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Mined Land Reclamation Division December 29, 1981 Page Two Stipulation 9 Coors Energy Company must collect ad di tioi season for vegetative productivity of the communities so as to achieve a confidence sample mean within 10% of the true mean). submitted to the Division before December ral samples in the 1981 growing Valent sand and Osgood sand level of at least 80% (with a This information must be 81, 1981. Vegetative productivity of both the Osgood and Valent Sands in the area to be mined was completely resampled on September 28, 1981 to achieve the stated MLRD requirement of an 80% confidence level (with a sample mean within 10% of the true mean). An explanation of the samp- ling procedures and productivity results comparing the area to be mined with the reference areas is contained in the attached three page report from our vegetation consultant, Mr. Don Hyder. Stipulation 10 Coors Energy Company and the Division shall work jointly to establish a woody plant density standard for the Keenesburg mine by December 31, 1981. The sandsage density recommended for the Keenesburg Mine area reclamation revegetation is described by our consultant on pages 78 - 81 in the Permit Application text. He notes that sandsage densities on the Osgood and Valent sands in the area to be mined statistically average 1840 plants per acre. Furthermore, he notes that the range condition was heterogeneous and where range condition was good the sandsage density varied from 200 to 900 per acre. Selecting 400 plants per acre as "near ideal" and then applying statistical computations, he arrives at a success standard of 302 sandsage per acre. The major intent of this recommended density is to refrain from setting a success standard that would reproduce poor range conditions for cattle grazing. The Colorado Division of Wildlife has suggested reclamation sandsage densities for wildlife habitat based on three variations of related topographical and botanical conditions existing on the Tamarac in eastern Colorado. This information is contained in a letter from the Division of Wildlife dated June 19, 1981, shown in our Permit Application on pages 137 and 138. Our consultant believes that Condition 2 most closely typifies the terrain and botanical composition found at the Keenesburg Mine site. The topography is best described as "gently rolling" as opposed to "depressions" (Condition 1) and "other side slopes and ridge tops" (Condition 3). Elevations over the 1500 acre total mine site area vary from 4775 ft, to 4900 ft., a range of only 125 feet, and ground slopes are around 1% to 4%. The site is neither a major depression area nor composed of steep slopes and ridges. Reclamation topography will approxi- mate the premining surface; however, the terrain features will be even further "rounded down".