(REUTERS) -- Mineral exploration company Sandspring Resources Ltd raised its estimates for the measured and indicated resources at its Guyana gold-copper project and cut the project's pre-production capital costs.

Measured and indicated resources increased 72 percent to 6 million ounces gold at the Toroparu Gold-Copper Project in the Republic of Guyana, South America, the company said in a statement.

Measured and indicated resources give an initial estimate of the size of a natural resource deposit and serve as a basis for feasibility studies.

Sandspring also lowered its pre-production capital cost estimate by 30 percent to $482 million, it said in a statement.

Shares of the company, which expects to start open pit operations in 2015, closed at C$1.37 on Friday on the Toronto Venture Exchange.