Uranium Mining & Milling to Power America

World Nuclear

Supply of Uranium

(updated August 2012)

  • Uranium is a relatively common metal, found in rocks and seawater. Economic concentrations of it are not uncommon.
  • Its availability to supply world energy needs is great both geologically and because of the technology for its use.
  • Quantities of mineral resources are greater than commonly perceived.
  • The world’s known uranium resources increased 15% in two years to 2007 due to increased mineral exploration.

Uranium is a relatively common element in the crust of the Earth (very much more than in the mantle). It is a metal approximately as common as tin or zinc, and it is a constituent of most rocks and even of the sea. Some typical concentrations are: (ppm = parts per million).

Very high-grade ore (Canada) – 20% U 200,000 ppm U
High-grade ore – 2% U, 20,000 ppm U
Low-grade ore – 0.1% U, 1,000 ppm U
Very low-grade ore* (Namibia) – 0.01% U 100 ppm U
Granite 3-5 ppm U
Sedimentary rock 2-3 ppm U
Earth’s continental crust (av) 2.8 ppm U
Seawater 0.003 ppm U

Where uranium is at low levels in rock or sands (certainly less than 1000 ppm) it needs to be in a form which is easily separated for those concentrations to be called “ore” – that is, implying that the uranium can be recovered economically.  This means that it need to be in a mineral form that can easily be dissolved by sulfuric acid or sodium carbonate leaching.

An orebody is, by definition, an occurrence of mineralisation from which the metal is economically recoverable. It is therefore relative to both costs of extraction and market prices. At present neither the oceans nor any granites are orebodies, but conceivably either could become so if prices were to rise sufficiently.

Measured resources of uranium, the amount known to be economically recoverable from orebodies, are thus also relative to costs and prices. They are also dependent on the intensity of past exploration effort, and are basically a statement about what is known rather than what is there in the Earth’s crust – epistemology rather than geology. See Appendix 2 for mineral resource and reserve categories.

Changes in costs or prices, or further exploration, may alter measured resource figures markedly. At ten times the current price, seawater might become a potential source of vast amounts of uranium. Thus, any predictions of the future availability of any mineral, including uranium, which are based on current cost and price data and current geological knowledge are likely to be extremely conservative.

From time to time concerns are raised that the known resources might be insufficient when judged as a multiple of present rate of use. But this is the Limits to Growth fallacy, a major intellectual blunder recycled from the 1970s, which takes no account of the very limited nature of the knowledge we have at any time of what is actually in the Earth’s crust. Our knowledge of geology is such that we can be confident that identified resources of metal minerals are a small fraction of what is there. Factors affecting the supply of resources are discussed further and illustrated in the Appendix.

Uranium availability

With those major qualifications the following Table gives some idea of our present knowledge of uranium resources. The total and several country figures are lower than two years earlier due to economic factors, notably inflation of production costs. It can be seen that Australia has a substantial part (about 31 percent) of the world’s uranium, Kazakhstan 12 percent, and Canada and Russia 9 percent each.

Known Recoverable Resources of Uranium 2011

tonnes U percentage of world
South Africa
World total

Reasonably Assured Resources plus Inferred Resources, to US$ 130/kg U, 1/1/11, from OECD NEA & IAEA, Uranium 2011: Resources, Production and Demand (“Red Book”).  The total to US$ 260/kg U is 7,096,600 tonnes U, and Namibia moves up ahead of Niger.

Reasonably Assured Resources of Uranium in 2009

Current usage is about 68,000 tU/yr.  Thus the world’s present measured resources of uranium (5.3 Mt) in the cost category around present spot prices and used only in conventional reactors, are enough to last for about 80 years.  This represents a higher level of assured resources than is normal for most minerals.  Further exploration and higher prices will certainly, on the basis of present geological knowledge, yield further resources as present ones are used up.

An initial uranium exploration cycle was military-driven, over 1945 to 1958. The second cycle was about 1974 to 1983, driven by civil nuclear power and in the context of a perception that uranium might be scarce. There was relatively little uranium exploration between 1985 and 2003, so the significant increase in exploration effort since then could conceivably double the known economic resources despite adjustments due to increasing costs. In the two years 2005-06 the world’s known uranium resources tabulated above and graphed below increased by 15% (17% in the cost category to $80/kgU). World uranium exploration expenditure is increasing, as the the accompanying graph makes clear. In the third uranium exploration cycle from 2003 to the end of 2011 about US$ 10 billion was spent on uranium exploration and deposit delineation on over 600 projects. In this period over 400 new junior companies were formed or changed their orientation to raise over US$ 2 billion for uranium exploration. About 60% of this was spent on previously-known deposits. All this was in response to increased uranium price in the market and the prospect of firm future prices.

The price of a mineral commodity also directly determines the amount of known resources which are economically extractable. On the basis of analogies with other metal minerals, a doubling of price from present levels could be expected to create about a tenfold increase in measured economic resources, over time, due both to increased exploration and the reclassification of resources regarding what is economically recoverable.

This is in fact suggested in the IAEA-NEA figures if those covering estimates of all conventional resources (U as main product or major by-product) are considered – another 7.6 million tonnes (beyond the 5.3 Mt known economic resources), which takes us to 190 years’ supply at today’s rate of consumption. This still ignores the technological factor mentioned below. It also omits unconventional resources (U recoverable as minor by-product) such as phosphate/ phosphorite deposits (up to 22 Mt U), black shales (schists) and lignite (0.7 Mt U), and even seawater (up to 4000 Mt), which would be uneconomic to extract in the foreseeable future, although Japanese trials using a polymer braid have suggested costs a bit over $250/kgU. Research proceeds.

Known U Resources and Exploration Expenditure

It is clear from this Figure that known uranium resources have increased almost threefold since 1975, in line with expenditure on uranium exploration. (The decrease in the decade 1983-93 is due to some countries tightening their criteria for reporting.  If this were carried back two decades, the lines would fit even more closely.  The change from 2007 to 2009 is due to reclassifying resources into higher-cost categories.)  Increased exploration expenditure in the future is likely to result in a corresponding increase in known resources, even as inflation increases costs of recovery and hence tends to decrease the figures in each cost category.

About 20% of US uranium came from central Florida’s phosphate deposits to the mid 1990s, as a by-product, but it then became uneconomic.  With higher uranium prices today the resource is being examined again, as is another lower-grade one in Morocco.  Plans for Florida extend only to 400 tU/yr at this stage. See also companion paper on Uranium from Phosphate Deposits.

Coal ash is another easily-accessible though minor uranium resource in many parts of the world.  In central Yunnan province in China the coal uranium content varies up to 315 ppm and averages about 65 ppm.  The ash averages about 210 ppm U (0.021%U) – above the cut-off level for some uranium mines.  The Xiaolongtang power station ash heap contains over 1000 tU, with annual arisings of 190 tU.  Recovery of this by acid leaching is about 70% in trials. This project has yet to announce any commercial production, however.

Widespread use of the fast breeder reactor could increase the utilisation of uranium 50-fold or more. This type of reactor can be started up on plutonium derived from conventional reactors and operated in closed circuit with its reprocessing plant. Such a reactor, supplied with natural or depleted uranium for its “fertile blanket”, can be operated so that each tonne of ore yields 60 times more energy than in a conventional reactor.

see also WNA position paper.

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