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quadrats were located at predetermined paced intervals within each control plot thus ensuring complete coverage of each plot. The techiv que used in locating the production exclosure and cover quadrat at each systemati- cally located point was identical to the technique used in the affected area. Data Collection. Cover was estimated using a 20x50 an steel frame quadrat (1/lOm2) at each of the randomly located points in each vegetation type. A total of 122 quadrats were sailed for cover during this study as shv.,m in Table 1. This sample size and all production and cover sample sizes were determined on the basis of several criteria: 1. OBI and CMT.RR Permanent Regulatory Programs and 'r7yoming DEQ Guideline #2 (March, 1979) suggest that sarq~le sizes be established on the basis of pre-sample data, that is, a small number of production and cover samples are taken during the gracing season prior to actual baseline data collection. Sono idea of natural variation in the vegetation types to be stL3ied is obtained from the pre-sample data and this information facilitates the establishment (• of correct sample sizes needed to meet the specified data confidence levels. Some pre-sample data were available from previous studies at Seneca II bLine and these 3ata were closely scrutinized in attempts to asse;iLble information regarding natural variation in vegetation types to be sampled. 2. Because pre-sample data alone are seldom reliable in accurately establishing sample size, a great deal of judgement based on the observer's experience in similar vegetation types, other studies perfornt.,d in similar types and interviews with other experienced ecologists were used in establishing sample sizes at Seneca II Mine. Interviews with Dr. Robert Dorn of t4yoming DEQ (April, 1979) provided some insight into establishing adequate sample size. ~. -7-