Oroco rises on ‘robust’ copper resource at Santo Tomas in Mexico

Shares in Oroco Resource (TSXV:OCO; US-OTC:ORRCF) gained after the explorer said a deposit estimate for the Santo Tomas copper project in northwest Mexico “significantly” expands on 1990s studies.  

The project in Sinaloa state holds 487.3 million indicated tonnes grading 0.36% copper equivalent for 3.86 billion lb. copper equivalent, Oroco said in a news release on Wednesday. It also holds 599.9 million inferred tonnes at 0.36% copper equivalent for contained metal of 4.7 billion lb. copper equivalent.  

That compares with a 1994 reserve estimate by Exall Resources of more than 1 billion tonnes of ore and a subsequent prefeasibility study suggesting a mine could recover 1.25 billion kg (2.75 billion lb.) copper, 20.8 million grams (733,700 oz.) gold and 622 million grams (21.9 million oz.) silver. 

“This mineral resource estimate represents a key milestone,” Oroco CEO Richard Lock said in the release. “We have a substantial resource at Santo Tomas that is exposed at or near surface and has robust potential to support a large, low-cost open-pit mining operation.” 

The project marks another example of re-probing old plans as metals demand for the green energy transition makes them more economically viable to develop. Oroco says the resource estimate paves the way for a prefeasibility study.