Marimaca widens Pampa Medina 600 metres west

Marimaca Copper (TSX: MARI, ASX: MC2) drills pushed the emerging Pampa Medina deposit 600 metres farther west with another run of thick copper-silver assays, improving the odds that the Chilean target can grow into a much larger feed source for the company’s namesake project.

The best new hole, SWRD-02, cut 74 metres grading 1.21% copper and 7.9 grams silver per tonne from 520 metres downhole, including 12 metres of 2.07% copper and 17.2 grams silver, Marimaca said Wednesday.

Hole SMRD-34, drilled midway between that fence and earlier drilling, returned 36 metres of 1.08% copper and 13.8 grams silver from 158 metres, plus 24 metres of 1.37% copper and 12.2 grams silver from 600 metres. A second western step-out, SWRD-01, cut 38 metres of 1.43% copper and 11.8 grams silver from 694 metres.

“Pampa Medina continues to extend significantly. Our area of interest, defined by drilling, now extends 3 km by 2 km,” CEO Hayden Locke said in a statement. “What is incredibly unusual, is the average true thickness of the mineralized sediments.”

Marimaca now plans to increase drilling at Pampa Medina to 10 rigs and 100,000 metres this year after a 30,000-metre second round widened the mineralized footprint.

Pampa Medina and nearby Madrugador sit about 25 km from the planned processing plant for the Marimaca oxide deposit, where the company has already outlined a proven and probable reserve of 178.6-million-tonnes grading 0.42% copper and a 213.5-million-tonne measured and indicated resource grading 0.40% copper.

District scale

Marimaca is chasing a district-scale build, with satellite oxides that could lift cathode output and extend mine life and sulphides that could turn Sierra de Medina into a much larger deposit.

The western holes kept tracing the same lower sedimentary package across 300-metre spacing, which is what gave the result weight, the company said. Even the weaker holes helped: SWRD-04 cut both upper and lower mantos but ran into pre- and post-mineral dykes, while SWRD-03 hit splays of the Ancla fault system and still returned lower-grade deep mineralization.

Marimaca is not reporting copper-equivalent grades yet because it has not finished initial metallurgical work at Pampa Medina. Still, the silver is becoming hard to ignore. The company pointed to nearby Chilean manto deposits such as Capstone Copper’s (TSX: CS; ASX: CSC) Mantos Blancos and Antofagasta’s (LSE: ANTO) Cachorro as evidence that silver can matter in this style of system.

Big project

At the main Marimaca project, a feasibility study last year outlined a 13-year mine producing 50,000 tonnes per year of copper cathode with $587 million (C$798 million) in initial capex, a post-tax net present value of $709 million at an 8% discount rate and a 31% internal rate of return at a $4.30 per lb. copper price.

The project is 25 km from the port of Mejillones and 40 km from Antofagasta. Marimaca said environmental approval arrived late last year while detailed engineering and project financing moves ahead.

What Marimaca still lacks at Pampa Medina is a resource and the metallurgical work to show how the sulphides would fit into that district plan.

Marimaca shares rose 2.6% to C$9.59 Wednesday in Toronto, boosting the company’s market value to about C$1.3 billion. The stock has traded between C$4.20 and C$13.49 in the past year.