A positive engineering report has prompted
Kansanshi is Zambia’s oldest mine, dating back to the fourth century. The ancient workings were rediscovered at the turn of the 20th century, resulting in subsequent production of 80,000 tonnes from higher-grading zones using both underground and open-pit mining methods.
In 1997, when Zambia privatized its mining industry, Cyprus Amax Minerals acquired an 80% stake, reducing the interest of state-owned Zambia Consolidated Copper Mines’ (ZCCM) to 20%. Cyprus was taken over by
In 2000, Phelps Dodge completed a prefeasibility study based on 121,000 metres of drilling sunk by Cyprus and ZCCM. The study pegged open-pit resources at 267 million tonnes grading 1.28% copper, plus gold.
The resource is divided among two zones, known as Main and Northwest. Each is made up of oxidized, mixed and hypogene mineralization.
Using the old data, Perth, Australia-based GRDMinproc envisages a 2-stage development program relying on open-pit mining methods. The first stage focuses on copper oxide and mixed ores; the second, on primary sulphides.
Potentially minable resources for the first phase are pegged at 73 million tonnes grading 1.74% copper and 0.27 gram gold per tonne. This is sufficient for 11 years of production at the proposed annual milling rate of 6.6 million tonnes.
Stripping ratios are expected to average 2-to-1.
Upwards of 624,000 tonnes copper cathode, 413,000 tonnes copper-in-concentrate and 460,000 oz. gold are expected to be produced during the first phase. This assumes average recovery rates of 82% for copper and 73% for gold.
About 60% of mined material will be processed on site in a solvent extraction-electrowinng (SX-EW) plant. The remainder will be concentrated for shipment to smelters about 200 km to the southwest.
Operating costs are expected to average US$12.90 per tonne of material treated, or US35 per lb. copper produced, net of byproduct credits.
Capital costs, including the investment in the plant, are projected at US$155 million.
Potentially minable resources for the second stage are pegged at 197 million tonnes grading 1.16% copper and 0.27 gram gold. The estimate derives directly from the Phelps Dodge study and is thus still being economically reviewed.
Overall, GRDMinproc estimates Kansanshi’s measured and indicated resource at 302 million tonnes grading 1.17% copper and 0.l7 gram gold. Another 111 million tonnes grading 1.11% copper and 0.12 gram gold are classified as inferred.
The estimates include results of infill drilling by First Quantum and are based on a cutoff grade of 0.5% copper. When that cutoff grade is doubled, volumes in all three categories are dramatically reduced, though average metal grades are significantly increased.
The Kansanshi deposit lies in the Lufilian Arc, a major fold-thrust tectonic belt that hosts all of the deposits in the famous Copperbelt. The belt passes through both Zambia and the neighbouring Democratic Republic of Zaire (DRC).
Locally, the property is dominated by the northwesterly trending Kansanshi antiform, which exposed rocks of the Late Proterozoic Kansanshi Mine formation in the core of a major refolded fold. Copper mineralization occurs in steeply dipping, north-trending quartz-carbonate veins and in flat-lying stratabound layers within altered phyllitic rocks of the Mine formation.
Should First Quantum advance the deposit to production, it must pay Phelps Dodge US$25 million within 30 days of the event. The payment will be reduced by an amount equal to 1.4 million of the shares of First Quantum that were issued to Phelps Dodge as partial payment for the deposit.
In related news, First Quantum has arranged an US$18-million credit facility with Standard Chartered Bank. Proceeds are earmarked for an ongoing expansion program at the Bwana Mkubwa SX-EW tailings recovery plant, near the town of Ndola, about 200 km southwest of Kansanshi.
So far, First Quantum has installed the necessary crushing, milling and pre-leach filtration facilities needed to blend Bwana Mkubwa tailings with Lonshi ore. The current phase will see the leach, filtration, SX-EW facilities expanded to accomodate the extra feed.
Once in full swing, the expanded Bwana Mkubwa plant is expected to crank out 30,000 tonnes copper cathode annually, or three times as much as before. Cash costs will likely average US30 per lb. copper, net of sulphuric acid credits.
First Quantum purchased Lonshi in mid-2000 and advanced it to production 16 months later. As of May, the company had stockpiled 563,000 tonnes grading 4.5% copper for future processing.
Resources stand at 5.1 million tonnes grading 5.75% copper.
The resource is based on a 2% cutoff grade and 138 drill holes totalling 5,474 metres. The program included 10 core holes, 91 reverse-circulation holes, and 37 air-blast holes.
Exploration drilling along strike and downdip continues. Holes are being collared to test mineralization at depths of 65-140 metres below surface.
Results are pending for several holes, all of which tested mineralization at depths of 65-140 metres below surface.
First Quantum holds an 85% interest in the deposit through a subsidiary. The company also holds a 16.9% interest in the Mufulira and Nkana mines, including a copper and cobalt smelter and copper refinery.
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