Mineral Processing Tarkwa Gold Mine In Africa

The Tarkwa Gold Mine operates under leases mining with a total area of ​​approximately 20,825 hectares. Five mining leases of 18 April 1997 which cover the Tarkwa property while two mining leases acceded on 2 February 1988 to 18 June 1992 to cover the Teberebie property. The Tarkwa concession mining leases expire in 2027 and the property Teberebie mining leases expire in 2018. 

Application for renewal of mining leases has been applied to and submitted all required fees and documentation at the Minerals Commission of Ghana. There is therefore no reason to expect that this will be granted. All necessary legal mining permits and approvals is entitled in place for the Tarkwa mine lease and GFG to mine all the material covered in the lease. 

Mine infrastructure consists of six open pit there, two heap leach facilities and a CIL plant. The ore body consists of a series of sedimentary banket quartz reef units (conglomerates) of the Tarkwain system that are similar to those mined in the Witwatersrand Basin in South Africa.

The operation mining at present with several reef horizon of open pits, and it is for underground mining for future potential. Tarkwa has a Mineral Resource of 15.3 million ounces of gold and a mineral reserve of 9.9 million ounces 

Location Tarkwa Gold Mine : 

Located in the south-western Ghana, Approximately 300 kilometers west of Accra , the capital of Ghana, West Africa. It approximately four kilometers west of the city Tarkwa area, which is a Nice access roads, has an established infrastructure and by a main road connecting the port of Takoradi Approximately 60 kilometers away on the Atlantic coast.

Owner Tarkwa gold mine in Africa: 

Goldfields Ghana Limited acquired the 18.9% IAMGold interest in Tarkwa now holds 90%, the remaining 10% held to Ghanaian government. 

Mineral deposit Tarkwa gold Mine :

Body Tarkwa are ore in Tarkwaian system, which forms a substantial part of the stratigraphy of the AshantiBelt in southwestern Ghana. The AshantiBelt is a northeasterly striking broadly synclinal structure consisting of Lower Proterozoic sediments and by metavolcanics and metasediments of Birimian system underlain volcanics. The contact between the Birimian and Tarkwaian is usually marked by zones of intense shearing and hosts instead of a number of significant shear gold deposits. 

Tarkwa Goldmine is dominated by the Banket Series, which are further divided in a footwall and hanging wall barren quartzite, separated by a sequence of mineralized conglomerates and quartzites gravel.

The stratigraphy of each quartzite units is well established, with auriferous reefs inter-bed with barren immature quartzites. The units thicken to the west and the current flow parameters flow from the east and northeast. 

Structurally, the Tarkwaian belt moderate wrinkles, and at least five sequences of the deformation can be detected. The original deposition occurred in a district basin environment with associated low to high angle normal faults.

Subsequent compression and folding led to development of thrust faults and reversing of previous normal faults. The final stages involved further thrusting in a southwest direction.

Mining Operations And Mineral Processing Tarkwa gold Mine In Africa:

Tarkwa North Heap Leach Phase V pad

The open pit surface operation currently uses the tabular auriferous conglomerates of four open pits – Pepe Mantraim, Teberebie, Akontansi and Kottraverchy 

Four large open pits currently exploit the stacked narrow auriferous conglomerates, similar to the Witwatersrand Basin of South Africa.

The used mining methodology is highly selective. The location of the mining areas is defined by the long term planning process. The boundaries of the mines are marked out by survey and the area is cleared of bush and topsoil with a bulldozer. 

The topsoil floor is laid for rehabilitation. After clearing, reverse circulation grade control drilling is carried out and geological models constructed. The Near-term plans and forecasts are updated with this grade control information prior to the commencement of mining.

From the highest point in the pit material is free-dug or blasted with the first beam reference level. Currently drilled fresh rock and transition zones and blown up in 6 m lifts, with excavation in 3m rinds.

Fourteen excavator used to select waste from the ore, and vice versa, along the sedimentary horizons in an average accuracy of 30 cm on the roof and 20 cm on the footwall of a reef.

Pit geologists and geotechnical engineers monitor all digging and mineral material is classified as either RoM, supplied with one of two primary crusher or inferior, which is stored close to the primary crusher. The waste material to the nearest landfill is towed.

Blasting currently utilises relatively close patterns and Little diameter holes, typically a 3.4 m by 3.8 m grid with a Gap diameter of 118 mm and a powder factor of 0.75 kg / BCM. Larger diameter holes and an increased screen size will be used in the partially weathered material,  while grid sizes are reduced are used in harder material. The Little diameter holes are used to obtain, as far as possible, the integrity of the ore / waste contacts for selective mining. 

Truck allocation (Dispatching) by means of the LP-based, GPS support Modular Mining Fleet Management System. Management reporting of material movement is via an intranet-based system (MMRS), which reads the data from the modular database in which all relevant information is stored. 

Ore is processed by using conventional CIL plant, is supplied with a gyratory crusher, a SAG mill and ball mill. Gold is recovered from the solution by electro-winning and melted in an induction furnace. Current plant capacity is 13.5Mtpa, 

LoM tailings deposit made with expansion 15.5Mtpa under evaluation in 2015 of requirements for the final lift sequences in the operation TSF 1, 2 and 3 plants in a Near time and in the medium term by TSF 5 (under EPA review) and in the longer term through planned TSF 4 and 6. 

Since 1999 all ore were taken from open pit and is currently estimated at 9.8 million tonnes per year and the conditioning 12.3 Mtpa CIL. A third plant was the South heap leach facility and in December 2008 this facility closed

The ore is free milling conglomerate with negligible sulphide content. Weathering has rocks near the surface and a higher degree of weathering is associated with increased porosity and increased Heap Leach dissolution and recovery

The North Heap Leach was commissioned in 1998 to process the initial high porus ore. Phase V Heap Leach pad construction was completed in 2009 and a further three phases of Heap Leach pad construction have been accounted for in the LoM plan. 

As the mine gets deeper so the proportion of weathered ore accessible Heap Leaching decreases. This justified the construction of the CIL plant in 2004 and the subsequent expansion, in January 2009.

The CIL milling process provides a 97% recovery which is not possible when using Heap Leaching for the harder, unweathered ore, the percentage of which increases over the LoM.

The North Heap Leach employs three stages of crushing before agglomeration crush. Agglomeration includes the addition of 4 kg / t of cement on the gravel to bind the fine material and produce an agglomerate, which are stacked on the Heap Leach Pads.

After agglomeration, the ore is transferred by the conveyor and stacked on the leach pads by a stack conveyor. The heaps are irrigated with a cyanide solution which dissolves the gold as it percolates through the heaps. 

The pregnant solution on the layer is collected at geotextile that lines the base of the heaps and through a series of ponds on the adsorption / desorption / recovery (ADR) plant is pumped, where the gold adsorbed on activated carbon , removed from the carbon by acid washing, and recovered using electro winning. 

The CIL process route has a 54 x 75 Gyratory crusher that feed two crushed ore stockpiles that have a live capacity of 45,000 t (30 hours). Underneath each stockpile is a reclaim tunnel, with apron feeders that feed onto a conveyor belt, which in turn feeds the milling circuit. 

The grinding circuit consists of a SAG and ball mill crushing with recycling with the SAG mill in a closed circuit. The SAG mill has an effective grinding length of 42 with an inner diameter of 27 and 14 MW of installed capacity (2 x 7000 kW dual drive motors). 

The ball mill has an effective grinding length of 36 installed with an internal diameter of 26 and 14 MW (2 x 7000 kW dual drive motors). The grinding circuit operating at a capacity of 1490 tonnes per hour. The CIL circuit is supplied to the tank of two trains of eight tanks in series from a common leaching.

The loaded carbon passes into a 15 t acid wash column. The gold is recovered from the loaded carbon in two 15 t elution circuits. Gold is recovered from the solution by electrowinning . The gold is smelted in the CIL smelt house in an induction furnace.

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Gold In Quart ( Video )

Natural gold in quartz samples are crystalline gold nuggets constitute gold that are still attached in host rock which is typically made of quartz. Gold in quartz is the result of hard rock mining, where gold veins apart the gold-laden exposing the gold laden quartz within the vein.

Gold veins that are so wealthy in gold which can be seen with the naked eyes is visible are very rare, and veins so wealthy that they produce the kind of natural gold in quartz samples. In epithermal gold deposits, it is quite common for significant gold veins running through quartz rock, and these samples can be found with a high quality metal detector. 

Often quartz samples these gold are very beautiful and interesting, so they are greatly appreciated by mineral collectors, sometimes even more than the value of gold itself.

With sample-grade gold such as this, it is recommended that looking for gold collectors who pay a premium for them rather than crushing these mineral samples. However, there are occasions when it is the best interest of the prospectors to destroy these pieces of ore. 

The first discovery of gold in quartz appears from a man named Davidson, a Baptist preacher, in February 1851,on the south side of Amador creek near the spring then used by the miners. Boulders of great size were lying on top of the Soil

The intelligent men who worked while gold rush in the canyons and rivers in the early days, they found gold in the gravels. Sometimes gold was found with quartz adhering. The quartz veins lining the hills near the richest placer, also served on this rock demonstrate as the original source of the gold. In Carson Hill, and then Mariposa County, quartz found immensely wealthy, but the expense of blasting the rock out  and crushing, so that no serious attempts were made until 1851. 

The whole California gold country swarming with quartz; in some places in mountains, which had filled the ravines with broken quartz, but not all the quartz had gold in it. The miners to found gold in quart with the hard way, until some experienced men were put on many locations.

VIDEO QUARTZ VEIN GOLD ORE SPECIMEN ~ FROM GOLD MINE

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Semi Autogenous Grinding Mill In Mining ( SAG Mill Video )

SAG mill in the mining constitute equipment used in the mining industry for grinding material, it uses steel balls next to large rocks to grind. SAG is an acronym for Semi Autogenous Grinding Mill and the SAG mills use minimum ball charge 6-15%. It has a large diameter and short length in the equipment SAG. 

The liner is made of wear-resistant steel and provided with lifters, which when the mill rotates can in increasing the load support. The load consists of dry ore, steel balls and water, which occupies 30% of the volume. 8% of this volume is steel balls. 

A SAG mill is most common used in the mining areas, especially in the mining of precious metals,  such as gold, copper, silver and nickel. The SAG mill is used in the line of industrial mining equipment designed to process, crushing, separating, or locate precious metals from coal. The SAG mill is one of the major mining equipment pieces and often requires machinery repair and maintenance.  

This is most often due to the large amount of heavy, residue bearing material being churned from grinding mill due to the Large amount. The SAG mill used plates along the inside of the drum, lift the material during rotation, causing them to fall onto each other to crushing. 

A semi-autogenous grinding mill or SAG mill is responsible for materials of Large chunks into Little pieces suitable for processing material. The SAG mill is usually part of the primary stage in the grinding process. Pieces of raw or reduced rock materials into smaller pieces for further processing or sorting. These machines are electrically driven , but changed and have been modified from powering systems over the years.

It may often be necessary to service a variety of industrial gold mining equipment, coal mining equipment, and other relevant major mining equipment. People who work in SAG mills must to understand involved in each phase of the machine repair process the intricate details, rehabilitation of mining equipment and great care. This information will necessity a trained eye and skillful hand, to ensure that the machine working properly.

SAG Mill & Maintenance

Some of the necessary services for the SAG mill machines comprise technical support during the construction and application processes for the mining equipment manufacturers. Other services include the production of parts, mining machinery repair and restoration of mining machinery. This type of equipment is extremely important for the production and economy, and it is necessary to take care when handling the equipment. Professionals should be very knowledgeable in this unit.

When machine has been shut down, or the process is problematic , so do production and profit slowed. Mining machinery maintenance and modifications keep production running at its best. SAG mill operations are no exceptions. In Specific, it is important to ensure that the lifting plates, rotating drums, mill rotators and other machine components their optimal operating functions maintained at all times by ensuring that preventive and routine maintenance completed on schedule and on time.

SAG mill mining machinery, and other mining equipment, are crucial for the mining industry. SAG mill has a far history in mining production and must be handled carefully and with caution to ensure safety and optimal production at any time. Gold-mining equipment and mining equipment are among the most waited mill types mining machinery, which requires maintenance and modification. 

Video Rubicon Minerals Corp: SAG Mill First Run Phoenix Gold Project 

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Video How To Test Silver

Silver is the first metal which was first smelted from ore. It comes from ancient Egyptian empire used and has been forged in household utensils, jewelry, etc. Pure silver is smooth as gold, copper usually alloyed to straighten his strength and can be used for making the production equipment and other items.

Without addition of alloying because of its softness, it would melt. Fine silver is pure Nearly 999/1000 percent, but it is too smooth to make jewelry, out of it a metal added in silver. But something called silver or sterling silver (which in it 92.5 percent pure silver and has 7.5 percent metal ) is pure silver.

Silver is a versatile chemical element. Sterling silver is 92.5 percent silver and 7.5 percent other metals, especially copper. It is harder than pure silver. Pure silver is smooth and often referred to as “fine silver.” Products can often be mistaken as silver when silver (only covered with a thin layer of fine silver). 

But how do you know you really have silver at home? Unless you are an silver holder, who knows quality is silver, and how pure the silver, you buy. You can not have the first clue how to test for silver purity at house. This article will Aid explain the purity of silver and how to confirm that not only is another gray metal.

The most obvious way to know pure silver, and the extent to which it is pure, is to check on your silver jewelry and silverware

Tips to determine purity of silver Or How to test silver

1. Test with a magnet , In the specially using a strong magnet, such as the magnet made of neodymium. Silver is paramagnetic and shows only a weak magnetic effect. If magnet very strong sticking on metal, it has a ferromagnetic core and is not silver. 

Note that there are a few other metals which a magnet will not stick and can be made to look visible as a silver. It is better to carry out the magnetic test in conjunction with another test to ensure that the core is not another metal.

2. Try the ring-test with each coin. Silver makes a really lovely bell like ringing when someone knocked on, especially if they are knocked with a different kind of metal. If you want to try this, you have to find metals silver quarter which made before 1965 in United States, it is made of silver 90% silver US. 

Were during quarters later than 1964 are made of a copper-nickel alloy. The elder quarter will give a whistle, clear ringtone, while the newer district give a thud of a sound. 

3. Perform a chemical analysis test to the point item. Use chemical analysis if no stamps indicating that the silver metal. Use gloves within silver test with chemicals, because if exposed to a corrosive acid solution, it will burn your skin

Note that this method has the potential to damaging silver element.

Buy a silver test. Silver acid tests for pure silver, but if you think your piece is silver, you will use a Little jeweler file to make a mark, revealing what might be under the plating.

Find. An inconspicuous place on the article in question and make a Little scratch on the silver piece. This is necessary in order to test the underlying metal silver it with acid. Scratch the piece a metal file. Scratch off enough so you can get to the surface of any plating layer.

If you do not want your piece scratch, or potentially leave a mark from the acid, you can use a black stone slab. These are generally made with a silver testing kit available. Rub your silver on the surface of the black stone, so that it leaves a thick and relatively Large deposit on the stone. Goal for a line that one thick one-half inch.

Apply a drop of acid to the scratched surface only. When the acid touches any portion of the piece that is not scratched, it will affect the polished look of the piece. If you want to use a black stone, a drop of acid will add to the line that you created on your stone. 

5. Analyze. The analyze  surface on part scratched with the acid. You have to analyze the color, the acid appears as decreases in the piece.
Be sure to follow the instructions and color of your specific silver test. In common, the color scale is as follows:

Bright Red: Fine Silver
Darker Red: 925 Silver
Brown : 800 Silver
Green : 500 Silver
Yellow: Lead or Tin
Dark brown: Brass
Blue: Nickel

This video constitute How to test silver

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The South African Gold Market

The economy of South Africa depends largely on its mining industry. It  is mines  precious metals like  gold , copper, platinum, and diamonds. The South African gold market is 120 years old. It has seen a continuous cycle of ebbs, and falls in its economic history. Like many other countries, it depended upon the London bullion market to sell its gold to the global gold market. Individual  gold   mining  companies and brokers marketed  gold  through London.

Later, The Reserve bank of South Africa took over the control of the gold market of South Africa in the early twentieth century, after the First World War ended, and used The Bank of England as its selling agent to channel gold to the London bullion market.

Later in 1968, during the Vietnam conflict, the London gold market was closed for two weeks. When it reopened, the future of the global gold market had changed forever. It had lost a number of its potential clients. The three main Swiss banks formed a Zurich gold pool, and approached The South African Reserve Bank to channel its gold. Even today, Switzerland is known to handle most of the gold produced in South Africa in the global gold market.

South Africa has the second largest gold reserves in the world. In the beginning, it contributed as much as half the total gold produced in the world. However, over a period, its  gold  production slowed down, despite the low-cost of  gold   mining  in South Africa. With the  gold  rush in California, and later in Australia,  gold   mining  companies focussed their attention to the newly discovered mines.

Gold   mining  is anyway a difficult job, and in a country like South Africa, where the geological factors make it unbearable to work, the instability of the country further hampers the growth of  gold   mining  industry. The geothermal temperature is more than 50 degree Celsius.

It needs tons and tons of water to be pumped in to cool the inner temperature. Moreover, it requires massive amounts of dynamite, and Cyanide to blast the  mines , and extract  gold  from there. The refining process of course needs uninterrupted power supply.

So altogether, the cost of  mining  and  processing  raw  gold  is extravagant for the government. With its limited resources, and insufficient power supply, coupled with the civil wars, and political instability, it has failed to deliver a prospective gold market. Rand, the South African currency is constantly losing its value against other currencies. The  gold  market has not yet shown signs of recovery, but the government is initiating projects like thermal power stations to generate more electricity for the  gold   mines  to increase their production by 2010.

Related Article :

- History Of Gold Mining In South Africa
- Gold Mining Industry In South Africa