Hochschild Mining has received positive feasibility studies from Ausenco for its Inmaculada and Crespo projects in southern Peru. During the coming year, work will focus on engineering, permitting, and construction activities at both projects, with startup of both projects planned for the fourth quarter of 2013.
“Execution risk is expected to be considerably reduced as a result of both projects’ proximity to our current operations and our longstanding knowledge and experience of working closely with the surrounding communities,” said Hochschild CEO Ignacio Bustamante. “In addition, exploration work will continue at both sites to add more resources not included in the feasibility studies but which we are confident will positively impact the projects going forward.”
The Inmaculada project is 60%-owned by Hochschild and is an underground operation with planned production rates of 3,500 mt/d of ore and 12 million oz/y of silver equivalent ounces. Initial capital cost to develop the project is estimated at $315 million. Resources at the project total 150 million silver equivalent ounces.
The Angela vein of the Inmaculada mine will be accessed via a ramp from a portal located at an elevation of about 4,400 m above sea level, declining to about 4,300 m toward the middle and lower end of the vein. Sub-level stoping utilizing long-hole drilling and paste backfill will be used to mine about half of the ore reserve, with the remainder being mined using cut-and-fill, with horizontal drilling.
A primary crusher will be sited close to the portal, with a 1.5-km conveyor belt transporting ore to the plant and a waste dump located 1 km to the south. The processing flowsheet includes primary crushing, SAG milling, secondary grinding, cyanide leaching, Merrill Crowe processing, pressure filter separation, and smelting to obtain a doré product.
Hochschild owns 100% of the Crespo project, which will be a relatively simple open-pit operation. Production is planned at 6,850 mt/d of ore and 2.7 million oz/y of silver equivalent ounces. The strip ratio is 1.15:1. Drilling and blasting will be carried out directly by Hochschild, with earthworks being developed by contractors.
Processing will include primary, secondary, and tertiary crushing; agglomeration; heap leaching with cyanidation; Merrill Crowe processing; pressure filter separation; and smelting to obtain a doré product.
Initial capital cost to develop the Crespo project is estimated at $111 million.
