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INTRODUCTION <br />Quantitative sampling of reclaimed areas on the Peabody Western Coal Company (PWCC) Seneca <br />II Mine was undertaken in July 1993 by ESCO Associates to facilitate PWCC's continuing <br />monitoring of the progress of these areas in relation to revegetation performance standards. <br />Methods, sample areas, and sample sizes were those specified by PWCC. <br />Reclamation sampling units are shown on Map 1, '1993 Vegetation Monitoring Map'. The 1993 <br />reclamation units include: Wadge and Wolf Creek mining areas reclaimed in 1986; Wadge and <br />Wolf Creek mining areas reclaimed in 1989; Wadge and Wolf Creek mining areas reclaimed in <br />1991; Pre-law areas (areas reclaimed before 1978); as well as the Wadge Pasture Area <br />reclaimed between 1978 and 1985 and grazed from 1988 to the present, and the Wadge Pasture <br />1991 Area, likewise reclaimed between 1978 and 1985, but ungrazed until 1991. In addition, <br />an area known as PECOCO Pasture that includes both reclaimed and unmined areas, and that has <br />been grazed since 1992 was sampled to assess productivity and cover information for use in <br />grazing management. The Seneca II Mountain Brush and Sagebrush Reference Areas were also <br />sampled. <br />Within each reclamation unit identified in the PWCC Scope of Work, the PWCC-specified <br />number of samples were located randomly on maps produced by PWCC using numbered grid cells <br />and random numbers generated by computer. The PWCC-assigned numbers of samples for a <br />given parameter in a given area reflected previously experienced sample variability or the <br />level of precision required in a given area (i.e. production in the 2-year old reclamation is not <br />as informative as in older areas, so fewer samples were appropriate in tfie younger areas). On <br />the other hand, the desire to have finer estimation of mean values in areas experiencing grazing <br />and in the reference areas that provide control data necessitated larger sample sizes. <br />Grid cell size was 100 feet x 100 feet in reclaimed areas, and 50 feet x 50 feet in reference <br />areas. These grid cells were placed contiguously by computer in a Geographical Information <br />System (GIS) rendering of reclamation areas to be sampled. Random numbers provided by <br />computer were used to select grid cells, in the middle of which a sample point was placed, and <br /> <br />1 <br />