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forth in Chapter 10 of Cochran (1977). Two-stage sampling is undertaken by dividing the entire area to be monitored into smaller units that are known as "primary units". A subset of primary units is randomly selected and each selected primary unit is then divided into "subunits". Randomly selected subunits are sampled and represent the second-stage of sampling. At the Kerr Mine, each area to be monitored was divided into 20 equal-sized primary sample units and 12 of these were randomly selected to be sampled. (For reclaimed area sampling, see Map 1, Sheets 5, 6, and 7. For reference area sampling, see Map 3, Sheet 2; Map 4, Sheet 2; and Map 5, Sheet 2). Within each selected primary sample unit, three of the potential secondary units within each primary unit were randomly chosen in the same fashion that was used for single stage random sampling. These points were then placed on the field maps and located as accurately as possible in the field. Three production samples and three shrub density samples were placed in each of twelve primary units in each sampled area for a total of 36 production samples and 36 shrub density samples per sampled area. The initial array of 36 production samples and 36 shrub density samples per sampled area met the conditions of sample adequacy and no additional samples were taken. Sample Adequacy Calculations Two formulas were used to calculate sample adequacy. Sample adequacy calculations for parameter estimation without hypothesis testing were carried out for all sampling in the 1995 Reclamation Area, Alkali Sagebrush Reference Area, Sagebrush-Grass Reference Area, and Sagebrush-Gravel Reference Area. This formula was also used to calculate sample adequacy for total annual production sampling and shrub density sampling in the Pre-1986 Reclamation Area. An alternate formula was used for reclamation areas when the parameter mean for the bond release block was less than 90 percent of the reclamation success standard and hypothesis testing was required to test the statistical significance of this difference. The sample adequacy calculation for parameter estimation with hypothesis testing was required for cover samples in the Pre-1986 Reclamation Area. Because estimated cover for the 1996 Reclamation Area was marginally greater than the 90 percent reclamation standard, the alternate formula for use when the bond release block is less than 90 percent of the reclamation success standard was used to ensure an adequate sample size. Stele Adeguacv Calculations for Reference Areas and Reclaimed Area Parameter Estimation without Hvoothesis Testing Sample adequacy calculations parameter estimation without hypothesis testing were carried out using the formula as prescribed by the Colorado Mined Land Reclamation Board for parameter estimation without hypothesis testing (CMLRB) (1995): tZ sZ Nmin= '°-------- ~d X ~z where: to =one-tailed t-value with (n-1) degrees of freedom, a=0.10 s2 =sample variance d = 0.1 (level of precision or desired detectable reduction) x =sample mean