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communities. Standards, therefore, must be 'derived which not only take into account • ~ premining native vegetation conditions, but also consider the inherent reclaimed community characteristics resulting from these applied technologies and the successional time frames and community development levels achievable in reclaimed areas in'the semiarid west after a minimum of ten years. For the II-W mine area, the four dominant affected types in the permit area' include aspen woodland, mixed brush, sagebrush, and western wheatgrass/alkali sagebrush. These types are well.diatributed across the undisturbed north, east, south, and west portions of the permit area. ~ After .very careful consideration for maximum disturbance impacts, the following minimum acreages of the four major types will be available for comparison sampling: aspen woodland - ~ 100 acres, mixed brush - 450 acres, sagebrush - 300 acres, and western wheatgrass/alkali sagebrush - 50 acres. These acreages represent the minimum acreages to 6e used; however, whenever possible, comparisons will 'consider the maximum undisturbed area available at any given time as the sampling universe. These types will serve as the basis for developing' weighted averages for cover and production comparisons in the II-W area. For the II-W South area, there are five dominant vegetation types which will be affected during • mining. These vegetation types include aspen forest, mountain brush, steep mountain brush, sagebrush, and western wheatgrass/alkali sagebrush. After careful consideration of potential maximum disburbance impacts, the following minimum acreages will be available in the II-W South area for comparison sampling: aspen forest - 230 acres; mountain brush - 300 acres; steep mountain brush - 150 acres; sagebrush - 200 acres; and western wheatgrass/alkali , ' sagebrush - 100 acres. These acreages represent the minimum acreage to be used and will serve as the basis for developing weighted averages for cover and production comparisons in the II-W South area. Statistical Testing to Demonstrate Revegetation Success Statistical testing will be used when the parameter sample mean for the reclaimed release area is less than 90 percent of the standard. In this case, hypothesis testing will be used to demonstrate the difference is not statistically significant. A one-sample t-test• will be used ~in the hypothesis testing. Hypothesis testing, as well as the sample adequacy formulas to be used when hypothesis testing is required or when parameter estimation alone is sufficient, will. be consistent with the , Division's April 1995 Guideline Regarding Selected Coal Mine Bond Release Issues or the current guideline in effect at the time of a bond release application. The parameters to be • tested for revegetation success are cover, production, and woody plant density.. 39 ~ ~ Revised~tl99