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STATE OF COLORADO DIVISION OF RECLAMATION, MINING AND SAFETY Department of Natural Resources 1313 Sherman St., Room 215 Denver, Colorado 80203 Phone: (303) 866-3567 FAX: (303) 832-8106 November 6, 2006 TO: Kent Gorham FROM: Sandy Brown RE: Golden Eagle Phase III Vegetation Sampling COLORADO DIVISION O F RECLAMATION MINING -&- SAFETY siu ovens Governor Russell George Executive Director Ronald W. Cattany Division DireROr Natural Resourm Trustee I have reviewed the Golden Eagle vegetation report for Phase III bond release. Sampling was conducted in 2005 and 2006. After reviewing the 2005 data, the Division questioned the methods being used for the productivity sampling. Greystone, the consultant collected production data using 6 .1m2 quadrats along each 50 m transect. Each quadrat was placed at the same points on each transect. Fifteen transects were sampled. Sample adequacy was not achieved in 2005 for productivity when the 6 samples along each transect were combined. Therefore, each quadrat was considered a single sample unit for a total of 90 samples. This practice is no longer allowed by our Rules that became effective November, 2005. We are requesting additional documentation as discussed below in question 3. For the 2006 sampling the size of quadrat was increased to .Sm2. One quadrat was randomly located along each of 30 transects. Sample adequacy was not achieved for either of the reclaimed areas or for either of the reference areas. After discussions with the Division, it was suggested that the reverse null two sample t-test demonstrations of success be used for the 2006 production data. The Satterthwaite formulas for standard error and degrees of freedom calculation, and the t-test formulation itself are correctly presented on pages A-5 and A-6. Calculations and t-test results presented on page A-9 through A-11 for the rangeland and AVF types (2006 data) appear to have been done appropriately (in accordance with the formulae), and the results appeaz to be reasonable. I have the following comment and questions with regard to the submitted report. Tables A-4 and A-5, list the production mean field "wet"weights. However, it appears that sample adequacy was calculated using the dry weights as required by the regulations. The dry weights are calculated and recorded on the data sheets in Tables A-9,11, 13, 15, 17 and 19. For review purposes, it would have been helpful to have a similar table using the dry weights summarized for each of the reclaimed and reference areas. 2. The statistical methods and formulas used for the 2006 production demonstrations appear to be appropriate and correct, except the undesirable perennial forb component does not appear to have been defined or removed from the data sets prior to calculation of sample statistics. From the data, it appears that the Office of Office of Mined Land Reclamation Active and Inactive Mines