2012-04-19_REPORT - M1977004 (2)

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Pitch Reclamation Project Colorado Mined Land Reclamation Board — 2011 Annual Reclamation Report showed an increase over the maximum water levels in 2009 and 2008 and similar to 2007. This may also due to silt built in the standpipe and will be monitored closely in 2012. Based upon the 2011 monitoring data and embankment inspections, 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. A Sediment Embankment Report is submitted annually to the Colorado Division of Water Resources (CDWR) providing the results of the embankment - monitoring program. The 2011 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 2011, 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 2011 indicate stable conditions for the Indian Creek and Tie Camp waste rock dumps. In the past, water levels in several of the piezometers have had seasonal fluctuations and generally fall back within an acceptable range by mid - summer. Following the dry conditions of 2001 through 2003, the seasonal variations have increased in recent years as heavier snow packs have occurred. The increases in the maximum water levels are related to the spring snow melt and the saturated zones within the dump remain thin. We will continue to evaluate the cause and possible effects of the seasonal spikes in the water levels in some piezometers, and observe surface features of the dumps. However, there continues to be no indication of instability in either of the waste rock dumps. Once again in 2011, a few of the piezometers became plugged with silt and required flushing with high pressure water to get the probe down to the water. Each piezometer behaves differently and their flushing requires experience to be successful. The water levels in the rock dump piezometers in 2011 continued to show normal seasonal fluctuations when the silt was not an issue. Prior to October 2001, data was not obtained from Piezometer IC10600 due to the presence of a gravel obstruction that blocked the passage of the piezometer. Additionally, in 2007, the local elk herd destroyed the stand -pipe casing in Piezometer IC 10370 and consequently caused the upper part of the borehole soil to collapse into the piezometer casing. This resulted in approximately six feet of rock debris being introduced into the bottom of the piezometer, rendering it non - functional until the fall of 2009 when the obstruction was cleared from the bottom of the casing by high pressure flushing. This allowed us to remedy that problem and to begin using the Piezometer IC10370 as part of the monitoring system. Piezometer IC10300 was also flushed in 2009 & 2010 to remove the silt in the casing. In late 2011 it was decided that piezometers IC10300 and IC10370 would be replaced in 2011 to allow more accurate measurement of the phreatic surface in this portion of the Indian Creek rock dump. In August 2011, both piezometers IC10300 and IC10370 were sealed and were replaced with two new piezometers at approximately the same locations as shown on Figure 3. The replacement piezometer IC10300R is located approximately 30 feet to the west of the former location of IC10300. Piezometer IC10370R is located approximately 67 feet to the west of the former location of IC10370. Piezometers IC- 10300R and IC- 10370R were designed in accordance with Colorado Office of the State Engineer Rules for water well construction rule 14 "Minimum Construction Standards for Monitoring and Observation WeIIs /Holes and Test Holes ". The existing piezometers IC -10300 and IC10370 were abandoned in accordance with Colorado Office of the State Engineer Rules for water well construction Pitch 2011 Reclamation Finalreport 19Apr12.Doc 16