Peru's largest underground gold mine, privately owned Minera Aurífera Retamas (Marsa), is working on two important exploration projects, one at the mine and another right next to Alto Chicama, a company official told BNamericas.
Marsa is exploring up to 1,000m below its current operational level of 1,000m deep at the mine, located at about 4,000m above sea level in the province of Pataz in northwest Peru's La Libertad department.
"Exploration has been very positive up to now," said Marsa deputy general manager Juan Gonzales Vigil. "We can't confirm anything yet but results have been encouraging."
The mine, which produces 160,000oz/y of gold, currently has reserves that will last a further four or five years.
Gonzales said an "important" investment was required to advance the exploration with an estimated US$6mn-7mn needed just to put in the structure required to carry out the planned exploration activities at the mine.
At Muqui, located adjacent to Barrick Gold's Alto Chicama gold project in La Libertad's Santiago de Chuco province, Marsa is working with local company Muqui to take foward what looks to be a promising project, said Gonzales.
"It's very similar to [Alto Chicama's] Laguna Norte deposit. It has the same kind of topographical and geological features. We hope the results will be as good as Laguna Norte but we need time to demonstrate this," said Gonzales.
Gonzales said that Marsa was providing the know-how and Muqui the investment in the project. To date, geological, geochemical, geophysical IP/resistivity surveys and additional sampling work has been carried out with up to 25,000m of drilling planned to start in August.
A company geologist, Victor Manrique, told BNamericas that surface sampling had returned low but anomalous values of gold but high levels of pathfinder elements such as mercury, arsenic and lead. The indications were that Muqui was an epithermal, disseminated system, he said.
Marsa was founded by Dr Andrés Marsano in 1981. A 50t/d flotation plant was built in 1983 on the basis of initial known reserves of 23,280t with a grade of 10.7g/t.
Today, Marsa's flotation-cyanidation plant has capacity of 1,200t/d and utilizes Merril-Crowe technology to produce doré bars with 99.98% purity.