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With the rising gold prices in recent years, it further stimulated the rapid development of gold industry. As the exhaustion of high-grade gold ore, researching on middle-low grade and refractory gold ore and strengthen the traditional gold mining process undoubtedly have become the main trend in global gold beneficiation industry.

Under the new situation, Copper Mountain Corp Mining  has paid long-term attention to gold recovery process, technology and equipment research & development. After 20 years of continuous studies, according to the different types of gold ore characteristics and user requirements, Copper  Mountain Corp Mining  is suggesting to review the Gravity Concentration methods, and  systems for our gold mining project in Namibia  .

General Mobile Gold Wash Plant Flowsheet

We also provide the design and installation of many landscape construction projects including walkways, steps, retaining walls, patios, veneer stone, planting, trans-planting, drainage systems, lawn renovation and installation, paver driveways, cobblestone edging, and excavation.

The initial mining methods we intend to apply towards our mining projects are .

Gravity Concentration Methods

1.Panning. Panning using water to separate heavy gold particles from other lighter particles within a medium sized pan. …

2.Sluicing. Sluices using water to wash ore or alluvium down a series of angled platforms. …

3.Shaking Tables. …

4.Spiral Concentrators. …

5.Vortex Concentrators. …

6.Centrifuges. …

7.Magnets. …


NO Chemical Gravity Gold Recovery Equipment Option 1

NO Chemical Gravity Gold Recovery Equipment

This complete gravity gold process plant is to extract silver and/or gold metals from precious metal rich ore deposits. Provided here are all major equipment for a plant arranged to recover gold without any chemicals (no mercury, no cyanide). The initial “in grinding” gravity circuit will extract any coarse gold while the second stage of gravity concentration with extract the finer and final GRG gold and silver.

This simple process plant includes single stage crushing, conveying, primary grinding, spiral classification, gravity concentration, slurry pumping and bullion pour in small refinery.

With this simple flowsheet, you will recover silver and/or gold into a bullion bar.

Our standard packages are for process plants of:

  • 25 Tonnes/Day = 1 Tonne/Hour
  • 50 Tonnes/Day = 2 Tonne/Hour
  • 100 Tonnes/Day = 4 Tonne/Hour
  • 250 Tonnes/Day = 10 Tonne/Hour

This is a standard process plant which includes only the major components of the complete metallurgical flowsheet. A detailed engineering study is required to identify unforeseen omissions that may be required to design the optimum plant.

Additionally, we offer two separate packages for plant tailings thickening/filtration and water treatment. Contact us for details.

Our gold mining plant offers all the major components of this complete process plant designed using these key design parameters:

Coarse/fine ore bin

Vibrating Grizzly feeder

Jaw crusher

Conveyor belts

Ball Mill

Spiral classifier

Sump pumps

Trash screen

Centrifugal concentrators

Shaking table

Smelting Furnace

Reagent used: NIL

•Au grade = 15 g/t

•Ag grade = 8 g/t

•ROM = 4″

•Jaw crusher F80 = 75 mm

•Jaw crusher P80 = 12 mm

•Steel balls = 2.5″

•Steel balls charge = 1900 kg

•Ball Mill F80 = 12 mm

•Ball Mill P80 = 90 µm

•Spiral classifier overflow = 30%

•Gold production = 225 g/day

•Silver production = 90 g/day

Process development testwork and detailed engineering are essential services 911Metallurgy Corp. offers separately. The equipment package described herein does not include any permitting, infrastructure, foundation, electrical, assembly, reagents/supplies or commissioning. These are all additional paid-for services we do offer if you need them.

NO Chemical Gravity Recovery Equipment Option 1 Flow Sheet

NO Chemical Gravity Gold Recovery Equipment Option 1 Test Specifications

1.The test should be statistically reliable. This calls for a minimum mass to be treated which varies from ore to ore (depending on gold content and particle size), but has been found to be around 40 to 70 kg for most.

2.The test should rely on technologically up-to-date separation equipment. Centrifuge units have been shown to outperform devices that rely on the earth’s natural gravity field. Since these units (especially the iCON for gold) are now commonly used at plant scale, they should also be used at lab scale to characterise recoverability.

3.The test should indicate not only how much gravity recoverable gold (GRG)’ the ore contains, but its size distribution and the grind at which it is liberated. This should preferably be available with a single test, to minimize the mass of sample required (as sample mass is often in short supply, especially for greenfield applications).

4.The test should be free of the usual pitfalls of gravity testing, such as gold traps, using samples from circulating loads non representative of steady-state operation, or producing a concentrate that cannot be upgraded to smelting grade (i.e. recovering gold that is not GRG).

5.The test has to be inexpensive, as gravity will not be the main recovery method, and its use justified only on the basis of economy of effort, inclusive of the planning stage.

The test is based on the treatment of a sample mass of typically 50 kg with a laboratory gravity concentrator. Three stages are used, the first on the sample crushed and rod milled to 100% -850 µm, and the next two on part of the tails of the previous stage, ground to achieve further gold liberation. Stage two is performed on typically 24 kg ground at 45-55% -75 µm, and stage three on 18 to 21 kg ground at 75-80% -75 µm.

The GRG tests are performed at increasingly lower feed rates and fluidization water pressures to match the finer feed, typically from 1000 g/min and 25 kPa for stage 1 to 400 g/min and 12 kPa for stage 3. These correspond to optimal settings as determined by extensive test work with both gold ores and synthetic feeds, but must be adjusted for gangue density. Because the test is optimized, it yields the maximum amount of GRG; actual plant recoveries will be lower, because of limitations in equipment efficiency and of the usual approach of processing only a fraction of the circulating load. Linking projected plant recovery to the results of the GRG test will be briefly discussed later.

For each stage, all of the concentrate and 600 g of tails are screened from 25 to 600 µm (the tail sample is wet screened first). The tail fractions above 105 µm are further pulverized prior to assaying. All of the concentrate screen fractions and up to one assay ton of tails are fire-assayed.

The test was used on more than 30 ore types, ranging from completely oxidized to complex sulphides. Some ores were tested twice with the regular procedure to assess natural variability. Additional work included performing either a single or all three gravity stages at final grind, to check the validity of the basic approach and explore possible simplifications. These additional tests are discussed at length in; they show that the progressive grinding (as opposed to testing only at final grind) is necessary to obtain the correct size distribution of GRG, as well as a measure of progressive liberation. Testing only at final grind normally underestimates the GRG content, because of over-grinding. Testing feed masses below 10 kg can result in a slight overestimate of GRG content for ores with a low sulphide content.

The size distribution of the GRG is very useful in determining how gold should be recovered. This includes both the choice of recovery unit and feed preparation (usually screening). For example, it is pointless to present to the recovery unit a coarser fraction that is barren and lowers both its capacity and efficiency. Prior screening would then be appropriate, at a size that should hinge on the coarsest GRG. If GRG is fine enough and the main process route is flotation, it may be more effective to use flash flotation, which can significantly decrease the circulating of GRG below 75 µm, and can even be followed by gravity recovery.

Even when the response of the test is intermediate to highly amenable, results should be used cautiously. It should be understood that since the laboratory iCON recovers gold very efficiently, actual plant performance will always be inferior to the measured GRG. By how much depends on the efficiency of the gravity circuit. Circuits that are extremely efficient can probably achieve a recovery equal to two thirds of the measured GRG, but this has never been observed in plant practice. The economic incentives of gravity recovery do not normally warrant achieving the full gravity potential. Two factors can limit recovery. First, gravity is used only in the first of two loops in the grinding circuit, which implies that unliberated GRG in the primary cyclone overflow will never be recovered by gravity. Second, the recovery effort in the primary loop is limited to treating 25% of the circulating load, which is certainly reasonable.

NO Chemical Gravity Gold Recovery Equipment Option 2

Gravity Concentration Methods

NO Chemical Gravity Gold Recovery Equipment Option 3

Crushing & Screening Plant

Capacity : 500 Metric Tons Per Hour


Sluices use water to wash ore or alluvium down a series of angled platforms. As water washes sediment down a sluice, gold particles sink and are captured by material covering the bottom of the sluice, often carpets. Sluices are usually inclined at 5 to 15 degree angle. As moving water travels down a sluice, it generates greater force and keeps gold particles from sinking easily. For this reason most gold is captured at the beginning of the sluice. Carpets or other capturing devices on the bottom of sluices can be removed and washed in a bucket to remove the captured dense material.

Sluice design can lead to higher gold recovery if the force of the water traveling through the sluice is decreased. A series of rifles can help break the flow to improve recovery. A zig zag sluice also achieves this by creating a drop between the first and second platform that disrupts the velocity of the water as it travels down the sluice.

 A simpler alternative to the zig zag sluice is a combination of two sluice surfaces. The first is tilted at a steeper angle then the second, decreasing the velocity of the water as it hits the second sluice, increasing gold recovery.

Sluices can be relatively expensive or affordable depending on the complexity of their design. Simple sluices can be a single angled platform a few feet in length and others can be very elaborate.

Having an available and consistent water supply is necessary to have a functioning sluice operation. This can be done with piping, drums, buckets, or natural flowing water bodies. A constant flow will be better than a bucket-driven flow.

Sluices are good at concentrating large amounts of ore and sediment in a relatively short time but often do not yield concentrates with high amounts of gold. The resulting concentrate must usually undergo further methods of concentration, such as panning.

Using Concentration Methods

Concentration means increasing the amount of gold in ore or sediment, by selectively removing lighter particles. If employed effectively, concentration methods can eliminate or greatly reduce the need for mercury.

Before concentration can begin, ore must be crushed or milled to liberate gold particles from rock and to decrease grain size.

Concentration works best when grain size of the milled material or sediment is relatively consistent, so that most particles are of similar size. An appropriate grain size can be achieved using screens or sieves.

Once the gold-containing material has the appropriate grain size, one (or several) of the methods described below can be employed to concentrate gold bearing material.

Most concentration methods rely on the high density of gold relative to other minerals in ore or alluvium mixture. These are referred to as gravity methods, and this is the methods we intend to use for mining in Namibia .

Magnetic or chemical properties can also be exploited to enhance concentration.

Each mining operation is unique.  Concentration methods must be selected after considering factors such as the type of ore or sediment, other minerals present, gold particle size, and the availability of water and electricity.

Copper Mountain Corp has been involved with gravity concentration for the last years, having designed two distinct ranges of equipment; a semi-continuous Copper Mountain Corp range for installation into grinding circuits and the recently released  range for pre-concentration and scavenging in a wide range of mineral industries.

Understanding the Gold Centrifuge by Comparing it with a Sluice Box

Our biggest suggested units for this projects are the SB21 and SB38 semi-continuous , the SB38 being of 38 inches in bowl diameter with a concentrating surface area of 16720cm². The reason why I have included the surface area (in section 4 of this booklet there is a complete list of the  SB specifications with each individual units concentrating surface area) is that centrifugal gravity concentrators are similar to concentrating tables in that they can only treat a certain tonnage per given surface area. For this reason Falcon specifically designed deep bowls to ensure that a bigger tonnage could be treated using the same given bowl diameter.

A centrifugal device, acts as a pump forcing the material up the sidewalls. The faster that the bowl is spun, the higher the G-forces and hence the greater the tonnage that can be treated by the unit. Falcon operates its equipment at G-forces of 200Gs. Copper Mountain Corpengineer Abdon Narvaez, and his son Abdon M. Alejandro has also designed their bowls to be extremely plant friendly in the sense that the bowl is not fabricated from any exotic materials, in other words most of the maintenance can be carried out onsite without having to import exotic materials from Namibia . Below is an exploded schematic of the bowl on which I would like to focus your attention.

Spiral Concentrators

Spiral concentrators are specialized pans tilted on an angle with spiraled grooves. The spiral grooves in the pan lead toward the center where a hole is connected to a container to catch material.

A motor is used to rotate the pan continually as concentrate is fed onto the pan by an operator.  A pipe extending horizontally across the pan sprays water along the surface of the pan as the concentrator spins. The water washes lighter particles down the spiral concentrator into a bucket while denser particles, including gold, are carried by the spiral grooves toward the hole in the center of the concentrator.

After this process is repeated multiple times, the operator is left with a high grade concentrate, and often liberated gold. Spiral concentrators are relatively easy to operate but do represent a larger capital investment than panning or sluices.

With Falcon Anything Is Possible.

Falcon has spent a major amount of time adhering to our motto, “designing simple and cost effective equipment that can be easily maintained onsite”. The riffles are manufactured from 304 stainless steel and are independent of the bowl. This means that the riffles can be replaced at a fraction of the cost without having to purchase an entire new bowl. The bowl has also been designed to be a long wear life item in that it has a sacrificial rotor baffle that can easily be replaced, and increased rubber thickness in the areas where there is a change in direction of the pulp i.e. adjacent to the impeller. Falcon rarely replaces bowls and prides itself in this unique design which is definitely a cost advantage to you the client.

Falcon prides itself in the recovery of very fine gold particles (below 10 microns), this can only be achieved with the use of low water pressures to fluidize the concentrate riffles (50 – 80 kPa) and with high outward G-forces (200Gs). Other equipment encountered in the industry make use of high water pressures and lower G-forces resulting in the ejection of fine gold from the collected concentrate.

Vortex Concentrators

Vortex concentrators use a rotating flow of water to separate lighter materials from a concentrate and remove them via a raised drain hole.

A vortex concentrator is a circular tub with water input on the side of the tub and a raised drain in the center. The tub is filled with water until it reaches the level of the drain hole. Then concentrate is added in a thin layer around the bottom of the bowl. Water is then pumped into the side input, creating a rotating vortex of water that drains in the center. The vortex pulls lighter material up from the bottom of the bowl and out the drain hole.  Dense materials such as gold remain in the bottom of the tub. After the miner sees only gold left on the bottom of the bowl the water source is turned off and the gold is ready to be removed.

Miners must pay attention to the amount of water flow going into the tub. If it is too great the velocity of the water will carry gold particles out of bowl and this will lead to losses of gold. When vortexes are operated correctly, the result is a fine gold concentrate that is usually very high grade. Vortexes are easy to operate and are good at capturing fine gold that is hard to extract through other methods.

Shaking Tables

Shaking tables are elevated tables tilted to one side with raised ridges running horizontally down their length. Mineral feed (crushed ore or sediment) and water are released at one end of the table. The water washes the feed down the table. As the material is washed down the table, specialized grooves trap gold and direct it to collection points on the side of the table as lighter minerals are washed away. During this process, the table is continually shaken by a motor to agitate the material and aid in the separation of gold particles.

Shaking tables are very effective and can concentrate sizeable amounts of ore at a time, providing high grade concentrates and liberated gold, but they are also relatively expensive and require some experience to operate.



A centrifuge is a vessel that rotates about a central point. It is used to separate materials in a mixture by density. To separate gold particles from a concentrate, concentrate is fed into the centrifuge through a pipe at the top of the machine in a slurry of around 60-75% water and 40-35% solids. The material collects in a vessel in the center of the machine where high speed rotation creates force that moves the material up the sides of the vessel’s walls. As the material is pushed up the sides of the bowl’s wall, denser material like gold is caught in ridges while lighter material is ejected from the vessel.

Centrifuges operate in cycles that can be preprogrammed or determined manually depending on the equipment and the material processed. After a cycle is completed, the miner can then extract gold from the ridges of the centrifuge vessel. For small scale centrifuges, cycles usually last around 0.5-2 hours.

Operating a centrifuge takes skill as it must be tuned to the material it is processing. This is accomplished by adjusting feed grain size, rate of feed, rotation velocity, and cycle duration. Centrifuges can be more effective at concentrating gold than other methods of gravity concentration but are generally more expensive.

Other Concentration Methods


Magnets can be used to remove magnetic minerals such as magnetite from concentrate. They can be used after or in conjunction with other method of concentration. One technique for extracting magnetic minerals is to place hand held magnets on the bottom of a pan containing dried concentrate to separate metallic from non metallic material. Care must be taken to avoid losing gold particles during the separation. It can be helpful to cover the magnet with a piece of paper.  After magnetic minerals are attracted to the surface of the paper, it is removed to easily discard the metallic material.


Flotation is usually used by large scale miners but can also be applied in small scale operations. It is a process that works best for processing complex ore types, especially ores that are difficult to process using gravity methods. In flotation, a mixture of slurry (crushed ore and water) and frothing agents are added into a flotation machine. A tube releases air into the tank of the machine and an agitator creates air bubbles at the bottom of the tank.

Minerals that are hydrophilic, such as gold, attach to the bubbles’ surface and are brought up to the top of the tank. Other minerals fall to the bottom of the tank and are discarded as tailings. Bubbles containing gold and other hydrophilic minerals accumulate at the top of the water level as froth. This froth is then scraped off to create a concentrate of gold and other hydrophilic minerals.  Flotation creates high quality concentrates and is good at capturing fine gold. Flotation usually requires a substantial amount of capital investment.

There are a variety of possible frothing agents. Depending on the chemical, specific precautions must be taken when employing the method to protect human health, and waste materials must be disposed of appropriately.

Gold Heap Leaching Process

Process Introduction

Heap leaching (HL) is a flexible and economic mineral processing method, commonly used to extract gold from low-grade gold ores. In this process, ore is firstly crushed to fine particles. By spraying leaching solution to the large piles, the gold-containing solution is leached. Then used the method of carbon adsorption, zinc powder displacement device and so on to separate gold from the liquid.


Heap leaching method is always used for low-grade ore, small gold mine, or both. These ore can not to process by using the conventional method.

Chemical Leaching

Chemical leaching makes use of the chemical properties of gold to leach it from ore, concentrate, or tailings. This process is mostly used in large scale mining operations but has been increasingly adopted in small scale mining because of its high gold recovery rate and low cost. The best practices for chemical leaching are a combination of pre-concentration and mill leaching, as they lead to the least amount of waste, a short processing time for miners, and high gold recoveries. First, concentration is done through gravity techniques. Then the concentrate is simultaneously milled and leached. When chemical leaching is employed, it is important for miners to handle the chemicals properly and ensure that they are properly used and stored to avoid health and environmental concerns.

Cyanide is often the preferred chemical used in leaching. Cyanide is highly toxic and great care must be taken when using it. However, in contrast to mercury, cyanide is does not persist in the environment. Cyanide leaching must not be used on tailings where mercury is present, as soluble mercury-cynanide complexes will form, mobilizing mercury to great distances.

60 Years of Experience

Copper Mountain Corp is a mining company founded by the Varela family in 1954 in Brazil.

Licensed & Insured

We take pride in the legal exporting, and extraction of all resources that we deal with. A safe route to your goals is our mission.

Honest & Dependable

We strive to provide transparency, and reliability with all of our projects. Being honest and on time is our top principle.

In many countries, elemental mercury is used in artisanal and small-scale gold mining. Mercury is mixed with gold-containing materials, forming a mercury-gold amalgam which is then heated, vaporizing the mercury to obtain the gold.

This process can be very dangerous and lead to significant mercury exposure and health risks. In some jurisdictions, mercury use may be illegal or restricted in certain ways. The Minamata Convention on Mercury, a global agreement for reducing mercury pollution, recognizes the risks of using mercury in artisanal and small-scale gold mining, and calls upon nations to reduce, and where feasible eliminate mercury use in this sector. We intend to mine 100% without the use of mercury .

Although many miners use mercury in artisanal and small-scale gold mining, we believe it is possible to safely and economically recover gold without it. Mercury-free techniques are safer for miners, their families and local Namibian communities.  They may also help miners’ market their gold at higher prices.

Our small-scale mine will achieve  high rates of gold recovery without mercury, benefiting our health, the health of our Namibian communities, and the environment.  On this page, we summarize some of the techniques we  intend to apply to towards our mining project with  mercury-free  techniques.

Expanding Our Community


We are Environment Friendly


Creating Viable Logistics Routes


Saving Power and Energy


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    Amazing Support and Attentiveness.

    Copper Mountain Corporation has been very professional since the day we started to work with them. Always on time with document handling, and reliable with all logistics. I definitely recommend CMC if you're looking for a good honest company.

    David Mearlstrep

    - Senior Engineer, BHP