Diversified explorer Golden Deeps (ASX: GED) began drilling less than a week ago at its historic Khusib Springs copper-silver mine and has already intersected copper carbonate mineralisation in two holes.
The Khusib Springs mine closed in 2003 due to low copper prices, with the red metal having fallen to around US$1,500 per tonne at the time — a stark contrast to the US$9,876/t close at the London Metal Exchange last night and the recent Goldman Sachs’ forecast of US$11,000/t by the end of 2021.
The drilling program is testing for high-grade copper on the margins of the mine’s historic stopes.
The mine produced 300,000t at 10% copper and 584 grams per tonne silver from 1996 until its closure.
Khusib Springs is located in the Otavi Mountain Land region of Namibia, near the town of Grootfontein.
Malachite and azurite intersected
The copper carbonate mineralisation (malachite and azurite) was intersected in two of the holes drilled into the up extension of the deposit, near shallow surface workings.
The reverse circulation program is targeting copper and silver in the upper part of the deposit adjacent to the historic stopes.
It will also test for up plunge extensions to the deposit that was mined from underground but not extended to surface.
Khusib Springs is one of three major projects being undertaken by Golden Deeps, the others being the advanced Abenab vanadium-lead zinc deposit (also in Namibia) and the Tuckers Hill and Havilah projects on the Lachlan Fold Belt in NSW.
High-grade historic intersections
Historic intersections at Khusib Springs include 4.5m at 35.19% copper, 3.67% lead, 2.23% zinc and 2,090.91g/t silver, along with 14m at 8.12% copper, 0.75% lead, 0.52% zinc and 385.06g/t silver.
Golden Deeps says the Khusib Springs mine is considered analogous with the Tsumeb mine, located 40km to the northwest.
Between 1905 and 1996 that mine produced 30Mt of ore grading 4.3% copper, 10% lead and 3.5% zinc.
Last year, Golden Deeps commissioned a geological study of Khusib Springs.
The consultants, after validating historic drilling data and examining mine and stoping plans, concluded that there were remanent zones of copper-silver mineralisation on the margins of the mined stopes as well as at depth.
The company believes that the remaining ore was probably left because of the prevailing low copper prices at the time.
Drill rig will next move to historic copper-vanadium mine
Following completion of the drilling at Khusib Springs, the drill rig will move to the historic Nosib mine.
Copper was discovered at Nosib Block in 1917 and mined through to 1920, with the No 2 shaft being worked at three levels, and reaching a depth of 120m.
The company has described Nosib Block, 16km west of Khusib Springs, as a “high-grade copper-vanadium mine”.
Golden Deeps’ geologists assessed all three of the old levels and concluded that high-grade copper-silver-vanadium-lead mineralisation dips moderately to the north.