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
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.
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.
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:
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| 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.
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 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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