Wheal Tremayne (incl. Wheal Treasury) was at Leedstown, Crowan,
Mount's Bay District, Cornwall. These were
two closely related setts, which were worked from 1815 to 1870
Wheal Treasury was worked earlier. James Watt sold them an engine, and in 1793 writes to Mr Wilson in Truro " ''I find great need of the agreement by which the adventurers at Wheal Treasury agreed to pay a monthly sum for the Engine which was removed from Hallamanin to that mine. Please to favour me with this Agreement if you have it or can procure it''
They produced 12,000 tons of copper and 1,490 tons of tin. Extensive shafts and dumps can still be seen on Gwinear Downs and Burnt Downs, north to northeast of Leedstown
Richard Trevithick went to work with his father at Wheal Treasury mine and soon revealed an aptitude for engineering. After making improvements to the Bull Steam Engine in 1796 , Trevithick was promoted to engineer of the Ding Dong mine at Penzance.