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32 <br />sites are at mines where the coal bed of interest is Cretaceous <br />• (Boreck and others, 1977). The overburden at all the sites is composed <br />mostly of shale with some sandstone, and occasionally some coal. The <br />thickness of the overburden and the thickness of the regraded spoils <br />fluctuate greatly, even within a site, due to irregular topography and <br />dipping coal beds (Table 2). <br />Native vegetation in North Park Coal Region and lower elevations <br />of northwest Colorado is dominated by big sagebrush (Artemisia triden- <br />tata) and grasses (Berg, 1975; Heil and others, 1977). The brush-grass <br />community in northwest Colorado gradually gives way at higher elevations <br />(2000-2500 m) to a mountain shrubland community dominated by service- <br />berry (Amelanchier sQ.) and Gambel oak ( uercus gambellii) with occas- <br />ional stands of aspen (Po ulus tremuloides) on rtpist sites near the <br />Edna mine. Pinyon-Juniper woodland is the dominant native vegetation <br />type of the sampling sites at the GEC 5 and A and Delagua mines (Table <br />3). <br />The pre-mine land use at all sites involved grazing by domestic <br />livestock and wildlife habitat, with some occasional summer fallow <br />wheat farming in the northwest. Berg (1975) believes defining the post- <br />mine use for which the land will be reclaimed will be one of the major <br />problems of revegetation in the northwest. He visualizes three dif- <br />ferent management alternatives: (1) grading and reclaiming the land <br />for intensively managed pastures, (2) seeding the land for grazing, <br />and (3) establishing browse species. Reclamation of the North Park, <br />Canon City, and Raton Mesa Regions is likely to be more limited to est- <br />ablishment of species for grazing since the climates in those regions <br />• are more constraining. <br />