Mining waste was a significant environmental problem in nineteenth-century Victoria, an Australian colony dependent on gold mining for its economic prosperity. Sludge from alluvial workings and hard-rock mining flowed into rivers across the colony causing significant damage and disruption to downstream communities. The sludge problem was eventually resolved by the passage of legislation early in the twentieth century. The struggle to control sludge reveals changes in public perception over a 50-year period from acceptance of sludge as an inevitable consequence of industry to the identification of sludge as pollution that should be eliminated. Significantly, at a time when the cost of dealing with noxious waste from other industries was still being borne by the public purse, the anti-sludge legislation held the mining industry responsible for its own pollution and required miners to return clean water to river systems.