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1998 and 2004, and after successfully meeting revegetation success standards, were released <br />from Phase R liability in 2006 and Phase III liability in 2009 by CDRMS. Release from Phase <br />II liability was initially approved by CDRMS for Reclamation Areas 2, 5, 6, 7, 9, 10, 15, 16, <br />19, 23, and 29 in October 2010, with final approval pending completion of the public <br />comment period. <br />2.2 FIELD SAMPLING <br />2.2.1 Timing <br />Field investigation for Reclamation Area 30 was undertaken during the period August 24-25, <br />2010. This time period coincided with anthesis and maximum development of the majority of <br />plant species found in the reclaimed areas at the mine site and adjacent native areas. Total <br />annual precipitation at the mine in calendar year 2010 to date was above normal. Cumulative <br />precipitation between September 2009 and July 2010 (growing season precipitation) was 29.6 <br />percent above the seventeen year mine average. While precipitation in the autumn and early <br />winter of 2009 was slightly above average, April and June 2010 precipitation levels far <br />exceeded average, providing significant growing season moisture for cool season species. <br />Hot and dry conditions throughout July and August 2010 affected growth of warm season <br />species, with decreased stature and delayed anthesis this season. <br />2.2.2 Vegetation Cover <br />Vegetation cover was estimated by the use of the point-intercept method. An ocular point <br />frame (ESCO Associates) was used to minimize instrument error and maximize precision <br />and observer accuracy. Cover transects were 25 meters in length, with two sample data <br />points collected at 1.0 meter intervals along the transect on opposite sides of the transect <br />centerline, 1.5m apart. Transect direction was established randomly through the use of <br />computer generated random directions (0-360°). In no event were transects allowed to <br />extend within ten feet of the revegetated area boundary to minimize impacts from "edge <br />effect." <br />For statistical purposes, each cover transect (comprising 50 data points) served as a sample <br />unit. Data points recorded the first vertical "hit" on vegetation (above or below the <br />instrument), soil (bare ground), rock, litter, or cryptogamic crust. Subsequent "hits" on <br />vegetation (prior to interception of the ground) were also recorded. Cover data were <br />recorded and reported by individual plant species. The first interception was used to calculate <br />total vegetation cover values. Additional interceptions were used to calculate relative cover <br />of individual plant species and lifeforms. The quantitative cover data also provided the basis <br />for calculation of species composition and relative importance. <br />2.2.3 Herbaceous Production <br />Herbaceous production was estimated by the harvest method. One herbaceous production <br />plot was located and randomly oriented at the origin of each cover transect. Additional <br />production plots were randomly located. Herbaceous production plots were 0.50 meter2 in <br />area. All current year above ground live herbaceous plant biomass was clipped within the <br />Coors Energy Company Keenesburg Mine Page 7 <br />2010 Revegetation Monitoring Report