In September 2004, Century Mining acquired the Sigma–Lamaque Complex and began mining and milling of a 250,000 tonne bulk sample in February through May of 2005. On May 25, 2005 the Sigma Mine started commercial production following completion of the bulk sample program and produced 45,152 ounces of gold from 940,000 tonnes of ore milled in 2005. An additional 9,638 ounces of gold were recovered from the bulk sample program in 2005.

Currently the Sigma open pit reserves are being extracted using conventional open-pit mining. Mill feed is sourced 100 percent from the pit and temporary run-of-mine (ROM) stockpiles. The 2007 mining plan is based on a mill production rate of 4,500 tonnes per day, with peak capacity of 5,400 tonnes per day, operating seven days a week.

Open pit mining utilizes 15 foot benches for ore and 30 foot or higher benches for waste. In addition, mining around and through existing underground workings has been successfully implemented.

The current mining fleet provides a nominal mining production capacity of 15 million tonnes per annum. The fleet consists of haul trucks, front shovels, excavators, drills, and various other equipment typically used in open pit mining operations.

Continuous improvements to mining operations are being made, including four new 100-tonne haul trucks that were delivered in August and September of 2006 for the haulage of waste to expose new ore faces for mining. The new trucks have improved the availability and productivity of the mining fleet, which has been a limiting factor on operations. On a daily basis, an average of 35,000 tonnes of material (ore and waste) are being hauled from the open pit.