Tarkwa made a transition from owner mining to contract mining in 2018, where the mining and the maintenance of heavy mining equipment is outsourced to two local contract miners, BCM and Engineers and Planners. In 2018, Tarkwa's Mineral Reserves decreased by 128koz (2%), but Mineral Resources increased by (15%). As at 31 December 2018, Tarkwa's Mineral Resources and Mineral .