2010-02-19_REVISION - C1981028 (4)

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2.0 METHODS 2.1 SAMPLING DESIGN • Discussions with revegetation specialists at CDRMS in February 2007 and April 2009 formalized the sampling design for vegetation sampling at the Keenesburg Mine. Areas revegetated in 1998, 1999, and 2000 would be treated as one sampling unit as parcels within the revegetation areas and revegetation years were contiguous (or nearly so) and received the same seed mixes and reclamation management. Prior to initiation of fieldwork, the permit document and applicable maps were reviewed to evaluate topography, reclamation timing, seed mixes, revegetation methods, management, and applicable revegetation standards. A map of the mine site at 1:2400 scale (1 "=200') was used to delineate the revegetated areas (Coors Site Plan; Vegetation Sampling Locations). On a gridded overlay of the revegetation map, a Cartesian coordinate grid (50x50 feet) was established. Computer generated random numbers were used to establish a pool of x,y coordinates. The acreage of each revegetated area was established. Random sample locations were established for each revegetated area. Within each year's revegetation parcels, sufficient samples were established to represent each area by proportional acreage. The following table identifies the location of each parcel quantitatively sampled, the acreage, and the number of cover and herbaceous production samples taken. Location Cover/Herb. Prod. (minimum # of samples) 2009 # of Cover samples taken 2009 # of Herb. Prod. samples taken 1998,1999, and 2000 Reclamation Areas Area 2 (1.95 ac.) 2 2 3 Area 7 (1.60 ac.) 1 1 2 Area 10 9.69 ac. 9 9 12 Area 15 (2.73 ac.) 3 3 3 Area 16 1.67 ac. 1 1 1 Area 5 (2.63 ac.) 2 2 2 Area 9 14.73 ac.) 13 13 18 Area 6 (4.06 ac.) 8 8 11 Area 19 3.23 ac• 7 7 9 Total Samples 46 46 61 Sample sites were located in the field through compass triangulation and pacing from known landmarks. Figure 1 illustrates the location of the reclaimed areas and sample point locations within each area sampled. Coors Energy Company Keenesburg Mine Areas 2, 5, 6, 7, 9, 10, 15, 16, and 19 Vegetation Study (2009) Page 5