2004-05-03_REPORT - M1977004 - Laserfiche WebLink

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Pitch Reclamation Project April 29, 2004 2003 Annual Reclamation Report Page 7 Technical Revision #4 (TR4) -Pinnacle Adit Closure, Pitch Project, Technical Revision for Permit #77-4HR (Golder Associates, Inc.). Conditional approval of the Technical Revision request was granted by the Colorado -Division Of Minerals and Geology in a letter dated May 26, 1995. The intention of the plug was to partially seal the Pinnacle Adit and allow the area around the mine workings to resaturate. The resaturation of the workings was predicted to re-establish a geochemically reducing environment and lower the solubility of uranium and radium within the underground workings of the Pinnacle Mine. DMG's approval of TR4 required Homestake to monitor the effects of resaturation in the Pinnacle workings for five years or until hydrologic conditions stabilized. Components in the Monitoring Plan outlined in TR4 (Section 4.0), included continuation of discharge water quality monitoring at the POC (SW-33), monitoring of groundwater resaturation levels, annual spring and seep surveys in areas down-gradient from Pinnacle workings, and monitoring for changes in water quality that could be attributable to resaturation. The stated purpose of the monitoring program was to verify the intended effectiveness of the adit plug. Homestake has continued to monitor the following facets of resaturation through 2003: • Survey of springs and seeps, • Groundwater levels in piezometers installed in the area of the Pinnacle workings, • Water Quality and flow from the Pinnacle Adit at sampling point PP-01, and • Monitor discharges from the property at the Point-of-Compliance SW-33. For 2004, HMC will continue to monitor the resaturation of the south wall of the North Pit as done in 2003. 4.3.1 Spring and Seep Monitoring Spring and seep surveys were conducted to monitor changes in shallow groundwater conditions due to construction of the Pinnacle Adit plug. These surveys have been conducted annually since July 1995 and repeated in 2003. In general, flow from some springs and seeps increased for a brief period after the adit plug installation and have declined to a steady state since the spring of 1997. Small variances, noted since 1997, are believed to be attributable to conditions including precipitation, depth of snow pack, timing of snowmelt, and the potential for infiltration with respect to frozen ground. Two new springs were monitored during spring 2003: a) IC-10, approximately 100 yards above the Indian Creek inlet to the Sediment Pond, located between the road and the Indian creek channel and just east of the creek; and b) IC-11, originating along the south side of the road leading up to the P-wells, approximately 200 yards East of the shop building. All spring and seep locations are presented in Figure 3. A nine-year cumulative summary of the spring and seep flow measurements is provided in Table 2.