The Spud Patch area comprises about 8 square in T. 43 M., R. 18 and 19 W., San Miguel County, Colo., and is about 4 miles northeast of Egnar, Colo. Claims of the United States Vanadium Co. and the Vanadium Corp. of America cover about half the area. Claims of other owners, public land, and patented agricultural land, comprise the remainder of the area. The area is about 38 miles from the Government mill at Montecello, Utah, and 55 miles from the Vanadium Corp. of America mill at Naturita, Colo.
Between 1940 and 1951, the Spud Patch area yielded about 24,000 short tons of carnotite ore that probably averaged 0.21 percent U3O8 and 2.2 percent V2O5.
The deposits are in a broad sandstone lens near the top of the Salt Wash member of the Jurassic Morrison formation. Although the deposits mined have been mainly impregnations of sandstone by carnotite and gray vanadium-bearing clay minerals, some of the richer deposits found by Geological Survey drilling have a finely disseminated black uranium mineral but no carnotite. The deposits commonly are thin irregular tabular layers, which locally thicken to form elongate masses called "rolls". These rolls have a dominant northeasterly trend. Geologic features found to be most useful as guides to ore are listed.
From November 1949 to May 1952, the U.S. Geological Survey drilled 415 diamond-drill holes totaling 67,215 feet in the Spud Patch area. The purpose of this drilling was to find deposits that would make new mines and to appraise the reserves in the unexplored area.
As a result of Geological Survey drilling, indicated and inferred reserves computed at the cutoff of 1 foot or more thick and 0.10 percent U3O8 or 1.0 percent V2O5 total 20,500 short tons, averaging 0.28 percent U3O8 and 2.1 percent V2O5. These reserves and those computed at a lower grade cutoff of 0.05 percent U3O8 or 0.50 percent V2O5 and the pounds of contained metal are summarized in table 1.
Potential reserves, whose existence is based on geologic evidence alone, are predicted to total about 42,000 short tons, averaging 0.25 percent U3O8 and 2.0 percent V2O5.
No additional exploratory-type drilling by the Geological Survey is planned in the Spud Patch area. Recommendations are offered for additional development-type drilling, preferably by claim owners or lessees in specific areas in the vicinity of deposits discovered by Geological Survey drilling.