2011-09-30_REPORT - C1981010 (2)

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September 28, 2011 TRAPPER MINING INC. Mr. Robert Zuber, PE Environmental Protection Specialist Colorado Division of Reclamation, Mining, and Safety 1313 Sherman Street, Room 215 Denver, CO 80203 Dear Mr. Zuber: SEP 3 0 2.011 Division of Reclamation Mining and Safety RE: Semi - annual Geotechnical Monitoring Report — September 2011 Trapper began submitting semi- annual monitoring reports to the Division, beginning March 2008 with the last report sent on March 31, 2011. Trapper has been monitoring the 2006 landslide area for movement through the use of a continuous monitoring system. Section 3.3.3 of Trapper's permit details the initial configuration of the monitoring system. This report updates the configuration of the system. Since March's 2011 report, due to normal advance mining operations, the systems at site 2 and 4 were decommissioned in June 2011. An aerial photograph has been attached to show the locations of these two decommissioned sites along with the current four functioning sites. Inclinometer, piezometer and surface displacement graphs for both of the decommissioned sites are attached covering the time period of April 1, 2011 through the time each site was decommissioned In your last letter acknowledging receipt of the March 2011 report, you requested the depths, in feet below the surface, for sensors at Station 5. The sensor depths for all the functioning sites are shown in Table 1. Station 5 is located within the slide area. Inclinometer, piezometer and surface displacement graphs covering the time period of April 1, 2011 through September 22, 2011 are attached. There are two graphs showing the data collected from the inclinometer sensors at site 5. The first graph has data from April 1, 2011 through September 1, 2011. A decision was made to wire the inclinometer sensors consistently with the other locations. After the sensor wires were moved around, the sensors had new baselines, which are shown in the second graph that covers the period of September 2, 2011 through September 22, 2011. Station 6 was installed this summer and is located northwest, just outside the slide boundary. This site has both inclinometer and piezometer sensors; however there is not a GPS monitoring system. Inclinometer and piezometer graphs are attached covering the period of installment through September 22, 2011. The depths for inclinometer sensors were adjusted to the coal intercepts on September 22, 2011. Table 1 has the original and adjusted sensor depths for this site. Station 7 was established this summer and is located on the southeast side of the slide. Inclinometer, piezometer and surface displacement graphs are attached covering the time period of installment through September 22, 2011. The inclinometer sensors were also adjusted to the actual coal intercepts on September 22, 2011. Site 8 is located just outside the southwest end of the slide. Inclinometer and piezometer graphs for this site are attached covering the time period of installment through September 22, 2011. The GPS monitoring system at this site is currently not operating. The receiver and radio were simultaneously not functioning properly. A new receiver has been installed and the radio has been sent off to be repaired. The monitoring system has shown no significant movement during the period. Please contact me if you have any questions. Sincerely, dartta, Tonia Perkins, P. E. Senior Mining Engineer P.O. Box 187 Craig, Colorado 81626 (970) 824 -4401