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Status Report; Robinson Seep Investigation Climax Molybdenum Company <br />3.0 ADDITIONAL INVESTIGATIONS <br />Characterization of groundwater constituents between Robinson Lake and the Robinson Lake <br />seepage collection system was performed through the conduct of a series of field investigations. <br />The purpose of the field investigations was to delineate the distribution of constituents in shallow <br />groundwater (and determine approximate groundwater flow paths) between Robinson Lake, the <br />Robinson Lake seepage collection system and the Eagle Park Reservoir. Investigations were <br />carried out in three field exercises: <br />1. Field reconnaissance and water sampling - During this field exercise six water samples, <br />including four surface water samples and two groundwater samples, were collected <br />within the study area. Field work was conducted in June 2013; <br />2. Initial drilling program using direct push and solid stem auger drilling method — Field <br />parameters were collected on 11 water samples throughout the Eagle River drainage, <br />with eight samples being submitted for laboratory analyses. Field work was conducted in <br />August 2013; and <br />3. Additional drilling program using air rotary method — A total of ten boreholes were drilled <br />to record field parameters, with seven samples submitted for laboratory analyses. <br />Additionally, field parameters of groundwater within the drainage area downstream of <br />EVMW -1 S were collected by use of a hand auger. Field work was conducted in <br />September 2013. <br />A discussion of these field investigations is provided in the following sections. <br />3.1 Field Reconnaissance and Water Sampling <br />A preliminary site investigation was conducted on June 18, 2013. Following review of site <br />conditions, six water samples were collected, including two toe drain piezometer samples taken <br />below Robinson Lake Dam and four spring samples at various locations within the area <br />downstream of Robinson Lake. Samples were field filtered, and where required, acidified, and <br />placed on ice before being transported under chain of custody to ACZ Laboratories. Samples <br />were analyzed for Al, Sb, As, Ba, Be, Cd, Ca, Cl, Cr, Co, Cu, CN, WAD CN, F, Fe, Pb, Mg, Mn, <br />Hg, Mo, N, Ni, K, Se, SO4, Ag, Na, TI, V, Zn, alkalinity, total organic carbon, and TDS. Sample <br />identification and field parameters including pH and electrical conductivity (EC) are shown in <br />Table 3.1. Sampling locations are illustrated in Figure 3.1. <br />Pertinent field observations are noted below: <br />• The outlet of the toe drain pipe (EVS -007) showed evidence of iron precipitation on the <br />surface immediately below the discharge. <br />• One spring (EVS -006) showed evidence of iron precipitation with a reddish - orange color. <br />• The northern edge of the cutoff wall is in contact with fractured sandstone /conglomerate <br />bedrock (Minturn Formation). This rock is likely permeable to some extent due to its <br />lithology and the presence of fractures and may lead to preferential leakage entering the <br />unconsolidated sediments downstream of the cutoff wall. <br />• Sediment within the stream channel down gradient of EVMWAS has a silty -clay texture <br />and redoximorphic (iron coloration) features. <br />Tetra Tech, Inc. November 2013 25 <br />