Using the IntelligenceMine database of our sister company Infomine, The Northern Miner compiled five projects with the top copper intersections (grade multiplied by width) globally in March 2017, as reported publicly.
1. Exploration firm Xanadu Mines (ASX: XAM) topped the list, returning exceptional results from its flagship Kharmagtai copper-gold project in Mongolia’s Omnogovi province, 420 km southeast of Ulaanbaatar. Kharmagtai is within the South Gobi porphyry copper province, which is home to several porphyry deposits in the South Gobi region, including the large Oyu Tolgoi copper-gold mine (120 km south).
On March 29, Xanadu reported an update on the ongoing exploration at Kharmagtai, including multiple drill holes confirming the depth extension of the project’s Altan Tolgoi copper-gold deposit.
Diamond drill hole 394 returned 646 metres (from 18 metres) grading 0.51% copper (or 393 metres × % copper per tonne), plus 0.87 gram gold from 16 metres, including 64 metres at 1.06% copper and 3.15 grams gold. The 646-metre intercept, which is the best drilled to date at Kharmagtai, confirms mineralization extends from surface to almost 625 metres vertically.
Hole 394a hit 385 metres (from 351 metres) of 0.52% copper (or 200 metres × % copper per tonne), plus 0.6 gram gold.
“We are yet to define the extents of the Altan Tolgoi porphyry system, and further drilling is planned below the breccia zone-hosted chalcopyrite-gold mineralization to test whether a higher-grade bornite core is in the root of this large breccia system,” Andrew Stewart, the company’s chief executive, said in a release.
Kharmagtai has a Joint Ore Reserves Committee-compliant resource of 1.5 billion lb. copper and 2.2 million oz. gold (203 million tonnes of 0.3% copper and 0.3 gram gold).
2. Indonesia-focused miner Finders Resources came in second place. On March 6, Finders reported significant drill results from pre-development activities at the Lerokis deposit on its 73.5%-held Wetar copper project, which also contains the producing Kali Kuning deposit. The project is on the north coast of the remote island of Wetar in the Maluku Barat Daya province of eastern Indonesia.
Finders notes that high-grade copper intersections in geotechnical and metallurgical diamond drill holes indicate the potential to expand the existing resource in the southwest and northeast parts of Zone 5, and in the northwest of Zone 1S. The zones are part of the planned Lerokis mine development.
Metallurgical holes in Zone 1S returned 26.2 metres of 8.01% copper (or 210 metres × % copper per tonne), 1.35 grams gold, 73 grams silver, 2.6% zinc and 0.69% lead from 4 metres, and 34 metres at 5.28% copper (or 179.5 metres × % copper per tonne), 1.09 grams gold, 75 grams silver, 3.59% zinc and 0.84% lead from 10 metres.
Geotechnical hole 14 in Zone 5 cut 24 metres at 5.84% copper (or 140.2 metres × % copper per tonne), 0.48 gram gold, 25.3 grams silver, 0.39% zinc and 0.16% lead from 12 metres.
Finders expects to incorporate the results into the planned resource update after finishing the upcoming 2,900-metre, reverse-circulation drilling program. Lerokis is set to start producing in 2019.
3. Mariana Resources (TSXV: MRA; LON: MARL) trailed in third, with encouraging results from its 30%-held Hot Maden gold-copper project in northeastern Turkey’s Artvin province. Turkish partner Lidya holds the rest.
On March 23, Mariana published assays from 19 holes completed around the project’s Main zone and the Ridge area, which is the transitional zone between the Main zone and the New Southern deposit.
Highlights include hole 106 returning 116.5 metres grading 6.7 grams gold and 1.7% copper (or 198 metres × % copper per tonne) from 224.5 metres, including 16 metres of 35.7 grams gold and 2.9% copper. This infill hole “confirmed the continuity of high-grade gold-copper mineralization within the core of the Main zone resource,” Mariana says.
Hole 88, a step back to hole 75, hit 79 metres of 8.1 grams gold and 1.9% copper (or 116.2 metres × % copper per tonne) from 326 metres, which extended the downdip extension of the gold-copper mineralized zone.
Mariana says the gold-copper mineralization in the Main zone is “multistage, and ranges from early, massive sulphide-type mineralization to later tectonic brecciation, consisting of chalcopyrite-pyrite-bearing quartz stockworks and veining with distinctive red jasperoid.”
Mariana and Lidya have three rigs turning on Hot Maden, in advance of completing a prefeasibility study.
4. Vancouver-based Imperial Metals (TSX: III) took fourth place, after announcing underground drill results at the Mount Polley copper-gold open-pit mine in south-central British Columbia, 56 km northeast of Williams Lake.
After markets closed on Feb. 28, Imperial reported the results from the first nine underground holes completed at Mount Polley’s Martel and Green zones beneath the Wight pit, 400 metres east of the recently mined Boundary zone.
Hole 16-6 returned 147.5 metres of 1.03% copper (or 152 metres × % copper per tonne) and 0.2 gram gold from 92.5 metres, including a 15.8-metre interval of 1.9% copper and 0.3 gram gold. Imperial notes that the long, lower-grade hole may be amenable to sublevel caving.
Meanwhile, hole 17-7 intersected 110 metres of 1.27% copper (or 139.7 metres × % copper per tonne), plus 0.24 gold, including 57 metres of 1.9% copper and 0.37 gram gold.
The results are part of the first underground exploration at the Martel zone, where Imperial drilled 6,600 metres in 25 holes. Imperial expects to release assays from the remaining holes shortly.
5. Subiaco, Western Australia-based Mod Resources (ASX: MOD) ranked fifth, after reporting results from its 70%-held T3 copper-silver project in Botswana’s Kalahari copper belt. Metal Tiger (LON: MTR) holds the other 30%.
Mod released two assay results on March 6 from the newly discovered Zone 2 below the T3 resource area (now named Zone 1).
Hole 65D returned 72.6 metres (from 250 metres) of 1.5% copper (or 108.9 metres × % copper per tonne), plus 27 grams silver, including 18 metres of 2.7% copper and 52 grams silver.
On March 30, Mod said drilling has extended Zone 2’s disseminated mineralization, 700 metres along strike. Since discovering Zone 2 in February 2017, Mod completed 16 diamond core holes over six weeks to define the zone to 300 metres deep. The zone remains open downdip.
Depending on the remaining assay results, Mod notes it may include Zone 2 in a potentially expanded T3 resource. “This is a high priority because Zone 2 lies directly below the proposed open pit and could have a material positive impact on the economics of the T3 PFS, already in progress,” Julian Hanna, Mod’s managing director, said in a release.
To accelerate the assay turnaround, the company is installing a sample preparation facility on-site.