An investigation was undertaken by the Bureau of Mines to devise a flotation method for concentrating the pyrochlore in a Powderhorn, Colorado, ore (0.43 pct cb2o5). The technique involved regrinding and flotation of pyrochlore from a rougher tailing product obtained by flotation of the biotite and apatite gangue. Cocoamine acetate and hydrofluosilicic acid were used in the pyrochlore flotation step that produced a rougher concentrate containing 17 pct of the feed, assaying 1.21 pct cb2o5 and representing 47 pct columbium recovery. Tests on the rougher concentrate to float a cleaner concentrate yielded a 2.62-Pct-cb2o5 product at a recovery of 22.6 pct of the columbium in the ore. Fine grinding was used to liberate the pyrochlore from the gangue minerals and, as such, resulted in the generation of slimes that contributed to problems in flotation. Yet, the flotation technique investigated indicates that flotation has potential as a beneficiation method for the Powderhorn, Colorado, ore.