A recent drilling campaign on the Zone 5 deposit at Cupric Canyon Capital subsidiary Khoemacau Copper Mining, in Botswana, has defined a 100-million-ton high-grade copper and silver ore resource, the company said on Tuesday. “This most recent drilling and feasibility work has established Zone 5 as one of the most attractive new copper projects in the world,” commented chairperson Timothy Snider. Favourable geology and metallurgy, combined with the recent acquisition of the nearby fully functional Boseto mill and a competent and supportive government, had set the company on a path to first production with “very favourable capital intensity” in 2018, he said.
“We are also very excited about the numerous additional exploration targets we have identified on our expansive land position,” Snider commented. The Zone 5 resource now totalled an estimated 100.3-million tons of measured, indicated and inferred ore, grading 1.95% copper and 20 g/t of silver. Total contained metal included two-million tons of copper and 64-million ounces of silver. The strata-bound orebody, with an average width of 10 m, a strike length of 4.2 km, a dip of 56° to 60° and competent stratigraphy, lent itself to low-cost underground mining, with no backfill required.
The orebody, in which ore was first encountered at 70 m below the surface, remained open at depth and along strike. In a bid to establish a plan for near-term initial production from the developing copper district, Cupric Canyon had completed a feasibility study that had demonstrated the viability of using the recently acquired Boseto mill to process Zone 5 ore. Capital expenditure of $350-million would be required to develop three interconnected underground mines along strike to extract 10 000 t/d of ore, construct an ore transportation system over 30 km and expand the Boseto mill.
“This operation, with a 27-year mine life, will produce about 50 000 t/y of copper, grading 42% copper, and 1.4-million ounces of silver contained in concentrate. “Cash production costs are estimated to be between $1.05/lb and $1.10/lb of copper, which is in the lowest quartile of the industry cost curve. Capital intensity of $6 460/t of yearly copper equivalent production is about half of the industry average for brownfield projects of $12 000,” he remarked. Cupric Canyon had also completed a prefeasibility study that had demonstrated that production of 16 800 t/d of ore from six interconnected underground mines along strike in the Zone 5 orebody was achievable. Processing of the ore would be accomplished either with installation of new mill capacity at the mines capable of handling the entire mine output or a combination of new capacity and the Boseto mill.
The company put total project capital at $600-million, resulting in an operation with a 16-year mine life that produced about 87 000 t of copper, grading 42% copper, and 2.5-million ounces of silver contained in concentrate. Cash production costs were estimated to be between $0.90/lb and $0.95/lb of copper.