The Thorncliffe Chrome Mine is wholly owned by Xstrata, and lies to the north of Xstrata’s Helena Chrome Mine on the Eastern Limb of the Bushveld Complex. Mining the MG1 orebody, the mine consists of a four barrel decline shaft system sunk on a reef. The shaft system produces between 100,000 and 110,000 tons per month using a mechanised bord-and-pillar mining method. Ore is transported to the Thorncliffe Plant by means of overland conveyors.

The initial development of the Thorncliffe shaft portal commenced in March 1997. The reef that is mined is the MG1, mined at a stoping width of between 2 m and 2.2 m with very little external waste. In the reef itself, lenses of waste are encountered which give a level of dilution, which usually does not exceed seven per cent. Mining takes place using a mechanised bord-and-pillar mining method. The reef strikes from south to north and dips at about 12°. However, mining is on an apparent dip of nine degrees. Access to the mine is via a set of twin declines.