| Description |
Rock samples were processed by ALS Geochemistry using their PREP-31 package. The samples were crushed to greater than 70 percent passing 2 mm, and a 250 g split was pulverized to greater than 85 percent passing 75 microns. Prior to crushing, samples for whole-rock analysis were trimmed by DGGS staff to remove weathering, and cut surfaces were sanded to remove any saw metal. Major- and trace-element values for rock samples were determined by ALS Geochemistry method ME-MS61: Four-acid digestion followed by inductively-coupled plasma-atomic emission spectrometry (ICP-AES) and inductively-coupled plasma-mass spectroscopy (ICP-MS); Au values were analyzed using flux digestion and fire assay and ICP-AES (ALS Geochemistry method Au-ICP21); Hg values were analyzed by aqua regia digestion followed by ICP-MS (ALS Geochemistry method Hg-MS42). Samples that exceeded detection limits for elements of interest were reanalyzed using specific elemental tests. Over-limit values for Au were analyzed using 30-g fire assay with gravimetric finish (ALS Geochemistry method Au-GRA21). Overlimit values for Ag were analyzed by four-acid digestion followed by inductively-coupled plasma-atomic emission spectrometry (ALS Geochemistry method Ag-OG62) or by 30-g fire assay with gravimetric finish (ALS Geochemistry method Ag-GRA21). Overlimit values for Pb were analyzed by four-acid digestion followed by inductively-coupled plasma-atomic emission spectrometry (ALS Geochemistry method Pb-OG62). |