Figs 4 and 5 show the number of deposits (874) and total amount of uranium discovered (10.53 Mt U) in the world since 1940, that most of these were found in the four decades between 1945 and 1985, and that most of the metal found is contained in a handful of giant deposits. It should be noted that there is often a delay between a deposit being first discovered and it being publicly reported. Furthermore, it can take several years to drill-out a deposit and its true size being fully recognized. Based on past experience, the author has made an estimate of the likely number of unreported discoveries (and associated metal) found. This boosts the reported numbers for the last decade.
25 FIG. 4. Number of primary uranium deposits (>200 t U) found in the world: 1940–2016.
FIG. 5. Total amount of uranium metal (in primary uranium deposits >200 t U) found in the world:
1940–2016.
Table 3 gives details on the size and status for those discoveries with >100 kt U. These 18 deposits account for ~34% of the world’s total primary uranium resource. It is significant to note that six of these have not been mined, even though many of them were discovered several decades ago.
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TABLE 3. SIZE, DISCOVERY HISTORY AND CURRENT STATUS OF PRIMARY URANIUM DEPOSITS
>100 KT
Camp Sweden 5412.0 0.014% 756.2 post 1946 Feasibility study
Elkon U Camp Russian
Fed. 238.1 0.150% 357.1 ca. 1962 Pre-feas/scoping
Imouraren Niger 419.1 0.067% 279.2 1966 Feasibility study
McArthur River Canada 3.2 8.264% 264.4 1988 2000 2017 Care & maintenance Priargunsky U
Camp Russian
Fed. 127.7 0.192% 244.7 1963 1969 Operating mine
Rossing Namibia 987.8 0.023% 231.6 ca. 1965 1978 Operating mine
Ronneburg U Camp Germany 202.3 0.099% 200.2 1949 1950 1990 Closed mine
Husab Namibia 583.2 0.034% 197.3 2006 2016 Dev’t/construction
Ranger U Camp Australia 114.9 0.151% 173.5 1969 1981 Operating mine
Mynkuduk Kazakhstan 330.3 0.035% 115.3 1975 1987 Operating mine
Lagoa Real Brazil 86.3 0.122% 105.3 1977 1999 Operating mine
Etango Namibia 658.9 0.016% 104.1 1976 2020 Dev’t/construction
Rabbitt Lake U
Table 3 shows that many of the large deposits were found several decades ago. This raises the general concern for industry over whether or not all the best deposits have been found, i.e., “all the big fish have now been caught”. On closer analysis this does not appear to be the case. Fig.
6 plots the cumulative size-frequency of 87 known discoveries (>200 t U) made in the last 20 years and compares it against the distribution for the total of all known discoveries (previously shown in Fig. 1). While the curve for the most recent period is lower7 than the total, what is significant is that the angle of the slope for the two curves is the same. This can be seen in the dotted-line that refers to the most recent period multiplied by 8. In other words, the frequency of finding a giant deposit relative to that for major- or moderate-sized deposit has not changed.
Instead, the apparent lack of giant discoveries in recent years is simply due to a lack of
7 Mathematically this is not surprising – as the last 20 years only covers part of the total time period for the industry. By definition, the latter will always be bigger.
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exploration effort. In other words, we simply have not ‘rolled-the-dice’ enough times to find them.
Embedded in Fig. 6 is a table showing the number and size of discoveries made in the last two decades. For example, it shows that 4 out of 87 (i.e., ~5%) of the discoveries by number were deposits with >50 kt U. These discoveries contained ~37% (or 420.7 out of 1147.9 kt U) of the total metal found. In contrast, deposits in the size range 1000–5000 t U accounted for ~55% (48 out 87) by number but only 10% by metal content of all discoveries made in this time period.
In other words, most discoveries made were small in size, and collectively these do not contain much metal. However, these size-frequency distributions are used later in Section 7 to predict the likely size distribution of future discoveries.
3.2. Trend in deposit size
Related to the generally held perception that the best deposits have already been found, it is the author’s view that the quality of deposits found is getting worse over time. Fig. 7 shows that trend in the average size of discoveries since 1940; it shows that there has been an apparent downward trend in the maximum size of deposit being found. In detail, the largest discovery made in recent years (Husab deposit in Namibia, which was found in 2006) contains 196 kt U.
This is one-quarter of the size of the largest known primary uranium deposit, namely the Alum Shale camp in Sweden, with 756 kt U. This deposit was found back in 1946. As noted in the previous section, this may simply be an artefact of the lack of exploration effort in recent years.
A more meaningful metric is to look at the trend line for the weighted average size of the discoveries. Surprisingly, this has remained relatively constant over time; varying between 7000 t and 25 kt, with an average of 9000 t U. In other words, the recent average size of discoveries is the same as that 50 years ago8.
FIG. 6. Cumulative size-frequency curves for primary uranium deposits found in 1997–2016 versus all-years.
8 It could also be argued that the reason why the weighted average size has stayed constant this may simply be due to fewer small-size discoveries are being reported. Such deposits still exist, but companies have no incentive to drill them out / report them – as they are unlikely to be economic to develop.
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FIG. 7. Trend in the size of primary uranium discoveries found in the World: 1940-2016.
3.3. Trend in deposit grade
Fig. 8 shows the grades of primary uranium deposits found since 1940. Surprisingly, the maximum grade achieved appears to have risen over time, from <1% U in the 1960s to >10%
in recent years. One such discovery is the Phoenix deposit found in 2002 in Saskatchewan. This deposit has a resource of 0.18 Mt @ 15.67% U = 27.4 kt U. As noted in Fig. 3, these high-grades are often associated with unconformity-related style deposits.A more meaningful metric is to look at the trend line for the weighted average grade of the discoveries. As seen in Fig. 8, the weighted average grade of discoveries made in the last decade is ~0.034% U. This is less than half of that observed for discoveries made in the 1960s (~0.077% U). Notwithstanding the wide spread in results for individual deposits, there does appear to be slow downward trend in grade over time. As a general rule, lower grade deposits tend to be less economic and so are less likely to be developed into mines.
29 FIG. 8. Trend in the ore grade of primary uranium discoveries found in the world: 1940–2016.
3.4. Trend in the companies making discoveries
Fig. 9 shows the types of companies associated with the 873 known primary uranium deposits (>200 t U) found in the world since 1940 in 5-year increments. Fig. 10 shows the relative importance of each company type for each increment of time. As can be seen from these figures, the relative importance of the various groups (majors, junior explorers, prospectors and state-owned companies, etc.) varied significantly over time.
In the first decade (1940-49), 46 discoveries were made: ~22% by prospectors and ~75% by state-owned companies. The high-level of discoveries from the latter reflects the strategic nature of the industry prevailing at the time9. In the 1950s, 251 deposits were found in the world; ~51% of these were by state-owned companies, ~15% by prospectors and ~17% by junior explorers while mining companies only played a peripheral role – finding only ~4% of the deposits. By the late 1950s, military requirements for uranium were largely met, and government agencies cut back on their purchases and exploration efforts. The uranium price correspondingly dropped and less exploration was carried out (see Fig. 14 in Section 5). This led to a fall in the rate of discovery – with only 128 deposits being found in 1960–1969; ~69%
of these were by state-owned companies, as private industry abandoned the sector. In the early 1970s, uranium prices rebounded due to the rapid growth in demand from nuclear power stations. The major and moderate-sized mining companies became much more active – and discovered ~20% of the 225 deposits found in that decade. The 1970s were also a time of upheaval in oil market – and many of the major oil companies made a strategic decision to diversify into the energy minerals sector (namely coal and uranium) – leading them to find 1~3% of the uranium deposits. The 1980s was a period of decline. Uranium and oil prices fell, and the oil companies unwound their investments in the mineral sector. Mining companies also cut-back on their exploration efforts; ~56% of the 102 discoveries made that decade were made
9 This trend continues through to the present for the Centrally Planned Economies (of the FSU, Eastern Europe, China and North Korea). In these countries, virtually all uranium exploration and mine production is controlled by the State. Similar restrictions apply in many of the open-economy countries (such as India, Indonesia and Brazil).
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by government geologists. The 1990s was a decade in hibernation. Very low uranium prices led to minimal exploration efforts by private industry. State-owned companies in the former Soviet Union (FSU) and in Eastern Europe were in disarray due to the collapse of the Soviet Union, and very little exploration was done. Only 31 discoveries were made in the world in that decade; ~90% of these were by state-owned companies – mainly in emerging markets in Asia (such as Mongolia and Vietnam). The decade 2000–2009 was a time of rising uranium prices, which led to a substantial increase in exploration efforts by private industry – especially the junior exploration companies. The junior sector accounted for ~57% of the 61 discoveries made in that decade. State-owned companies only played a minor role – accounting for 26% of all discoveries. This trend has continued into the most recent period (2010–2016) – with ~70% of all the discoveries coming from the junior sector. Major mining companies and government agencies now only play a small role in the discovery process.
FIG. 9. Number of uranium deposits found in the world by company type: 1940–2016.
31 FIG. 10. Percentage of uranium deposits found in the world by company type: 1940–2016.