The Bagdad mill, built in 1977, was designed for a mill capacity of 36,300 tpd. An ABC (Autogenous Mill-Ball Mill-Crusher) grinding circuit was chosen. The original mill contained three completely independent grinding circuits, each containing one 9.75 m diameter by 3.96 m long fixed speed autogenous mill, one 4.72 m diameter by 6.71 m long ball mill and one 2.13 m diameter short-head cone crusher.
Autogenous mill screen undersize combines with ball mill discharge in the cyclone feed sump. Four of the six available 0.7 m diameter cyclones are normally operated. Cyclone feed density typically ranges between 63 and 68 percent solids. Cyclone pressure ranges between eight and ten psi.
The crusher bypass belt is used to allow circuit operation when the crusher is down for repairs. This has allowed the circuit to be studied with the crusher excluded from the grinding circuit. Due to critical size pebbles in the circuit, operation without the crusher results in severely reduced throughputs.
In June of 1991, Nordberg was asked to conduct a pilot plant to test this technology on Bagdads recycle material. The study indicated that a 1.83 m diameter unit powered with a 520 kw motor would be needed to handle either present dry crusher feed or crusher product. The pilot plant crusher product was much finer than that produced by the present crushers.
It is apparent that many options are available to modify the present grinding circuit by running the autogenous mills in open circuit and producing ball mill feed through one or more stages of crushing. Since the optimum circuit configuration is not obvious, the Cyprus Bagdad staff has chosen to install a WaterFlush crusher on one grinding circuit with the ability to operate either in single stage or in series with the existing dry short-head cone crusher.
We only focus on one thing- stabilizing the performance of natural soils where greater performance is demanded. No matter the name, any aggregate containing sand, silt or clay sized particles is considered a soil.
A Cone Crusher is a compression type of machine that reduces material by squeezing or compressing the feed material between a moving piece of steel and a stationary piece of steel. Final sizing and reduction is determined by the closed side setting or the gap between the two crushing members at the lowest point. As the wedge or eccentric rotates to cause the compression within the chamber, the material gets smaller as it moves down through the wear liner as the opening in the cavity gets tighter. The crushed material is discharged at the bottom of the machine after they pass through the cavity.
A Cone Crusher will deliver a 4:1 to 6:1 reduction ratio. As we set the closed side setting tighter to create a finer output, we also reduce the volume or throughput capacity of the machine. Generally speaking, multiplying the closed side setting by two is a good guide to the top size of the gradation exiting the machine.
The technology that makes a MSP Cone Crusher outperform competitive cones on the market is the combination of all of the factors of performance i.e. balanced eccentric, higher speeds, fulcrum point position, and stroke. By using sound engineering with years of field testing a truly tried and tested new Cone Crusher has emerged.
A balanced eccentric coupled with a fulcrum point ideally placed over the crushing chamber yields highly effective compression crushing. This allows higher eccentric speeds to maximize performance without disruptive forces. The eccentric stroke is designed to work with the eccentric speed and fulcrum position to produce higher yields and minimize recirculating loads. The torque and resultant crushing forces are as effective as virtually any Cone Crusher on the market.
Spiral bevel gears provide the turning force to the eccentric. The spiral gear is mounted on a sturdy countershaft of the Cone Crusher, which rides in bronze bushings. The gears are precision cut for quiet operation. Misalignment problems are eliminated.
The MSP Cone Crusher features one of the largest volume displacements by a crusher head. When there is a large volume of material displaced this way, it means that more material is crushed in each cycle, more material can be fed to fill the larger void left when the crushing head recedes, and more material flows through the crusher due to the larger throughput and gyrating cycles allowing material to drop further. The benefits of high efficiency, greater crushing force and high capacity coupled with the durability the market expects are the reasons why this design is the best way to increase your productivity and profitability.
Sleeve bearings make removal and installation of the MSP Cone Crusher head and main shaft simple. The tapered main shaft fits into a large opening at the upper end of the tapered eccentric bushing. The shaft does not require precise alignment. It can be inserted from a vertical position and will self-align.
With the MSP Cone Crushers automatic hydraulic overload relief system, the crusher immediately opens in the event of an overload. This action reduces the crushing pressure, allowing the obstruction to pass through the chamber. After the chamber has been cleared, the hydraulic control system automatically returns the crusher to its original setting. Shock loads on the crusher are reduced for longer component life.
MSP Cone Crushers are built to make your operations run more smoothly and easily. Its simple and easy to read control panel provides you with the necessary information to properly run your crusher. For example, the MSP Cone Crusher shows you the exact cone setting to allow the operator to stay on top of a critical set point.
To enhance your Cone Crusher's life and maintain optimal crushing capacities, an automatic liner change reminder is included for your convenience. When the new mantle and liners are installed, the automated reminder is reset. As the crusher operates, the system will track production capacities and calculate the liner wear rate. When the cone liners reach the maximum wear point, it sends a flashing reminder to 'change cone' on the cone setting meter. After the wear parts are changed, simply reset the automated reminder system and continue efficient, reliable crushing.
The MSP Cone Crushers are built heavier than most competitive Cone Crushers. The extra weight means lower stress on the machine, which results in longer operational life. There is no question that the proper use of mass makes for more durable crushers. Additionally, a broad array of manganese liners is offered for each size MSP Cone. A unique and patented feature allows the Liners to fit without the use of any backing material. Improved Chamber matching with crusher feeds virtually eliminates any trial and error.
All these factors combine to give producers more effective compression crushing. This reduces liner wear, which reduces wear cost and allows higher yields, resulting in decreased overall cost per ton of finished product.
In the Symons principle, which is utilized by the MSP Cone Crusher, each cycle is timed so that the feed material and the upward thrust of the crushing head meet at the moment of maximum impact. The optimum speed of gyration and the large eccentric throw produce two important results: 1) the rapidly closing head catches the falling feed material and delivers the extremely high crushing force and 2) on the other side of the chamber the rapidly receding head allows material to fall freely to the next point of impact or exit the chamber. The combination of superior crushing force and free flow of material in the MSP Cone Crusher results in production levels that are unsurpassed and means lower power consumption per ton.
Ten years of testing went into the final combination of speed, stroke, and head angle to deliver the most efficient use of power. Greater efficiency delivers lower power consumption, reduced cost per ton, less maintenance and higher profits.
The power input imparted by the driven eccentric results in a bearing force in opposition to the crushing force at a point on the lower portion of the main shaft. The bearing force as it is transmitted to the main shaft provides the required moment to crush the rock. The distance between the bearing force and the fulcrum point is called the force arm. The longer the force arm, the greater the momentum, which produces a greater crushing force.
Crushing loads are distributed over a large spherical bearing. The socket liner keeps full contact with the crushing head ball and carries all of the vertical component and part of the horizontal. The long force arm, represented by the main shaft, reduces the load transmitted through the eccentric bushing.
Capacities and product gradations produced by Cone Crushers are affected by the method of feeding, characteristics of the material fed, speed of the machine, power applied, and other factors. Hardness, compressive strength, mineral content, grain structure, plasticity, size and shape of feed particles, moisture content, and other characteristics of the material also affect production capacities and gradations. Gradations and capacities are most often based on a typical, well-graded choke feed to the crusher. Well-graded feed is considered to be 90% to 100% passing the closed side feed opening, 40% to 60% passing the midpoint of the crushing chamber on the closed side (average of the closed side feed opening and closed side setting), and 0 to 10% passing the closed side setting. Choke feed is considered to be material located 360 degrees around the crushing head and approximately 6 above the mantle nut. Maximum feed size is the average of the open side feed opening and closed side feed opening.
Minimum closed side setting may vary depending on crushing conditions, the compressive strength of the material being crushed, and stage of reduction. The actual minimum closed side setting is that setting just before the bowl assembly lifts minutely against the factory recommended pressurized hydraulicrelief system.
Overall, industry acceptance of the Symons principle and performance, the McLanahan Cone Crusher works to deliver lower recirculating loads at higher tonnage rates with lower maintenance costs by combining:
A general rule of thumb for applying Cone Crushers is the reduction ratio. A crusher with coarse style liners would typically have a 6:1 reduction ratio. Thus, with a 34 closed side setting, the maximum feed would be 6 x 34 or 4.5 inches. Reduction ratios of 8:1 may be possible in certain coarse crushing applications. Fine liner configurations typically have reduction ratios of 4:1 to 6:1.
The difference between the volume displaced by the crushing head when it is fully closed and fully open is called the displacement volume. A large displacement volume results in greater capacity because:
In order to maintain the maximum levels of capacity, gradation, and cubical product, a Cone Crusher must be choke-fed at all times. The best way to keep a choke-feed to the ConeCrusher is with a surge bin (or hopper) and feeder that are located prior to the crusher. Choke-feeding is almost impossible to achieve without a hopper and feeder.
There are a number of different criteria to consider when selecting the right chambers for your crushing needs. However, the one that must always be considered isthat you have a well-graded feed to the chamber. A well-graded feed is generally thought to be 90 to 100% passing the closed-side feed opening, 40 to 60% passing the midpoint, and 0 to 10% passing the closed-side setting.
One thing you should never do is place a new concave liner in a crusher with a worn mantleor place a new mantle in a crusher with a concave liner. Why? If you have properly selected the replacement component, you will change the complete profile of the Cone Crusher by mating new and worn components. The receiving opening will tend to close down, restricting the feed from entering the chamber and causing a reduction in tons per hour.
If the liner is wearing evenly throughout the chamber, you should consider changing out the manganese when it has worn down to about 1" (2.5 cm) thick at the bottom. At about 3/4" to 5/8" (1.9 to 1.6 cm) thick, the manganese will crack, causing the backing material to begin to disintegrate. This, in turn, will cause the liners to break loose. If this should happen, continued operation could destroy the seat on the support bowl or the head of the Cone Crusher.
McLanahan Symons Principle (MSP) Cone Crushers utilize a combination of improved factors of performance, which are enhanced by the Symons Principle of crushing, as well as the latest hydraulic features and electrical features that create a modern, efficient, reliable and durable Cone Crusher that ultimately leads to a faster ROI. MSP Cone Crushers are designed to make your operation run more smoothly and easily, as well as ensuring lower operating costs and minimal downtime so that MSP Cone Crushers are more frequently fully operational and processing optimal amounts of material.
Efficiency can be defined by the ratio of the work done by a machine to the energy supplied to it. To apply what this means to your crusher, in your reduction process you are producing exactly the sizes your market is demanding. In the past, quarries produced a range of single-size aggregate products up to 40 mm in size. However, the trend for highly specified aggregate has meant that products have become increasingly finer. Currently, many quarries do not produce significant quantities of aggregate coarser than 20 mm; it is not unusual for material coarser than 10 mm to be stockpiled for further crushing.
A sectional view of the single-toggle type of jaw crusher is shown below.In one respect, the working principle and application of this machine are similar to all types of rock crushers, the movable jaw has its maximum movement at the top of the crushing chamber, and minimum movement at the discharge point. The motion is, however, a more complex one than the Dodge motion, being the resultant of the circular motion of the eccentric shaft at the top of the swing jaw. combined with the rocking action of the inclined toggle plate at the bottom of this jaw. The motion at the receiving opening is elliptical; at the discharge opening, it is a thin crescent, whose chord is inclined upwardly toward the stationary jaw. Thus, at all points in the crushing chamber, the motion has both, vertical and horizontal, components.
It will be noted that the motion is a rocking one. When the swing jaw is rising, it is opening, at the top, during the first half of the stroke, and closing during the second half, whereas the bottom of the jaw is closing during the entire up-stroke. A reversal of this motion occurs during the downstroke of the eccentric.
The horizontal component of motion (throw) at the discharge point of the single-toggle jaw crusher is greater than the throw of the Dodge crusher at that point; in fact, it is about three-fourths that of Blake machines of similar short-side receiving-opening dimensions. The combination of favorable crushing angle, and nonchoking jaw plates, used in this machine, promotes a much freer action through the choke zone than that in the Dodge crusher. Capacities compare very favorably with comparable sizes of the Blake machine with non-choking plates, and permissible discharge settings are finer. A table of ratings is given.
The single-toggle type jaw crusher has been developed extensively. Because of its simplicity, lightweight, moderate cost, and good capacity, it has found quite a wide field of application in portable crushing rigs. It also fits into the small, single-stage mining operation much better than the slower Dodge type. Some years since this type was developed with very wide openings for reduction crushing applications, but it was not able to seriously challenge the gyratory in this field, especially when the high-speed modern versions of the latter type were introduced.
Due to the pronounced vertical components of motion in the single-toggle machine, it is obvious that a wiping action takes place during the closing strokes; either, the swing jaw must slip on the material, or the material must slip along the stationary jaw. It is inevitable that such action should result in accelerated wear of the jaw plates; consequently, the single-toggle crusher is not an economical machine for reducing highly abrasive, or very hard, tough rock. Moreover, the large motion at the receiving opening greatly accentuates shocks incidental to handling the latter class of material, and the full impact of these shocks must be absorbed by the bearings in the top of the swing jaw.
The single-toggle machine, like the Dodge type, is capable of making a high ratio-of-reduction, a faculty which enables it to perform a single-stage reduction of hand-loaded, mine run ore to a suitable ball mill, or rod mill, feed.
Within the limits of its capacity, and size of receiving openings, it is admirably suited for such operations. Small gravel plant operations are also suited to this type of crusher, although it should not be used where the gravel deposit contains extremely hard boulders. The crusher is easy to adjust, and, in common with most machines of the jaw type, is a simple crusher to maintain.
As rock particles are compressed between the inclined faces of the mantle and concaves there is a tendency for them to slip upward. Slippage occurs in all crushers, even in ideal conditions. Only the particles weight and the friction between it and the crusher surfaces counteract this tendency. In particular, very hard rock tends to slip upward rather than break. Choke feeding this kind of material can overload the motor, leaving no option but to regulate the feed. Smaller particles, which weigh less, and harder particles, which are more resistant to breakage, will tend to slip more. Anything that reduces friction, such as spray water or feed moisture, will promote slippage.
Leading is a technique for measuring the gap between fixed and moveable jaws. The procedure is performed while the crusher is running empty. A lead plug is lowered on a lanyard to the choke point, then removed and measured to find out how much thickness remains after the crusher has compressed it. This measures the closed side setting. The open side setting is equal to this measurement plus the throw of the mantle. The minimum safe closed side setting depends on:
Blake (Double Toggle) Originally the standard jaw crusher used for primary and secondary crushing of hard, tough abrasive rocks. Also for sticky feeds. Relatively coarse slabby product, with minimum fines.
Overhead Pivot (Double Toggle) Similar applications to Blake. Overhead pivot; reduces rubbing on crusher faces, reduces choking, allows higher speeds and therefore higher capacities. Energy efficiency higher because jaw and charge not lifted during cycle.
Overhead Eccentric (Single Toggle) Originally restricted to sampler sizes by structural limitations. Now in the same size of Blake which it has tended to supersede, because overhead eccentric encourages feed and discharge, allowing higher speeds and capacity, but with higher wear and more attrition breakage and slightly lower energy efficiency. In addition as compared to an equivalent double toggle, they are cheaper and take up less floor space.
Since the jaw crusher was pioneered by Eli Whitney Blake in the 2nd quarter of the 1800s, many have twisted the Patent and come up with other types of jaw crushers in hopes of crushing rocks and stones more effectively. Those other types of jaw crusher inventors having given birth to 3 groups:
Heavy-duty crushing applications of hard-to-break, high Work Index rocks do prefer double-toggle jaw crushers as they are heavier in fabrication. A double-toggle jaw crusher outweighs the single-toggle by a factor of 2X and well as costs more in capital for the same duty. To perform its trade-off evaluation, the engineering and design firm will analyze technical factors such as:
1. Proper selection of the jaws. 2. Proper feed gradation. 3. Controlled feed rate. 4. Sufficient feeder capacity and width. 5. Adequate crusher discharge area. 6. Discharge conveyor sized to convey maximum crusher capacity.
Although the image below is of a single-toggle, it illustrates the shims used to make minor setting changes are made to the crusher by adding or removing them in the small space between the crushers mainframe and the rea toggle block.
The jaw crusher discharge opening is the distance from the valley between corrugations on one jaw to the top of the mating corrugation on the other jaw. The crusher discharge opening governs the size of finished material produced by the crusher.
Crusher must be adjusted when empty and stopped. Never close crusher discharge opening to less than minimum opening. Closing crusher opening to less than recommended will reduce the capacity of crusher and cause premature failure of shaft and bearing assembly.
To compensate for wear on toggle plate, toggle seat, pitman toggle seat, and jaws additional shims must be inserted to maintain the same crusher opening. The setting adjustment system is designed to compensate for jaw plate wear and to change the CSS (closed side setting) of the jaw crusher. The setting adjustment system is built into the back frame end.
Here also the toggle is kept in place by a compression spring. Large CSS adjustments are made to the jaw crusher by modifying the length of the toggle. Again, shims allow for minor gap adjustments as they are inserted between the mainframe and the toggle block.
is done considering the maximum rock-lump or large stone expected to be crushed and also includes the TPH tonnage rate needing to be crushed. In sizing, we not that jaw crushers will only have around 75% availability and extra sizing should permit this downtime.
As a rule, the maximum stone-lump dimension need not exceed 80% of the jaw crushers gape. For intense, a 59 x 79 machine should not see rocks larger than 80 x 59/100 = 47 or 1.2 meters across. Miners being miners, it is a certainty during day-to-day operation, the crusher will see oversized ore but is should be fine and pass-thru if no bridging takes place.
It will be seen that the pitman (226) is suspended from an eccentric on the flywheel shaft and consequently moves up and down as the latter revolves, forcing the toggle plates outwards at each revolution. The seating (234) of the rear toggle plate (239) is fixed to the crusher frame; the bottom of the swing jaw (214) is therefore pushed forward each time the pitman rises, a tension rod (245) fitted with a spring (247) being used to bring it back as the pitman falls. Thus at each revolution of the flywheel the movable jaw crushes any lump of ore once against the stationary jaw (212) allowing it to fall as it swings back on the return half-stroke until eventually the pieces have been broken small enough to drop out. It follows that the size to which the ore is crushed.
The jaw crusher is not so efficient a machine as the gyratory crusher described in the next paragraph, the chief reason for this being that its crushing action is confined to the forward stroke of the jaw only, whereas the gyratory crusher does useful work during the whole of its revolution. In addition, the jaw crusher cannot be choke-fed, as can the other machine, with the result that it is difficult to keep it working at its full capacity that is, at maximum efficiency.
Tables 5 and 6 give particulars of different sizes of jaw crushers. The capacity figures are based on ore weighing 100 lb. per cubic foot; for a heavier ore, the figures should be increased in direct proportion to its weight in pounds per cubic foot.
The JAW crusher and the GYRATORY crusher have similarities that put them into the same class of crusher. They both have the same crushing speed, 100 to 200 R.P.M. They both break the ore by compression force. And lastly, they both are able to crush the same size of ore.
In spite of their similarities, each crusher design has its own limitations and advantages that differ from the other one. A Gyratory crusher can be fed from two sides and is able to handle ore that tends to slab. Its design allows a higher-speed motor with a higher reduction ratio between the motor and the crushing surface. This means a dollar saving in energy costs.
A Jaw crusher on the other hand requires an Ely wheel to store energy. The box frame construction of this type of crusher also allows it to handle tougher ore. This design restricts the feeding of the crusher to one side only.
The ore enters from the top and the swing jaw squeezes it against the stationary jaw until it breaks. The broken ore then falls through the crusher to be taken away by a conveyor that is under the crusher.Although the jaws do the work, the real heart of this crusher is the TOGGLE PLATES, the PITMAN, and the PLY WHEEL.
These jaw crushers are ideal forsmall properties and they are of the high capacity forced feed design.On this first Forced Feed Jaw Crusher, the mainframe and bumper are cast of special alloy iron and the initial cost is low. The frame is ribbed both vertically and horizontally to give maximum strength with minimum weight. The bumper is ruggedly constructed to withstand tremendous shock loads. Steel bumper can be furnished if desired. The side bearings are bronze; the bumper bearings are of the antifriction type.
This bearing arrangement adds both strength and ease of movement. The jaw plates and cheek plates are reversible and are of the best-grade manganese steel. The jaw opening is controlled by the position of an adjustable wedge block. The crusher is usually driven by a V-to-V belt drive, but it can be arranged for either V-to-flat or fiat belt drive. The 8x10 size utilizes a split frame and maybe packed for muleback transportation. Cast steel frames can be furnished to obtain maximum durability.
This second type of forced feed rock crusher is similar in design to the Type H listed above except for having a frame and bumper made of cast steel. This steel construction makes the unit lighter per unit of size and adds considerable strength. The bearings are all of the special design; they are bronze and will stand continuous service without any danger of failure. The jaw and cheek plates are manganese steel; and are completely reversible, thus adding to their wearing life. The jaw opening is controlled by the position of an adjustable wedge block. The crushers are usually driven by V-to-V but can be arranged for V-to-flat and belt drive. The 5x6 size and the 8x10 size can be made with sectionalized frame for muleback transportation. This crusher is ideal for strenuous conditions. Consider a multi jaw crusher.
Some jaw crushers are on-floor, some aboveground, and others underground. This in many countries, and crushing many kinds of ore. The Traylor Bulldog Jaw crusher has enjoyed world wide esteem as a hard-working, profit-producing, full-proof, and trouble-free breaker since the day of its introduction, nearly twenty years ago. To be modern and get the most out of your crushing dollars, youll need the Building breaker. Wed value the privilege of telling you why by letter, through our bulletins, or in person. Write us now today -for a Blake crusher with curved jaw plates that crush finer and step up production.
When a machine has such a reputation for excellence that buyers have confidence in its ability to justify its purchase, IT MUST BE GOOD! Take the Type G Traylor Jaw Crusher, for instance. The engineers and operators of many great mining companies know from satisfying experience that this machine delivers a full measure of service and yields extra profits. So they specify it in full confidence and the purchase is made without the usual reluctance to lay out good money for a new machine.
The success of the Type G Traylor Jaw Crusheris due to several characteristics. It is (1) STRONG almost to superfluity, being built of steel throughout; it is (2) FOOL-PROOF, being provided with our patented Safety Device which prevents breakage due to tramp iron or other causes of jamming; it is (3) ECONOMICAL to operate and maintain, being fitted with our well-known patented Bulldog Pitman and Toggle System, which saves power and wear by minimizing frictionpower that is employed to deliver increased production; it is (4) CONVENIENT to transport and erect in crowded or not easily accessible locations because it is sectionalized to meet highly restrictive conditions.
Whenever mining men need a crusher that is thoroughly reliable and big producer (which is of all time) they almost invariably think first of a Traylor Type G Jaw Crusher. By experience, they know that this machine has built into it the four essentials to satisfaction and profit- strength, foolproofness, economy, and convenience.
Maximum STRENGTH lies in the liberal design and the steel of which crushers parts are made-cast steel frame, Swing Jaw, Pitman Cap and Toggles, steel Shafts and Pitman rods and manganese steel Jaw Plates and Cheek Plates. FOOLPROOFNESS is provided by our patented and time-tested safety Device which prevents breakage due to packing or tramp iron. ECONOMY is assured by our well-known Bulldog Pitman and Toggle System, which saves power and wear by minimizing friction, the power that is used to deliver greater productivity. CONVENIENCE in transportation and erection in crowded or not easily accessible locations is planned for in advance by sectionalisation to meet any restrictive conditions.
Many of the worlds greatest mining companies have standardized upon the Traylor Type G Jaw Crusher. Most of them have reordered, some of them several times. What this crusher is doing for them in the way of earning extra dollars through increased production and lowered costs, it will do for you! Investigate it closely. The more closely you do, the better youll like it.
AG and SAG mills are now the primary unit operation for the majority of large grinding circuits, and form the basis for a variety of circuit configurations. SAG circuits are common in the industry based on:
Though some trepidation concerning AG or SAG circuits accompanied design studies for some lime, such circuits are now well understood, and there is a substantial body of knowledge on circuit design as well as abundant information that can be used for bench-marking of similar plants in similar applications. Because SAG mills rely both on the ore itself as grinding media (to varying degrees) and on ore-dependent unit power requirements for milling to the transfer size, throughput in SAG circuits are variable. Relative to other comminution machines in the primary role. SAG mill operation is more dynamic, and typically requires a higher degree of process control sophistication. Though more complex in AG/ SAG circuits relative to the crushing plants they have largely replaced, these issues are well understood in contemporary applications.
AG/SAG mills grindore through impact breakage, attrition breakage, and abrasion of the ore serving as media. Autogenous circuits require an ore of suitable competency (or fractions within the ore of suitable competency) to serve as media. SAG circuits may employ low to relatively high ball charges (ranging from 2% to 22%, expressed as volumetric mill filling) to augment autogenous media. Higher ball charges shift the breakage mode away from attrition and abrasionbreakage toward impact breakage; as a result, AG milling produces a finer grind than SAG milling for a given ore and otherwise equal operating conditions. The following circuits are common in the gold industry:
Common convention generally refers to high-aspect ratio mills as SAG mills (with diameter to effective grinding length ratios of 3:1 to 1:1), low-aspect ratio mills (generally, a mill with a significantly longer length than diameter) are also worth noting. Such mills are common in South African operations; mills are sometimes referred to as tube mills or ROM ball mills and are also operated both autogenously and semi-autogenously. Many of these mills operate at higher mill speeds (nominally 90% of critical speed) and often use grid liners to form an autogenous liner surface. These mills typically grind ROM ore in a single stage. A large example of such a mill was converted from a single-stage milling application to a semi autogenous ball-mill-crushing (SABC) circuit, and the application is well described. This refers to high-aspect AG/SAG mills.
With a higher density mill charge. SAG mills have a higher installed power density for a given plant footprint relative to AC mills. With the combination of finer grind and a lower installed power density (based on the lower density of the mill charge), a typical AG mill has a lower throughput, a lower power draw, and produces a finer grind. These factors often translate to a higher unit power input (kWh/t) than an SAG circuit milling the same ore. but at a higher power efficiency (often assessed by the operating work index OWi, which if used most objectively, should be corrected by one of a number of techniques for varying amounts of fines between the two milling operations).
In the presence of suitable ore, an autogenous circuit can provide substantial operating cost savings due to a reduction in grinding media expenditure and liner wear. In broad terms, this makes SAG mills less expensive to build (in terms of unit capital cost per ton of throughput) than AG mills but more expensive to operate (as a result of increased grinding media and liner costs, and in many cases, lower power efficiency). SAG circuits are less susceptible to substantial fluctuations due to feed variation than AG mills and are more stable to operate. AG circuits are more frequently (but not exclusively) installed in circuits with high ore densities. A small steel charge addition to an AG mill can boost throughput, result in more stable operations, typically at the consequence of a coarser grind and higher operating costs. An AG circuit is often designed to accommodate a degree of steel media for circuit flexibility. AG mills (or SAG mills with low ball charges) are often used in single-stage grinding applications.
Based on their higher throughput and coarser grind relative to AG mills, it is more common for SAG mills to he used as the primary stage of grinding, followed by a second stage of milling. AG/SAG circuits producing a fine grind (particularly single-stage grinding applications) are often closed with hydrocyclones. Circuits producing a coarser grinds often classify mill discharge with screens. For circuits classifying mill discharge at a coarse size (coarser than approximately 10 mm), trommels can also be considered to classify mill discharge. Trommels are less favorable in applications requiring high classification efficiencies and can be constrained by available surface area for high-throughput mills. Regardless of classification equipment (hydrocyclone, screen, or trommel), oversize can be returned to the mill, or directed to a separate stage of comminution.
Many large mills around the world (Esperanza with a 12.8 m mill. Cadia and Collahuasi with 12.2-m mills, and Antamina. Escondida #IV. PT Freeport Indonesia, and others with 11.6-m mills) have installed SAG mills of 20 MW. Gearless drives (wrap-around motors) are typically used for large mills, with mills of 25 MW or larger having been designed. Several circuits have single-line design capacities exceeding 100,000 TPD. A large SAG installation (with pebble crusher product combining with SAG discharge and feeding screens) is depicted here below, with the corresponding process flowsheet presented in Figure 17.9.
Adding pebble crushing as a unit operation is the most common variant to closed-circuit AG/SAG milling (instead of direct recycle of oversize material ). The efficiency benefits (both in terms of grinding efficiency and in capital efficiency through incremental throughput) are well recognized. Pebble crushers are effective at reducing the buildup of critical-sized material in the mill load. Critical-sized particles are those where the product of the mill feed-size distribution and the mill breakage rates result in a buildup of a size range of material in the mill load, the accumulation of which limits the ability of the mill to accept new feed. While critical-size could be of any dimension, it is most typically synonymous with pebble-crusher feed, with a size range of 1375 mm. Critical-sized particles can result from a simple failure of a mills breakage rates to exceed the breakage rate of incoming particles, and particles generated when breaking larger particles. Alternatively, a second type of buildup of critical-sized material can result due to a combination of rock types in the feed that have differing breakage properties. In this case, the harder fraction of the mill feed builds up in the mill load, againrestricting throughput. Examples of materials in this category include diorites, chert, and andesite. When buildup of these materials does occur, pebble crushing can improve mill throughput even more dramatically than when the critically sized fraction results purely from a breakage rate deficit alone. For these ore types, a pebble-crushing circuit is tin imperative for efficient circuit operation.
Currently, every AG/SAG flowsheet evaluation is likely to consider the inclusion of a pebble crusher circuit. Flowsheets that do not elect to include pebble crushing at construction and commissioning may include provisions for future retrofitting a pebble-crushing circuit. Important aspects of pebble crusher circuit design include:
The standard destination for crushed pebbles has been to return them to SAG feed. However, open circuiting the SAG mill by feeding crushed pebbles directly to a ball-mill circuit is often considered as a technique to increase SAG throughput. An option to do both can allow balancing the primary and secondary milling sections by having the ability to return crushed pebbles to SAG feed as per a conventional flowsheet, or to the SAG discharge. Such a circuit is depicted here on the right. By combining with SAG discharge and screening on the SAG discharge screens, top size control to the ball-mill circuit feed is maintained while still unloading the SAG circuit (Mosher et al, 2006). A variant of this method is to direct pebble-crushing circuit product to the ball-mill sump for secondary milling: while convenient, this has the disadvantage of not controlling the top size of feed to the ball-mill circuit. There have also been pioneer installations that have installed HPGRs as a second stage of pebble crushing.
The unit power requirement for SAG milling (both individually and as a fraction of the total circuit power) is worthy of comment. It can be very difficult operationally to trade grind for throughput in an SAG circuitonce designed and constructed for a given circuit configuration, an SAG mill circuit has limited flexibility to deliver varying product sizes, and a relatively fixed unit power input for a given ore type is typically required in the SAG mill. This is particularly true for those SAG circuits designed with a coarse closing size. As a result, under-sizing an SAG mill has disastrous results on throughput across the industry, there are numerous examples of the SAG mill emerging as the circuit bottleneck. On the other hand, over-sizing an SAG circuit can be a poor utilization of capital (or an opportunity for future expansion!).
Traditionally, many engineers approached SAG circuit design as a division of the total power between the SAG circuit and ball-mill circuit, often at an arbitrary power split. If done without due consideration to ore characteristics, benchmarks against comparable operating circuits, and other aspects of detailed design (including steady-state tests, simulation, and experience), an arbitrary power split between circuits ignores the critical decision of determining the required unit power in SAG milling. As such, it exposes the circuit to risk in terms of failing to meet throughput targets if insufficient SAG power is installed. Rather than design the SAG circuit with an arbitrary fraction of total circuit power, it is more useful to base the required SAG mill size on the product of the unit power requirement for the ore and the desired throughput. Subsequently, the size of the secondary milling circuit is then sized based on the amount of finish grinding for the SAG circuit product that is required. Restated, the designed SAG mill size and operating conditions typically control circuit throughput, while the ball-mill circuit installed power controls the final grind size.
The effect of feed hardness is the most significant driver for AG/SAG performance: with variations in ore hardness come variations in circuit throughput. The effect of feed size is marked, with both larger and finer feed sizes having a significant effect on throughput. With SAG mills, the response is typically that for coarser ores, throughput declines, and vice versa. However, for AG mills, there are number of case histories where mills failed to consistently meet throughput targets due to a lack of coarse media. Compounding the challenge of feed size is the fact that for many ores, the overall coarseness of the primary crusher product is correlated to feed hardness. Larger, more competent material consumes mill volume and limits throughput.
A number of operations have implemented a secondary crushing circuit prior to the SAG circuit for further comminution of primary crusher product. Such a circuit can counteract the effects of harder ore. coarser ore. decrease the size of SAG mill required, or rectify poor throughput due to an undersized SAG circuit. Notably, harder ore often presents itself to the SAG circuit as coarser than softer oreless comminution is produced in blasting and primary crushing, and therefore the impact on SAG throughput is compounded.
Circuits that have used or do use secondary crushing/SAG pre-crush include Troilus (Canada), Kidston (Australia), Ray (USA), Porgera (PNG). Granny Smith (Australia), Geita Gold (Tanzania), St Ives (Australia), and KCGM (Australia). Occasionally, secondary crushing is included in the original design but is often added as an additional circuit to account for harder ore (either harder than planned or becoming harder as the deposit is developed) or as a capital-efficient mechanism to boost throughput in an existing circuit. Such a flowsheet is not without its drawbacks. Not surprisingly, some of the advantages of SAG milling are reduced in terms of increased liner wear and increased maintenance costs. Also, pre-crush can lead to an increase in mid-sized material, overloading of pebble circuits, and challenges in controlling recycle loads. In certain circuits, the loss of top-size material can lead to decreased throughput. It is now widespread enough to be a standard circuit variant and is often considered as an option in trade-off studies. At the other end of the spectrum is the concept of feeding AG mills with as coarse a primary crusher product as possible.
The overall circuit configuration can guide selection of die classification method of primary circuit product. Screening is more successful than trommel classification for circuits with pebble crushing, particularly for those with larger mills. Single-stage AG/SAG circuits are most often closed with hydrocyclones.
To a more significant degree than in other comminution devices, liner design and configuration can have a substantial effect on mill performance. In general terms, lifter spacing and angle, grate open area and aperture size, and pulp lifter design and capacity must be considered. Each of these topics has had a considerable amount of research, and numerous case studies of evolutionary liner design have been published. Based on experience, mill-liner designs have moved toward more open-shell lifter spacing, increased pulp lifter volumetric capacity, and a grate design to facilitate maximizing both pebble-crushing circuit utilization and SAG mill capacity. As a guideline, mill throughput is maximized with shell lifters between ratios of 2.5:1 and 5.0:1. This ratio range is stated without reference to face angle; in general terms, and at equivalent spacing-to-height ratios, lifters with greater face-angle relief will have less packing problems when new, but experience higher wear rates than those with a steeper face angle. Pulp-lifter design can be a significant consideration for SAG mills, particularly for large mills. As mill sizes increases, the required volumetric capacity of the pulp lifters grows proportionally to mill volume. Since AG/SAG mill volume is roughly proportional to the mill radius cubed (at typical mill lengths) while the available cross-sectional area grows only as the radius squared, pulp lifters must become more efficient at transferring slurry in larger mills. Mills with pebble-crushing circuits will require grates with larger apertures to feed the circuit.
No discussion of SAG milling would be complete without mention of refining. Unlike a concentrator with multiple grinding lines, conducting SAG mill maintenance shuts down an entire concentrator, so there is a tremendous focus on minimizing required maintenance time; the reline timeline often represents the critical path of a shutdown (but typically does not dominate a shutdown in terms of total maintenance effort).
Reline times are a function of the number of pieces to be changed and the time required per piece. Advances in casting and development of progressively larger lining machines have allowed larger and larger individual liner pieces.
While improvements in this area will continue, the physical size limit of the feed trunnion and the ability to maneuver parts are increasingly limiting factors, particularly in large mills. The other portion of the equation for reline times is time per piece, and performance in this area is a function of planning, training/skill level, and equipment.
Abroad range of AG/SAG circuit configurations are in operation. Very large line plants have been designed, constructed, and operated. The circuits have demonstrated reliability, high overall availabilities, streamlined maintenance shutdowns, and efficient operation. AG/SAG circuits can handle a broad range of feed sizes, as well as sticky, clayey ores (which challenge other circuit configurations). Relative to crushing plants, wear media use is reduced, and plants run at higher availabilities. Circuits, however, are more sensitive to variations in circuit feed characteristics of hardness and size distribution; unlike crushing plants for which throughput is largely volumetrically controlled. AG/SAG throughput is defined by the unit power required to grindthe ore to the closing size attained in the circuit. Very hard ores can severely constrain AG/SAG mill throughput. In such cases, the circuits can become capital inefficient (in terms of the size and number of primary milling units required) and can require more total power input relative to alternative comminution flowsheets. A higher degree of operator skill is typically required of AG/SAG circuit operation, and more advanced process control is required to maintain steady-state operation, with different operator/advanced process control regimens required based on different ore types.
Many mills have been built based on data from inadequate sampling or from insufficient tests. With the cost of many mills exceeding several hundred million dollars, it is mandatory that geologists, mining engineers and metallurgists work together to prepare representative samples for testing. Simple repeatable work index tests are usually sufficient for rod mill and ball mill tests but pilot plant tests on 50-100 tons of ore are frequently necessary for autogenous or semiautogenous mills.
Preparation and selection of the test sample is of utmost importance. Procedures for autogenous and semiautogenous mill pilot plant tests are relatively simple for those experienced in running them. Reliable and repeatable results can be obtained if simple fundamental procedures are followed.
The design of large mills has become increasingly more complicated as the size has increased and there is little doubt that without sophisticated design procedures such as the use of the Finite Element method the required factors of safety would make large mills prohibitively expensive.
In the past the design of small mills, up to +/- 2,5 metres diameter, was carried out using empirical formulae with relatively large factors of safety. As the diameter and length of mills increased several critical problem areas were identified. One of the most important was the severe stressing which took place at the connection of the mill shell and the trunnion bearing end plates, which is further aggravated by the considerable distortion of the shell and the bearing journals due to the dynamic load effect of the rotating mill with a heavy mass of ore and pulp being lifted and dropped as the grinding process took place. Incidentally the design calculation of the deformations of journal and mill shell is based on static conditions, the influence of the rotating mass being of less importance. An indication of shell and journal distortion is shown in Figure 1.
Investigations carried out by Polysius/Aerofall revealed that practical manufacturing considerations dictated some aspects of trunnion end design. Whereas the thickness of the trunnion in the case of small diameter mills was dictated by foundry practice which required a minimum thickness of metal the opposite was the case in the design of large diameter mills where the emphasis was not to exceed a maximum thickness both from the mass/casting temperature point of view and the cost aspect.
While the deformation of shell and end plates was acceptable in the case of small mills due in some extent to the over stiff construction, the deformation in the large, more flexible, mills is relatively high. The ratio of the trunnion thickness to trunnion diameter in a mill of 2,134 m diameter is almost twice that of a mill of 5,8 m diameter, i.e. a ratio (T/D) of 0,116 to 0,069 for the large mill.
The use of large memory high speed computers coupled with finite element methods provides the means of performing stress calculations with a high degree of accuracy even for the complex structures of large mills. The precision with which the stress values can be predicted makes the use of safety factors based on empirical formulae generally unnecessary.
In the case of large diameter trunnion bearing mills the distortion which takes place is further compounded by the fact that the deformation varies across the width of the bearing journal due to the fact that the end of the journal attached to the mill end plate is less liable to distortion than the outlet free end of the journal. This raises serious complications as far as the development of the hydrodynamic fluid oil film of the bearing is concerned since the minimum oil gap may be only 0,05 mm.
Obviously a thinner oil film is adequate where the deformation of the journal is less while at the unsecured end of the journal widely varying oil film thickness is necessary to maintain the correct oil pressure to support the mill. A solution to this problem has been the advent of the hydrostatic bearing with a supply of high pressure oil pumped continuously into the bearings.
Incorporating the mill bearing journals as part of the mill shell reduced the magnitude of the problem of distortion although there is always out of round deformation of the shell. The variation across the width of the journal surface is less pronounced than is the case with the trunnion bearing.
The replacement of a single bearing with a number of individual self adjusting bearing pads which together support the mill has lessened the undesirable effects of deformation while improving the efficiency of the bearing.
The ability of each individual bearing-pad to adjust automatically to a more localised area of the shell journal gives rise to improved contact of the oil film with both the bearing surface and the journal and in the case of hydrodynamic oil systems makes it unnecessary to supply oil at constant high pressure once the oil film has been established. A cross-section of a slipper pad bearing is shown in Figure 3.
Kidstons orebody consists of 44.2 million tonnes graded at 1.79 g/t gold and 2.22 g/t silver. Production commenced in January, 1985, and despite a number of control, mechanical and electrical problems, each month has seen a steady improvement in plant performance to a current level of over ninety percent rated capacity.
The grinding circuit comprises one 8530 mm diameter x 3650 mm semi-autogenous mill driven by a 3954 kW variable speed dc motor, and one 5030 mm diameter x 8340 mm secondary ball mill driven by a 3730 kW synchronous motor. Four 1067 x 2400 mm vibrating feeders under the coarse ore stockpile feed the SAG mill via a 1067 mm feed belt equipped with a belt scale. Feed rate was initially controlled by the SAG mill power draw with bearing pressure as override.
Integral with the grinding circuit is a 1500 cubic meter capacity agitated surge tank equipped with level sensors and variable speed pumps. This acts as a buffer between the grinding circuit and the flow rate sensitive cycloning and thickening sections.
The Kidston plant was designed to process 7500 tpd fresh ore of average hardness; but to optimise profit during the first two years of operation when softer oxide ore will be treated, the process equipment was sized to handle a throughput of up to 14 000 tpd. Some of the equipment, therefore, will become standby units at the normal throughputs of 7 000 to 8 000 tpd, or additional milling capacity may be installed.
The SAG mill incorporates a design which allowed expedient manufacturing to high quality specifications, achieved by selecting a shell to head to trunnion configuration of solid elements bolted together. This eliminates difficult to fabricate and inspect areas such as a fabricated head welded to shell plate, fabricated ribbed heads, plate or casting welded to the head in the knuckle area and transition between the head and trunnion.
Considerable variation in ore hardness, the late commissioning of much of the instrumentation and an eagerness to maximise mill throughput led to frequent mill overloading during the first four months of operation. The natural operator over-reaction to overloads resulted numerous mill grindouts, about sixteen hours in total, which in turn were largely responsible for grate failure and severe liner peening. First evidence of grate failure occurred at 678 000 tonnes throughput, and at 850 000 tonnes, after three grates had been replaced on separate occasions, the remaining 25 were renewed. The cylinder liners were so badly peened at this stage that no liner edge could be discerned except under very close scrutiny and grate apertures had closed to 48 percent of their original open area.
The original SAG mill control loop, a mill motor power draw set point of 5200 Amperes controlling the coarse ore feeder speeds, was soon found to give excessive variation in the mill ore charge volume and somewhat less than optimal power draw.
The armature, weighing 19 tonnes, together with the top half magnet frame, were trucked two thousand kilometers to Brisbane for rewinding and repairs. The mill was turning again on January 24 after a total elapsed downtime of 14 days. After a twelve day stoppage due to a statewide power dispute in February, the mill settled down to a fairly normal operation, apart from some minor problems with alarm monitoring causing a few spurious trips. One cause of the mysterious stoppages was tracked down to the cubicle door interlocks which stuttered whenever the mining department fired a bigger than usual blast.
The open trunnion bearings are sealed with a rubber ring which proved ineffective in preventing ingress of water, and occasionally solids, from feed chute chokes and spillages. Contamination and emulsification of the oil with subsequent filter choking has been responsible for nearly eighteen percent of SAG mill circuit shutdowns. Despite the very high levels of contamination, no damage has been sustained by the bearings which has at least proved the effectiveness of the filters and other protection devices.
Design changes to date have, predictably, mostly concentrated on improving liner life and minimising discharge grate damage. Four discharge grates with thickened ends have performed satisfactorily and a Mk3 version with separate lifters and 20 mm apertures is currently being cast by Minneapolis Electric.
Cylinder liners will continue to be replaced with high profile lifters only on a complete reline basis. While there is the problem of reduced milling capacity with reduced lifter height towards the end of liner life, it is hoped to largely offset this by operating at higher mill speeds.
Mill feed chute liner life continues to be a problem. The original chrome-moly liners lasted some three months and a subsequent trial with 75 mm thick clamped Linhard (rubber) liners turned in a rather dismal life of three weeks.
A pebble tray or pebble saucer is a simple, easy-to-make gardening tool used mostly for indoor plants. Any low dish or tray can be used along with water and pebbles or gravel to create a humid local area for plants that need a little moisture. Read on for tips on using a humidity tray for plants and how you can make your own.
A pebble tray is exactly what it sounds like: a tray that is full of pebbles. Its also full of water, of course. The main purpose of a pebble tray is to provide humidity for plants, typically houseplants.
Most houseplants are tropical varieties, but most houses have dry, conditioned air. A pebble tray is a simple, low-tech way to provide those plants with a healthier, more humid local environment. Orchids are examples of houseplants that can really benefit from a pebble tray. With a tray in place, you wont need to spend as much time misting these water-hungry plants.
You dont have to get a humidifier or increase the moisture in the air throughout your entire home if you just create strategic pebble trays. The plant sits on top of the pebble in the tray and benefits from the moisture created by water in the tray.
Making a humidity or pebble tray is one of the simplest of all gardening DIY projects. All you really need is a shallow tray of some type and rocks or pebbles. You can buy purpose-made trays at garden centers, but you can also use old drainage trays from pots, cookie sheets, the top saucer of an old bird bath, or anything else that is about an inch (2.5 cm.) deep.
Fill the tray with a single layer of pebbles and add enough water so that it rises just about halfway up the rocks. You can use decorative pebbles from a garden center, rocks right out of your own garden, or inexpensive gravel.
PebbleGo is a curricular content hub specifically designed for K-3 students. Packed with informational articles, ready-made activities, and literacy supports for students of all abilities, it boosts engagement and fosters independent learning in core subject areas. Your students will love exploring PebbleGo time and time again.
No matter the subject you're teaching or the unique needs and interests of your students, PebbleGo has you covered. Complete with scaffolding to support differentiated instruction, engaging multimedia within eacharticle to maximize comprehension,and interactive lessons, activities, and games to reinforce learning, PebbleGo is the go-to K-3 resourcefor teachers across the country.
This calculator is to help you estimate the amount of pebbles, stone or gravel that you will need to cover a driveway, garden paths or garden beds and more. You can view our range of stone products by clicking here
There are many particle size reduction devices including jaw crushers, impact crushers, cone crushers, and hammer crushers, among which jaw crusher, as the longest and most popular crushing equipment, has been widely used in the primary crushing of materials.
Jaw crusher is the traditional crushing equipment with many models and large output. PE jaw crusher is mainly used for primary crushing of various ores and undisturbed materials, also used for both coarse and fine crushing.
There are many models of PE jaw crushers, among which the most popular models arePE-7501060, PE-600900, PE-150250, etc. In order to meet the strict requirements of customers, the crusher has been extended to the PEX jaw crusher under the constant innovation of engineers, which is also known as the fine crusher.
This crusher has been widely used in mining, building materials, roads, railways, water conservancy, and chemical industries, as well as crushing various soft and hard ores with a compressive strength of 350MPa and a diameter of 500-1800 mm, such as river pebble, granite, basalt and other metal ores. The PE jaw crusher has a significant crushing efficiency with a large crushing ratio and a high output, which is favored by the majority of users.
This crusher is used in almost all minerals and mining industries. Whether dealing with metal ore or non-metallic ore, we can offer you a solution that reduces the size, for a series of our products are available for crushing, downsizing, beneficiation with reliable design and versatility for your application. PE jaw crusher can process 1-2,000 tons of ore per hour, so in Africa, many gold mines choose our Jaw Crusher as the primary crushing of their entire beneficiation line.
In September last year, Mr. Brighton from Zimbabwe found us and consulted us about the mineral processing equipment that he needed equipment that could process 10 tons of gold ore per hour whose feed size was 200 mm and discharge size was 7-30 mm.
According to the project information he provided, our technical manager designed a complete production line for him, including jaw crusher, cone crusher, ball mill, spiral classifier, flotation machine, and dryer. In this situation, a jaw crusher must be used for primary crushing in order to achieve the required discharge size, granularity, and higher quality end product.
As a result, the technical manager proposed a PE-250400 jaw crusher for Mr. Brighton to meet his requirements for incoming and outgoing materials. This type of jaw crusher can reduce 5-21 tons of ore per hour which is suitable for his requirements now, even the future when he wants to expand the production. Compared with raw gold ore, the gold ore processed by the mineral processing equipment is more expensive and more versatile in the world, and also more attractive to the customers for higher profits it brings.
Many infrastructure industries have a solid foundation, which is a variety of rock aggregates. Recognizing that the widespread use of these aggregates has prompted us to continuously create and improve our rock crushing equipment to help boost your production, reduce maintenance times and increase overall operational efficiency.
Aggregates that are crushed from large stones are essential raw materials in construction, transportation, and other infrastructure construction. Therefore, the role of crushing equipment in the aggregate crushing production line is critical.
Our PE jaw crusher is commonly used throughout the industry to reduce the pieces into the required sizes and to impart fineness to the broken material with high quality and efficiency. It can make rocks, sandstones, river pebbles, and other materials into various granularity that meet the requirements of construction sand with high compressive strength, being more in line with building requirements, and characteristic of improving building quality.
In June 2018, a construction company from Ethiopia found our promoters, because they were about to carry out the road construction project and hoped to crush the basalt raw materials (250 mm to 500 mm) into the sizes of 00, 01, 02, 03 (00 stands For fine below 4 mm the dust; 01 between 4 mm to 8 mm; 02 stands for 20 mm; 03 stands for 20 mm to 32 mm.), and due to the large amount of work, it is necessary to crush 200 tons of basalt per hour.
Based on customer's information, we had customized basalt crushing solutions for customers, including jaw crusher, cone crusher, sand washer and circular vibrating screen, among which, the PE-7501060 jaw crusher model can meet all the requirements of customers, which means that the crushed basalt had a uniform particle size and was very suitable for road construction.
PE jaw crusher is widely used in coal mine operations and attractive to customers because of its uniform end granularity, lower noise, less dust, and less pollution. Under strict environmental regulations, a good deal of coal mine projects has been suspended due to large pollution, which has seriously hindered the development of mining plants, resulting in low efficiency in major mining areas.
However, we have actively responded to the call for environmental protection by using advanced technologies and new materials to manufacture this crusher to meet national environmental standards. Coupled with PE's superior discharge size and simple operation characteristics, our company has been chosen by many users.
The rapid development of society has led to the production of many construction wastes. The original construction waste is not treated, not only occupies the land, but also causes pollution of rivers. The application of the crusher not only solves environmental pollution but also brings a high economic benefit for investors by recycling the construction waste into valuable materials.
The brand is shaped by innovation. This new generation of jaw crushers has redefined itself with advanced technical design, which can improve material flow and production in quarrying, mining, demolition and recycling applications, and for which this machine has become a deal solution for large manufacturers and crushing operators.
This crusher adopts the most advanced crushing technology and digital component processing equipment to make the internal structure precise, thus there is no dead zone in the deep cavity crushing, which could avoid blockage effectively, improving the production efficiency.
Continuous collaboration with laboratories enables state-of-the-art technological innovations in the durability of wear parts and the reliability of mechanical components, extending the service life of the whole set of equipment, among which, the movable plate is made of high-speed steel castings, and the eccentric shaft is processed by forging blanks, which makes the equipment more reliable, efficient and durable.
The PE series jaw crusher can be driven by a diesel generator and an electric motor. The diesel enters the generator to drive the belt and the pulley, and the eccentric shaft moves the movable plate up and down for the operation. Or use electricity for operation.
But in general, customers will still prepare a backup generator to prevent the mine from being too far away from the city. The power of a PE-400600 crusher generator is 30KW, and the cost is 37-40 yuan if using 30KW electricity (it is different in different countries). The specific generator to be configured is determined by the customer's site conditions and budget.
The performance and the overall structure of the crusher have been improved by reasonable design, thus easy operation and convenient maintenance increase the plant's global availability and profitability.
The development of the PE series jaw crusher demonstrates that the manufacturer has been focusing on customer success by combining the best technology solutions and providing reliability to allow our customers to focus on their own operations.
With professional production technology and export experiences for 40 years, we understand exactly the different needs of customers in various countries. And PE series products are mainly exported to India, Brazil, Vietnam and other countries.
We also have established a sandstone equipment research institute, established an international advanced production line and a first-class modern testing base to R&D the innovative equipment, making the PE series jaw crusher closely fit the customer's actual production needs.
River pebble is a kind of purely natural stone which loses its irregular angle by gravel collision under the action of crustal movement and running water. It is buried in the ground and silenced for millions of years together with the sediment.
There are many pebbles in the sea, smooth, round, and the color more abundant. Therefore, the demand is larger and the price is higher. The Philippines is strategically surrounded by the sea with many rivers on the island, so it is rich in pebble resources.
River pebble has natural characteristics of compression, wear and corrosion resistance which is ideal for green building and important material for making pebble sand after the procedures of crushing, sand making, and screening. It is widely used in the engineering field of water conservancy and hydropower, high-grade highways, bridges, airport runways, municipal works, and high-rise buildings, also as an aggregate for concrete. The pebbles have a high application value for its rich resources and low collection cost.
In March 2017, our promoters contacted a quarry manager from Mindanao, the Philippines on a social platform. The manager told us that he was looking for a suitable machine to reduce the 25-40 cm river pebble to Sand1. -5 mm and 1/4, 1/2, 3/4 stones (6.35 mm, 12.7 mm, 19.05 mm), and expected to process 200 tons per hour.
He also said that he would not start his project before he solved the problem of what kind of equipment is suitable for him, for his mining site was on a remote beach on the island which had rich pebble resources, but the temperature was high, and the rainy season was coming, so the customer worried that the equipment could not withstand the high temperature and humid environment.
After understanding his situation, we designed a sandstone production line suitable for him, including ZSW490110 vibrating feeder, PE7501060 jaw crusher, conveyor, HXCYS400 cone crusher, 3YK2870 vibrating screen, XS3020 sand washer, etc.
Knowing that the customer's site was not very steep, Hongxing advised a fixed machine for him which has a stable operation and less investment than the mobile crusher plant. As for the question that whether can the machine work normally under the high-temperature and humid environment? The answer is yes. But the customer must do the daily maintenance of the machine that we would teach them.
Rainwater enters the inside of the machine, which will corrode the inside of mechanical parts to accelerate mechanical wear and increase mechanical failure. It always causes the bigger problem because of its invisible corrosion, so the operators should take effective measures according to local weather conditions and air pollution at that time to reduce the impact of chemical corrosion on machinery, with emphasis on preventing rainwater from invading machinery. If necessary, you can build a plastic greenhouse or cover.
Every part has its own normal range of temperature. It is necessary to check every the value on various thermometers frequently for its smooth working, otherwise, the machine will be damaged. There are two cooling systems should be paid more attention. For water-cooled machinery, it must be checked before daily work to add cooling water, and for air-cooled machinery, the dust on the air-cooled system should be cleaned regularly to ensure smooth air circulation.
The PE jaw crusher can process materials with a side length of 100-500 mm with the characteristics of large crushing ratio and producing cubic end materials. The PE7501060 jaw crusher is used as the primary crushing equipment for the river pebble with the feed size of 25-40 cm. The big size of the material must be crushed into different granularity by the jaw crusher for secondary crushing.
And the selection is just like this: raw and bigger materials - vibrating feeder - jaw crusher (the primary crushing) - belt conveyor - cone crusher (the secondary crushing) - belt conveyor - vibrating screens (different sizes of end materials). Different granularity can meet the requirements of different specifications of customers.
In the past two years, our crushing equipment has been running smoothly in this mining site. We also conduct regular return visits to the equipment there and help customers with any problem in time. We will also go to the customer's location at any time they need us to inspect and maintain the equipment on the spot, hoping to help our valued Filipino customers reduce losses and expand benefits.
The customer also gave a very high evaluation of our equipment and services. The manager once told the technical manager: "Before you find me, I have contacted several companies from all over the world, but very few of them puts me in the place to consider for me. Only you have tirelessly helped me customize the machine and production plan, and led the technicians to give us professional guidance in production debugging. I am very grateful to you that you helped me complete my project. Now the equipment is running well, and the sand and gravel produced are sold to the construction company. My success is inseparable from your help and guidance."
When it comes to choosing a smartwatch, do you really need to spend $370 on a device that almost does more than your phoneincluding reminding you to breath? No. The Pebble has always been about simplifying the smartwatch, and even with improved fitness features, the Pebble 2 remains exactly as much smartwatch as you really need.
While companies like Apple and Samsung try to cram as much functionality into a wearable device as technology allows, Pebble continues to take a simpler approach, focusing on the best uses for having a second screen strapped to your wrist. And while the Pebble 2+ Heart Rate isnt quite as simple as the original, its fitness tracking upgrades are a welcome addition that never bring the Pebble 2 down.
If you can remember all the way back to 2012, the original Pebble hit Kickstarter with a $150 price tag that reflected its basic functionality. It could show notifications, do basic fitness tracking, and shrug off water, but it also only had a simple black and white LCD display, and a reliance on physical buttons to navigate its UI, instead of a touchscreen.
So whats new? The most obvious upgrade to the new Pebble is the addition of a photoplethysmography, or PPG, sensor on the back. Its the same heart rate monitor method used by nearly every other wearable on the market. PPG uses a pair of LEDs to blast multiple light into the wearers skin, and a camera to detect how that light is then scattered. Depending on the flow of blood under the skin, the light scatters in different ways, allowing the Pebble 2 + Heart Rate to monitor the wearers heart rate.
The recent fitness-focused updates to the Pebble app, available for iOS and Android devices, now includes the ability to keep tabs on your heart rate throughout the day as the Pebble 2 + Heart Rate takes periodic measurements, depending on your level of activity, to conserve battery life. But you can also activate a Workout mode on the smartwatch, specifying various levels of physical activity, to force the heart rate monitor to take constant readings.
More and more dedicated fitness trackers with heart rate tracking capabilities have been gaining smartwatch-like features, but few work as well as the Pebble dowhich is a smartwatch first. If youre already a fan of Pebbles wearables, this improved fitness tracking functionality is a welcome upgrade since it means you dont have to wear a second device, or abandon the smartwatch youve come to love.
Now do you really need a heart rate monitor strapped to your wrist 24/7? No. Believe it or not, humans managed to stay active and fit well before the words fitness and tracker were ever placed side-by-side. For some people, however, a constant update on how lazy theyre being can be a great motivator to get up off the couch. And given how cheap the hardware has become, it just makes sense for Pebble to jump on the heart rate bandwagon.
If the addition of the PPG sensor on the back of the Pebble 2 had resulted in a big uncomfortable bulge sticking out, or the wearable doubling in size, it would have certainly been a misstep for the product. But the new features are unobtrusive when you dont need them, and surprisingly robust given the limitations of the Pebble hardware. The Pebble app gives you a thorough breakdown of your day to day fitness statssteps, calories burned, distance, active minutesand compares it to your average performance on a given day.
While not as robust as the stat tracking youll find for dedicated fitness trackers, the Pebble 2 provides more than enough information for those of us who know we should be more active, and want to be reminded of the fact. And if the Pebble mobile apps UI isnt working for, all the of data the Pebble 2 collects can be shunted over to Apples HealthKit.
The other big improvement with the Pebble 2 is its design, which is now much sleeker than the original, but still very much reminiscent of the Pebble Classic if, for some reason, you have a soft spot for the originals bulky square look. I have to admit, the original Pebbles design was a complete dealbreaker for me.
Yet the Pebble 2 is much thinner, making it feel less garish on the wrist, even with the new optical heart rate sensor protruding out the back. And the bezel surrounding its display doesnt look as thick as it did on the original Pebble, even if its the exact same size and only appears thinner because of how the LCD panel is now being framed. The changes are minor, but I dont mind the look of the Pebble 2 on my wrist, despite not being a fan of the original.
The Pebble 2 has also gained a microphone, like the one youll already find on the Pebble Time, for sending text and voice replies right from your wrist. However, this functionality can still only be used when the smartwatch is paired with an Android phone, or with a select number of carriers when paired to the iPhone. It is far from being a key selling point for the wearable.
The Pebble 2 excels most in the places the Pebble Classic excelled before it. Pebbles worked out a formula for a topnotch smartwatch and isnt about to deviate. The Pebble 2 + Heart Rate has the same black and white LCD display as the original, without touch functionality, and the same user interface as all the Pebble smartwatches preceding it. Youll still be relying on a set of four physical buttons to hop around menus, scroll through your notifications, and check your daily schedule. If youre trying to impress your friends with the latest and greatest smartwatch on your wrist, the Pebble 2 simply isnt for you.
Navigating a mobile device with a screen without being able to touch it does take some getting used to, but eventually I found myself not missing the touchscreen. Particularly since it means the Pebble 2 can survive for upwards of seven days without a charge. Do you really need to be able to send doodles from your wrist to your friends? I dont.
Having worn the Pebble Time with its color display for the past year, I did find the black and white display on the Pebble 2 limiting. Notifications on the Pebble Time are color-coded, making it easy to distinguish between an important email, an urgent text message, and an ignorable Twitter update at a quick glance. But its not quite as easy with the Pebble 2's monochrome display, and its something I would consider to be a major drawback to Pebbles basic offering.
In the past we have complained about the weak magnets used to secure the charger to the Pebble wearables, and unfortunately it doesnt appear as if thats changed with the Pebble 2. So if you accidentally bump the watch while its charging on your nightstand in the middle of the night, theres a chance the cable will pop off, but that still beats trying to plug in a tiny microUSB cable.
Unlike the Apple Watch, which in the coming years will most likely replace the iPhone altogether, the Pebbles raison dtre has always been as a cheap sidekick to your mobile device, with great battery life, that puts notifications and other important information on your wrist where its always easily accessible at a glance. Its greatest feature has always been its simplicity.
So had the Pebble 2 + Heart Rate arrived with an inflated price tag as a result of its fitness tracking upgrades, it would have been hard to recommend it when the original Apple Watch is now $269. But at $130, which is actually $20 cheaper than the original Pebble Watch first sold for, the Pebble 2 is a fantastic bargain if youre just dabbling in smartwatches, or want a well-equipped fitness tracker with additional functionality.
Ive had the Pebble Time Steel since it came out (Kickstarter backer) and Ive loved it. Im a gadget freak so I always early adopt, but almost always have some sort of regret and that simply hasnt been the case here. Its been great from day 1.Its strong AF! I have worn this all day every day. Through sleep, showers, baths, bathing my kids, cutting down trees, filming out in the field, house construction, whatever. I never take it off except to charge once every 8-10 days. And its gotten some serious abuse. I mean *serious* freakin abuse and it still looks almost brand new. Not a single scratch on the screen and only one small nick in the bezel. And they keep updating it constantly and making it better. The fitness tracking is moving to the forefront of usage and is getting seriously good. The music control is great and just automatic which is perfect for runs, etc. Voice dictation is surprisingly good and even having the quick canned responses is perfect for times when you need to be more subtle or quick. Battery life is legitimately 10 days for the Time Steel. I use my watch all day every day and STILL get 10 days out of it. My only complaint is that I *do* wish there were multiple designs for different aesthetics. I know theres the Time Round, but that was a bust as the battery life is much shorter and only splash proof. The screen is totally serviceable but I wish the backlighting was better. However that would clearly sacrifice battery life and Id much rather have that with a totally usable display than a shorter life with a better display.
Cobblestoneis widely used in architecture, decoration, garden, sewage treatment and other fields. However, raw cobblestone material can not meet the requirements of industrial production in most cases. The cobblestone crusher can solve the problem and turn raw pebble materials into small particles. Therefore, the crusheralso has very wide application. Next, Aimix will introduce some detailed informations about the crusher from the following aspects.
Cobblestone crushers refer to a series of machines which are used to crush pebbles and other stone materials. Cobble crusher has large crushing ratio, uniform particle size, reasonable structure, reliable work, easy maintenance, economical operation cost and other characteristics. It is widely used in mining, smelting, building material, highway, railway, water conservancy, chemical industry and many other industrial fields.
Like stone cone crusher machine, the pebble crusher is not a specific machine, either. On the contrary, cobble crusher botw consists of jaw crusher, sand making machine, vibrating feeder, vibrating screen, sand washing machine, etc. Different kinds of crushing machines work in different crushing stages.
The pebble crushing process line has high automation degree, low operation cost, large crushing ratio, less pollution and other features. And the finished product has uniform size, good grain shape and high quality. Therefore, the finished product conforms to the national construction sand standard.
The cobblestone crusher machine mainly used in this stage is jaw crusher. A track mounted jaw crusher machine can crush cobblestone coarsely. Because this kind of pebble stone crusher has large production capacity and big crushing ratio, this machine is quite suitable for the stage.
At this stage, the small pebble crusher you can use is a impact crusher or a cone crusher. The two kinds of equipments are all finely crushers, and users can choose flexibly according to their needs. The pebble stones are crushed into smaller particles in this stage.
This stage is an important part. It is necessary to use sand making machine to shape the pebbles. So that the particle size can satisfy the requirements of machine-made sand, and the grain shape is fine. And then the pebbles are screened by the vibratory screen separator. Particles which do not meet the requirements will be crushed again. PSG900-cone-crusherType: PSG900 Model: 0910 Diemeter of large end of crushing cone(mm): 914 Adjusting range of discharging opening(mm): 9-22 Feed opening size of the open edges when recommending the min discharge opening (mm): 102 Max feed size(mm): 85 Processing capacity(t/h): 45-91 Main motor power(kw): 75 Weight(kg): 9980
The pebble crusher designed and manufactured by Aimix Group adopts advanced technology and has many performance advantages, such as: large crushing ratio, high crushing efficiency, long service life, stable working condition, etc. Besides, pebble mill crusher has simple operation methods. As for crushers operation, Aimixs experts summarize the following points.
At this stage, you should ensure that all fasteners of the cobblestone crushing plant must be firm and tight. The flywheel and groove wheel should run smoothly. Besides, the adjusting device of the material outlet should be able to ensure the adjusting range of the discharge port.
You should check the condition of the protective device. If there is an unsafe problem, you should solve it immediately. In addition, checking the crushing chamber is very important. If there is ore or debris in the crushing chamber, you must clean up the materials to make sure the crusher cavity starts.
Aimix, a professional crusher manufacturer and exporter, has exported all kinds of crushers and screeners to more than 60 countries! We have best quality and lowest price! You can contact us to know more details about the automatic cobblestone crusher and other related crushers. We will provide you the best equipments!
Utilizing just a single USB-C connection for both audio and power, enjoy amplified USB audio from Creative Pebble V3 with doubled audio intensity as well as improved acoustics performance! The 2.0 speakers also offer a wireless connectivity option so you can enjoy wireless streaming from mobile devices with the latest Bluetooth 5.0.
Plus, Creative Pebble V3 features Clear Dialog audio processing technique, to achieve clearer spoken dialogs in movies and shows. Retaining the same minimalistic design for any desktop, it is an ideal addition to any home, office, or even gaming setup!
Improved from its predecessors in the same series, enjoy enhanced USB audio performance at higher power output without distortion! Now powered entirely via USB-C for both audio and power, our newest Creative Pebble V3 also features larger 2.25" full-range drivers that are capable of delivering 50% louder* audio and rich acoustics performance, at double the sound intensity.
*While plugged into a 10W USB-C Port / USB-C Power Adapter / 5V 2A USB-A Power Adapter, Creative Pebble V3 SPL (Sound Pressure Level) is 50% louder than Creative Pebble, the doubling of sound intensity also increases loudness by 3 decibels which results in higher volume.
Enhance your binge-watching experience even at high volume levels without distortion! In newer devices with 10W USB-C or USB-A port, the built-in gain switch located at the bottom of the Pebble V3's right speaker automatically activates high gain mode for amplified audio, with capabilities to fire acoustics power of 8W RMS and peak power of up to 16W.
When dialog gets drowned out by the ambient sound effects, you lose focus on the flow and story of the show. Creative Pebble V3 is engineered with Clear Dialog audio processing that picks up vocals to give you rich and clear dialogs, so you can hear every word without having to turn up the volume, and without sacrificing any ambient effect.
Stream your favourite beats from your phone* with the latest Bluetooth 5.0, and enjoy music at your desk or while lounging on your sofa across the room! Simply press and hold the Bluetooth button beside the volume control knob to initiate pairing, and select Creative Pebble V3 from your device to pair. After pairing, head over to your music app of choice, and you can start playing music from your device wirelessly!
And where versatility meets flexibility, the Creative Pebble V3 can be powered via USB-C or with a power adapter, and set up over various connectivity options! It also has a 3.5 mm AUX-in jack that allows for universal compatibility across other analogue audio devices.
Creative Pebble V3 is a plug-and-play device and do not require driver installation. For PC users, Creative Pebble V3 will be automatically detected when you plug in the USB cable. If you have multiple audio devices connected to your PC, you can also manually select Creative Pebble V3 as the default output speaker in the Sound' setting. For Mac users, there is one more step to take:
Creative Pebble V3 retains the same 45 elevated drivers that are specifically angled, so audio is directed to your ears, placing you in the audio sweet spot for an immersive personal listening experience.
Creative Pebble V3 can be connected to your laptop or desktop with a single USB-C cable for both power and audio, which mean less clutter, and more desktop space to work with! It also features a small footprint with a clean and minimalistic design that blends naturally into any minimalist's desk.
The Creative Pebble V3 not only sound great for the money, but they also look good on your desk and dont take up much room. Add Bluetooth connectivity into the mix and its easy to see why we selected this set as our runner up in the category.
The Creative Pebble V3 are a huge upgrade for your desktop audio, and theyll work with your mobile phone, PC, laptop and more. Not only that, but they look stunning too, which is something other speakers in this price range often fail at.
After connecting the Pebble V3 to a power source with a minimum delivery of 10W, we have turned on high gain from the right speaker and started listening to various audio content. The clear highs are the ones you will notice first, and this means very clear voice delivery, ideal when having long conferences while working at home as well! The included sound card really pays off (Clear Dialog), and thanks to the larger drivers versus V2, the bass response is now better but do not expect it to have low frequencies as when you would use a separate subwoofer.
Fast delivery with nice packing and cover up with bubblewrap and box! This badass was amazing! Loud and with some bass ,its not strong on bass but is pretty enough for private use only .Design are small and strong, if there is another option for colors will be much better!
I was looking for a compact, space-saving bluetooth speaker that would fit comfortably under my computer monitor and have good sound quality. At first I doubted if I could find it, but I can safely say: this product is incredible! Quite loud already at medium volume, adequate bass and high sound range (in terms of price). Im pretty critical, but for me, this speaker is 5 stars!!! + I ordered to Hungary on the evening of December 21, 2020, and I received it on the morning of the 23rd. Super fast delivery! Nice work Creative Labs Europe!
WARNING: This product can expose you to chemicals including Lead, which are known to the State of California to cause cancer and birth defects or other reproductive harm.
To meet the requirements of Proposition 65, it is our responsibility to notify consumers in the State of California that they can be exposed to chemicals that are known to cause cancer and/or reproductive toxicity. It does not mean that the product is in violation of any product-safety standards or requirements.
Gain Switch SettingThe default setting of Pebble V3's Gain Switch (located at the bottom of the right speaker) is set to H' for optimal audio performance. Sometimes, your connected device may not be able to power that. Try switching the Gain Switch from H' to A'. It should resolve the cracking noise issue.
Underpowered DevicesFor users with an older device, your device might not be capable of powering Creative Pebble V3 at its optimal level. Try connecting to a higher current via a USB Power Adapter of up to 5V 2A output, or a USB-C 10W Power Adapter. The higher current supply from these adapters should be able to resolve the issue.
If Creative Pebble V3's volume remains low when both device and speakers are at maximum volume while connected to a laptop's USB port, this may be caused by Creative Pebble V3 being underpowered, and is commonly found in older laptop versions. To overcome this issue, try connecting the speakers to a wall adapter and connect your laptop via AUX-in cable instead to achieve optimum volume level.Get in Touch with Mechanic