USGS Fact Sheet 2017–3078, November 2017. Assessment team: Susan M. Hall, Mark J. Mihalasky, Bradley S. Van Gosen and George N. Breit (USGS); Brent A. Elliott (Texas Bureau of Economic Geology); Clyde L. Yancey (Uranium Energy Corporation).
The U.S. Geological Survey estimates a mean of 40 million pounds of in-place uranium oxide (U₃O₈) in undiscovered deposits in the Southern High Plains of Texas, New Mexico and Oklahoma, using a method built for calcrete uranium deposits.
Why it matters
- Demand: the U.S. is the world's largest consumer of uranium for nuclear power, which makes about 19 percent of the nation's electricity.
- Supply: in 2016, only 11 percent of the uranium bought by civilian reactors came from U.S. sources.
- Planning: long-term nuclear power needs both identified resources (for the short term) and undiscovered ones that could be found and mined economically later.
A new kind of deposit for the U.S.
In 2015 the USGS learned of two unreported uranium deposits in the Southern High Plains: Buzzard Draw and Sulphur Springs Draw. They are near-surface uranium-vanadate minerals in Pliocene and Pleistocene carbonate-rich sediments, called calcrete. Such deposits occur in dry regions of Australia, Namibia and elsewhere, but had never been reported in the United States. Together with other exploration targets, they justified a search for more.
How it was assessed
The USGS three-part method:
- Tracts: map areas where the geology permits such deposits, guided by known deposits and a deposit model.
- Count: estimate how many undiscovered deposits each tract probably holds.
- Size: estimate the uranium they contain, using grade-tonnage models from calcrete deposits worldwide.
The whole Southern High Plains is permissive, split into a north and a south tract. The south tract rates higher because of:
- the known deposits and exploration sites;
- favorable groundwater chemistry;
- hydrology that forms deposits — more permeable sands, faster recharge and shallower groundwater.
Inside it, a prospective area of highest potential was drawn around the known deposits and sites.
The results
| Sub-tract | Area (km²) | Known deposits | Undiscovered deposits | Probability 0.9 of at least (lbs) | 0.5 | 0.1 | Mean undiscovered (lbs) | Identified (lbs) |
|---|---|---|---|---|---|---|---|---|
| North | 43,920 | 0 | 1.1 | 0 | 4,200,000 | 26,500,000 | 9,000,000 | 0 |
| South | 46,630 | 2 | 3.9 | 8,100,000 | 26,500,000 | 59,500,000 | 30,900,000 | 2,660,000 |
| Total | 90,550 | 2 | 5.0 | 39,900,000 | 2,660,000 |
U₃O₈ in pounds, estimated in place.
- In all: a mean of 39.9 million pounds of undiscovered U₃O₈.
- The south: about 80 percent of it, 30.9 million pounds.
- For scale: the two known deposits hold about 2.6 million pounds combined.
What it means
The study points to a new uranium region that has drawn little attention: the Southern High Plains of northwestern Texas, eastern New Mexico and western Oklahoma. The deposits are shallow and in soft rock, well suited to open-pit mining when uranium prices and other factors are favorable. Method details: USGS global mineral assessments.
Sources
Based on Assessment of Undiscovered Resources in Calcrete Uranium Deposits, Southern High Plains Region of Texas, New Mexico, and Oklahoma, 2017, USGS Fact Sheet 2017–3078, U.S. Geological Survey; a work of the United States government in the public domain. The results table is taken from the fact sheet's PDF; its tract map, drawn with Esri rivers and boundaries, is not reproduced.
Licence: CC0 1.0 (public domain) · Adapted from pubs.usgs.gov
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