gold mining equipment

gold mining equipment

911MPE hassmall gold mining equipment for sale andmore specifically mineral processing equipment. Our equipment is best used in small scale extractive metallurgyoperations operated by small miners or hobbyist prospectors and mining fanatics. 911MPE offers gold mining equipment as well as processing equipment applicable to most any base metals: copper, lead, zinc, nickel, tin, tungsten and more. For the relatively small size of equipment offered, sample preparation and metallurgical laboratories can economically buy good alternatives to the usually unaffordable equipment for sale in the classic market place.

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.

You can buy from us mineral processing equipment starting from crushing, grinding, classification, dredging, gravity separation, flotation, pumps, water treatment and smelting. A line of ovens, furnaces and laboratory equipment is also available.

Making a complete list of gold mining equipment starts with defining the type of gold mining you are doing and the budget you have at your disposal. The type of mining relates to hard rock,eluvial, or placer; alluvial deposits. The capital budget you have to invest in buying your equipment with dictate the scale at which you want to mine and influence the long-term operating costs of your mining operation.

Since most of the information online provides lists of gold mining equipment for amateur level mining with equipment like: gold pans, metal detectors, mini sluice box, blue bowl, geologist rock pick, soil scoop, hand screens/classifiers. The items listed just now fall closer to gold prospecting tools and equipment than actual mining.

I will present here what I consider are major equipment lists for 3 types of mining operations. Remember now, a metallurgist is writing. This will not be flawless and since my speciality is process equipment, that is mostly what will be discussed.

Some amateur level gold prospecting equipment such as metal detectors are often classified as mining equipment by small miners/prospectors operating as a hobby. These items include but are not limited to:

crusher for gold mining and processing line

crusher for gold mining and processing line

Gold is one kind of the rarest and most precious metals. It is with the features of soft and corrosionresistant. The color of gold is golden yellow, and with a metallic sheen. Its hardness is about 2 to 3. For physical characteristics, gold is with good ductility, high thermal conductivity and electrical conductivity. Since gold has excellent stability, good electrical conductivity and thermal conductivity, so the uses of it become wider and wider in the electronics industry. In the chemical industry, gold also has a unique purpose. It can be used as the materials in nuclear chemical plants, man-made fiber factory, and so on.And at the same time, gold is still has some gold consumption in the traditional industries, such as photography, pens, dental, and other industries.

Because of a wide range of applications, gold ore mining and processing developed greatly in recent years. Since the 21st century, the world's gold production stabilized at an average of 2,600 tons. Gold ore is very unevenly distributed on Earth. Though, there are more than 80 countries produce gold in the world, the gold productions are quite different among these countries. In 2004, the world's top 10 gold production countries are South Africa, USA, Australia, China, Russia, Peru, Canada, and so on. While gold production has increased in some countries, such as Australia, Peru, Indonesia, but gold production in South Africa, the United States and other gold producing countries has declined.

Gold ore beneficiation process includes preparing operations and sorting operations. Prepare job mainly consists of two processes, they are crushing and screening. Crushing process is mainly to crush the large of gold ore into small pieces, and to separate the clay mineral from metal particles. Screening process is mainly to screen the coarse particles which without gold out. Commonly, flat screen and cylindrical sieve are usually used as the gold ore screener. As for gold ore beneficiation, gravity separation method is mainly used. On the one hand, the proportion of placer gold (average 17.50 to 18.0 mm) is bigger than coarse grain (typically 0.074 to 2 mm). On the other hand, gravity separation method is one kind of relatively economical and simple beneficiation method. Jigging machine and shaking table are the commonly used beneficiation equipment of gold ore.

According to the survey, people usually adopt jaw crusher for primary crushing in gold plant. And then, adopt cone crusher and impact crusher for secondary crushing and fine crushing. In order to increase the production capacity, we need to adopt efficient gold production equipment and improve the processing technology.

PEW series jaw crusher is common gold ore primary crushing equipment. It is designed based on the traditional jaw crusher. It is suitable to process all kinds of medium-grained into small pieces. It is often associated with cone crusher, grinding mill and other equipment to form a complete gold ore processing line. Its structure is stable and reliable, so the performance of it is quite outstanding. The crushing chamber of it adopts a "V"-type structure, which effectively increasing the crushing area and improving the crushing rate and yield.

HCS series single cylinder hydraulic cone crusher is a high efficiency gold ore crusher.Compared with similar products, it has great advantages. It can meet the demands of gold ore medium and fine crushing. It is with the features of simple structure, reliable performance, and stable operation. And this cone crusher is equipped with hydraulic adjustment and hydraulic protection device. Soit is easy to clean the chamber. As a result, it can effectively save the downtime.

gold flotation

gold flotation

Though the gold recovery methods previously discussed usually catch the coarser particles of sulphides in the ore and thus indirectly recover some of the gold associated with these and other heavy minerals, they are not primarily designed for sulphide recovery. Where a high sulphide recovery is demanded, flotation methods are now in general use, but in the days before flotation was known, a large part of the worlds gold was recovered by concentrating the gold-bearing sulphides on tables and smelting or regrinding and amalgamating the product.Though the modern trend is away from the use of tables, because flotation is so much more efficient.

The flotation process, which is today so extensively used for the concentration of base-metal sulphide ores and is finding increased use in many other fields. In1932flotation plants began to be installed for the treatment of gold and silver ores as a substitute for or in conjunction with cyanidation.

The principles involved and the rather elaborate physicochemical theories advanced to account for the selective separations obtained are beyond the scope of this book. Suffice it to say that in general the sulphides are air-filmed and ufloated to be removed as a froth from the surface of the pulp while the nonsulphide gangue remains in suspension, or sinks, as the expression is, for discharge from the side or end of the machine.

For more complete information reference is made to Taggarts Hand book of Mineral Dressing, 1945; Gaudins Flotation and Principles of Mineral Dressing; I. W. Warks Principles of Flotation; and the numerous papers on the subject published by the A.I.M.E. and U.S. Bureau of Mines.

Flotation machines can be classed roughly into mechanical and pneumatic types. The first employ mechanically operated impellers or rotorsfor agitating and aerating the pulps, with or without a supplementary compressed-air supply. Best known of these are the Mineral Separation, the Fagergren, the Agitair, and the Massco-Fahrenwald.

Pneumatic cells use no mechanical agitation (except the Macintosh, now obsolete) and depend on compressed air to supply the bubble structure and tohold the pulp in suspension. Well-known makes include theCallow and MacIntosh (no longer manufactured) the Southwestern, and the Steffensen, the last, as shown in the cross-sectional view in Fig. 47, utilizing the air-lift principle, with the shearing of large bubbles as the air is forced from a central perforated bell through a series of diffuser plates.

The number and size of flotation cells required for any given installation are readily determinedif the problem is looked upon as a matter of retention time for a certain total volume of pulp. The pulp flow in cubic feet per minute is determined from the formula

For ordinary ratios of concentration the effect on cell capacity of concentrate (or froth) removal can be neglected, but where a high proportion of the feed is taken off as concentrates, or where middlings are removed for retreatment in a separate circuit, due allowance should be made for reduced flow and, in consequence, increased detention time toward the tail end of a string of cells. Not less than a series of four cells and preferably six or more cells should be used in any roughing section in order to prevent short-circuiting.

It is not intended here to discuss the subject of flotation reagents in anydetail. The subject is a large one with a comprehensive technical and patent literature. Research leading to the development of new reagents and to our understanding of the mechanism involved has been largely in the hands of academic institutions and the manufacturers of chemical products.

Recent work reported by A. M. Gaudin on the use of Radioactive Tracers in Milling Research described, for instance, the use of a flotation reagents containing radioactive carbon to determine the extent of collector adsorption. The bubble machine devised to measure the angle of contact of air bubbles on collector-treated mineral surfaces has been extensively used for determining the theoretical value of various reagents as flotation collectors, but for the most part the actual reagent combination in use in commercial plants is usually the result of trial-and-error methods.

The following is a brief discussion of the reagents ordinarily used for the flotation of gold and silver ores prepared from notes submitted by S. J. Swainson and N. Hedley of the American Cyanamid Company.

Conditioning agents are commonly used, especially when the ores are partly oxidized. Soda ash is the most widely used regulator of alkalinity. Lime should not be used because it is a depressor of free gold and inhibits pyrite flotation. Sodium sulphide is often helpful in the flotation of partly oxidized sulphides but must be used with caution because of its depressing action on free gold. Copper sulphate is frequently helpful in accelerating the flotation of pyrite and arsenopyrite. In rare instances sulphuric acid may be necessary, but the use of it is limited to ores containing no lime. Ammo-phos, a crude monoammonium phosphate, is sometimes used in the flotation of oxidized gold ores. It has the effect of flocculating iron oxide slime, thus improving the grade of concentrate. Sodium silicate, a dispersing agent, is also useful for overcoming gangue-slime interference.

Promoters or Collectors. The commonly used promoters or collectors are Aerofloat reagents and the xanthates. The most effective promoter of free gold is Aerofloat flotation reagent 208. When auriferous pyrite is present, this reagent and reagent 301 constitute the most effective promoter combination. The latter is a higher xanthate which is a strong and non-selective promoter of all sulphides. Amyl and butyl xanthates are also widely used. Ethyl xanthate is not so commonly used as the higher xanthates for this type of flotation.

The liquid flotation reagents such as Aerofloat 15, 25, and 31 are commonly used in conjunction with the xanthates. These reagents possess both promoter and frother properties. When malachite and azurite are present, reagent 425 is often a useful promoter. This reagent was developed especially for the flotation of oxidized copper ores.

The amount of these promoters varies considerably. If the ore is partly oxidized, it may be necessary to use as much as 0.30 to 0.40 lb. of promoter perton of ore. In the case of clean ores, as little as 0.05 lb. may be enough. The promoter requirement of an average ore will usually approximate 0.20 lb.

The commonly used frothers are steam-distilled pine oil, cresylic acid, and higher alcohols. The third mentioned, known as duPont frothers, have recently come into use. They produce a somewhat more tender and evanescent froth than pine oil or cresylic acid; consequently they have less tendency to float gangue, particularly in circuits alkaline with lime. The duPont frothers are highly active frothing agents; therefore it is rarely necessary to use more than a few hundredths of a pound per ton of ore.

When coarse sulphides and moderately coarse gold (65 mesh) must be floated, froth modifiers such as Barrett Nos. 4 and 634, of hardwood creosote, are usually necessary. The function of these so-called froth modifiers is to give more stable froth having greater carrying power.

The conditioning agents used for silver ores are the same as those for gold ores. Soda ash is a commonly used pH regulator. It aids the flotation of galena and silver sulphides. When the silver and lead minerals are in the oxidized state, sodium sulphide is helpful, but it should not be added until after the sulphide minerals have been floated, because sodium sulphide inhibits flotation of the silver sulphide minerals.

Aerofloat 25 and 31 are effective promoters for silver sulphides, sulphantimonites, and sulpharsenites, as well as for native silver. When galena is present, No. 31 is preferable to No. 25 because it is a more powerful galena promoter. Higher xanthates, such as American Cyanamid reagent 301 and amyl and butyl xanthates, are beneficial when pyrite must be recovered. When the ore contains oxidized lead minerals, such as angle-site and cerussite, sodium sulphide and one of the higher xanthates may be used. In some instances reagent 404 effects high recovery of these minerals without the use of a sulphidizing agent.Silver ores require the same frothers as gold oresviz., pine oil, cresylic acid or duPont frothers.

Aero, Ammo-phos, and Aerofloat are registered trade-marks applied to products manufactured by this company. The Great Western Electro-Chemical Company, California, makes amyl xanthate, butyl xanthate, potassium xanthate, and sodium xanthate. In the United States these reagents are used on the gold ores of California and Colorado and in Canada on the gold ores and sulphides of Ontario and Quebec.

Flotation reagents of the Naval Stores Division of the Hercules Powder Company are as follows: Yarmor F pine oil, a frother for floating simple and complex ores; Risor pine oil, for recovering sulphides by bulk flotation; Tarol a toughener of froth, generally used in small amount with Yarmor F, but with some semioxidized ores where high recovery is essential yet the grade of concentrate not so important, Tarol does good work; Tarol a frother for floating certain oxide minerals, but it can be used in selective flotation of sulphide minerals and in bulk flotation where tough frothis desirable; Solvenol, for the floating of graphite in conjunction with Yarmor F.

The statement has come to the attention of the American Cyanamid Company that organic flotation reagents, such as xanthates, even in the small amounts used in flotation, cause reprecipitation of gold from pregnant cyanide solutions. The ore-dressing laboratory of this company is studying the question, and preliminary results indicate that this statement is unfounded. The addition of xanthate, in the amount usually found in flotation circuits, does not precipitate gold from a pregnant cyanide solution containing the normal amount of cyanide and lime.

Valueless slime, in addition to its detrimental effect in coating gold-bearing sulphide, thereby limiting or preventing its flotation, also becomes mixed with the flotation concentrate and lowers its value. Sometimes the problem in flotation is that, although the gold is floatable, the concentrate product is of too low grade. Talc, slate, clay, oxides of iron, and manganese or carbonaceousmatter in ores early form slime in a mill, without fine crushing. Such primary slime, according to E. S. Leaver and J. A. Woolf of the U.S. Bureau of Mines, interferes with the proper selectivity of the associated minerals and causes slime interference. The tendency of primary slime is to float readily or to remain in suspension and be carried over into the concentrate. Preliminary removal and washing of this primary slime before fine crushing is one method of dealing with it. At the Idaho-Maryland mill, Grass Valley, Calif., starch is regularly used as a depressant during flotation. Flotation tests using starch were made on a quartz ore containing carbonaceous schist from the Argonaut mine, Jackson, Calif.; a talcose ore from the Idaho-Maryland mine mentioned; a talcose-clayey ore from Gold Range, Nev.; a siliceous, iron and manganese oxide ore from the Baboquivari district, Nevada; carbonaceous and aluminous slime from the Mother Lode and some synthetic ores. The conclusions from the foregoing tests were in part as follows:

It acts first on the slime; then, if a sufficient excess of starch is present, it will cause some depression of sulphides and metallic gold, either by wetting out or by producing an extremely brittle froth. Therefore, care must be taken in regulating the amount of starch added to obtain the maximum depression of the slime commensurate with high recovery of the gold. In this, as in all other phases of flotation, each ore presents an individual problem and must be so studied.

It wasdescribe by the use of 600 series of flotation reagents which were developed primarily for the purpose of depressing carbonaceous and siliceous slimes in the flotation of gold ores. Carbonaceous material not only greatly increases the bulk and moisture content of a flotation concentrate, but its presence makes cyanidation of the concentrate difficult or impossible owing to reprecipitation of the gold during treatment.

In the treatment of an auriferous sulphide ore associated with carbonaceous shale from South Africa, up to 77 per cent of the carbon was eliminated by the use of 1 lb. per ton of reagent 637 with a 90.5 per cent gold recovery at 20.4:1 ratio of concentration.

A gold carbonaceous sulphide ore from California carrying free gold yielded a 93 per cent recovery into a concentrate at 14.4:1 to ratio of concentration after conditioning with 0.50 lb. per ton of reagent 645.

In each case the ore was ground to about 70 per cent minus 200 mesh and conditioned at 22 per cent solids with the reagents as indicated. Flotation reagents included reagents 301 and 208 and pine oil. In the second case some soda ash and copper sulphate where also used.

It is obvious that the most suitable treatment for ores carrying gold and silver associated with pyrite and other iron sulphides, arsenopyrite or stibnite, will depend on the type of association. Cyanidation is usually the most suitable process, but it often necessitates grinding ore to a fine size to release the gold and silver. Where it is possible to obtain a good recovery by flotation in a concentrate carrying most of the pyrite or other sulphides, it is often more economical to adopt this method, regrinding only the comparatively small bulk of concentrate prior to the leaching operation.

That the trend over the last 10 years has been in this direction will be noted from the numerous examples of such flow sheets in Canada and Australia (see Chap. XV). A number of plants formerly using all-cyanidation have converted to the combined process.

The suitability of the method involving fine grinding and flotation with treatment of the concentrate and rejection of the remainder should receive careful study in the laboratory and in a pilot plant. Mclntyre-Porcupine ran a 150-ton plant for a year before deciding to build its 2400-ton mill. Comparative figures given by J. J. Denny in E. and M. J., November, 1933, on the results obtained by the all-sliming, C.C.D. process formerly used and the later combination of flotation and concentrate treatment showed a saving of 12.1 cents per ton in treatment cost and a decrease of 15 cents per ton in the residue, a total of 27.1 cents per ton in favor of the new treatment.

Flotation may also prove to be the more economical process for the ore containing such minerals as stibnite, copper-bearing sulphides, tellurides,and others which require roasting before cyanidation, because this reduces the tonnage passing through the furnace.

Even when recovery of gold and silver from such ores by flotation is low, it may be advantageous still to float off the minerals that interfere with cyanidation, roasting, and leaching or possibly to smelt the concentrate for extraction of its precious metals. Cyanidation of the flotation tailing follows, this being simpler and cheaper because of prior removal of the cyanicides.

It is a good practice to recover as much of the gold and silver as possible in the grinding circuit by amalgamation, corduroy strakes, or other gravity means to prevent their accumulation in the classifier; otherwise gold that is too coarse to float may escape from the grinding section into the flotation circuit where it will pass into the tailing and be lost.

To prevent this, several companies including the Mclntyre-Porcupine at Timmins, Ontario, have inserted a combination of flotation cell and hydraulic cone in their tube-mill classifier circuits. At the Mclntyre- Porcupine, according to J. J. Denny in E. and M. J., November, 1933, this cell is a 500 Sub-A type. The total pulp discharged from each tube mill passes through 4-meshscreens which are attached to the end of the mills. The undersize goes to the flotation cell, and the oversize to the classifiers. Tailing from the cell flows to the classifiers, and the flotation concentrate joins the concentrate stream from .the main flotation circuit. The purpose of the hydraulic attachment is to remove gold that is too coarse to float, thus avoiding an accumulation in the tube-mill circuit. The cones have increased recovery from 60 to 75 per cent. Every 24 hr. the tube-mill discharge is diverted to the classifiers. Water is added for 15 min. to separate the gangue in the cells from the high-grade concentrate, after which a product consisting of sulphides and coarse gold is removed through a 4-in. plug valve equipped with a locking device. Each day approximately 400 lb. of material worth $2000 to $3000 is recovered. This is transferred to a tube mill in the cyanide circuit,with no evident increase in the value of the cyanide residue. The object of this arrangement is, of course, primarily to deplete the circulating load of an accumulation of free gold and heavy sulphides.

Flotation is used to recover residual gold-bearing sulphides and tellurides. The Lake Shore mill retreatment plant is an interesting example of this technique. The problem here was, of course, to overcome by chemical treatment the depressing action of the alkaline cyanide circuit on the sulphides. A full discussion of this and of the somewhat controversial subject as to whether flotation should in such an instance be carried out before, or after cyanidation will be found in J. E. Williamsons paper Roasting and Flotation Practice in the Lake Shore Mines Sulphide Treatment Plant elsewhere referred to. Summing up the specific considerations governing the choice oftreatment, the author says:

Incidental matters that influenced the choice of treatment scheme included the realization that preliminary flotation would have involved two separate treatment circuits with additional steps of thickening and filtration following the flotation. Furthermore, in the conditioning method evolved, as much as 60 per cent of the dissolved values in the cyanide tailings were precipitated and recovered.

There are, however, cases where flotation equipment was put in for the purpose of recovering the gold in a concentrate and rejecting the tailing only to find that the tailing was too valuable to waste and had finally to be cyanided before discarding.

It is generally true that cyanidation is capable of producing a tailing of lower gold content than flotation. At a price of $35 per ounce for gold this fact is of much greater importance than when gold was valued at $20.67 per ounce. The possible gold loss in the residue to be discarded will influence the choice of a method of treatment.

gold processing technology for viable mining

gold processing technology for viable mining

Rising wealth fosters demand for technology and luxury products securing a lasting demand for gold. However, if you want to run a sustainable business, you need a more economically viable mean of extracting gold from existing reserves as well as from refractory, low-grade ores.

In the future, this is likely to change. We have developed Rapid Oxidative Leach (ROL), a pre-treatment process that has already generated interesting results in the copper industry and now has its own development track for refractory gold.

Your typical refractory ore contains tiny inclusions, or sub-microscopic gold, within a sulphide mineral matrix, requiring physical and chemical altering of the mineral matrix to liberate the gold for subsequent leaching. We see a great potential to unlock value in applying ROL to treat undeveloped gold deposits as it could make it feasible to extract gold from refractory low-grade ores.

Large gold deposits are becoming increasingly scarce, and new gold deposits are often found in remote areas and in fragile ecosystems. Tensions with local communities fearing contamination of water can make it time-consuming to obtain your license to operate.

Together with Goldcorp, we have developed EcoTailsthat blends filtered tailings with waste rock creating a high-density geotechnically stable product called GeoWaste. This makes dry-stacking possible even for large scale operations, and even in areas with high seismic activities. Furthermore, EcoTails enables recirculation of 90-95 per cent of your process water.

This saves you operational costs on your gold mine and reduces closure costs. It also makes it easier to obtain your social license to operate, as it reduces the risk of water contamination and tailings dam failure and thereby lessen your projects environmental impact.

FLSmidth provides sustainable productivity to the global mining and cement industries. We deliver market-leading engineering, equipment and service solutions that enable our customers to improve performance, drive down costs and reduce environmental impact. Our operations span the globe and we are close to 10,200 employees, present in more than 60 countries. In 2020, FLSmidth generated revenue of DKK 16.4 billion. MissionZero is our sustainability ambition towards zero emissions in mining and cement by 2030.

gold processing,extraction,smelting plant design, equipment for sale | prominer (shanghai) mining technology co.,ltd

gold processing,extraction,smelting plant design, equipment for sale | prominer (shanghai) mining technology co.,ltd

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.

gold processing | equipment, process flow, cases - jxsc machine

gold processing | equipment, process flow, cases - jxsc machine

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.

melcher brothers, durango, co

melcher brothers, durango, co

As a sideline to industrial machinery fabrication, Melcher Brothers Inc., also fabricates historical ore cars usedin Colorado mines between the 1860's and up until the 1950's. Here is a sample of our products. For full details, pricing, and shipping visit

The scoop car was popular in early small mines with low headroom. It could be tilted down and loaded by scooping into it rather than having to shovel over the sides. It has a 360 degree turntable that allows it to align with the material to be loaded.

End dump cars show the evolution of mining cars from boxes on wheels to much more efficient designs. The end gate and hinging the box to the wheel frame allowed dumping the heavy ore load by a single miner.

There are many types of side dump cars. The onewe reproduce is called a "Gable Car" because its floor has two slopes which peak at the center. The side opening doors allow the ore to be dumped out each side.

Our full line of historic ore cars and other "mining reproduction items" is available on We build 1/3 to full size car replicas that exactly follow the original design used in Colorado mines in the late 1800's. The replicates are build of steel and are fully operational. We also use our trademarked five spoke wheel. Cars are available in both welded or riveted construction. Correct scale rail sections may also be ordered for each size car.

Mining is worldwide. Melcher Bros is proud to supply custom mining equipment to various countries as demand warrants. Some past custom equipment orders are for gold mining operations in South America.

more sorting success for steinert in australian gold at eganstreet's rothsay - international mining

more sorting success for steinert in australian gold at eganstreet's rothsay - international mining

EganStreet Resources announces that it has identified an opportunity to optimise and significantly enhance the financial outcomes of its 100%-owned Rothsay Gold Project, located 300 km north-east of Perth in Western Australia, through the application of state-of-the-art ore sorting technology. The Company has received highly favourable initial results from ore sorting testwork completed on a low-grade stockpile from the historical underground mine at Rothsay, with the key outcome that the use of a Steinert Multi-Sensor Ore Sorter provides an opportunity to increase underground mine production (being fed to a similar-sized process plant), reduce the impact of dilution from the main ore-hosting structure at Rothsay, reduce life-of-mine processing costs and substantially enhance project economics.

Ore sorting technology is increasingly being adopted across the gold mining industry in Western Australia, with highly encouraging results. Representative samples collected from the low-grade stockpile located adjacent to the portal of the historical Rothsay Gold Mine returned an average stockpile grade of 2.5g/t Au. This compares favourably with previous sampling of this stockpile in 2013, which returned results ranging from 2.7 4.1g/t Au. More importantly, the results demonstrated that the Steinert Multi-Sensor Ore Sorter was able to successfully reject the barren ultramafic material located in the hanging wall of Woodleys Shear. The PFS production target of 936,000 t grading 7.0g/t Au consisted of 43% planned mine dilution (or 400,000 t of the total 936,000 t production target). The ultramafic component of this planned mine dilution represents 59% of the total dilution (or 236,000 t of the total 936,000 t production target).

The ability to substantially reduce, or potentially virtually eliminate, this hanging wall dilution may allow an increase in mine production, which will have a corresponding positive impact on underground mine productivity, operating costs and economics. Further test work will be conducted in the 1st Quarter of 2018 to confirm these encouraging initial results. The potential of the multi-sensor ore sorter is that underground mine production rates can be increased by 34% without any increase in process plant size.

EganStreet Managing Director Marc Ducler said the application of ore-sorting technology represented a potential game-changer for the Rothsay Gold Project. These results, albeit early stage, have shown the ease with which the mine production grade can be selectively upgraded prior to processing. This provides us with significantly greater flexibility in how we develop the mine as well as the ability to optimise our mining and production rates. Given that Rothsay is relatively narrow but high-grade mine, the ability to significantly reduce the substantial amount of planned mine dilution already built into our mine design and financial model through the use of a Steinert Multi-Sensor Ore Sorter is an exciting and very positive development. We are confident that follow-up testing to be undertaken this quarter will confirm a pathway to significantly enhance and optimise our development plan, adding considerable value to the project and representing an important new input to the Definitive Feasibility Study to be finalised next quarter.

He added: Technological advances such as this are increasingly being adopted across the gold mining industry in Western Australia and are a great example of how innovation can contribute to improved productivity and enhanced financial outcomes for new mine developments such as Rothsay. With exploration drilling resuming on site this week, further assay results expected in the near future from some of the holes completed prior to Christmas and Feasibility activities in full swing, shareholders can look forward to strong and consistent news-flow over the coming weeks. We are confident that 2018 will be a breakthrough year for EganStreet, with the Company set to make the transition from explorer to developer in the second half of the year and become a new high-grade Australian gold miner in 2019.

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gold mining: the importance of ore grade | gold news

gold mining: the importance of ore grade | gold news

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NOW IS the time for investors to brush up on their knowledge of NI-43-101-compliant resources and deposit grades with one of the world's foremost experts. In this interview with The Gold Report, Andrew Richmond, a principal at geological consulting firm Martlet Consultants in Brisbane, Australia, discusses the importance of grade, selectivity and size in establishing the economic value of deposits.

The Gold Report: Andrew, you do a lot of work vetting deposits. You have worked on epithermal gold, copper-gold porphyries, iron and coal depositsjust to name a few. We're here today to help retail investors gain a better understanding of NI-43-101-compliant resources and deposit grades. Let's start with resource classifications.

Andrew Richmond: The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) defines an "Inferred mineral resource" as that part of a mineral resource for which quantity and grade or quality can be estimated on the basis of geological evidence, limited sampling and reasonably assumed, but not verified, geological and grade continuity. The estimate is based on limited information and sampling gathered through techniques from locations such as outcrops, trenches, pits, workings and drill holes.

An "Indicated mineral resource" is that part of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics can be estimated with a level of confidence sufficient to allow the appropriate application of technical and economic parameters to support mine planning and evaluation of the economic viability. The estimate is based on detailed and reliable exploration and testing information gathered through appropriate techniques from locations that are spaced closely enough for geological and grade continuity to be reasonably assumed.

A "Measured mineral resource" is that part of a mineral resource for which quantity, grade or quality, densities, shape, and physical characteristics are so well established that they can be estimated with confidence sufficient to allow the appropriate application of technical and economic parameters to support production planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration, sampling and testing information gathered through appropriate techniques from locations that are spaced closely enough to confirm both geological and grade continuity.

Andrew Richmond: The CIM defines a mineral reserve as the economically mineable part of a Measured or Indicated mineral resource demonstrated by at least a preliminary feasibility study (PFS). This study must include adequate information on mining, processing, metallurgical, economic and other relevant factors that demonstrate that economic extraction can be justified. A mineral reserve includes diluting materials and allowances for losses that may occur when the material is mined.

A Probable mineral reserve is the economically mineable part of an Indicated and, in some circumstances, a Measured mineral resource demonstrated by at least a PFS. This study must include adequate information on relevant factors that demonstrate that economic extraction can be justified.

A Proven mineral reserve is the economically mineable part of a Measured mineral resource demonstrated by at least a PFS. This study must include adequate information on factors that demonstrate that economic extraction is justified.

Andrew Richmond: A qualified person is an engineer or geoscientist with at least five years of experience in mineral exploration, mine development or operation or mineral project assessment, or any combination of these, who has experience relevant to the subject matter of the mineral project and the technical report; and is a member or licensee in good standing of a professional association.

Andrew Richmond: If you were to do a survey of mining experts, you'd come up with responses indicating that a prefeasibility study could have a margin of error anywhere between plus-or-minus 1525%. A feasibility study, which used to be known as a bankable feasibility study, could be within plus-or-minus 515%. The feasibility study is more detailed. It's the final study that's done before the directors of a company will give the go-ahead for a project to proceed.

Andrew Richmond: No. A PEA can pre- or postdate a PFS. A PEA can make assumptions about some of the criteria and parameters that go into the study. At that point, some of the studies may not have been done. For example, one of the things that is often done late for an open-pit deposit is special geotechnical drilling where the pit walls are going to be to determine what the slope angles may be. But until you've done a feasibility study, a company can't work out where the pit walls are going to be and do that type of drilling. Whereas if you get to the PFS and the final feasibility study, the technical studies that are required for sign-off on a mining project are all done.

Andrew Richmond: If I'm looking at an acquisition, merger or even just a joint-venturing project for a client, I work under the following three principles. First, I assume nothing. Second, I check everything. Third, and it may not sound very good, but I trust no one. I follow up on everything and a number of times people try and pull the wool over my eyes. It happens regularly.

These studies are often rushed to make corporate deadlines. But they may have underestimated the amount of time it takes and these studies are almost invariably late. A study arriving to market late could be good or bad. It may mean that the economics are not stacking up, so they're looking at different ways of mining it. There may be some metallurgical issues that need fine-tuning.

Companies often use optimistic commodity prices and capital expenditure (capex) costs. If these are in the lower-quartile cost curve for the region, type of project and commodity, I look for a good justification for those assumptions. Sometimes there is no risk analysis, or it's extremely limited.

My area of expertise is resource estimation, so I look for whether the resource-modeling techniques consider the geology adequately and whether they also suit the proposed mining methods. A very simple test is to use the average grade of the samples that have been used to estimate the block model. Are they the same or within 510%? The average grade of the samples in the drill holes must be the same as the average grade of the block model.

In precious metal deposits, I look for companies not cutting the extreme grade values. If the average grade of a deposit is, say, 2 grams per ton (g/t), there may be one or two samples that are over 100 g/t. Those samples need to be treated very carefully. Otherwise, they have the potential to increase the average grade of the block model quite substantially.

Andrew Richmond: RAB and the RC drilling are percussive-type drilling techniques, which means that they break the rock sample up. RAB drilling is a technique that tends to be used mostly for scout drilling to test near-surface material. There can be the potential for contamination because the sample comes up between the rod and the edge of the drill hole.

Diamond drilling is the only one that returns core samples. In general, diamond drilling is better. There are a few instances where the mineralization may be preferentially washed out during diamond drilling, because it uses water to keep the drill bits cool at the base.

Andrew Richmond: Grade is king in a deposit. But, in reality, it's the relationship between grade, tons, geometry and depth of the mineralization that indicate if it could potentially be extracted economically. It may well have a high-grade intercept, but it may be so narrow that it's not going to make a deposit, or there may be insufficient tons to justify the capital of a plant and other infrastructure.

Andrew Richmond: There are several different types of mineralized systems for gold. The higher-grade ones often tend to be epithermal deposits, known normally as high- or low-sulfur epithermal deposits. Both types can be extremely high grade, but they tend to be narrow zones that can be mined favorably underground. Porphyry systems can have significant amounts of gold, in some instances more gold than copper. They can have billions of tons and still be economic even if it's only 0.5 g/t.

Andrew Richmond: Normally, 30 g/t or more if it's small tonnage. If it's bigger than 100 million tons (Mt), even 2 g/t could be considered good with the current Gold Price. Anything above 5 g/t for this size would be considered an excellent deposit. There are very few of those around the world.

Andrew Richmond: As they tend to be several 100 Mt or more than a billion tons, anything where the combined copper and gold is above 2%. Copper and gold are both significant economic contributors in those types of deposits.

Andrew Richmond: They can be extremely important. First, there's the economic benefit. However, there are also other elements in the core that need to be assayed because they may have environmental impacts that require a costly remediation, such as pyrite, or have penalties associated with them during concentrate sales.

Andrew Richmond: Definitely. If there's a lot of pyrite in the drill core, a company has to manage the disposal of that in some way. If there were nothing in the feasibility study about that, it would be a red flag that the company hasn't done the work appropriately.

Andrew Richmond: They should all reach the life-of-mines potential, but that's theory. In practice, because these studies are based on assumed commodity prices and that tends to be the biggest risk, the commodity price with the lowest potential downside would be the one that most often reaches its planned potential. Normally, that's the bulk commodities.

Probably 60 to 80 iron ore projects out of 100 may do well. Some actually go well beyond the original life potential, because commodity prices tend to go up over time and the cutoff grade can drop, so the deposit is reassessed every five years. One of the problems with looking at it that way is that those projects may be the ones with the lowest potential downside, but they also can miss out on the potential for the greatest upside price movement.

Andrew Richmond: Definitely, but especially if they have a high-risk tolerance. If they want to get the big payoff, buy after even just one drill result. A series of drill results would be safer, but they've probably lost some of the potential upside. Maybe 1 in 20 exploration companies will eventually pay off. But the payoff for getting in early at the initial drill hit could be 50- to 100-fold. There's a reasonable chance of getting a good return on average.

Andrew Richmond: The South Pacific is an area a lot of investors may not be familiar with. It's got some specific issues related to landowners. It does tend to be high risk, high reward. It's also got high exploration costs. For example, a lot of projects in Papua New Guinea are done all by helicopter. On some of the other islands, there's political risk related to being able to keep the equity in the projects.

Andrew Richmond: Investors need to be skeptical of stock exchange announcements and read between the lines. Every exploration company is trying to get funding, but not all of their projects are going to go ahead. Investors need to pay close attention to stock exchange announcements and pick companies carefully.

The Gold Report is a unique, free site featuring summaries of articles from major publications, specific recommendations from top worldwide analysts and portfolio managers covering gold stocks, and a directory, with samples, of precious metals newsletters.

Please Note: All articles published here are to inform your thinking, not lead it. Only you can decide the best place for your money, and any decision you make will put your money at risk. Information or data included here may have already been overtaken by events and must be verified elsewhere should you choose to act on it. Please review our Terms & Conditions for accessing Gold News.

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