Ergo started in 1978 to treat tailings dams in the East Rand to recover gold and uranium and produce sulphuric acid and was the largest surface retreatment plant in the world. In later years a CIL plant was added to treat lower grade material and uranium and acid production ceased. The tailings dams were first hydraulically mined and then pumped to the plant. after treatment then pumped to a tailings dam at Withok. The plant shut down in 2005 after treating 870 million tons of tailings to produce more than 250,000 kgs of gold.