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:~ SOIL AND VEGETATION INVENTORY AND REVEGETATION RESEARCH ON THE PROPOSED KEENESBURG SURFACE COAL DINE ABSTRACT The feasibility of surface mining coal from the Laramie Formation north of Keenesburg, Colorado is under investigation by Adolph Coors Company. As a part of the study the Department of Agronomy, Colorado State University contracted to inventory soils and vegetation on the six square mile site and to carry out revegetation research. Wind-deposited sand averaging about 20 feet deep lies above the bedded clay shales of the Laramie Formation. Two soil series in 4 soil mapping units cover most of the area that may be disturbed west of the Ennis Draw. The soils are very sandy and thus are very sus- ceptible to wind erosion when disturbed. The Osgood soil series which covers about one-third of the area west of Ennis Draw is the most suitable soil for use as topsoil; approximately 30 inches of the sand Al horizon and the loamy sand 82 could be used. The Valent soil series which covers most of the remainder of the area has a surface layer 4 to 6 inches thick which could be used as topsoil. Tests on the soils show no adverse chemical or fertility char- acteristics other than that the subsurface horizons are deficient in plant-available phosphorus. The clayey overburden is moderately salty and sodic. Thus a minimum of 3 feet of sand over the clayey spoil is recommended for reclamation. Almost all of the proposed mine area west of Ennis Draw is in the deep sand range site which is dominated by sandsage and prairie sandreed. No rare or endangered plant species were found on the deep sand range site. In Ennis Draw the range site is a sandy meadow. Here one species, tulip gentian (Eustoma gradifZorum), was found that is listed as rare in the computerized Plant Information Network of Colorado State University. However, this species is not on the Colorado or national lists of rare or endangered species. The revegetation studies showed that intensive management was required to establish ground cover adequate to stabilize drastically disturbed topsoil. The vegetation was established by seeding a mix of native grass species, applying manure to stabilize the sand, and then applying 9 inches of irrigation water over a 3-month period. Applying 9 inches of water to the soil surface requires about a total of 13 inches as about 304 is lost to evaporation when sprink- ling. The present concept is to irrigate for establishment only during the first growing season. With proper long-term grazing management most of the seeded 1 '.. vegetation should persist. ii