TORONTO (miningweekly.com) – Ivanhoe Mines on Friday said it had found more “exceptional” high-grade zinc and copper drill intercepts from its current drilling campaign at the Kipushi copper/zinc/germanium/lead and precious-metals mine, in the Democratic Republic of Congo.

The exploration drilling from Kipushi's 1 272 m level mainly aimed to establish an updated, compliant resource in the mine’s Big Zinc zone, which had not been mined since its discovery in the late 1980s.

Ivanhoe reported that drilling highlights included hole KPU011, which returned 16.1 m, grading 4.9% copper, 5.8% zinc and 23 g/t silver; hole KPU013, which returned 13.7 m, grading 9.9% copper, 12.1% zinc, 37 g/t silver and 24 g/t germanium; KPU014, which returned 8.7 m, grading 5.7% copper, 22.5% zinc, 33 g/t silver and 28 g/t germanium; KPU015, which returned 9.7 m, grading 9.0% copper, 0.5% zinc and 30 g/t silver; and KPU020, which returned 5.2 m, grading 21% copper, 2.3% zinc, 190 g/t silver and 10 g/t germanium.

The company noted that it had started drilling the Big Zinc zone from the hangingwall drill drift on the 1 272 m level, a significant development since drilling from this drift provided the geometry for near-true-width intercepts across the Big Zinc zone.

The first hole from the 1 272 m level, hole KPU040, had just been completed and represented the first of Ivanhoe's holes designed to allow it to estimate the historical Big Zinc indicated resource – originally established through pre-1993 drilling by the previous owner – in line with current guidelines set by the Canadian Institute of Mining, Metallurgy and Petroleum.

Hole KPU040 intersected massive sulphide mineralisation over a downhole distance of about 90 m, containing massive sphalerite (zinc), chalcopyrite and bornite (copper) and pyrite of the Big Zinc zone. A second hole in the hangingwall drilling programme, targeting the Big Zinc zone, was currently under way.

To date, Ivanhoe had completed 35 holes comprising about 7 350 m of its planned 20 000 m underground diamond drilling programme, with two diamond-drill rigs being active.

The first was in the hangingwall drill drift on the 1 272 m level, targeting the Big Zinc zone. The second rig was expected to complete the drilling of five remaining holes in the Série Récurrente zone in about two weeks, after which it would be relocated to the 1 272 m level.

Hole KPU040 represents the first of 24 holes and 5 680 m of drilling planned for the Big Zinc hangingwall drilling programme. A further 12 drill holes were also planned to test for deep extensions to the Big Zinc zone, of which seven would be completed from the hangingwall drift and the remainder from various locations on the decline.

Meanwhile, Ivanhoe was busy implementing significant infrastructure upgrades on the surface and underground as part of its planned redevelopment of the Kipushi mine. Most fabrication work was done on site using the recommissioned machine shop and boilermaker shop facilities.

Recent key upgrades included installing and commissioning the new main ventilation fan at Shaft No 4; building a water dam and installing a major pumpstation on the 1 112 m level, and winder upgrades at Shaft No 5 to enable the installation of permanent pumping arrangements and shaft restoration.