2013-10-07_REVISION - C1981025 (8)

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laboratory sampling of the discharge from the pond has been recovered during this review. Mine No. 2 water was once reported as acid and toxic (a field measurement of a 2.5 pH by Division staff). Field measurements were taken of the treatment pond discharge on May 20, 2003 by Division staff. The measurements were: pH – 8.2, TDS – 1780 mg/1 and the flow was 1.09 gallons/minute. Only two springs, Spring 1 and Spring 2, are identified in the PAP. A tributary from the southwest discharges into North Thompson Creek between the upstream and downstream monitoring stations. Alluvial groundwater may flow into North Thompson Creek. In addition, there was no monitoring of a bed-rock seep below Mine No. 1. See the discussion of ground water for these potential contributions. III. Sealing of Drilled Holes and Underground Openings A. The applicant has proposed to manage development, exploration, drill or bore holes, wells or other exposed underground openings in a manner other than by sealing and plugging. The Division proposes to approve the manner proposed since it should prevent acid or toxic drainage, minimize disturbance to the prevailing hydrologic balance, and ensure the safety of people, livestock, fish and wildlife, and machinery in the permit and adjacent areas (4.07.1). B. The Division required that each hole, well, or other underground opening be capped, sealed, backfilled, or otherwise properly managed (4.07.3). All shafts and portals have been backfilled and sealed. Portals of Mine No. 1 and Mine No. 3 have been fitted with pipes to permit mine drainage. The airshaft at the No. 1 Mine portal was backfilled, and a 36" culvert was installed for access to a dewatering pipe. A locked cover was placed over the open culvert end. This plan is illustrated on drawing D-2-5 of the permit application package. All drill holes and wells have been sealed with the exceptions of two surface wells, perhaps three underground piezometers, and two surface piezometers. The status of the three underground piezometers, P2-1, P2-2, and P2-3, located inside Mine No.3, is unknown. The piezometers are thought to be open. The history of these piezometers has been lost. However, the Mine No. 3 portal has been sealed, and the holes should present no threat to people, livestock, or wildlife in the area. Holes M-8 and M-9 have been permitted as permanent to monitor the permanent Developed Water Resources operations on the site. Following the termination of monitoring (TR-23, approved on February 23, 2004) monitoring wells D-1A and D- 2A were reclaimed. 19