A 390% increase in the size of the Lonshi copper deposit sets the stage for
The Lonshi deposit is in the Democratic Republic of Congo, close to the Zambian border and 28 km by road from Bwana Mkubwa.
The measured and indicated resource now stands at 5.1 million tonnes grading 5.75% copper, or 294,890 tonnes of contained copper. The previous estimate was 60,000 tonnes of copper at an average grade of 5%.
The revision 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. (A reverse-circulation hole that was twined by two core holes returned similar results.)
The zone of mineralization, in the same Roan clastic rocks that play host to most of the Zambian copper belt’s deposits, is 15 metres thick, 800 metres long and dips gently to the east. It extends to 65 metres below surface, where it remains open. The deposit remains open along strike as well.
The resource, as outlined, indicates that Lonshi can be exploited by open-pit mining and direct acid-leaching. Test recoveries have averaged 86% copper.
Based on the new estimate, First Quantum is considering a three-fold expansion of the Bwana Mkubwa plant. Currently, the plant cranks out 10,000 tonnes of copper cathode annually by treating tailings left over from historic operations. Excess sulphuric acid is produced in the process and sold to other operations in the copper belt.
Crews are already constructing the necessary crushing, milling and pre-leach filtration facilities needed to blend the two ore types. However, these additions, which should be finished by year-end, are being built to accomodate the original resource. If the expansion proceeds, another year of construction would be required.
First Quantum holds an 85% stake in the Lonshi deposit and a full interest in the Bwana Mkubwa project. Similarly, the miner holds 44% interests in the Nkana and Mufulira mines, also in Zambia. The former includes a concentrator and cobalt plant, whereas the latter comes with a concentrator, smelter and copper refinery.
In related news, Thomas Dale has resigned as chief executive officer of Mopani Copper Mines, the Zambian-incorporated subsidiary of First Quantum. A replacement is being sought, though in the interim, William Blamires, currently chief financial officer of Mopani, will fill the role.
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