I am researching the history of mining and smelting activities in Cumbria in the 16th and 17th Century. Can anyone here help me better understand the waste product from smelting, forging and other industrial activities involving high temperatures ? In particular I am trying to differentiate between the waste product of smelting metals (such as copper, lead, Iron) and the waste product left by the smithy and whether these materials differ over the centuries as production technologies changed. The waste varies from simple blackened ash, to a glassy material that distinctly “clinks”, a light and very aerated pumice stone type, to solid banks of fused rock waste, to black bituminous like lumps.