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Logan Wash Mine Annual Report <br /> Permit No. M-1977-424 <br /> 2.3 Structures <br /> 2.3.1 Vaults, Pipelines, and Evaporation Pond <br /> Structures that remain at the mine site include two vault structures, one on the Lower Bench and <br /> one on the Research Mine Bench, one sealed ventilation shaft, and one capped and vented <br /> ventilation shaft. Pipelines include the retort water pipeline which conveys retort mine water from <br /> the sealed L-1 portal at the mine site to the Evaporation Pond;the Logan Wash Mine mine water <br /> drainage pipeline(LW-001)which extends from the sealed Ll portal to the Lower Bench Vault <br /> and then to an infiltration gallery on the Lower Bench; and the Research Mine mine water <br /> drainage pipeline(LW-002) which extends from the sealed Research Mine portal through the <br /> Research Mine Vault to the Lower Bench Vault and on to Lower Bench discharge point. See <br /> Figure 2 for the locations of these structures. <br /> The two bench vaults are administered as confined space concrete structures with surface access- <br /> ways constructed just above grade. Depending on the final mine closure method, these structures <br /> may remain as permanent structures on the mine site to manage and monitor mine water drainage. <br /> The retort water pipeline was constructed with manhole clean-outs approximately every 600 feet; <br /> two manholes,the Upper Manhole and Lower Manhole, are accessed periodically to measure <br /> retort water discharge rates. The Upper Manhole is located in the vicinity of the former Heater <br /> Treater(Area 15), in the upper part of Logan Wash near the confluence with Dry Gulch. The <br /> Lower Manhole is located immediately north of the Evaporation Pond, approximately 40 feet <br /> from the pond gate. Other manholes exist on the retort water pipeline that are buried by shallow <br /> road fill,colluvium, and vegetative litter, and have not been accessed in recent years. <br /> 2.3.2 Monitoring Wells <br /> Monitoring wells associated with the Logan Wash Mine were constructed within and outside of <br /> the immediate mine area. Past reconnaissance has been conducted to locate and confirm the <br /> existence of these well sites. Eight wells were located and identified within the mine area and <br /> within Logan Wash. Several other wells were located at some distance from the mine(see Figure <br /> 3 and Table 3). Of the 8 identified wells in the mine area,two wells, Well LWCW-IA and Well <br /> LW-22A, will remain in place as monitoring wells until final permit closure. Well LWCW-lA <br /> and LW-22A are sampled for water quality on a semi-annual basis. <br /> Wells LW-108, LW-112, and LW-242 were abandoned in 2005 in accordance with Colorado <br /> Division of Water Resources rules. The other 4 wells, LW-32, LW-45, and LWA 16, remain in <br /> place in the case they may be of value in the evaluation of mine closure investigations. Casing <br /> access and downhole conditions are unknown for wells LW-32, LW-45, and LW-116. <br /> Reconnaissance to date has not revealed any other monitoring wells within the permit area and <br /> the Logan Wash drainage. <br /> Reconnaissance for wells located outside the permitted area in distant drainages was conducted in <br /> past reporting periods. Wells LW-102 and LW-243 were located in Smith Gulch, Well LW-103 <br /> was located in Kelly Gulch, and Well LW-104 was located in Riley Gulch. Well LW-121, <br /> apparently constructed in Bowdish Gulch, was not located after a thorough search and is assumed <br /> abandoned. Wells LW-102, LW-104 and LW-243 were abandoned in 2007. Table 3 shows the <br /> status of well abandonment as of this reporting period. <br /> Western Water & Land, Inc. 4 <br />