The first recorded experimental work in copper was conducted by Cushing in 1894 in order to demonstrate that copper plate found in Hopewell mounds in Ohio could have been produced by the Hopewell people and not come from European trade.  In his experiments, Cushing used antler and stone tools to cut out sheets of copper and puncture round holes in them through a method of pressure and grinding.  In addition to the copper sheet experiments, Cushing also conducted smelting experiments reconstructed from finding at Salado Valley, Arizona pueblo excavations to reproduce copper artifacts.