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quantitatively sampled for four vegetation parameters; vegetation cover, herbaceous <br />production, species composition, and woody plant numbers. Additionally, the soil <br />characteristics of the selected area were quantitatively analyzed and evaluated in 1996. <br />Precipitation data over a ninety year period (1905-1995) was analyzed to specify a <br />precipitation regime range. A requirement of the historic record approach was to sample <br />the historic record vegetation community over a range of precipitation conditions (dry, <br />normal, and wet years). From the historic precipitation records, a "normal" precipitation <br />regime (in inches of precipitation) was developed based on the amount of precipitation <br />received during the eight months preceding the growing season (October through May). <br />Relative to this "normal" precipitation amount, "dry" and "wet" precipitation years were <br />defined, using the standard deviation of the "pre-growing season" precipitation record. <br />The initial quantitative vegetation sampling of the historic record vegetation community <br />took place in 1996. In 1998, the third year of quantitative vegetation sampling was <br />undertaken. Discussions with the CDRMS in 1999 revealed a desire to undertake <br />additional quantitative sampling during a defined "wet" year. Subsequent to the 1999 <br />meeting, changes in staff at both CDRMS and MCC, and the lack of a defined "wet" year, <br />caused years to pass without resolution and establishment of the final revegetation <br />standards accepted under the revised historic records approach accepted by CDRMS in <br />1995. <br />In an effort to finalize establishment of revegetation success criteria for the West Elk <br />Mine, quantitative sampling was undertaken in 2010 at the Historic Records Study Area. <br />The results of the sampling have been compiled in this summary report with additional <br />evaluations of precipitation trends and correlations of the sampled vegetation parameters <br />and prevailing precipitation regime. <br />With the submittal of the 2010 quantitative sampling data, it is anticipated that productive <br />discussions between MCC and CDRMS will establish final revegetation success criteria <br />for the West Elk Mine. <br />2.0 PRECIPITATION REGIME (2010) <br />The historic record study area is located within the North Fork Valley, an incised riverine <br />drainage valley trending east-west. Two basic types of climate are characteristic of the <br />area of the West Elk Mine (which includes the Historic Record Study Area); semi-arid <br />and undifferentiated highlands (MCC, 1997). The climate of the mine and surrounding <br />area is characterized by a wide temperature fluctuation; from below freezing in winter, to <br />very warm in the summer months. Precipitation in the area is predominantly provided by <br />Pacific Ocean weather systems and is most frequent and reliable during the winter <br />months. <br />The National Weather Service (NWS) has collected precipitation data in the vicinity of <br />the mine since 1905. The most complete record of precipitation is from the Paonia 1 SW <br />station located in Paonia, Colorado. This station has been in operation since 1905, and <br />Mountain Coal Company, LLC Page 2 <br />Historic Record Study Area Vegetation Sampling Report: 2010