the capacity of the dozer feeder to extract the ore from the drawpoint at a reasonable rate (200 t/h on average), allowing a proper flow within the ore column . With these positive results, the process validation moved forward to Phase II.
The second phase in the process validation of CMS was also executed in Salvador Mine. This time, a prototype of a modular system of continuous extraction, haulage, and crushing was tested. The module considered one haulage drift with four drawpoints, each one of them with a dozer feeding the panzer, which transported the ore to a roller impact crusher . The module was built between 2006 and 2007 and the test itself carried out between 2007 and 2008. During this period, approximately 200,000 t were extracted in total. The results achieved in Phase II were satisfactory, in terms of the performance of the different equipment and their interaction, though the roller impact crusher was dismissed for further tests due to its low availability and high components wear. In its place, a sizer crusher was incorporated afterwards .
Due to the promising results in previous phases of validation, the company decided to move forward to Phase III, to validate at an industrial level the CMS method. This test aimed to evaluate the performance of the CMS method under real operating conditions, in Andina Division of Codelco. The design considered a sector of four haulage drifts (equipped with panzers) and eight drawpoints per drift (each one of them equipped with a dozer feeder), and a total test period of 38 months .
Phase III was defined as the validation test of CMS for its application in the Chuquicamata Underground Mine Project, which commissioning was planned for the first semester of 2019. In this sense, the main expected benefits from its applicability in the Chuquicamata Underground Mine originally were :
The construction of the test module started in 2012. However, due to significant deviations in the execution period and budget, the works were stopped in December 2015. After more than 2 years of being paralyzed, and in the light of new studies and re-evaluations performed by Codelco, the project was finally cancelled in 2018, totaling US$ 138.1 million of loss .
Developing an innovation project for a technological breakthrough often requires long periods of time. Since the idea is conceived, conceptual studies must be carried out before initiating pilot and industrial validation tests. In the case of Codelcos CMS, over 20 years passed since the concept was first introduced until the industrial validation project was finally cancelled. During this time, other technologies are developed, which can be incorporated in the innovation project being tested, changing its potential value and future impact of its application. Specifically, during the process validation of CMS, significant advances were made in preconditioning techniques and digital technologies (e.g., automation, robotics). The project team must evaluate the impacts of new technologies developed along the way and incorporate them in the project if they prove to add value.
Process validation can be expensive, especially the industrial validation phase. Special care must be taken in the economic evaluation that justified the project and in the execution time and budget estimation. CMS project was stopped and finally cancelled due to problems in its construction phase, not because of unsatisfactory results of the test itself: this did not even get to be executed (similarly, also the first Epiroc Mobile Minerback then Atlas Copcowas initially not accepted for prototype testing by the foreseen mine site ).
New designs for extraction and material handling methods must be proved under real conditions for their industrial validation. For this, first the company needs to have access to ongoing mining operations, of its own property or coordinate with another company, in other cases. Then, a proper coordination with the current operation must be conducted, to minimize interferences and ensure the availability of resources (e.g., energy, water).
It is important to highlight the relevance of the CMS project, regarding its potential to improve extraction rates and safety in caving operations. Material handling systems through batch operations, such as the use of trucks and LHDs, are highly inefficient, from a macro point of view. Equipment show low levels of utilization and the productivity of the overall operation remains restricted. The design proposed by the CMS initiative offered the possibility of achieving higher production levels with lower requirements of active area, reducing CAPEX and OPEX, and gaining future dividends of the project earlier in time. All these factors have a positive effect on the economic indicators of a mining project: net present value increases and payback period is reduced, for example.
Finally, continuous mining and automated operations are trends that will likely shape the mining of the future. Initiatives like the CMS design should not be immediately dismissed, especially considering that this particular project failed in the construction stage of its industrial validation phase, having no chance to prove its applicability (or inapplicability) in a real operation.
Innovation plays an important role in the mining industry as a tool to improve the efficiency of its processes, reduce costs, but also to meet the increasing social and environmental concerns among communities and authorities. Technological progress has also been crucial to allow the exploitation of new deposits in more complex scenarios: lower ore grades, extreme weather conditions, deeper deposits, harder rock mass, and high-stress environments.
That is, the importance of innovation for the mining industry, as a critical factor in the improvement of labor productivity through past decades, was analyzed. Though its relevance, mining companies usually show low levels of R&D intensity, similar to mature industries and far from high-tech sectors. The tendency to vertical disintegration has led firms to focus on their core business, relying mainly on equipment manufacturers and suppliers for the development of innovative solutions. Also, collaborative alliances between mining companies, suppliers, and research centers share a significant participation in the development of new technologies.
Nowadays, several technological trends can be identified as main factors that will shape the mining of the future. The first and most relevant one is the digital transformation (DT), as the process of adoption and incorporation of a set of tools, the so-called technologies 4.0, into the mining business. Automation, robotics, remotization of operations, internet of things, analytics, and digital twinning, among others, have the potential to enhance processes along the whole value chain of mining. However, though DT is frequently mentioned as one of the main concerns among most large-scale mining companies, the level of digitization of the industry remains low, indicating that most of the potential of DT for the sector is still to be unlocked. The main challenges that firms must face to achieve a successful digitization are the commitment and joint-task coordination between the different business units, implementing proper organizational structure changes, and promoting a new cultural mindset regarding cybersecurity strategies and their continuous improvement.
Other important trends are electromobility, invisible zero-waste mining, and continuous mining. These concepts answer the necessity of building a more sustainable and efficient industry, reducing the environmental footprint, and enhancing safety of mining operations. The replacement of fossil fuel-powered vehicles is a must in a world moving away from such energy sources to cleaner ones, and stricter safety and environmental regulations being implemented all around the world are a reflection of that. Every day more companies are evaluating the incorporation of electric-powered fleets into their operations, as existing technologies can already offer economic alternatives, while R&D keeps advancing in this matter.
Invisible mining strategies, such as in situ leaching methods, have minimal impact on the surface and surroundings, and generate practically no waste. Yet, for a widespread application of this mining method, progress must be made in rock mass permeability enhancement (e.g. preconditioning techniques) and hydrogeological management, to ensure an optimal leaching process, in the first case, and minimize risks associated with groundwater pollution, in the second one.
Finally, though the concept of continuous mining has been applied for many years in the coal mining industry, its application in other mineral sectors has the potential to increase productivity, reduce costs, and improve safety, along with technological tools brought by DT, such as automation, robotics, and remotization of operations.
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In modern times though, mining for gold is a much more intensive, yet sophisticated process. Most surface, or alluvial gold has been found, which is why gold is mainly mined from the earth today. Its largely a matter of technology and requires much expertise and elaborate equipment.
Mining for gold today can essentially be broken down into 9 steps. Continue reading to learn more about how gold is discovered, how its brought out of the ground and how its refined to produce beautiful gold coins, bars, jewelry and other items.
The first step is discovering where gold deposits may be. Geologists use special geology maps to look for promising areas to explore further. They examine physical and chemical characteristics of surface rocks to determine if any gold is in the ground beneath.
Once some promising areas are identified through their geological characteristics, targets for drill testing are outlined using a variety of techniques, including remote sensing, geophysics and geochemistry (both air and ground based).
Next, rock samples are taken through drill testing and analyzed. Geologists and mining engineers use these samples to determine if gold actually exists, the size of the deposit and the quality of gold in the ground beneath. This information is used to determine if enough gold exists under the surface to make mining worthwhile.
If its determined the amount and quality of deposits makes mining worthwhile, engineers will next determine the type of mine thats needed, any physical obstacles and the impact the mine will have on the surrounding environment.
Before any mining can take place, infrastructure like roads and processing facilities must be constructed. Even the simplest open-pit mines can take up to a year to construct before any mining can occur. And since many potential mines are in remote areas, entire infrastructures like roads, administrative offices, equipment storage areas and even whole towns have to be built. Much of the time, it can be up to 5 years between the times discovery is made to when actual mining takes place.
Once ore is extracted, processing it into pure gold must be done. Ore is first crushed and then undergoes various processes depending on the nature of associated minerals. Processing low-grade ore is relatively simple while higher grades require more extensive processing.
Once basic processing is done, the ore is taken to a refinery where the remaining impurities are stripped out. Crude gold is melted and treated with chloride, which converts any remaining foreign metals to chloride which will then drift off the gold. The result is 99.5% pure gold, which is then cast into electrodes (known as anodes) where it is then placed into an electrolytic cell. A current is then passed through the cell, with the end product being 99.99% pure gold.
After a few years, gold reserves in the mine will be exhausted. In the old days, the mine would be boarded up and abandoned. Today though, a reclamation project is done to try and return the land to its previous natural state as much as possible anyway.
As you can see, the process of taking metal ore from the earth and converting it to gold bullion is quite extensive and requires a lot front-end investment and time. In the end though, we get these shiny coins and bars to enjoy.
Gold miners too take special care to make the impact of mining for gold as light as possible. Reclaiming land to its previous natural state is the final and perhaps most important step to ensuring the process of obtaining gold doesnt result in permanent damage to the landscape.
The post on the 9 steps of how gold is refined, has helped me to relate the process of Gods divine will has a child of God, when one is choosen by God, he or she has to go through a process in order to accomplish the will of God and also to embrace others in knowing God. I was inspired spiritually by God in researching the steps and process gold has to go through to become the finest gold.
It seems that many have thought on the gold mentioned in the Bible and having done so, think further about the processing of it spiritually in ones own life. The temple was covered in gold. We go through processes in our lives too so that God can clothe us in His righteousness not our own, and it is a costly process and time-consuming but the value of it will one day be revealed not now but when the process is completed in His time.
Prominer maintains a team of senior gold processing engineers with expertise and global experience. These gold professionals are specifically in gold processing through various beneficiation technologies, for gold ore of different characteristics, such as flotation, cyanide leaching, gravity separation, etc., to achieve the processing plant of optimal and cost-efficient process designs.
Based on abundant experiences on gold mining project, Prominer helps clients to get higher yield & recovery rate with lower running cost and pays more attention on environmental protection. Prominer supplies customized solution for different types of gold ore. General processing technologies for gold ore are summarized as below:
For alluvial gold, also called sand gold, gravel gold, placer gold or river gold, gravity separation is suitable. This type of gold contains mainly free gold blended with the sand. Under this circumstance, the technology is to wash away the mud and sieve out the big size stone first with the trommel screen, and then using centrifugal concentrator, shaking table as well as gold carpet to separate the free gold from the stone sands.
CIL is mainly for processing the oxide type gold ore if the recovery rate is not high or much gold is still left by using otation and/ or gravity circuits. Slurry, containing uncovered gold from primary circuits, is pumped directly to the thickener to adjust the slurry density. Then it is pumped to leaching plant and dissolved in aerated sodium cyanide solution. The solubilized gold is simultaneously adsorbed directly into coarse granules of activated carbon, and it is called Carbon-In-Leaching process (CIL).
Heap leaching is always the first choice to process low grade ore easy to leaching. Based on the leaching test, the gold ore will be crushed to the determined particle size and then sent to the dump area. If the content of clay and solid is high, to improve the leaching efficiency, the agglomeration shall be considered. By using the cement, lime and cyanide solution, the small particles would be stuck to big lumps. It makes the cyanide solution much easier penetrating and heap more stable. After sufficient leaching, the pregnant solution will be pumped to the carbon adsorption column for catching the free gold. The barren liquid will be pumped to the cyanide solution pond for recycle usage.
The loaded carbon is treated at high temperature to elute the adsorbed gold into the solution once again. The gold-rich eluate is fed into an electrowinning circuit where gold and other metals are plated onto cathodes of steel wool. The loaded steel wool is pretreated by calcination before mixing with uxes and melting. Finally, the melt is poured into a cascade of molds where gold is separated from the slag to gold bullion.
Prominer has been devoted to mineral processing industry for decades and specializes in mineral upgrading and deep processing. With expertise in the fields of mineral project development, mining, test study, engineering, technological processing.Get in Touch with Mechanic