The Colorado Plateau covers some 130,000 square miles in the Four Corners region. The properties currently held by Energy Fuels Resources Corporation (EFRC) lie mostly in the Canyon Lands Section in the central and east-central part of the Plateau in Utah and Colorado. This portion of the Plateau’s basement rocks are mostly Proterozoic metamorphics and igneous intrusions. The area was relatively stable throughout the Paleozoic and Mesozoic Eras with minor uplifts, subsidences, and tiltings resulting in fairly flat-lying sedimentary rocks ranging from evaporites and marine sediments through eolian sandstones to fluvial systems clastics. This thick stratigraphic sequence is interrupted locally by salt-cored anticlines in the Paradox Basin area, basement fault-related monoclines, and Tertiary/Late Cretaceous laccolith intrusions.

Major uranium deposits occur principally in two of the fluvial sequences. The older one is located at or near the base of the upper Triassic Chinle Formation. Areas of uranium deposits occur where the basal Chinle consists of channels filled with sandstone and conglomerate that scoured into the underlying sediments. This channel system is known as the Shinarump Member in southern Utah. Farther north in eastern Utah, the basal member of the Chinle is a younger channel system known as the Moss Back. The Chinle deposition followed a period of tilting and erosion, therefore, the basal contact is an angular unconformity. Where the Chinle channels are in contact with sandstones of the Permian Cutler Formation, good uranium deposits locally occur in the Cutler, as well.

The other significant uranium deposits occur in the late Jurassic Morrison Formation. The Morrison comprises four members. The lower member, the Salt Wash, which interfingers with the Recapture Member in southeastern Utah, is the main host. (In the Henry Mountain district farther west in southern Utah, there is another unit, the Tidwell that interfingers and underlies the Salt Wash). The upper part of the Morrison is the Brushy Basin Member, which interfingers with the Westwater Canyon Member in southeastern Utah. In most of the area of EFRC properties, only the Salt Wash and Brushy Basin Members are present. The Salt Wash consists of about equal amounts of fluvial sandstones and mudstones deposited by meandering river systems. The Brushy Basin was deposited mostly on a large mud flat, probably with many lakes and streams. Much of the material deposited to form the Brushy Basin originated from volcanic activity to the west. The majority of the uranium production has come from the upper sandstones of the Salt Wash Member (Top Rim).

Uranium occurrences have been found throughout most of the Colorado Plateau; however, there are numerous belts and districts where the deposits are larger and more closely spaced. In addition to the uranium, many of the deposits contain considerable amounts of vanadium. In fact, in some districts the vanadium content is 10 times or more the uranium content. In general, the Cutler and Shinarump ores contain very little vanadium. The vanadium content in Moss Back ores ranges from insignificant to as much as 3:1 V2O5:U3O8 in portions of some districts. The Salt Wash deposits usually contain large amounts of vanadium. The V2O5:U3O8 ratio averages about 4:1, ranging up to 15:1. The economics of the Salt Wash deposits is obviously enhanced by the vanadium content, even when vanadium prices are lower than they presently are.