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• coal fields are apparent. For example, the Green River (Yampa) coal t <br /> region had a wide range of sampled infiltration rates (1.2 to 5.1 cm/hr). ' <br /> However, most of the sites clustered towards the low end of the range. <br /> The North Park (Marr Strip) also was rated at the low end of the infil- t <br /> tration range (2.0 to 3.0 cm/hr). Average infiltration rates for the <br /> Canon City and Uinta Coal Regions were at the high end of the range <br /> (4.9 to 5.5 cm/hr). Multiple correlation analysis of infiltration rates ~~ <br /> vs. site characteristics showed that infiltration rates were most closely <br /> correlated with the depth of wetting, the amount of mulch cover, and <br /> site slope. The depth of wetting was highly correlated with the depth <br /> of the topsoil and the bulk density of the spoil. In general, the <br /> topsoil at all sites appeared to be highly permeable to water intake <br /> but once saturated, subsequent infiltration depended upon characteristics <br />• of the underlying spoil. Vegetation cover affected infiltration on <br /> individual mine sites but was not as pronounced as topsoil characteristics <br /> <br /> or mulch. <br />Erodibility of topsoil and spoils, as determined by Wischmeier's r <br />"K" factor, ranged from 1.34 to 0.56 tonnes/ha. (topsoil) and 1.25 to ` <br />0.66 tonnes/ha. (spoils). Definite trends in erodibility are evident. <br />The Green River (.Yampa) Coal Region displayed consistently higher erodi- I~ <br />bilities (1.34 to 0.75 tonnes/ha.) than other coal fields (0.72 to 0.56 <br />tonnes/ha ). Lowest erodibilities were observed in the Uinta, North Park, <br />and Raton Mesa Coal Regions (0.56 .to 0.62 tonnes/ha). Erodibilities of i <br />underlying spoils showed similar trends as the topsoils. <br />Erosion potential (the product of soil erodibility and rainfall <br />• erosivity) was determined using calculated "K" factors and rainfall <br />erosivities (R) taken from Clyde (1976). Results show that the Delagua <br />iii <br />