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PEABODY <br />,WESTERN. <br />Mr. Wallace Erickson <br />Division of Minerals and Geology <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203-2273 <br />Dear Ms. Burgmaier: <br />g99 <br />Peabody Western Coal Company <br />March 29, 199~r-~'.FI~/ED <br />ANk 0 ~ 1995 <br />Uiwsiun ~. ~.,,~,~~a~~ n ~eoiogy <br />Please find enclosed two copies of the 1994 Revegetation <br />Monitoring Report for the Seneca II Mine. The report is <br />submitted on behalf of Seneca Coal Company (SCC). The field <br />work and reporting was conducted by ESCO Associates, Inc., with <br />Dr. David Buckner as principal investigator. I am confident <br />your staff will find the monitoring report of the quality <br />exhibited in previous reports. Monitoring at the Seneca II Mine <br />is oriented towards measuring the status of variously-aged <br />reclaimed units and the success of revegetation procedures. <br />More importantly, monitoring aids in evaluating the affects of <br />successional processes on reclaimed communities. Additional <br />elements include evaluation of grazing in reclaimed lands and <br />the applicability of new sampling procedures. <br />In the 1994 studies, a two-stage sampling procedure was used in <br />the 300-acre Wadge Pasture to study methods to reduce woody <br />plant density sampling intensity. The large number of samples <br />required to meet sample adequacy for woody plant density has <br />been an ongoing problem, especially when bond release is <br />considered. The two-stage sampling procedure significantly <br />reduced the potential sampling effort and yielded a mean value <br />of 271 stems per acre with an adequate sample of 1 primary unit <br />(3 random secondary samples) compared to 296 stems per acre for <br />the simple random plot design which required a minimum of 399 <br />samples. The two-stage sampling method is described in Chapter <br />10 of W.G. Cochran's book, Sampling Techniques (1977). This is <br />a valid sampling technique and can be used to solve the problem <br />of essentially unattainable sample adequacy requirements for <br />woody plant density or other parameters; a problem which has <br />been investigated by the Division in cooperation with other <br />operators. The two-stage sampling method appears to be a <br />relatively simple and viable procedure where others have not <br />proven satisfactory. <br />Peabody Western Coal Company • 1300 South Yale Sfreef • Flagstaff, Arizona 86001 • Telephone (5'10) 774-5]53 Fa: (5]0) 773-4596 <br />