2014-04-17_REPORT - M1977004 - Laserfiche WebLink

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Pitch Reclamation Project Colorado Mined Land Reclamation Board — 2013 Annual Reclamation The 2013 survey results indicate that the amount of total vertical movement in the embankment is minimal, within historic levels, and lies within the range of survey error. There was no significant vertical displacement in any of the monuments located on the crest of the embankment in 2013. Piezometer water levels were approximately the same in 2013 as 2012 compared with 2011. All piezometers water levels declined slightly throughout 2013 in response to dry climatic conditions and the nearly constant pond level. A Sediment Embankment Report is submitted annually to the Colorado Division of Water Resources (CDWR) providing the results of the embankment - monitoring program. The 2013 report is provided in electronic Adobe Acrobat© Portable Document Format on the CD attached to this report. 4.5 Waste Rock Dumps The waste rock dumps were inspected monthly in 2013, except when winter conditions prohibited access, in accordance with the recommended monitoring program. The historical water levels in the piezometers show little fluctuations during the winter months. The visual inspections conducted in 2013 indicate stable conditions for the Indian Creek and Tie Camp waste rock dumps. In 2011, piezometers IC10300 and IC10370 were replaced after several years of issues associated with corrosion and silt buildup in the well casing making it difficult to get an accurate reading of the phreatic surface in the Indian Creek rock dump. They were replaced with two new piezometers at approximately the same locations as shown on Figure 3. The replacement piezometer IC1030OR is located approximately 30 feet to the west of the former location of IC10300. Piezometer IC1037OR is located approximately 67 feet to the west of the former location of IC10370. More details on the replacement piezometers were provided in a detailed report to the Division in October 2011. The 2013 water level measurements showed a maximum differential following snow melt above the 2012 measurements, but below that of the previous five years due to differences in snow pack and summer precipitation. Following the dry conditions of 2001 through 2003, the seasonal variations had increased in recent years as heavier snow packs had occurred, with 2012 being a relatively dry year. The replacement of two piezometers in the Indian Creek rock dump in 2011 has alleviated issues in monitoring the phreatic surface in the Indian Creek rock dump. Homestake will continue to monitor and evaluate the cause and effect of any seasonal spikes in the piezometric water levels, and also observe any changes in surface features of the rock dumps. There continues to be no indication of concern related to instability or foundation phreatic surfaces in either the Indian Creek or Tie Camp Creek rock dumps. A more detailed discussion of the waste rock dumps was presented in the 2013 Annual Geotechnical Report filed with the Division in December 2013. 4.6 Water Quality Monitoring As outlined in TR4, Homestake has monitored water quality since 1994 to verify the intended effectiveness of installation of the Pinnacle Adit plug. Water quality monitoring was conducted in 2013 including sampling points located at the North Pit Lake discharge (Sample Point NPL), the Tie Camp Creek drainage (Sample Points TCCDRN and TCC), the site discharge POC (Sample Point SW -33), as well as spring and seep surveys performed in the spring and fall. Monthly discharge- monitoring reports (DMRs), pursuant to Colorado Discharge Permit System (CDPS) number CO- 0022756, were submitted to the Colorado Department of Public Health and Environment (CDPHE) for 2013. Monitoring for the CDPS was conducted at the designated POC SW -33, shown on Figure 3. Analytical tests conducted for the DMRs at SW -33 consist of flow; dissolved radium 226; total radium 226/228; total uranium; pH; total Pitch 2013 Reclamation Report 14April2014.Docx 24