The Copperstone project encompasses approximately 3700 hectares of surface area and mineral rights in La Paz County, Arizona. The project is wholly held by Sabre Gold, which controls the 546 federal unpatented mining claims pursuant to long-term lease agreements.

Prior production at Copperstone included open pit mining with 2,500 tpd of combined whole ore and heap leaching from 1987 to 1993 resulting in total reported production of 514,000 ounces of gold from 5,600,000 tons of ore grading 0.089 oz/t (2.8 g/t) of gold. In 2011, a 450 tpd floatation mill was built on site and in 2012 underground mining commenced from two declines that were previously developed in the bottom of the open pit. Operations took place from January 2012 to July 2013 until production was suspended in a declining gold price environment.