Color copies of photomicrograph figures that accompany a report studying uranium in granites in the southwestern United States.

This report is an issue of the original draft copy of the "Interim Staff Report on Uranium Exploration on the Colorado Plateau", dated June 1951. The original draft copy was only recently located and is being published at this time because of the interest in the contained historical content.

The tabulations on these pages include all of the known areas in Colorado, Utah, New Mexico, and Arizona having economically important uranium-vanadium deposits of the type which are generally referred to by the terms roscoe-lite and/or carnotite. Though similar deposits are known to exist in other areas they are to be viewed as being little more than mineralogical curiosities.

Introduction: Vanadium ore is being mined at many places in western Colorado, southeastern Utah, northeastern Arizona, and northwestern New Mexico (fig. 1). Eight mills in this region produced about 4,300,000 pounds of V2 05 in 1942, representing about 90 percent of the vanadium obtained from domestic sources. Although ore production has mostly exceeded mill capacity since 1937, production during the last half of 1942 averaged only about 19,000 tons or ore a month, whereas the capacity of these mills total about 22,000 tons a month. At the expected rate of ore production, ore stockpiles will be exhausted sometime in 1944, and these mills will then have excess capacity. With more intensive prospecting than now practiced, however, it is believed that sufficient reserves can be indicated to sustain capacity operation of these mills for several years. This memorandum is prepared to specify those areas that are considered most favorable from a geologic standpoint for developing large reserves of vanadium ore by prospecting. It is based on intensive studies by the Geological Survey since 1939 in most of the areas that produce vanadium ore.

From introduction: The general distribution of known deposits of vanadium-bearing sandstone, which also contain some uranium and radium, is shown in figure 1 1/ and Exhibit A, plate 53. 2/ During 1939-41 the Geological Survey made detailed geological studies of these deposits in the Uravan district, Montrose County, Colorado, as well as preliminary examinations in other parts of the Colorado Plateau vanadium region. In 1942 detailed geological studies were made o the deposits in the Egnar-Slick Rock district, San Miguel Co., Colo.; 3/ the Carrizo Moungains district, Navajo Indian Reservation, Arizona and New Mexico; 4/ the Placerville district, San Miguel County, Colo. 5/ and the Monticello district, San Juan Co., Utah. 6/ Since May 3, 1943, the Gelogical Survey has guided the Bureau of Mines program of prospecting these deposits in parts of Colorado and Utah.

From introduction and acknowledgements: This report is written to supplement and complete the record contained in some fifty district and special reports already submitted, and duplication of material in district reports has been studiously avoided. The data herein contained are largely of a regional type, inclusion of which was not wholly appropriate to the district reports.

Introduction: Studies of uranium-vanadium occurrences in the Four Corners region show that, with the exception of the Lukachuai area, all of the major deposits in the Morrison formation are grouped around the various igneous masses which are scattered irregularly throughout the Colorado Plateau. The pattern of deposition varies from mountain group to mountain group and each will be described separately. Maps accompany this report to supplement the descriptions of ore occurrences in the vicinity of the La Sal, Abajo, Carrizo, and Henry mountains. Elsewhere, it is believed that a written description will suffice.