Gold production is improving at Orvana Minerals‘s (ORV-T) Don Mario mine, while exploration and development are advancing on the surrounding Don Mario property, 380 km east of the provincial capital, Santa Cruz de la Sierra, in eastern Bolivia.
Production increased to 159 kg gold in May, up from 134.5 kg in April due to an improved head grade averaging 8.74 grams gold per tonne in May.
The mill treated 20,404 tonnes of ore during the month, 11,241 tonnes from underground and 8,146 tonnes from a mini-pit.
The mine began commercial production in July 2003. The mill processes ore at a rate of 700 tonnes per day. By the end of 2003, a vertical shaft had been sunk 173.3 metres, and 1,196 metres of drifts and crosscuts had been developed; as well, 625 metres of open cut and ventilation raises had been completed.
As at June 30, 2003, the Don Mario contained an estimated proven open pit reserve of 32,000 tonnes grading 4.27 grams gold per tonne and a probable open pit reserve of 286,000 tonnes grading 6.05 grams gold per tonne. The estimate contained an additional proven underground reserve of 73,000 tonnes grading 9.58 grams gold per tonne, with a probable underground reserve of 1.08 million tonnes grading 9.52 grams gold per tonne.
Infill drilling is about to take place on the upper mineralized zone, to advance pre-feasibility work on this deposit.
The 539 sq. km property is covered by 8 contiguous mineral concessions in the San Juan Canton of the province of Chiquitos. The town nearest to the mine (San Juan) is 76 km away.
A series of northwest trending schists, intercalated with orthogneiss underlie the property and are intruded locally by granite. Gold mineralizaton is associated with shearing.
A Bolivian subsidiary of Orvana, Paititi, holds 100% of the property. The company has to pay a 3% net smelter royalty to Repadre International, a subsidiary of Iamgold (IMG-T).