The Felder ore deposit is a 5 million-lb uranium deposit in the South Texas coastal plain. It occurs in the basal sandstone of an Oakville Formation (Miocene) alluvial system. The host sandstone is a carbonate-rich arkose which contains virtually no carbonaceous debris and has been reduced by the local introduction of hydrogen sulfide. The ore lies well within the reduced zone and occurs as coffinite and uraninite that fill interstices and coat and replace grains.

The overall geometric configuration of the ore is that of a winged, crescentic ore roll. Weak mineralization extends the wings of the ore roll and gives greater expression to the roll character. Departures from the shape are controlled by discontinuities in bedding and by proximity of the ore to the surface. Associated with the uranium is a broad halo of anomalous molybdenum.

Subsidiary mineralized trends suggest a preexisting updip position for the main roll. Oxidation from the surface largely destroyed this previous roll by solubilization of uranium. Uranium subsequently migrated into favorably reduced sandstone and reprecipitated at the present roll position.

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