Marimaca Copper (TSX: MARI; ASX: MC2) has cut 216 metres grading nearly 1% copper at Pampa Medina in Chile’s Antofagasta Region while step-out drilling pushed the copper-silver system 300 metres beyond earlier holes.
Hole SPRD-15 returned 216 metres grading 0.96% copper and 7.2 grams silver per tonne from 466 metres downhole, including 62 metres at 2.2% copper and 21.5 grams silver from 602 metres, Marimaca said Tuesday. Pampa Medina lies 28 km east of Marimaca’s more advanced oxide depositwithin 40 km of Antofagasta, the mining region’s capital.
“Pampa Medina remains open in several directions and is materially under-tested,” Vice-President of Exploration Sergio Rivera said in a release. ”These results continue to strengthen our view that we are defining a large, high-grade copper-silver system.”.
The drilling adds scale to Pampa Medina as Marimaca advances its nearby oxide deposit towards a construction decision. The company plans 30,000 metres of drilling at Pampa Medina this year, while the deposit’s proximity to planned mine infrastructure gives Marimaca a potential growth source alongside a project already through feasibility and environmental review.
The company’s Toronto-listed shares jumped 13% on Tuesday to $9.10 apiece, giving it a market capitalization of $1.2 billion (US$870 million). Shares have ranged between $6.72 and $13.49 over the past 12 months.
Step-out gains
Near the southeastern edge of drilling, hole SPD-13 cut 222 metres grading 0.5% copper from 194 metres, including 48 metres at 1.05% copper from 368 metres. The hole extended both oxide and deeper sulphide mineralization.
About 300 metres west of previous drilling, SPRD-12 returned 56 metres grading 0.95% copper and 4.2 grams silver per tonne from 748 metres, including 22 metres at 1.8% copper and 9.7 grams silver from 750 metres.
SPRD-17, drilled 150 metres east of an earlier hole, cut 104 metres grading 0.65% copper from 522 metres. That interval included 30 metres at 0.96% copper from the same depth and 40 metres at 0.89% copper from 586 metres.
Marimaca estimates true widths at about 80% of reported downhole lengths.
The latest holes support continuity across a 3-km by 1.5-km area where drilling has traced copper through several sedimentary layers, the company said. Pampa Medina hosts near-surface oxide mineralization and deeper sulphides containing bornite, chalcopyrite, covellite and chalcocite. Silver grades generally rise with copper grades, according to company documents.
Deeper targets
Drilling has yet to define the northern and northwestern limits. Four scout reverse-circulation holes stopped before reaching the target sedimentary rocks at depths of 540 to 700 metres, prompting Marimaca to extend them with diamond drilling.
One of those holes, SWR-13, ended in mineralization after cutting 8 metres grading 1.47% copper and 7.5 grams silver per tonne from 580 metres in volcanic rocks above the interpreted sedimentary contact.
Marimaca consolidated the Pampa Medina project area and surrounding ground in 2024, then reworked the geological model to target deeper sedimentary units. This year’s program is testing the high-grade core, oxide extensions and the outer limits of the system.
Oxide base
The Marimaca oxide deposit gives the company a more advanced development base while it tests Pampa Medina’s scale. A 2025 feasibility study outlined proven and probable reserves of 179 million tonnes grading 0.42% copper for 748,000 tonnes of contained metal.
The study targets about 50,000 tonnes of copper cathode production a year over a 13-year mine life. It estimated US$587 million in pre-production capital and a post-tax net present value of US$709 million at an 8% discount rate using $4.30-per-lb. copper, with a 31% internal rate of return.
Marimaca is advancing detailed engineering, permits and project financing ahead of a possible final investment decision in the coming months.
Source: https://www.mining.com/marimaca-hits-thick-copper-silver-zone-at-pampa-medina-in-chile/
