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Coors Energy Company has collected precipitation data at the mine for a number of years. <br />This data represents the most complete record of precipitation from the mine area. Table 5 <br />• presents a summary of precipitation data collected from 1993 through 2009, corresponding <br />with the most recent vegetation monitoring. A review of the data illustrates that precipitation <br />generally is lowest during the late autumn and winter months (October through March), peaks <br />in April through June, and tapers off gradually until late autumn again. The months with the <br />highest average precipitation are May and June. Based on the 1993-2009 data, average yearly <br />precipitation was calculated. <br />Cumulative precipitation for the September-December 2008 period was 2.49 inches, 27.3 <br />percent below the average for those months (3.01 inches). <br />Overall total precipitation for 2009 from January through July was 11.22 inches, reflecting an <br />amount 41.6 percent above average precipitation for that time period. April, June, and July <br />2009 precipitation amounts were significantly above the averages recorded for the mine site, <br />resulting in above average moisture conditions during the 2009 growing season. <br />At the Keenesburg Mine, precipitation relevant to the growing season occurs from September <br />to the following July. Total cumulative precipitation for the period from September 2008- <br />July 2009 was 13.71 inches, the fifth highest value since 1993. Compared to the <br />corresponding averages, this represents a 23.5 percent above the average September-July <br />precipitation amount. <br />is 4.2 VEGETATION COVER <br />4.2.1 2002 Reclamation Areas <br />Table 6 presents a historical record of all vegetation cover and total herbaceous production <br />sampling results for monitoring at the mine since 1994. Though a number of the areas are no <br />longer quantitatively monitored (having been released from liability), this information <br />reflects the impact that varying precipitation regimes and stand age have on the vegetation <br />communities at the mine. The total vegetation cover values of the 2002 reclamation areas <br />reflect an increase of 34.2 percent from the 2007 growing season, when these areas were <br />monitored last. As the September-July precipitation amount from the 2007 growing season <br />was 35.0 percent above average and the corresponding precipitation amount from the 2009 <br />season was 23.5 percent above normal, the increased vegetation cover cannot be attributed <br />solely to an increase in precipitation. <br />Table 7 provides a comparison of the relative cover of species encountered during cover <br />sampling in the 2002 reclamation areas. The following depicts the significant changes in <br />relative cover for selected species in the 2002 reclamation areas (those reclamation areas with <br />a sampling record of three or more years). <br /> <br />Coors Energy Company Keenesburg Mine Page 13 <br />2009 Revegetation Monitoring Report