In a further bid to diversify its mining assets,
The Pamplona deposit hosts 60 million tonnes grading 13.8% elemental sulphur and 17% sulphide sulphur for a combined weighted average of 30.8% sulphur. The deposit has been deemed minable by open-pit methods and is 5 km from a deep-sea port. Sulphur is the largest cash component of the high-pressure acid-leach (HPAL) process, and the company now has an uninterrupted supply, as well as a stable price, for the life of the Mindoro operation. (The relatively new HPAL technology is expected to enhance previously sub-economic nickel projects by slashing production costs, much as heap-leaching has done for gold and solvent extraction-electrowinning has done for copper.)
In September 1999, Crew merged with Mindex, a Norwegian exploration company, and, as a result, added four exploration and development properties to its portfolio. Besides Mindoro, these include: Nalunaq, a gold deposit in Greenland; Roros, a zinc-copper property in Norway; and Hwini-Butre, a gold property in Ghana.
The most advanced of these is Mindoro, a wholly owned, shallow nickel laterite deposit with measured and indicated resources pegged at 70 million tonnes of laterite ore grading 1% nickel and 0.01% cobalt, sufficient for a 20-year mine life.
In August 1999, a prefeasibility study indicated that nickel could be produced using HPAL technology at a cost of US$1.06 per lb. (or US30 per lb. net of cobalt credits). The project will also produce about 126,000 tonnes of ammonium sulphate per year as a byproduct of the mining process. The Philippines imports about 400,000 tonnes of ammonium sulphate per year for its rice and sugar cane production. A full feasibility study, designed to determine the viability of a 40,000-tonne-per-year nickel operation, is to commence shortly.
Crew also holds a 65% interest in the Nalunaq gold project; the Greenland government holds the remainder. A prefeasibility study calls for a 500-tonne-per-day mine to produce gold at a cash cost of US$160 per oz. Capital costs are estimated at US$19.8 million.
Nalunaq has an indicated and inferred resource of 413,000 tonnes grading 32 grams gold per tonne, or 425,000 contained ounces gold, and Crew intends to increase the size of the deposit through further drilling. In the meantime, a $7.2-million exploration program will entail driving two new adits a total distance of 850 metres and extending an existing adit by about 150 metres. A total of 610 metres of raises will be driven between the three adits. A production decision is expected by 2001.
A recent private placement raised $8.4 million through Norwegian institutional and private investors. Proceeds will be applied to the Nalunaq gold project, as well as the final feasibility study at Mindoro.
In Norway, Crew holds a 100% interest in the 3,000-sq.-km Roros zinc-copper property, with
Although copper has been mined in the area for more than 333 years, zinc-rich portions of the former mines and prospects were neglected, the reason being that modern flotation technology was unavailable.
In Ghana, Crew holds a 51% stake in the Hwini-Butre gold project, with the remainder held by operator
In early 1997, Crew acquired a 40.5% interest in Metorex, a South African mining company. At the time, Metorex had three operating mines and annual revenue of about $45 million. Since then, it has acquired interests in four more mines and revenue has grown to about $150 million.
– Chibulumu — In Zambia, Metorex holds a 85% interest in the Chibuluma copper mine, which is divided into two deposits: Chibuluma West and Chibuluma South. The mine was acquired as a result of the privatization of Zambia Consolidated Copper Mines (ZCCM), with ZCCM retaining 15% ownership. At current production levels (8,400 tonnes of copper and 100 tonnes of cobalt per year), the mine is expected to last about five more years. A considerable amount of the existing Chibuluma West infrastructure will be used for Chibuluma South.
The Chibuluma South mine is about 12 km west of Chibuluma West and will be developed initially as an open-pit operation, with underground mining to follow. Reserves stand at 7.8 million tonnes grading 4.3% copper, and annual production, over a mine life of 16 years, is targeted at 18,000 tonnes copper.
Construction of Chibuluma South is to begin in May, with startup pegged for spring 2001.
The Chibuluma copper deposits occur on the southern flank of the Chambisi-Nkana basin and are hosted in thick quartzites deposited unconformably on to an uneven elevated basement complex.
– Antimony — Metorex also holds a 100% interest in the Antimony mining operation, formerly known as Consolidated Murchison. Situated in the Murchison range in South Africa’s Northern Province, the mine has been operating for more than 60 years. It remains the primary producer of antimony in South Africa, cranking out about 4,800 tonnes per year, or roughly 8% of the world’s total production. The metal’s primary use is in flame retardant. Antimony is also used in the production of white metals, lead batteries, metal bearings and specialty glass and ceramics.
Proven and probable reserves are pegged at 1.7 million tonnes grading 2.94% antimony and 3.88 grams gold per tonne. About 4,800 tonnes of antimony are produced per year. An additional 32,000 oz. gold per year is recovered as a byproduct. Gold-bearing stibnite ore is treated by flotation and pressure-leaching to produce low-arsenic antimony concentrates and gold bullion.
Mineralization is hosted in sub-vertical schists and quartz carbonate rock that occur along the so-called Antimony Line, which extends along an east-northeast trend for 50 km. Antimony concentrations occur in four nodes of resilient siliceous carbonate rocks in an envelope of talcose-chloritic schists. The deposits are lenticular and sinuous, with thickness ranging up to 25 metres.
– Maranda — Metorex also has a 100% interest in the Maranda zinc-copper mine, in the Murchison Range of South Africa. The mine, which been producing for about eight years, contains proven and probable reserves of 424,000 tonnes grading 17.66% zinc and 2.07% copper. Resources are estimated at 612,000 tonnes grading 17.82% zinc and 2.06% copper. The mine produces about 15,000 tonnes of zinc and 1,500 tonnes of copper per year, and Metorex says there is potential to expand the mine’s life since the company holds the mining rights for more than 80% of prospective ground in the surrounding area.
The Maranda deposits are in an Archaean-aged schist belt that extends for about 100 km and is up to 15 km wide. It strikes east-northeast, with the strata dipping steeply to the north. The deposits of economic interest occur as spaced pods of mineralization with steeply plunging mineralized shoots along the schist belt.
– O’okiep — Metorex holds a 100% interest in O’okiep copper mine, near Springbok in South Africa’s Northern Cape. The underground mine has been in production since the late 1930s, and proven reserves currently stand at 3.6 million tonnes grading 1.87% copper. Indicated resources are pegged at 1.5 million tonnes grading 1.33% copper. On an yearly basis, the mine produces 14,400 tonnes copper. Anorthosite, diorite and norite at O’okiep have intruded into granite that is unconformably overlain by metasediments. Copper mineralization is hosted in the norite unit and occurs primarily as disseminated, veined and massive chalcopyrite.
– Vergenoeg Fluorite — The open-pit Vergenoeg Fluorite mine, near Johannesburg, is owned 70% by Metorex and 30% by Minersa. On an annual basis, the mine produces 100,000 tonnes of acid-grade fluorite and 10,000 tonnes of metallurgical grade fluorite. It has been in operation for more than 44 years and still has 3.3 million tonnes of proven reserves grading 36.2% fluorite. Total indicated and inferred resources are pegged at 104 million tonnes grading 31.98% fluorite. At current production, the mine is expected to last another 50 or more years. Fluorite is used in the manufacture of steel, aluminum, ceramics and specialty glass; it is also an ingredient in the fluoridation of drinking water.
Vergenoeg ore is mined from a fluorite-bearing massive iron oxide deposit, formed about 1950 million years ago when a violent gas-vapour volcanic eruption occurred. The deposit occupies the volcanic vent and has a typical carrot-like shape.
– Wakefield — Metorex holds a 92% interest in Wakefield Investments, a coal mining company that operates three collieries in South Africa, namely Leeuwfontein, Bankfontein and Lakeside. Leeuwfontein is an underground mine, whereas both Lakeside and Bankfontein are open-pit operations. Wakefield produces coal mainly for the domestic South African market. Production from Wakefield’s operations represents 15% of domestic demand.
– Metmin — Metorex holds a 100% interest in the Metmin manganese dioxide mine in South Africa’s North West Province. Each year, the open-pit operation produces 24,000 tonnes of manganese dioxide concentrate as a catalyst for the uranium extraction process used in the gold mining industry. At current production levels, the mine life of Metmin is expected to exceed 50 years.
– Perkoa — The Perkoa high-grade zinc deposit in Burkina Faso, West Africa, is held 90% by Metorex, with the remainder owned by the government of that nation. A prefeasibility study pegs resources at 7 million tonnes averaging 17.6% zinc. The deposit is expected to crank out 60,000 tonnes of zinc metal in concentrates per year. Mineralization consists of pyrite, sphalerite, pyrrhotite and barite, with small amounts of lead and copper sulphides. The deposit hosts two parallel, steeply dipping bodies that have been delineated to depths of roughly 500 metres.
Crew also holds a 100% interest in Botswana Diamondfields, a junior diamond exploration company active in southern Africa. The company holds a 3.8% equity interest in
Asia Pacific Potash holds the rights to the Udon Thani Potash concession in northeast Thailand. To date, two potash deposits have been delineated on the concessions.
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