2015-04-17_REPORT - M1977004 (2)

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Pitch Reclamation Project Colorado Mined Land Reclamation Board — 2014 Annual Reclamation Report displacement has now reached about one inch, accounting for bias shift error of about one inch. The ' error threshold for 198 -1 is 0.75 inches meaning that the displacement appears to be valid. Inclinometer 198 -1 is located within an area of previous minor slope displacement. It appears that there is shallow creep type slope displacement in this area. The magnitude of displacement is consistent with slopes in the North Pit. No slope displacement was indicated by inclinometer monitoring at 198 -2 and 198 -3.. These inclinometers will continue to be monitored each summer. The data will be interpreted each year to assure that displacement is not occurring in areas where there has been no previous displacement, ' and to assure that rates of movement have not increased is areas where creep type displacement is taking place. 4.3 Pinnacle Mine Workings Monitoring A concrete plug was constructed in the Pinnacle adit in September 1995. Authorization for the placement of the Pinnacle adit plug was requested by Homestake in April 1995, through Technical Revision #4 (TR4) — Pinnacle adit Closure, Pitch Project, Technical Revision for Permit #M1977 -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 seal the Pinnacle adit and allow the historical underground working and adjacent area to resaturate. The resaturation of the workings was expected to reestablish a ' geochemically reducing environment and lower the solubility of uranium and radium within the underground workings of the Pinnacle Mine. The Division's approval of TR-4 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 is to verify the intended effectiveness of the adit plug. Homestake has continued to monitor the following facets of resaturation through 2014: ' • Survey of springs and seeps; • Groundwater levels in piezometers installed in the area of the Pinnacle workings; I • Water quality and flow from the Pinnacle adit at sampling point PP -01; and I • Monitor discharges from the property at the CDPS permit POC SW -33. I ' 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 were repeated in 2014. 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 a variety of conditions including precipitation, depth of snow pack, timing of snowmelt, and the potential for infiltration with respect to frozen ground; All "active" spring and seep locations are shown in Figure 3. Springs and seeps currently designated as "inactive" ' (no flow or seepage observed over the past five years) are not shown, but can be found on maps issued with past reports. A new spring (IC -12) was found and monitored in 2008. Its flow rate was consistent with the other springs. Table 1 shows spring and seep data, including flow measurements, from 1995 to the present. Spring IC-4 has experienced an increased flow over the past couple of years due to higher Pitch 2014 Reclamation Report 16April2015_Cw.Docx 23