Lumina hits more long intersects at Taca Taca

Lumina Copper (LCC-V) reports that the Taca Taca deposit in northwestern Argentina, 90 km east of Escondida, the world’s largest copper mine, has yielded the longest mineralized intercept to date with 813 metres grading 0.60% copper equivalent, including 134 metres of 1.22% copper equivalent. 

Breaking it down into various components: step-out hole 71 returned 813 metres grading 0.50% copper, 0.07 gram gold per tonne and 0.01% molybdenum for 0.60% copper equivalent, including 134 metres of 1.04% copper, 0.11 gram gold and 0.02% molybdenum at 1.22% copper equivalent. 

“The exceptional intersection in hole 71 not only comes from outside the resource area, but also is the best drilled to date in terms of thickness,” Andy Carstensen, Lumina’s vice-president of exploration, explains in an email to The Northern Miner. “Mineralization in the hole starts much nearer surface than seen in some other portions of the deposit,” which he says is “something certainly to influence early mine design and planning.”

Carstensen notes that hole 71 shows the deposit is open for northern expansion and says a second drill rig moving to the area shortly would speed-up resource delineation,and help the company understand and model this portion of the Taca Taca deposit.

 “Recent results from the northeastern and southern portions of the Taca Taca deposit show the system is in no way diminishing as step-out drilling continues in both directions,” he says.

Hole 71 was drilled 150 metres east of hole 52 as a step-out along the deposit’s northeastern boundary and intersected 590 metres grading 0.57% copper, 0.06 gram gold per tonne and 0.01% moly (0.66% copper equivalent), including 104 metres of 1.62% copper, 0.12 gram gold and 0.02% moly (1.81% copper equivalent). Assays from hole 52 were released late last year on Dec. 14.

Three hundred metres south of hole 71, hole 63 returned 437 metres of 0.56% copper, 0.06 gram gold and 0.02% moly (0.71% copper equivalent), including 54 metres of 1% copper, 0.03 gram gold and 0.01% moly (1.08% copper equivalent).

Infill holes 61 and 62 were drilled within the northern supergene enrichment zone and have further defined the continuity of Taca Taca’s high-grade copper zone. Hole 61 cut 444 metres of 0.73% copper, 0.14 gram gold and 0.03% moly (0.99% copper equivalent), including 74 metres of 1.36% copper, 0.25 gram gold and 0.06% moly (1.87% copper equivalent). 

Hole 62 returned 496 metres grading 0.67% copper, 0.13 gram gold and 0.02% molybdenum (0.87% copper equivalent), including 56 metres grading 1.92% copper, 0.22 gram gold and 0.04% molybdenum (2.29% copper equivalent).

The project’s most southerly hole, number 55 — intersected two zones of sulphide copper mineralization. In the upper zone, hole 55 cut 46 metres of 0.65% copper, 0.17 gram gold and 0.02% moly (0.87% copper equivalent), and in the lower zone, hole 55 contained 320 metres of 0.52% copper, 0.12 gram gold and 0.01% moly (0.65% copper equivalent). The hole was lost in mineralization grading greater than 0.5% copper.

Further defining the eastern boundary of mineralization at Taca Taca, hole 66 was drilled into the eastern portion of the central hole and intersected 172 metres of 0.23% copper, 0.11 gram gold and 0.02% moly (0.41% copper equivalent). 

Carstensen notes that hole 67, while returning no significant intercepts, was important geologically because the hole hit an extensive porphyritic intrusion indicating the series of dikes mapped at surface near the centre of the molybdenum geochemical anomaly coalesce at a shallow depth. “The location of the ‘mineralizing’ source intrusion has long been debated at Taca Taca. We may now have found it,” Carstensen says. “Delineation of its extent and geometry will aid exploration as we move to the south and southeast.”

Drilling at Taca Taca is focused on expanding the project’s resource estimate to the north, northeast, northwest, east, south and southeast, as well as upgrading mineralization from the inferred category to the indicated category.

So far Lumina Copper has drilled 96 core holes in 52,700 metres and 84 reverse-circulation (RC) holes in 13,400 metres, and has seven core and two RC drills on the property. The RC rigs are being used to pre-collar core holes and explore and delineate the oxide gold resources in the leached cap of Taca Taca’s porphyry system.

Taca Taca — 230 km west of  Salta in Argentina’s Puna region — has an indicated sulphide resource at a 0.4% copper-equivalent cut-off grade of 516 million tonnes of 0.58% copper, 0.12 gram gold and 0.018% moly (0.76% copper equivalent) for 6.6 billion lbs. copper, 2.1 million oz. gold and 204.6 million lbs. moly.

Inferred sulphide resources stand at 880 million tonnes of 0.43% copper, 0.09 gram gold and 0.015% molybdenum (0.57% copper equivalent) for 8.3 billion lbs. copper, 2.3 million oz. gold and 292.9 million lbs. molybdenum. 

Lumina Copper has also defined an oxide gold resource within the leached cap. At a 0.2-gram gold cut-off grade, the inferred resource stands at 190 million tonnes grading 0.25 gram gold for 1.5 million contained oz. gold. 

The copper-equivalent cut-off grade used in the calculation of the mineral resource estimate was determined using US$2 per lb. copper, US$800 per oz. gold and US$12 per lb. molybdenum.

Taca Taca contains a large, Andean-type copper porphyry hydrothermal system that has generated supergene and hypogene copper, molybdenum and gold mineralization. Other mineralization on the property includes remnant bodies of oxide and supergene deposits within the porphyry’s leached cap, gold-copper quartz veins north and west and exotic copper oxide mineralization east and southeast beneath the Salar de Arizaro. Taca Taca lies along the western edge of the salar, the largest dry salt lake in the country. A surface molybdenum anomaly also defines the Taca Taca system.

At presstime Lumina Copper traded at $15.40 per share.