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West Elk Mine 2011 Annual Hydrology Report 20 <br />2007, MCC contracted GEI Consultants (GEI) to install temperature data loggers in <br />Sylvester Gulch and in the North Fork of the Gunnison River, in order to monitor the <br />effects of discharge from Sylvester Gulch on the water temperature of the North Fork of <br />the Gunnison River. Five temperature loggers (ONSET Corp. HOBO Water Temp Pro <br />v2) were deployed within Sylvester Gulch, and three within the North Fork of the <br />Gunnison River (Table 4). The loggers were installed by GEI on September 21, 2007 <br />and were programmed to record temperature data at 15 minute intervals. The data <br />loggers were re- programmed in WY 2009 to collect data at hourly intervals. Data from <br />the temperature loggers are downloaded on -site monthly by HydroGeo (whenever ice or <br />dangerously high water levels do not prevent access to the loggers) using a laptop <br />computer and an ONSET adapter cable. <br />Each temperature logger was attached to a steel rebar rod (driven into the <br />streambed) using galvanized cable and stainless steel hose clamps. In October 2007, <br />HydroGeo re- anchored each of the loggers to secure points on the shore using 1/16 inch <br />aircraft grade galvanized steel cable. In the summer of 2008 or in WY 2009, all of the <br />data loggers were reprogrammed to record temperature data at one -hour intervals, in <br />order to increase the data logger battery life, and to increase the length of time it takes for <br />the logger memory to become full and overwrite previously recorded data. The <br />temperature logger sites were visited on a monthly basis in WY 2011 and the loggers <br />were downloaded whenever ice or dangerously high water levels did not prevent access <br />to the loggers. <br />The locations of the temperature monitoring sites are shown on Figure 8. Water <br />temperature data and graphs for WY 2011 from the eight temperature monitoring sites <br />are presented in Appendix I and J, respectively. MCC's current permit effective May 1, <br />2010 required installation of temperature monitoring equipment by January 1, 2011 <br />(Section 4.3.1.4). <br />June 2012 HydroGeo, Inc. <br />