The Sigma Mine was in continuous operation as an underground mine from 1937 to the third quarter of 2000 when it was closed down by McWatters Mining Inc. who, in September of 1997, acquired the mine as part of the Sigma-Lamaque Complex from Placer Dome Inc. The acquisition from Placer excluded the surface rights of the Lamaque property, which were acquired by McWatters from Teck Corporation in October of 1999. Total mine production by all previous owners, including McWatters, until mine closure was 24.8 million tonnes of ore with an average grade of 5.48 g/t gold for a total of 4.4 million ounces of gold.

The adjacent Lamaque underground mine, which is part of the same vein system, operated from 1935 to 1985, with total mine production of approximately 24.2 million tonnes of ore at an average grade of 5.81 g/t Au for a total of 4.55 million ounces of gold.  The mine was closed by Teck Corporation in 1985 due to low gold prices and a labour dispute.  The Company commenced an exploration and development program at the Lamaque underground mine in March 2006 with the objective of reopening the mine in the spring of 2007.

After acquiring the Sigma-Lamaque Complex, McWatters concentrated its efforts on outlining and mining surface reserves from the Sigma-Lamaque Complex. By February 2001, some 960,000 tonnes of ore at an average grade of 2.79 g/t Au for a total of 83,000 ounces of gold had been extracted by open-pit mining from four pits on the Sigma property, and 377,000 tonnes of ore at an average grade of 2.73 g/t Au for a total of 32,000 ounces of gold had been extracted by open-pit mining from three pits on the Lamaque property. All of the ore was processed at the Sigma mill.

McWatters and SOQUEM Inc., a subsidiary if SGF Mines Inc., through the Sigma-Lamaque Limited Partnership, invested $34.3 million and proceeded with the redevelopment of the Sigma-Lamaque Complex as a larger scale open-pit mine. The Sigma mill was expanded to 5,000 tonnes of ore per day and began processing ore in November of 2002. In April of 2003 McWatters commenced commercial production from the Sigma open pit, but suspended operations in October of 2003 due to mining inefficiencies and financial constraints.

In September of 2004, the Company acquired the Sigma–Lamaque Complex from the trustee of the Sigma-Lamaque Limited Partnership and commenced mining and milling of a 250,000 tonne bulk sample in February through May of 2005. On May 25, 2005 the Sigma Mine commenced 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. In the nine-month period ended September 30, 2006 the Sigma Mine produced 53,906 ounces of gold at a cash cost of US$407 per ounce.