Sciency Thoughts: Tantalum mining in the twenty first century.

Tantalum is a transition metal highly sort after for its ability to store and release electricity (in the form of electrons), ductability, tensile strength, resistance to corrosion and high melting point, which puts it in high demand from industries ranging from electronics to aircraft manufacturing. The United States is a major consumer of Tantalum, but the known reserves within the country are negligible and no tantalum has been produced there since the 1950s. This makes tantalum supplies a source of concern to the US, particularly as production is concentrated in a relatively small number of countries.

In a report published on 10 December 2015 Donald Bleiwas, John Papp and Thomas Yager of the United States Geological Survey National Minerals Information Center, discuss the changing nature of the tantalum mining industry over the period 2000 to 2014.

In 2000 the world's largest producer of tantalum was Australia, which was responsible for around 45% of global production followed by Brazil, which produced around 17%. However in 2014 the largest producer was Rwanda, producing around 50% of the global total, followed by the Democratic Republic of Congo, which was responsible for around 17% of global production. This represents a change not just in the geographical origin of the metal, but from highly mechanized large scale mines to small scale, labour-intensive artisanal mining operations.

Artisanal miners in central Africa washing tantalum ore to produce concentrate. Richard Burt/Tantalum-Niobium International Study Center in Bleiwas et al. (2015).

The production of tantalum in Australia was largely concentrated at two large mines, Greenbushes and Wodgina. Both of these mines recovered the metal from hard rock, requiring a high level of mechanical processing to process the ore. These mines were highly profitable during the dot-com boom of the late 1990s, when tantalum was in high demand in high-tech industries, but were badly hit when the dot-com bubble burst in 2000. However production persisted through the early 2000s, with reduction being scaled down at Greenbushes in 2006. The global economic crash of 2008 affected the profitability of these large scale mines, and production at both ceased in 2009.

The Brazilian mines, in contrast, are concentrated in poorly consolidated sedimentary rocks, requiring far less processing to access the ore. This is fairly common with rare metals and minerals; substances that are present at very low concentrations can become concentrated in sedimentary deposits. This has allowed production at the Brazilian mines to remain profitable and productive while those in Australia failed, and production in Brazil has remained relatively constant, falling behind the African countries due to the increased production there rather than any fall off in Brazilian production.

Production in the Rwanda and Democratic Republic of Congo was relatively constant between 2000 and 2006, but the began to climb sharply, with production increasing to match a global shortfall as production in Australia fell and a supply of tantalum in the US caused by a sell off of tantalum stock-piled for defense purposes. Following this production rose sharply first in the Democratic Republic of Congo and then in Rwanda.

Whereas other metals are for the most part traded through commodities exchanges, with documented internationally established prices, tantalum prices are determined between the buyer and seller without reference to any international trade framework. This means that documenting the point of origin of tantalum, and the destination to which it is sold on, is largely down to the individual dealer, not all of whom are likely to feel obliged to provide accurate information to any outside body.

Tantalum reserves in the Democratic Republic of Congo are concentrated in North and South Kivu provinces, in the unstable east of the country, and the sharp rise in the profitability of the commodity (and other metals used in high-tech industries) is thought to have fueled conflict in the region, with both domestic and foreign militia groups (and to some extent foreign governments) fighting for control over the industry. Concern over this led a clause in the 2010 Dodd-Frank Wall Street Reform and Consumer Protection Act which placed a duty of due diligence on companies importing tantalum to the US from the Democratic Republic of Congo or neighbouring countries to ensure that the metal does not originate from such a source. In practice this has meant that US importers have tried to avoid metal from North and South Kivu, though they have continued to obtain tantalum from other parts of the country, some of which may have actually originated from these provinces. The ban is not though to have had any great impact on production in North and South Kivu, with tantalum that cannot be exported to the US instead being sold to Chinese dealers at a reduced price.

Artisanal tantalum mining in central Africa. Richard Burt/Tantalum-Niobium International Study Center in Bleiwas et al. (2015).

Rwanda, while initially slower than the Democratic Republic of Congo to expand its industry in response to rising global demand and falling production, overtook that country to become the world's leading producer in 2012, selling off government-owned mines and granting new concessions to private investors and artisan cooperatives in order to meet the rising demand for tantalum in China.

Bleiwas et al. note that the Great Lakes area of Central Africa remains potentially politically unstable, and that with 67% of global tantalum production now concentrated in the area there is a strong risk that any regional conflict could severely affect the industry. They note that the Australian mines, while no longer in production, are still being maintained, and could presumably be brought back into production should such a situation arise, though production costs in Australia are not likely to fall, and therefore a switch back to Australia as a primary producer would be marked by a sharp rise in the cost of the metal.

Mine production of tantalum contained in concentrates, by country of origin, for (A) 2000 and (B) 2014. Bleiwas et al. (2015).

Pages

Tuesday, 15 December 2015

Tantalum mining in the twenty first century.