copper and molybdenum status of yearreclaimed mined-land and native range Spoil materhi repheed after 8trip mining for lignite co8l may differ from the origirui top soil with respect to concentrations of copper (Cu) and molybdenum (MO), consequently levels of these elements may be affected in plants grown on tbis soil. The objective of tbe study was to compare tbe Cu and MO status of yea&g steers grazing mined-land and native raoge forage to determine wbetber mined-land gazed steers were more prone to molybdenosis and/or Cu deficiency. Vegetation samples were collected from both mined-land and native range pasturea. Copper was marginai and MO was sligbtiy bigb, for beef cattle, in forage obtained loom both study sites. Blood serum and liver biopsy samples were taken from yearling steers at the initiation and termination of gr8zing on reclaimed mined-land and native range in 1978,1979,1982, and 1983. For the 4 years, there WNI no significant difference between forage sourcea with respect to Cu and MO levels in tbe liver or MO levels in tbe serum. However, serum Cu wn slightly (JY.10) lower in steers grazing on mined-land. Liver Cu levelr were marginal in steers grazing on either mined-land or native mnge. Initial liver MO levels were Igbtly above normal but did not increaae to levels expected if animals were consuming a diet excessively bigb in MO. No symptoms of Cu deficiency or molybdenosb were observed during tbe course of tbe study. However, ma&al serum, liver and forage Cu levels measured suggest that central North Dakota ranchers should be alert to the poesibiiity of a Cu deficiency, whether cattle are grazing reciaimed mined-land or nntive range.