|Commodity||Copper, Cobalt, Gold, Uranium|
Northwestern Province, Zambia
|Owners||Barrick Gold Corp.|
|Operator||Lumwana Mine (Zambia)|
|Production||159 Mlbs copper (2011)|
|Deposit Type||Shear zone hosted deposit|
|Reserves & Resources||4,909 Mlbs copper (proven & probable, December 31, 2011)|
|Mining Method||Open pit|
|Processing Method||Crushing, flotation|
|Mine Life||Beyond 2044|
|Mining Equipment||27 diesel electric hybrid Hitachi EH4500 trucks with 240 t load
capacity; seven Hitachi excavators and shovels (27 m3 buckets; 518t
machines; 3 diesel and 4 electric) and ancillary mining equipment
(Caterpillar light fleet of sixteen 40 t Articulated Dump Trucks +
5 Cat 777 100 t trucks, and 8 Sandvik drills).
|Processing equipment||Gyratory crusher, conveyor belts, 38 ft x 18 ft SAG mill, 26 ft x 40 ft ball mill, flotation circuit|
|Employees||Over 2,000 (2012)|
|Contact Information||Mike Feehan
Barrick Australia Pacific Ltd.
Brookfield Place - Level 9
125 St. George Terrace
Perth WA 6000
Ph: +61 8 6318 5777
Last updated: June 11, 2012
The Lumwana copper mine is located in Zambia, in one of the most prospective copper regions in the world. Lumwana is a high-quality, long-life producing copper mine with opportunities to materially increase resources, throughput and production.
Lumwana has proven and probable reserves of 4.9 billion pounds of copper, plus an additional 10.6 billion pounds of inferred copper resources. There is excellent potential for both brownfield and greenfield resource growth on the property, with no material drilling on targets outside of the existing resource areas for around 15 years.
Barrick is advancing an expansion study that could potentially double processing rates.
In 2011, Lumwana produced 159 million pounds of copper at total cash costs of $2.24 per pound.
Zambia - "One Zambia, One Nation" - is a landlocked country located in south-central Africa. It has been inhabited for thousands of years by old populations of Khoisan hunter-gatherers which were subsequently replaced by migratory Bantu speaking tribes.
Copper was mined in Zambia by indigenous people and circulated in central Africa as ingots and crosses long before the European colonization.
In the first part of the 19 century about 40% of the world's copper supply came from the British Empire, but that had declined to a negligible amount in the second part of the same century.
In 1902, prospector William Collier discovered rich copper mineralization at a site where he had shot an antelope - the Zambian Copperbelt was thus discovered and modern cities with schools and hospitals powered by electricity were established in the region.
The Lumwana mine is accessible via a 10 km two-lane bitumen highway branching off the Northwest Highway (T-5) that links Lumwana and Solwezi to the Copperbelt and other parts of the North-Western Province.
The Lumwana copper + cobalt + gold + uranium deposits of Malundwe and
Chimiwungo are hosted within the Mwombezhi Dome, which is a northeast trending
basement dome in the western arm of the Lufilian Arc thrust fold belt. The
Lufilian Arc is a major tectonic province characterised by broadly
north-directed thrust structures and antiformal basement inliers or domes
surrounded by Katangan metasediments, which host the Central African Copperbelt
in the central part of Zambia.
The project contains two major copper deposits, Malundwe and Chimiwungo, which are structurally controlled deposits of Central African Copperbelt type. Of the two major deposits, Malundwe is smaller, but with higher copper grade and contains discrete zones of uranium and gold mineralization with occasional sporadic high cobalt. Chimiwungo is much larger and lower in copper grade, but has higher overall cobalt, including a number of significant high grade cobalt zones, and some sporadic uranium mineralization. The copper mineralization at Malundwe and Chimiwungo is hosted almost entirely within high grade metamorphosed, intensely mylonitized, recrystallized muscovite-phlogopite-quartz-kyanite schists, with disseminated sulphides (typically <5%) dominated by chalcopyrite and bornite.
The Central African Copperbelt is a world-class metallogenic province which stretches from the Copperbelt Province in Zambia, through the Katangan Province of the Democratic Republic of Congo and in to the North Western Province of Zambia. The Lumwana Project lies within the North Western Province and contains two major copper deposits; Malundwe and Chimiwungo which are structurally controlled shear zone hosted deposits considered to be an end member of Central African Copperbelt class of deposits. Of the two major deposits, Malundwe is smaller, but with a higher copper grade and contains discrete zones of uranium and gold mineralization with occasional sporadic high cobalt (>0.1%). Chimiwungo is a much larger deposit that is lower in copper grade, but it contains a number of significant high grade (>0.1%) cobalt zones as well as some uranium mineralization.
The copper mineralization at Malundwe (including Kanga) and Chimiwungo (comprising the Chimiwungo Main, Chimiwungo South, Chimiwungo North and Chimiwungo East mineralized zones) is hosted almost entirely within high grade metamorphosed, intensely mylonitised, recrystallised muscovite-phlogopite-quartz-kyanite schists with disseminated sulphides (typically <5%) dominated by chalcopyrite and bornite. The ore host is locally referred to as Mineralized Ore Schist, which has an intensely transposed foliation defined by layer-parallel alignment of both mica and quartz. The mineralized zones, as interpreted, comprises a series of interbanded Mineralized Ore Schists and gneissic units, which are structurally derived. This fabric is the result of regional layer parallel shearing and subsequently thrusting and possible nappe folding that has caused the overturning of the sequence. The internal structure of the mineralized package is attenuated and boudinaged in part, causing lensing along strike and down dip. (May/11)
Uranium mineralization at Lumwana is associated with the same muscovite-phlogopite-quartz-kyanite Mineralized Ore Schist lithology that hosts the copper mineralization. At Malundwe the fresh uranium typically lies within the Mineralized Ore Schist at the hanging and foot wall contacts of the copper orebody, or in the immediate footwall to the copper mineralization. (May/11)
As of December 2011, proven and probable reserves were estimated at 423 Mt grading 0.522% copper for 4,909 Mlbs copper.
Lumwana is a truck and shovel operation executed in open pits. The project currently consists of two deposits, Malundwe in the north-west and Chimiwungo, 7 km from Malundwe, to the south-east, although there could be opportunities to include other deposits in the area as they are proved up.
Lumwana's first class mining fleet consist of 27 diesel electric hybrid Hitachi EH4500 trucks with 240 t load capacity; seven Hitachi excavators and shovels (27 m3 buckets; 518t machines; 3 diesel and 4 electric) and ancillary mining equipment (Caterpillar light fleet of sixteen 40 t Articulated Dump Trucks + 5 Cat 777 100 t trucks, and 8 Sandvik drills). The ancillary equipment is primarily being used in pre-stripping weathered material. The average strip ratio is estimated at 4.2 : 1 over its 37 years mine life.
The company has also extended the trolley assist infrastructure from the main ramp to the starter pit, enhancing trucking ramp speeds, reducing cycle times and lowering hybrid diesel-electric truck operating costs.
Mining has started in the Malundwe pit with the aim of setting it up to provide feed to the Copper Plant. Mining will be completed in Malundwe in 2014 with production then moving to Chimiwungo.
Total copper ore produced over the life of the mine will total 730 Mt at an average copper grade of 0.66% with mill feed continuing at a rate of 20 Mt/a until 2044.
The sulphide copper ore from Malundwe and Chimiwungo will be sent to the Copper Plant, which will produce a concentrate suitable for sale to a smelter. The oxide ore will be stockpiled close to the ROM pad for processing later in the mine life.
Total uranium ore mined is estimated to be 5.4 Mt with an average of 0.11% U3O8 and 0.91% Cu with uranium processing proposed to be continued until 2018. The uranium rich material is proposed to be sent to the separate Uranium Plant, which would produce a uranium concentrate.
Drilling is performed with jackleg and jumbo electro-hydraulic drills, drilling over head, 1.2 m cuts. The blasts are done with emulsion, gel dynamite explosives, and in some areas of the mine the company is permitted to use ANFO.
In general veins that are less than 1.8 m thick are mined with 15-30 hp slushers utilizing 25 to 36 inch buckets. For veins exceeding 1.8 m it is advantageous to muck with LHD scoop-trams of 1.25, 2.5 or 3.5 cubic meter capacity.
Lumwana ore, which is predominantly sulfide, is treated through a conventional sulfide flotation plant, producing copper concentrate for smelting.
Trucks from the mine deliver ore either directly to the crusher feed hopper or into a 400 t capacity ROM dump hopper for further size reduction.
Crusher product is then conveyed via a 4.5 km overland conveyor to a conical crushed ore stockpile with 16 hours live capacity. Ore is to be reclaimed via apron feeders onto a conveyor belt providing direct feed, at a rate of approximately 2 500 t/h, into the 38 ft x 18 ft SAG mill. The SAG mill trammel undersize discharges into a hopper and is pumped to conventional hydrocyclones, operating in closed circuit with a 26 ft x 40 ft ball mill. The hydrocyclone overflow reports to flotation, whilst the underflow returns to the ball mill
The flotation plant consists of two parallel trains of rougher/scavenger cells. The rougher/scavenger concentrate reports to the regrind circuit to further liberate the copper minerals. Following regrinding, the concentrate is cleaned in a conventional cleaner/recleaner circuit to reach final concentrate grade. Final concentrate grades of approximately 44 percent and 29 percent copper are expected from Malundwe and Chimiwungo respectively.
The concentrate will be dewatered in a circuit consisting of high-rate thickening followed by pressure filtration to produce a filter cake suitable for transportation. The concentrate will be stored in a 7 day capacity storage shed from which it will be subsequently loaded onto trucks and transported to market for smelting and refining. Flotation tailings will be thickened and pumped to the tailings dam.
The majority of the Copper Plant water will be recovered and recycled from the thickener overflows and tailings dam return water. Fresh make-up water will be supplied from a river water dam as required.
Copper concentrate is being shipped to Copperbelt smelters.
Proposed Uranium Plant
Uranium ore is proposed to be processed through the Uranium Plant at a rate of 1 Mt/a. In the first five years the Uranium Plant is estimated to produce 2.0 Mlb/a of uranium oxide (U3O8) and 12 800 t/a of copper concentrate. Uranium recovery to uranium oxide is estimated to be 93.1% and copper recovery to the Uranium Plant copper concentrate is estimated to be 80.1%.
Copper sulfides are removed as a copper concentrate in a flotation circuit prior to the extraction of the uranium. The thickened flotation tailings is leached with sulphuric acid at pH 1.8, and an oxidant then thickened, neutralized and pumped to the SX circuit.
The SX circuit comprises 4 extract, 2 scrub, 4 strip and one regeneration stage. Uranium is extracted from the PLS solution using an organic reagent.
The organic reagent is periodically regenerated using sodium hydroxide/sodium carbonate for optimal performance. The uranium is stripped from the organic (into solution) using ammonia and reports to the uranium precipitation circuit as "Strip Solution".
The barren solution (raffinate) is re-used in the circuit to minimize fresh water usage whilst a bleed stream (raffinate bleed) reports to the tailings neutralization circuit.
The uranium in the Strip Solution is precipitated using ammonia. A scrubber is used to capture fugitive ammonia emissions, with excess ammonia recovered and re-used in the process using a lime boil circuit.
The precipitate is dewatered and calcined to form uranium oxide (yellowcake at 99.7% U3O8). The yellowcake will be packaged and sealed in United Nations certified drums, samples taken for analysis, weighed and labeled prior to being stored in sea containers, ready for shipment.
Each shipping container stores approximately 45 drums (16 t to 18 t) and will be transported under IAEA guidelines at a frequency of once per week to a shipping port. The shipping container will subsequently be loaded onto a ship and exported to a uranium conversion facility, consistent with the Nuclear Non-Proliferation Treaty.
Neutralized uranium tailings will be stored in a dedicated uranium tailings storage facility ("UTSF"). The UTSF will be a purpose built facility designed to store up to 10 Mt of uranium tailings. The UTSF will be located within the footprint of the 550 Mt Malundwe waste dump and within the basin area of the 780 Mt Copper Tailings Storage Facility.
The project area is not pristine due to the impacts from tree felling, charcoal burners, slash and burn agriculture and mineral exploration activities. The soils of the area are typical of those found in sub-tropical regions, being heavily leached, low in nutrients and of poor fertility.
Subsistence farming is practiced using slash-and-burn methods. Farming is the main source of livelihood in the region.
Project development did not require the relocation of any indigenous peoples. Customary land is held by three local chiefdoms in the Lumwana area. A Memorandum of Understanding was signed on the 7 August 2005 under which The Royal Chiefs of Lumwana agreed to grant surface rights to Equinox for the Lumwana Project.
A fully sustainable township was constructed for the mine employees and their dependants, as well as associated contractors and suppliers required to work during mine operation.
HIV/AIDS, malaria and other diseases represent a threat to maintaining a skilled workforce in the mining industry in Zambia. The per capita incidence of HIV/AIDS has been estimated as being one of the highest in the world and as such, HIV/AIDS remains a major healthcare challenge faced by Equinox to ensure a skilled workforce is maintained. Allowances have been made by Equinox to cover the costs associated with the health and training of the workforce.
The mining company pays a corporate tax rate of 25% and a mineral royalty of 0.6% of gross product which generates revenue for the local government.