2022-04-11_PERMIT FILE - M2021058

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• Recently surveyed maps identified a concrete vault owned by Leadville Sanitation. The concrete vault lies within the AVS Project boundary. • The recent survey maps indicate manhole#1 is as close as four (4)feet of CJK-Slag's permit boundary. (See Figure 3). • Deed 6116 filed in Lake County accurately describes the sewer location. However,the Deed does not state the easement width. (See Attachment A-Easements). • Water Quality o Existing surface and groundwater quality data obtained from EPA and other contractors documented that C1K-Slag's, and adjacent landowners (including Leadville Sanitation's) surface and groundwater is contaminated. o Surface and groundwater quality contamination includes but is not limited to low pH, elevated concentrations of cadmium, iron, lead, zinc, sulfate, and total dissolved solids (TDS). o The contamination source includes Colorado Lead Zinc (CLZ)tailings and other identified sources upgradient of CLZ tailings, UK-Slag and Leadville Sanitation. o Downgradient of the AVS Project, perched aquifer well water quality has dissolved metal concentrations (Pb, Zn, Fe)that are absent from downgradient unconfined aquifer monitoring wells. 5.0 Evaluation Summary Using existing publicly available information, and the analysis performed, it is determined that no structural damage of LS buildings, infrastructure or the polishing pond will occur, and there will be no negative effects to LS utilities or water quality. • The AVS Project surface and groundwater are contaminated with dissolved metals and other ions and are believed to originate from upgradient sources. AVS Project operation will not impact groundwater. • Perched aquifers'water quality downgradient of leadville Sanitation and AVS Project suggests upgradient contaminant sources exist. • Since the AVS Project operating activities will be limited to excavating, crushing, and screening, the operation will not generate adverse ground vibration effects on Leadville Sanitation assets. • Since AVS Project operating activities will be limited to removal of slag that was previously placed on pre-existing land surfaces,there will be no impacts to underground facilities due to excavation. No blasting is contemplated. • To alleviate potential impacts to LS's sewer line, UK-Slag will be providing an adequate easement on either side of the sewer center line crossing the AVS Project property. (See Figure 2). UK-Slag has discussed this with LS. LS will determine the appropriate d' easement width, which will—among othe�criteria—be based on the depth of the sewer a Permit File#M-2021-058,112c CJK Milliog Company-CJK Specialty Aggregates Leadville SAoitation Permaneot Man-Made Structures