Ivanhoe Mines Ltd. said July 30 that an updated resource estimate for its majority-owned, polymetallic Kipushi project in the Democratic Republic of the Congo resulted in a 16% increase in measured and indicated zinc resources and a 40% jump in measured and indicated copper resources, both in terms of tonnage.
Kipushi hosts zinc-rich measured and indicated resources totaling 11.8 million tonnes grading 35.34% zinc, 0.80% copper, 1.05% lead, 23 g/t of silver, 13 parts per million of cobalt and 64 g/t of germanium. Contained metal comprises 9.18 billion pounds of zinc, 208.6 million pounds of copper, 272.2 million pounds of lead, 8.7 million ounces of silver, 340,000 pounds of cobalt and 24.4 million ounces of germanium.
Zinc-rich inferred resources are estimated at 1.1 million tonnes grading 33.77% zinc, 1.24% copper, 0.24% lead, 12 g/t of silver, 14 ppm of cobalt and 62 g/t of germanium, representing 850.7 million pounds of zinc, 31.3 million pounds of copper, 6.2 million pounds of lead, 460,000 ounces of silver, 40,000 pounds of cobalt and 2.3 million ounces of germanium.
The zinc-rich estimate covers the Big Zinc and Southern Zinc zones and uses a cutoff grade of 7% zinc.
Kipushi also hosts copper-rich measured and indicated resources of 2.3 million tonnes grading 4.03% copper, 2.85% zinc, 0.06% lead, 21 g/t of silver, 76 ppm of cobalt and 19 g/t of germanium, for 204 million pounds of copper, 144.2 million pounds of zinc, 3.1 million pounds of lead, 1.6 million ounces of silver, 390,000 pounds of cobalt and 1.4 million ounces of germanium.
Copper-rich inferred resources are pegged at 440,000 tonnes grading 3.89% copper, 10.77% zinc, 0.04% lead, 19 g/t of silver, 75 ppm of cobalt and 55 g/t of germanium, representing 37.9 million pounds of copper, 104.9 million pounds of zinc, 400,000 pounds of lead, 270,000 ounces of silver, 70,000 pounds of cobalt and 780,000 ounces of germanium.
The copper-rich estimate covers the adjacent Fault, Fault Splay and Série Récurrenté zones and uses a 1.5% copper cutoff.
Ivanhoe Mines noted that the initial estimate, completed in early 2016, outlined zinc-rich measured and indicated resources of 10.2 million tonnes grading 34.89% zinc, with copper-rich measured and indicated resources of 1.6 million tonnes grading 4.01% copper.
The update incorporates data from the company's second phase of underground drilling completed late last year to total 9,706 meters. The estimate will be used for a definitive feasibility study expected to be finalized by late 2018 or early 2019.
Ivanhoe said the planned return to production at Kipushi, which operated for more than 60 years before being placed on care and maintenance in the 1990s, will establish it as the world's highest-grade, major zinc mine.
The project is operated by Kipushi Corp., a joint venture between 68% owner Ivanhoe and 32% owner Gecamines SA, DRC's state-owned mining company.