2015-04-17_REPORT - M1977004 (2)

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Pitch Reclamation Project Colorado Mined Land Reclamation Board — 2014 Annual Reclamation not allowed the pipes to drain sufficiently to accurately reflect the phreatic surface in the embankment. In ' July 2009 both piezometers P4 and P5 were flushed with high pressure water in an attempt to minimize the silt and other debris that had built up in the standpipes. The high pressure flushing resulted in the water levels in both piezometers falling back to normal levels within a few days over the past two years, with the average water level in P4 dropping by more than 4ft. Piezometer P5 also fell back rapidly after being flushed. I ' Based upon the monitoring data and embankment inspections since 2001, it appears that the cutoff trench- and clay blanket reconstruction performed in 2001' have addressed the previous localized perched zone and related seepage through the embankment core, thus, allowing the embankment to function as designed. i The 2014 survey results continue to 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 ' 2014. 1 ' Piezometer water levels in 2014 increased compared to 2013 and 2012. Due to heavier than normal snow back, the pond water level was stored above the 9885.5 repair area for approximately a four -week period in May. The results were noted in water level increases in all piezometers for a short period in 2014, but with the exception of P7 and P8 all piezometers water levels dropped back to the normal range once the pond water level was below the 9885.4 ft amsl upstream embankment repair area. The outlet pipe on the embankment will be monitoring closely in 2015 to assure it is flowing freely. Piezometers P -7 and P8 will be flushed with high pressure water in the summer, if the water level hasn't dropped back to historic residual values at that time. The monuments will be surveyed again in the summer or early fall of 2014 and the piezometers will be monitored on a monthly basis or more often if it ' is necessary to store water above the 9885 ft amsl level. The downstream face of the embankment will be inspected following the spring melt for potential seepage, remove any pine seedlings and repair rill erosion as need. . ' A Sediment Embankment Report is submitted annually ,to the Colorado Division of Water Resources (CDWR) providing the results of the embankment - monitoring program. The 2014 report is provided in electronic Adobe Acrobat© Portable Document Format on the CD attached to this report. 4.5 Waste Rock Dumps I The inspections conducted in 2014 indicate stable conditions for the Indian and Tie Camp rock dumps. Reclamation repairs done in 2012 had alleviated drainage and erosion issues and only reseeding was required in 2014. ' Historically, the water levels in rock dump piezometers show little fluctuation in the winter months with a temporary rise in response to the spring snow melt. They usually return to normal levels in mid to late summer. The piezometer readings in 2014 were indicative of the heavier snow pack in 2014 and heavier ' summer precipitation. The rock dumps were inspected monthly in 2014, 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 and Tie Camp waste rock dumps. Pitch 2014 Reclamation Report 16April2015_Cw.Docx 26