61 samples were analyzed for copper using Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) after HCl:HNO3 (3:1) acid digestion. 45 samples were analyzed for lead using Atomic Absorption (AA). 68 samples were analyzed for zinc using ICP-AES after HCl:HNO3 (3:1) acid digestion. 285 samples were analyzed for gold using AA. 32 samples were analyzed for silver using AA. 24 samples were analyzed for molybdenum using AA. 286 samples were analyzed for tin using X-ray Fluorescence. 286 samples were analyzed for tungsten using Colorimetric methods after Potassium Pyrosulfate Fusion. 286 samples were analyzed for mercury using Cold Vapor Atomic Absorption. 4 samples were analyzed for arsenic using AA. 171 samples were analyzed [...]