Gold Processing at Boddington Mine

Gold processing plant at Boddington mine

The Boddington Gold Mine is a gold and copper mine the largest gold mine in the country, located about 130km south-east of Perth in Western Australia and 17 km northwest of Boddington

The Boddington deposits were previously mined between 1987-2001 for the production of 6.1 Moz of gold. The current mining operation is of significantly larger scale, producing 696 000 ounces of gold in 2014, along with 69 million pounds of copper.

Built on the footprint of the original Boddington gold mine, the operation involves open cut mining from two large pits. The process flow sheet at Newmont Boddington Gold (NBG) comprises primary crushing, closed circuit secondary and tertiary crushing using High Pressure Grinding Rolls (HPGR), ball milling and hydro-cyclone classification to generate a milled product with a P80 of 150 µm. The ground ore is then floated to produce a gold rich copper concentrate for filtration and sale to overseas smelters. Flotation tailings are then leached for further gold recovery. The ore processing rate is approximately 35 million tonnes per annum. Typical head grade is approximately 0.8 gram per tonne gold and 0.11 per cent copper.

How Process Smelting Gold

Smelting gold, silver, platinum and other metals at home is a popular trend these days, whereas it used to be of interest only to jewelry designers and artists.

Gold is purified by means of a smelting process, which utilizes pressure, high heat and chemicals to accomplish the task. Like any metal that appears naturally in the earth, there are impurities that must be removed. Removing minerals and other impurities allows gold to be used in its purest form

Have you recently scored some gold dust or small nuggets on a recent creek panning adventure?

Whether you are smelting natural gold you've recovered from prospecting, or the broken jewelry or beat up coins you no longer want, smelted gold is most easily sold or re-fashioned after first removing impurities and casting it into ingots.

Interested in The processes of smelting or roasting your ore to recover its gold and silver? Some fairly rich ores require a lot of work to get all the gold and silver out them.

Process Of Gold Mining And Gold Mining Production In Cortez Mine Nevada

The Cortez gold mine is located 100 kilometers southwest of Elko, Nevada in Lander County. The Cortez Pipeline property is 11 kilometers northwest and the Cortez Pediment property (which includes the Cortez Hills deposit) is four kilometers southeast of the original Cortez milling complex. The Pipeline and South Pipeline deposits are mined by conventional open-pit methods. The Cortez property covers approximately 2,800 square kilometers on one of the world’s most highly prospective mineral trends.

Process of gold mining in Cortez  Nevada United States of America

Conventional open-pit mining methods are used for the Pipeline and South Pipeline deposits, scheduled in nine stages. From 2001 to 2005, production averaged 70Mt/y. Mining is carried out with electric shovels, a hydraulic shovel and haul trucks. A fleet of miscellaneous equipment includes rotary/hammer blasthole drills, wheel loaders, bulldozers, graders and water trucks.

A pit dewatering system including 40 wells helps to prevent water inflows, the water being transported from the pit to a series of shallow infiltration ponds for recycling.

The original Cortez concentrator was placed on care-and-maintenance in late 1999, following the change from milling ore to heap-leaching ore from the Pipeline pit. Consisting of crushing, dry grinding, circulating fluid bed roasting, wet grinding and carbon-in-leach gold recovery facilities, it may be re-opened to treat suitable ore towards the end of the mine’s life.

The Pipeline concentrator has a throughput of 8,650t/d, having been designed to handle various types of oxide ore from the Pipeline and South Pipeline orebodies. Its flowsheet consists of primary crushing, autogenous/ball mill (AG) grinding, carbon-in-leach and carbon-in-column gold recovery systems, together with carbon stripping, reactivation and gold refining facilities. Low-grade, run-of-mine oxide ore is heap-leached, with gold-bearing carbon from this section being returned to the main concentrator for gold recovery.

Run-of-mine oxide ore is crushed and stockpiled before grinding in an autogenous mill and a ball mill. Discharge from the AG mill is screened, with screen oversize being conveyed to a cone crusher and recycled to the AG mill. Screen undersize and ball mill discharge are sized in hydrocyclones, the overflow being thickened to provide feed for the carbon-in-column (CIC) and carbon-in-leach (CIL) circuits.

The CIL circuit consists of eight CIL tanks, 16 screens and eight carbon-forwarding pumps. Retention time at the 9300t/d throughput rate is 44 hours, increasing to 54 hours when milling South Pipeline ore at 7500t/d. The CIC circuit consists of six carbon columns with a retention time of 18 minutes. After stripping the carbon using a pressurised Zadra process, the gold is recovered by electrowinning on to stainless steel wool cathodes. The filter cake is dried, melted in an induction furnace and poured into doré bars assaying approximately 90–94% gold and 3–6% silver for shipping to commercial refineries.

Gold mining production process Cortez  Nevada United States of America

The mine produced 902,000 ounces of gold in 2014 at all-in sustaining costs of $706 per ounce1. In 2015, production is expected to be 825,000-900,000 ounces at all-in sustaining costs of $760-$835 per ounce.

Proven and probable mineral reserves as at December 31, 2014, were 9.85 million ounces of gold.

Production began at Cortez in 1969 with the Pipeline deposits, where mining is now centred, being discovered subsequently. "Proven and probable reserves in January 2005 totalled 234Mt grading 1.4g/t gold, equivalent to 7.8Moz of gold at 74% recovery."

The Pipeline deposit is situated along the Cortez/Battle Mountain trend in the north-central Nevada basin-and-range province. Submicroscopic gold particles are evenly distributed throughout carbonate host rocks. The two principal lithological units are a sheared and altered thinly-bedded calcareous siltstone and quaternary alluvium varying from chert, argillite, siltstone, limestone and quartzite to fine sands and silts.

Proven and probable reserves in January 2005 totalled 234Mt grading 1.4g/t gold, equivalent to 7.8Moz of gold at 74% recovery. In September 2005, the joint venture approved the development of the nearby Cortez Hills deposit, discovered in 2003, where proven and probable reserves of 64.7Mt at a grade of 1.8g/t gold contain a further 5.5Moz.

A prefeasibility study for underground mining at Cortez below currently permitted levels will be completed in late 2015. Mineralization in this zone is primarily oxide and higher grade compared to the current underground mine, which is sulfide in nature. The limits of the Lower Zone have not yet been defined, and drilling has indicated the potential for new targets at depth. The exploration drift has been extended to the south, enabling additional step-out drilling, which is anticipated to begin in June. Drill results to date include 36.6 meters at 31.5 grams per tonne and 27.4 meters at 20.9 grams per tonne, both oxide in nature, which compare favorably with the average grade of 13.8 grams per tonne in refractory ore above the 3,800 foot level.

How To Process Gold Ore In Yanacocha Gold Mine Peru

Yanacocha is South America's largest gold mine, located in the province and department of Cajamarca, approximately 800 kilometers northeast of Lima, Peru. Yanacocha’s operations are situated between 3,500 and 4,100 meters above sea level with development activities in four primary basins. The operation is a joint venture between Newmont (51.35%), Minas Buenaventura (43.65%) and the International Finance Corporation (5%)

The Yanacocha gold district is a 10x4km zone of altered rocks within a belt of tertiary volcanics that extends the whole length of Peru. Andesitic domes and dome complexes have been silicified and leached by epithermal gold-bearing solutions in at least nine distinct deposits. The mineralised sequences, which can also contain significant amounts of silver, are flanked by extensive argillitic alteration, and subsequent events have created siliceous breccia pipes with localised high gold grades.

How To Process Gold Ore In Yanacocha Gold Mine Peru
 

The process of gold from mining the first is drilling using Ingersoll-Rand DM45E and Atlas Copco machines and blasting are the responsibility of Minera Yanacocha. elimination of materials containing gold and silver began with drilling the ground to make a hole that will then condition with explosives..

The explosions carried out and the subsequent removal of ground begin to form large holes in the ground called pits. Stone materials have been destroyed and then transported by haul trucks ( which can load up to 250 tons of mineral rock) The ore is transported 2.5km or more to the leach pads using wheeled loaders and 85t-capacity trucks, and is heaped by stackers

Heap leaching is the process to extract precious metals like gold, silver, copper and uranium from their ore by placing them on a pad (a base) in a heap and sprinkling a leaching solvent, such as cyanide or acids, over the heap. This process dissolves the metals and they collect at the bottom of the pad.

Ground Preparation and pad construction: Here the soil on a slightly sloping ground is compacted and covered by an impermeable pad (can be made of plastic). Ore stacking: Then the crushed ore is stacked in the form of big heaps. Amount of fines is decreases as low as possible to improve permeability. Then the leaching agent such as cyanide or acid is sprayed over the heap. As, the reagent passes through the heap; the valuable metals get dissolved in it. The solution containing metal is drained from the heap and collected in a pond and the solution is sent for subsequent process for metal recovery to the processing plant.

With gold mineral processing plant ball mill trying to process the metal that can not be obtained by heap leaching. Gold recovered within 24 hours, unlike the heap leach process lasted almost 60 days. Construction began in mid-2006 and concluded in early 2008, with an investment of 270 million dollars and the production plan for 9 years. 1500 workers participated in the construction of this important project which has a processing capacity of 5,000,000 tons / year.

Carbon In Columns comprise the cyanide leach solution, and agitated in the leach tanks, and agitated with the ore while the gold is being dissolved. This assures a rapid interface between the carbon and the gold loaded cyanide solution.  Granular, hard carbon is used, in the size range of 10-16 mesh. The carbon is then removed by screening, across a carbon screen, allowing the liquid and finely ground ore (-100 mesh) to pass through easily, and retaining the carbon on the screen.  The pregnant cyanide solution flows through the carbon columns, which are generally situated in step fashion, so that the overflow from the highest column will gravity flow to the next column, alleviating the requirement for pumping. The gold adsorbs onto the surface of the carbon. The loaded carbon is periodically removed from the columns, and sent to the stripping circuit.

The gold obtained in the Merrill Crowe process is subjected to operations of drying kiln retort at 650 ° C. Finally, the obtained product undergoes a process of smelting electric arc furnace to 1,200º C for the Dore, a bar made of a mixture of gold and silver. After recovery, the contained metal is smelted and cast as 400oz doré bars containing 75% gold and 20% silver. The UK-based refiner Johnson Matthey is responsible for shipping the bars.

Panning Of Gold In Deposit Placer With Gold Panning Equipment

       Gold panning, or simply panning, is a form of placer mining and traditional mining that extracts gold from a placer deposit using a pan. The process is one of the simplest ways to extract gold, and is popular with geology enthusiasts especially because of its cheap cost and the relatively simple and easy process.
        panning, in mining, simple method of separating particles of greater specific gravity (especially gold) from soil or gravels by washing in a pan with water. Panning is one of the principal techniques of the individual prospector for recovering gold and diamonds in placer (alluvial) deposits.

      The typical pan is a light but rugged circular metal dish with a flat bottom and sides that slope out at about 45°. Its inner surface must be smooth and free from grease and rust. In panning for gold from streams, the pan is first filled halfway or so with gravel, soil, and rocks from places where the current is slower (such as downstream of boulders or on the inner side of bends in the stream). The pan is then immersed in the water, and the mixture is thoroughly wetted and stirred. Lumps of clay are broken up, and large stones are picked out. The pan, still under water, is then given a combination shaking and gyratory motion. This allows the heavy particles to settle and brings the lighter material to the surface. At intervals the pan is tilted, and the light surface material is washed off. This process is continued until only heavy “black sands” (such as ilmenite, magnetite, and pyrite) and gold remain. The material is dried and the gold removed (perhaps after using a magnet to remove some of the black sand). Panning is slow, backbreaking work, but in experienced hands there is little or no loss of gold.

How to finding gold with gold panning equipment . . .
This is step by step : Panning of gold in deposit placer


Here are some gold panning equipment with low price that you can use :

 

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How The Extraction Of Gold By Method Of Carbon In Pulp

Gold processing methods with the Carbon in pulp are often used in large-scale gold mining processing, where the active carbon in pulp method used for recovery of gold ore minerals in the washing tank. Tanks that are used are usually equipped with an agitator and air bubbles equipment and tools are designed to maintain solids in suspension in the slurry, and the achievement of leaching. In the process adsorption ore minerals in the soil material condition of the tank should be good enough to form a slurry that can flow under gravity or when pumped. To form a slurry, mineral ore in the mix with water and the reagent was added to the tank to get the gold leaching reaction

How to work the gold extraction process with carbon adsorption in the pulp can be explained by the following system

     

Extracting Gold By Carbon In Pulp

        Carbon In Pulp is the absorption of compounds into carbon Dicyano Aurrat.In the process of carbon-in-pulp adsorption occurs after the leaching of mineral ore slurry in a tank. And during the washing, the carbon-in-leach and adsorption occur simultaneously. In both processes mineral ore leaching slurry will be transferred from one tank into the recovery tank of carbon using a pumping machine. This is generally accomplished by passing the slurry through a series of adsorption vessels coupled with the periodic transfer of carbon, usually associated with pulp, and in the opposite direction. Column tanks are often used consists of a large carbon column (diameter 5 to 8 feet) and 15 to 20 feet in height, and filled with activated carbon. Minimum load of carbon rule of thumb is one pound of activated carbon per 0.1 ounces of gold are present in solution, and usually it's a few pounds per 1 / 10 ounce

         Two main methods Carbon In Pulp (CIP) and Carbon Columns may consist of the most widely used technique for extracting gold today. Both methods use a large tank in the column parallel step where gold is dissolved in the slurry (pulp) through a chemical process and combine agitation, oxygen and cyanide. In CIP, the carbon is mixed with a solution of cyanide leach and ore agitated in the Tank leaching, and the adsorption process will separate the gold. This will bring together between carbon and gold cyanide solution which is attached to the carbon. Granular carbon is often hard to use in a variety of sizes between 10-16 mesh. Carbon is then filtered by using the screening, on-screen screening of carbon will settle and the liquid is finely ground ore (-100 mesh) will be screened out through the screen into the tank.CIP treatment system can be described simply as a picture diagram below:

Diagram of the processing of gold with carbon in pulp

READ MORE >>>  Extracting Gold By Carbon In Pulp with Activated Carbon

Gold By Cyanidation Leaching Tank

Cyanidation with a tank on mining has increased rapidly since the mid-1980s. Extraction of gold by using a tank leaching systems typically use a lot of multiple tanks in series within a building. Different from heap leaching are located at the open air. Gold leaching process carried out by stirring the gold ore is mixed with limestone and added with a solution of cyanide in a tank and aerated with air bubbles. The duration of stirring often for 24 hours to produce the optimum leaching. Tank and leaching efficiency of about 92% to 98% gold content of rocks

 

Gold is one of the noble metals and as such it is not soluble in water. A complexant, such as cyanide, which stabilizes the gold species in solution, and an oxidant such as oxygen are required to dissolve gold. The amount of cyanide in solution required for dissolution may be as low as 350 mg/l or 0.035% (as 100% NaCN). Alternative complexing agents for gold, such as chloride, bromide, thiourea, and thiosulfate form less stable complexes and thus require more aggressive conditions and oxidants to dissolve the gold. These reagents present risks to health and the environment, and are more expensive. This explains the dominance of cyanide as the primary reagent for the leaching of gold from ores since its introduction in the later part of the 19th century.

On cyanide leaching of gold in the tank system, activated carbon is very important to use when in the process of recovery of dissolved gold, either by introducing direct to the Carbon In Leach (CIL) in tank or to the Carbon In Pulp (CIP) separately outside the tank after washing. Carbon In Pulp (CIP) leaching  occurs in two stages in the process in a different tank, while the Carbon In Leach (CIL) slurry of minerals and activated carbon having a tank leaching simultaneously on the same premises. Carbon is then separated from the slurry by screening and have further treatment to recover adsorbed gold.Gold complexes of carbon absorbed directly as soon as the gold dissolves in cyanide solution. CIL is used if the rock contains a lot of natural carbon, because carbon will naturally absorb the gold complex. Add activated carbon in the CIL is more active than the natural carbon.CIL investment cost is less expensive when compared with the CIP so that this method is also used on many people's scale mines are. This method is higher than the absorption of gold compared to the Heap leaching. New technologies are applied in South Africa using ion exchange resins Resin In Pulp (RIP) is expected to lower the operational costs. Preparation of rock (including softening, solution concentration, as well as the type of solution) and the leaching time is different for each rock. Oxide rocks the size of 65 mesh requires a 0.05% NaCN (50% solids) with a leaching time of 4 to 24 hours. Sulfide rocks the size of 325 mesh needs 0.1% NaCN leaching time up to 72 (Weiss 1995)

READ MORE >>> Tank Leaching for Gold

ACID TREATMENT ON GOLD

The process of Acid Treatment on gold is very important to do before continuing on gold metal smelting processes, due to deposition of the cementation process is done is still a lot of metal-containing zinc, iron and lead are also entrained. Acid Treatment is a process of dissolution of metals such as zinc, iron and other metal impurities using dilute sulfuric acid (H2SO4).From this process of acid treatment will be easier to concentrate smelting process before the stage of purification to make pure gold, because the metal impurities such as zinc, iron and other impurities that integrates with the content of gold ore has been dissolved by the liquid sulfuric acid (H2SO4). In the use of dilute sulfuric acid (H2SO4) is a blend of metal impurities will easily soluble by dilute sulfuric acid (H2SO4), is a metal that has a positive electrode potential in electrochemical series is rather difficult to dissolve, because the greater the tendency to become ions, and vice versa. A metal with a more negative potential shifts the metal underneath any of the salt solution.

      
      The same thing applies when reacting sulfuric acid with potassium nitrate. This reaction will produce nitric acid and precipitate potassium bisulfate When combined with sulfuric acid nitric acid behaves as an acid as well as substance to dehydrate, forming nitronium NO2 + ion, which is important in nitration reactions involving electrophilic substitution aroma. Reactions of this type is very important in organic chemistry. Sulfuric acid reacts with most metals via a single replacement reaction, which produces hydrogen gas and metal sulfates. Dilute H2SO4 will attack the iron, aluminum, zinc, manganese, magnesium and nickel, but reactions with tin and copper require hot sulfuric acid and concentrated. Lead and tungsen not react with sulfuric acid. The reaction between sulfuric acid with metals normally would produce hydrogen as shown in the equation below. But the reaction with tin dioxide than will produce hydrogen sulfide.

Fe (s) + H2SO4 (aq) → H2 (g) + FeSO4 (aq)

Sn (s) + 2 H2SO4 (aq) → SnSO4 (aq) + 2 H2O (l) + SO2 (g) 

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Diagram Of Gold Mining Processing

Gold mining was first carried out in alluvial areas. Processing system is also very simple to do that is by panning using a tray, which then developed with gold mining wave table, and followed by gravity separation method using the amalgamation process with the capture of mercury. Gold exploration in the lower layers of soil to get the primary sediment deposits began in 1860 with gold using a cyanide treatment system. And in 1960 the method of processing low-grade gold began being applied, which carried out the processing system through leaching heap, this process is basically developed from gold processing system using cyanidation . Of all the gold mineral processing must go through several stages in all these stages it is absolutely live to get the desired results, as for some stages it can be underlined by the diagram below

GOLD ORE

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Zinc Precipitation Stage Of Gold Deposition

     Metal deposition method using Zn powder (Zinc precipitation) was first introduced by Sulman and Teed (1895). Basic usage of this method is the electron affinity of zinc metal is much higher than in metals gold and silver, then gold and silver metals will sink and be replaced by a soluble zinc. The Precipitate that occurs will be shaped cement sand. Although the use of activated carbon is used widely but many are also used primarily cementation in rocks that contain lots of silver because the cementation is a process very simple and very inexpensive.

How The Gold Amalgamation Process

The process of amalgamation is the gold processing is a very simple process of mixing between gold and mercury (Hg). Amalgamation Technique performed by mixing rocks containing metallic gold and mercury by using a drum machine tools. Amalgamation of Gold Processing techniques are mostly done by small scale miners and simple. In processing system that uses gold amalgamation technique is desperately needed water, where the function is to separate the water between the rocks that have been refined and amalgam, which will result from amalgam mud in the pool will be at capacity reservoirs.

Some simple steps that are used in gold processing system amalgamation with drum machines are as follows:
 

• Destruction of rocks from the mining conducted to obtain a smaller-sized rocks. Size obtained is usually ± 20mm. machine used is a machine or Stone Crusher Hammer Mill or Crusher Jaws

• Rocks that have been destroyed then in put in drum machine with a capacity of drum machine used. In order to rarefaction and binding of the metal content of gold by mercury can then be left up to a quarter of the capacity of drum machine used. After all the rock mineral inserted it inside the drum machine was added to the water a quarter of the above rocks are included.
• After all is ready for mashed inside the drum machine drum machine can be closed up tightly so that no liquid water in the machine until it comes out. Then let the mill running until approximately 4 hours or 5 hours. Until all the soft rock material such as flour.
• After all the rocks are soft, then the mercury can be inserted into the drum machine, then run the machine back to the time between 2 hours. To 25 kg of material processed mineral rocks better use of mercury 2 kg
• After all completed then all the mud from inside the drum machine is issued and placed in a large tub and on the inside of the drum machine can be sprayed with water, so that the remains of mud and Mercury are still attached to really clean the drum machine
• Then the mud bath that contains you fill with water until it is completely full and overflowing from the tub of mud mixed with water will flow into the storage pool, whereas the binding of mercury amalgam will settle to the bottom surface of the tub. The addition of water is continuously performed very well, because when mud is thickened mercury can be carried away by the thickened sludge  
• Amalgam that has been generated can then be filtered and squeezed using a parachute cloth until all the mercury out of the parachute fabric, it will produce the mineral content of ores that have tied up with mercury. Amalgam that has been generated and then decomposed into elements of mercury in gold bullion by heating the distillation because mercury will evaporate and be recouped to the condensation of mercury vapor that can be reused.     

Besides the distillation is another method that can be used to separate between the amalgam and mercury amalgam is by dissolving with nitric acid obtained by transformation of the reaction as follows:

HgAu 2HNO3 + -> Hg (NO3) + H2 + Au

Occurred after the deposition of gold in the form of foam, conducted separation nitrate solution. Mercury can be taken by the displacement of copper ions or other metal ions that have a more negative electrode potential of the mercury, by the reaction:
Hg (NO3) 2 + Cu -> Cu (NO3) 2 + Hg
Noteworthy in this method is contained in the silver content of mercury can reduce the infiltration. Periodically need to be done purification by distillation.

• The results of the distillation process that has been split between the metal containing gold with mercury it can be readily Processed Fusion.
  

Furthermore, the solution in the form of mud that has been deposited in the pool, when it has dried transported to re-processed using the Cyanide (NaCN), Because of the efficiency of processing the results of amalgamation technique can only reach 60%. 

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