Ivanhoe Mines has reported that early results from its underground diamond drilling programme at the Kipushi copper-zinc-germanium-lead and precious metals mine in the Democratic Republic of Congo have established significant down-dip extensions of the unmined high-grade Big Zinc Discovery.
Drilling has extended the Big Zinc mineralisation to a depth of about 1,700m below surface, around 200m deeper than the previous lowest level of its historical measured and indicated resources.
The company said the historical measured and indicated resources were recorded 20 years ago, before Kipushi was placed on care and maintenance in 1993 by its former owner.
Assays for copper, zinc, lead, germanium and precious metals contained in the first four Ivanhoe drill holes were still pending.
Two drill rigs are currently on-site and a third rig has arrived and is expected to start drilling soon.
The company anticipates accessing the important 1,272m level hanging wall drift this month, which will enable it to commence the drill programme's phase of twinning the historical drilling.
Ivanhoe Mines executive chairman Robert Friedland said that drilling at Kipushi continues to identify thick intersections of strong sphalerite and chalcopyrite mineralisation.
"We will continue to carry out more extensional drilling to enable us to identify potential high-grade material down-plunge below the 1,500m level," Friedland said.
"Given the close proximity of Kipushi to several copper smelters in neighboring Zambia, the intersections of copper-rich chalcopyrite and bornite mineralisation encountered in the drill holes below the former mine workings are highly encouraging."
The Kipushi mine is situated on the Central African Copperbelt in southern Katanga province, about 30m south-west of the provincial capital of Lubumbashi and less than a kilometre from the international border with Zambia.
Ivanhoe said the idled mine flooded in early 2011 due to lack of pumping maintenance over an extended period.
In November 2011, Ivanhoe acquired a 68% stake in Kipushi from Gécamines, which continues to hold a 32% interest.
Ivanhoe has also assumed responsibility for on-going rehabilitation and pumping, which has now reached the 1,265m level.
Image: Kipushi cross-section showing mine infrastructure, Big Zinc Discovery and Kipushi Fault Zone. Photo: courtesy of Ivanhoe Mines.