New Discovery Made at the Marimaca Sedimentary Copper Mine in Chile

According to MiningNews.net, Marimaca Copper has confirmed the discovery of high-grade copper sulphides beneath the Pampa Medina oxide deposit in Chile, with characteristics similar to some of the world's most significant deposits.

The main intersection was 100 meters at 580 meters depth, with a copper grade of 1.3%, including a 26-meter-thick ore body with a copper grade of 4.1%, and a peak grade of 12% over 6 meters.

Another hole intersected 132 meters at 278 meters depth, with a copper grade of 1%, including 40 meters of mineralization with a grade of 2.1%.

The thickness and grade of the intersections are promising, but what excites the company is the stratigraphic control of the ore body, which is not commonly found in Chile despite the country being the world's largest copper producer.

The drilling targeted the lower part of the oxide-chalcocite ore body within 600 meters of the surface at Pampa Medina, intersecting ultra-high-grade bornite-chalcopyrite, disseminated chalcopyrite, and high-grade oxide ore at intervals of 600 meters.

"This is the first time in my 40-year career that I have seen such a large-scale, stratigraphically controlled, ultra-high-grade copper deposit in Chile," said Sergio Rivera, Vice President of Exploration at Marimaca.

"The intensity of the chalcocite and chalcopyrite mineralization is truly remarkable."

He stated that the company's unconventional Chilean exploration model has been validated.

Copper belt similarities

Although drilling has confirmed that Pampa Medina is part of a larger mineralizing system, Marimaca believes its rocks are lithologically similar to those of the Copper Shale Belt or the Central African Copper Belt (CACB).

The CACB is considered the largest and highest-grade sedimentary-hosted copper province known on Earth, with a copper metal content of 200 million mt at a grade of 4%, and the world's largest cobalt reserves.

The CACB has been continuously explored and studied for over 100 years.

The European Copper Shale Belt, located between England and Belarus, covers an area of over 600,000 square kilometers, with copper grades up to 3%. It is considered one of the world's most important copper deposits and has been mined since 1199.

The exploration area at Pampa Medina spans 1,000 meters by 600 meters, with soil anomalies extending up to 1,400 meters by 1,200 meters.

Marimaca has added a second diamond drill rig to support the next phase of drilling, which includes 14 holes.

Earlier this year, the company paused its preliminary economic assessment to allow time to interpret the drilling results after the discovery of sulphides.

The measured and indicated copper resources in the oxide deposit amount to 899,700 mt, and the final feasibility study is nearly complete, which will determine the development approach. Additionally, the inferred resource is 141,300 mt.

Construction will commence in April 2026, with an estimated investment of $500 million, which will support an annual production capacity of 50,000 mt of copper cathode.

Hayden Locke, Executive Director of Marimaca, stated that once the Marimaca infrastructure is completed, Bampamedina can be developed with relatively low capital investment.

Bampamedina is located approximately 30 kilometers from the Marimaca copper oxide deposit, 40 kilometers from Mantos Blancos, operated by Capstone Copper, and 64 kilometers from Sierra Gorda copper mine, operated by South32.