In 1873, Joseph Henry Collins, a prominent figure in Cornish mineralogy and mining, began his involvement with the St Austell area by managing tin mining operations at Rock Hill. The mine operated under various names, including Rocks Tin Mine, Rocks & Treverbyn, Rock Hill United, Rock and Goonbarrow, and Rock Hill Mine (the opencut). Over the years, it produced a total of 551 tons of black tin between 1839 and 1873, with additional outputs in subsequent years. The remnants of ore dressing floors, including two stacks and the foundations of some mine buildings, can still be found at the site marked by the given grid reference. Although the mine workings were originally located nearby, they are now mostly hidden by the Goonbarrow and Rock Hill China Clay pits. However, in 1960, the shallow levels of the mine were uncovered in the southern part of the Rock Hill China Clay pit.