Centenario gives boost to Dom. Republic mining

The discovery, in recent years, of the Centenario gold deposit “has been one of the outstanding events” for the mining industry of the Caribbean island of Hispaniola, writes correspondent Gerald Ellis from Santo Domingo, Dominican Republic.

The deposit was uncovered by joint-venture partners Canyon Resources and Battle Mountain Gold in the exploration known as El Higo, within Dominican Republic. (Hispaniola Island is divided between Haiti on the west and Dominican Republic on the east.)

The companies’ geological team, comprising Dominican and American professionals, undertook a regional exploration program in part of the Central Cordillera, sampling stream sediments every kilometre. The result, Ellis says, was the definition of a target 15-20 km west of the city of Bonar in Monsenor Nouel province within central Dominican Republic. In 1991, the government granted an exploration concession for El Higo, 2,725 hectares in size. A drilling program of some 30 holes outlined the Centenario deposit. Almost all of the holes intersected gold-bearing mineralization in a complex of tuffaceous flows and volcanoclastic sediments of the Tireo Formation, Ellis says.

A reserve estimate of 2.3 million tonnes averaging 5 grams gold per tonne has been calculated from the drilling. Most of the holes, drilled to a depth of about 35 metres, bottomed in mineralization.

Mineralization consists of silicified matrix cut by veins and veinlets or stringers of quartz-barite-gold-pyrite and

quartz-pyrite-chalcopyrite-sphalerite material. The deposit is tabular-shaped and 150 metres long by 20 metres wide.

Current reserves would allow the partners to produce at a rate of 60,000 oz. (1.8 million grams) per year during a 4.5-year mine life. Ellis suggests that additional drilling in the contiguous zones of the deposit and at depth, as well as on the contiguous Arroyo Avispa concession, might prove up enough reserves to double the mine life. (Arroyo Avispa, 3,200 hectares in size, has been applied for as a minerals exploration concession by the partners.) An 8,000-tonne-per-day, open-pit mining operation is envisaged. The estimated cost of placing the property into production is US$31.5 million. The Dominican Republic government recently organized a mining seminar which included a summary of mineral exploration activities by foreign and local companies from the late 1970s to the present.