Particular care is taken when processing furnace linings, graphite crucibles and borax slag containing metallic gold and silver. Not only do we homogenize the by-product materials by crushing to reduce the particle size to less than 10mm (1/2inch) in size for sampling purposes, we proceed to feed the crushed materials through a rubber lined, vibratory, ball mill. We reduce the material size to less than minus 40 mesh. All the materials are screened through a Sweco vibratory screen, separating the metallic oversize from the milled material. The metallic oversize is melted in the JRI induction furnaces. Each bar is sampled using a vacuum tube.