Above: the Mir diamond mine in the Sakha Republic, Siberia. It's 525 meters deep, has a 1200m diameter and is one of the biggest excavated holes in the world.
As World War II drew to a conclusion, the alliance between the USA, Great Britain and the Soviet Union began to crumble. Escalating tensions over Soviet intentions in Eastern Europe lead to the Cold War, which began in 1944 and continued up to the collapse of the Soviet Union in 1991. The world became focused on an ideological split, with the city of Berlin at the centre, and the powerhouses of the United States and the Soviet Union at either side.
In June 1951, the United States tightened its grip on the Soviet Union with its Battle Act legislation. Congressmen believed that defeats in the Korean War were due predominantly to European - and particularly British - trade with China and Russia. The Battle Act ensured that US foreign economic aid became conditional on the non-transfer to Soviet-bloc countries of war related merchandise; this included industrial diamonds (Cain, 2007).
In the first half of the twentieth century, a number of critical uses had developed for industrial diamonds, not only in the manufacture of precision parts for airplanes, tanks and artillery, but also as a strategic material in just about every field of modern scientific progress. An increasingly industrialised Soviet economy required a reliable supply of diamonds, the vast majority of which were mined in the British or Belgian Empires (Kempton & Levine, 1995).
It’s important to note that the search for diamonds in Russia had, in fact, pre-dated the United States Battle Act of 1951. Small amounts of diamonds had been found in the foothills of the Ural Mountains since the 17th century, and in 1939, the Soviet State Planning Commission had decreed a wide search for diamonds on the Siberian platform, particularly in the Vilyuy Valley of Western Yakutia, an area of Russia known today as the Republic of Sakha.
Three men - two geologists and a petrographer - are credited with the initial thinking that spurred this state-sponsored search: AP Burov, GG Moor and VS Sobolyov. They believed that somewhere in the vast territories of the USSR there must be areas like the diamond fields of South Africa and other parts of the world. Foreign data was analysed and the similarity between the Kalahari Craton in Africa and Siberian Craton recognised. In 1941, the Germans invaded Russia and the State Planning Commission’s campaign ground to a halt.
Once fighting had ended, the Soviet quest for diamonds was revived and prospecting began in earnest. The task at hand was far from easy. Representing one fifth of Russia’s territory,Yakuita is a huge area of arctic or subarctic tundra and taiga, in which the intense cold of winter lasts for seven months, with highs of -40℃ and lows of -60℃, and a permafrost which penetrates 350m beneath the surface. Snow lies from the end of September and rivers freeze solid from October. When the thaw progresses in mid-May, the melting ice turns the ground deeply muddy. After spring come the short, hot and very wet summers that turn the area into a giant swamp.
Prospecting in Yakutia involved a huge amount of practical fieldwork. Hundreds of expeditions with thousands of workers - including many from forced labour camps - explored vast and remote areas. According to Kirby (1974), early maps of the area contained only the most basic topographical information. For example, those used in the 1947 expeditions had the Vilyuy River marked correctly, but all other rivers and trails were provisional. Aerial photography a few years later showed that some rivers were misplaced on these maps by fifty kilometres or more.
At first, alluvial areas and placer deposits were the main target. For several years, prospectors dug and washed thousands of tonnes of river gravel to search for platinum - at that time believed to be a satellite mineral of diamond - and also diamond itself. This was extremely hard labour due to the permafrost. Recovered mineral concentrate was sent to a field laboratory. There it was X-rayed by technicians and the fluorescent minerals assessed by mineralogists (Kirby 1974, Strnad 1991).
In 1952, work published by Sobolyov indicated that pyrope garnet was one of the most important kimberlite indicator minerals. This was not a new discovery - Brazilian Giampieroes looked for garnet when panning for diamonds, and pyrope was used to locate the Premier Mine in South Africa in 1902. But to Soviet geologists, with no experience in both diamond exploration and isolated from the rest of the world, it was new and crucial information. Soviet thinking at the beginning of the campaign had linked kimberlites with flood basalts like the Karoo Traps in South Africa and the Deccan Traps of India. But now, with pyrope identified, garnet finds were plotted on maps and a more confident search for kimberlite in Yakutia began (Strnad 1991).
By the early 1950s geophysics played an increasing part in the Soviet search for diamonds, though tests were all ground based. By 1955, exploration planes were equipped with a recording magnetometer - a first worldwide - and aeromagnetic surveys at a scale of 1:25,000 were flown on grids. Air photography was also carried out at scales of 1:10,000 or 1:15,000, with infra-red film giving better results than panchromatic. Results were interpreted by a ground team consisting of a geologist, geobotanist and an operational geophysicist (Satterly, 1971).
Aeromagnetic surveying was used with only limited success since specialist piloting was required and local conditions made the process immensely difficult. Mineralogical investigations were still necessary and work remained mostly ‘earthbound’ and labour intensive. In June 1954, mineralogist Larisa Popugaeva and her assistant Fedor Belikov landed in Yakutia on the shores of the Daldyn River. They took sand samples every 500 meters and traced pyropes upstream. After almost two months of exceptionally difficult searches, they found Yauktia’s first kimberlite pipe (Erlich, 2013).
Perhaps the most striking comparison between the Soviet search for diamonds and modern methods, is the human contribution. The Soviets instigated a state sponsored search on an unimaginable scale, sending thousands of men and women into harsh, unmapped terrain resulting in numerous fatalities from disease, starvation and accident (Strnad, 1991). While ultimately the campaign proved an enormous success, it is, thankfully, very difficult to imagine anything on this scale being organised anywhere in the world today, with perhaps the exception of North Korea. The other obvious comparison is the difference in initial approach. In modern day prospecting, the geomorphology of the proposed search area would be examined on detailed topographic maps, and also using existing aerial and satellite photography and any available geophysical data. Any unusual circular depressions, elliptical lakes or drainage patterns would be noted, along with vegetation anomalies. It is only after this already available data is studied, that ground searches for indicator minerals would be carried out (Erlich & Hausel, 2002).
The reverse was true for the Soviets at the beginning of their campaign, for whom topographical maps were incomplete and geological data extremely limited. Aerial geophysical data was non-existent, and though ground geophysical mapping had been developed, the vast majority of the Siberian craton had, for the most part, never been trodden by man. So the Soviet’s began their campaign on the ground, digging out frozen sands and panning for minerals, searching for a metaphorical needle in haystack. Searching for diamond indicator minerals in soil samples and stream sediments is still an important technique used in modern day diamond exploration, particularly before expensive geophysical methods are used. It was following a trail of diamond-indicator minerals that lead Charles Fipke to the Lake de Gras region of Canada in 1990, and the major diamond discoveries that followed (Harlow, 1998). As a more recent example, Diamond Fields International, on prospecting pipes in Liberia in 2006, reported that ‘ indicator mineral anomalies coincident with recessive swamps have been identified...stream sediment reconnaissance sampling continues to generate kimberlite indicator minerals’.
Once the first Yakutian pipe was found in 1954, it was quickly realised by Soviet geologists that magnesian ilmenite, picroilmenite, chromite, olivine and cr-diopside were also important indicator minerals (Satterly, 1971). But in comparison to modern day prospecting, the 1950s Soviet knowledge of the favourable geology and geochemistry involved in diamond exploration was limited. In comparison, today we understand that garnets are found in kimberlite as megacrysts and xenocrysts, and as components of xenoliths and cognate modules. Chrome rich pyropes (>2% Cr 2 O 3 ) are assigned to peridotites, and some of the more useful garnets used in diamond exploration are the G9 and G10 type pyropes (Erlich & Hausel, 2002).
Mineralogist Larisa Popugaeva
Both technology and geophysical methods have also improved since the 1950s. Data on anomalous structures and vegetation using high-altitude satellite imagery is now available to prospectors. Gravity and seismic surveys have been developed to measure relative densities of potential pipes. Electrical resistivity and conductivity tests have can detect layered variations in the Earth’s subsurface, and biogeochemical and geochemical surveys have been both developed and improved. Surface and aeromagnetic surveys, while improved in a technological sense, continue to be used with limited success, allowing some kimberlite and lamproite pipes with high magnetic susceptibility to be detected on known diamond fields (Erlich & Hausel, 2002).
In conclusion, while Russia’s diamond discoveries were not instigated by the Cold War, the embargo placed on the Soviets in 1951 undoubtedly strengthened their resolve, and pushed them well beyond the limits to which a modern day exploration would likely run - both financially and in human cost. Ultimately this paid off and today, Russia is the largest producer of diamonds in the world by volume. The basics of the Soviet search are not vastly different from today’s methods - and in fact in some areas such as aeromagnetic surveys they paved the way - but as the years have passed, research and knowledge has greatly expanded. Modern understanding of the geomorphology and geology of the Earth means that diamond exploration, while still incredibly expensive and time-consuming, is more efficient than it has ever been before.