First Tin, Then Copper, Recently Gold, and Now Indium Rides to Cornwall's Salvation

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The people of Cornwall in South West England have the twin blessing of living in one of the most beautiful parts of the country, considered by many a vacation destination, and the curse of high unemployment. The area’s remoteness from any centers of commerce or industry have contributed to its unspoiled countryside, but likewise to its lack of employment opportunities. So repeated promises of a return to good health of the county’s old mining industry are like a roller coaster to the aspirations of locals hoping for a boost to the local economy.

Perversely, Cornwall was once a highly successful mining area; the streams of Cornwall and Dartmoor were the source of almost all Europe’s tin in medieval times. True, underground mining started in the late 13th century, according to a Telegraph article documenting the area’s history, as miners began to exhaust the alluvial deposits and seek the mother lodes. By the mid-1700s, Cornwall was producing not just tin, but some 12,000 tons of copper too. Indeed, it remained of “world-class significance according to the paper until the first half of the 19th century. As a result there are over 2000 old mine workings scattered around the area, contributing to Cornwall’s dubious record of having more derelict land than any other county in the UK, some 12 percent of the total, in spite of it having very little industry today.

The last tin mine in Cornwall, South Crofty, near Redruth, closed in March 1998 but was resurrected by local businessmen in the middle of the following decade with a view to reopening the mine if rising metal prices made it viable. For the last ten years locals have had their hopes raised and dashed again and again by talk of the hundreds of jobs if or when the mine re-opens. The most recent was just last year when assays (low-level drilling for project evaluation is ongoing) showed gold levels as high as 1.6 grams per metric ton at the low end of commercial project ranges, but potentially viable in view of the proximity to the surface and multi-metallic nature of the deposit. Attention has switched between the different metals present in the order body, and now it is being proposed that not just gold but tin, copper and zinc could be extracted as well. In fact, while assaying for zinc, the latest research has identified deposits of potentially commercially viable indium used in iPods, iPads and other liquid crystal displays. Indium is most usually found in association with zinc ores, but commercially viable sources are limited, with Canada and Bolivia being the largest western producers. World production was only 574 tons last year, according to the USGS, so it is a small market. John Webster, Western United Mines’ chief operating officer, is quoted as saying, “We found up to 1,000 g of indium per ton in some assays, but generally the average has been about 100 g per ton which is about one kilo every ten tons. Each kilo is worth about £500 ($800/kg or $360/lb) and we estimate we will mine between 250,000 to 400,000 tons per year in the first phase.” That’s about 25-40 tons a year (if correct, a sizable quantity) although this www.indium.com study by Claire Mikolajczak of the Indium Corporation says only 50 percent of the indium in any ore treated is actually recovered, so 12.5 to 20 tons is a more likely figure. Whether that is sufficient to be commercially viable, along with recovery of the traces of gold, tin, copper and zinc, remains to be seen. Polymetallic deposits, while attractive in theory because they spread price risk across several metals, also bring major refining challenges. The more skeptical observers may say this is another attempt by the owners to drum up investor interest in a marginal deposit, but continued high metal prices are keeping the hopes of local Cornish people alive for a re-opening of the mines. Who are we to pour cold water on that?

–Stuart Burns

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