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V� Knight Pidsold <br /> CONSULTING <br /> the north, Chicago Creek district to the southwest, and the Freeland-Lamartine and Lawson-Dumont- <br /> Fall River districts to the west. <br /> The country rock of the Idaho Springs district consists of several varieties of ancient gneissic rocks <br /> (metamorphosed sedimentary and volcanic rocks) that have been invaded by granitic rocks, all of which <br /> have, in turn, been invaded by younger igneous rocks. These younger rocks, the Tertiary porphyries, form <br /> a prominent network of northeast-to-southwest-trending veins and dikes characteristic of the Front Range <br /> mineral belt. <br /> Ore deposits in the area have been mined from thin veins that occur principally along the faults of Tertiary <br /> age. The ore-bearing minerals were precipitated in openings that formed along the faults during movement <br /> of the opposing walls. Principal ore minerals include pyrite (iron sulfide), sphalerite (zinc sulfide), galena <br /> (lead sulfide), chalcopyrite (copper-iron sulfide), tennantite (a copper-iron-arsenic sulfide), small amounts <br /> of silver-bearing minerals, and trace amounts of metallic gold. Based on relative amounts of ore minerals, <br /> the veins have been classified as pyritic, pyritic copper, pyritic lead-zinc, and lead-zinc. The most <br /> economically important veins in the district are of the pyritic lead-zinc type. <br /> 2.0 SAMPLING METHODOLGY <br /> 2.1 SAMPLE COLLECTION <br /> Bulk grab samples were collected from three waste piles located at the site(Figure 2). These samples were <br /> then processed at Hazen Laboratories in Golden Colorado for metallurgical testing. A split of each of the <br /> grab samples was sent to Bureau Veritas (BV) Laboratory in Vancouver Canada for geochemical testing. <br /> The testing methods selected for waste characterization were acid base accounting(ABA)to determine the <br /> acid generation potential of the material and the synthetic precipitation leaching procedure (SPLP) to <br /> determine metal leachability. Additionally, the material was analyzed by the toxicity characteristic leaching <br /> procedure(TCLP)to determine if the waste material could potentially be characterized as hazardous waste. <br /> January 14,2021 <br /> DV-21-0024 2 of 6 <br />