Stillwater Mining Company (the USA)

The key operating assets of Stillwater Mining Company

In 2003, Norilsk Nickel became the owner of a 55.4% stake in Stillwater Mining Company –
the largest producer of platinum group metals in the United States. At the end of 2008, the stake of Norilsk Nickel in Stillwater Mining was amounted to 53.5%. Official web-site of Stillwater Mining Company: http://www.stillwatermining.com/

Data on the ore reserves of Stillwater Mining Company is provided as of December 31, 2009 in accordance with Industry Guide No. 7 as approved by the US Securities and Exchange Commission.

The ore reserves of Stillwater Mining Company are located in the J-M Reef deposit in the Beartooth Mountain Range in the south central area of Montana.

As of December 31, 2009, the proven reserves of Stillwater Mining Company totaled approximately  4.64 million tons1 of ore with average palladium and platinum contents of 0.56 ounces per ton1 containing a total of 2.58 million ounces of palladium and platinum2 The tonnage of proven ore reserves decreased by 6.7% as compared to the proven ore reserves at December 31, 2008.

As of December 31, 2009, the probable reserves of the Stillwater Mining Company totaled approximately 36.3 million tons1 of ore with  palladium and platinum contents of 0.50 ounces per ton containing a total of 18.03 million ounces of palladium and platinum. This is 9.4% more than the ore tonnage of probable ore reserves as of December 31, 2008.

The proven and probable ore reserves of Stillwater Mining Company changed compared to year end 2008 for the following reasons:

– increased amount of proven reserves as a result of exploration drilling;
– reduced amount of proven reserves as a result of mining;
– reduced part of probable reserves as a result of reclassification to proven reserves;
– increased amount of reserves as a result of follow-up exploration of the resource base;
– change in the volume of reserves as a result of the adjustment of reserve estimates and changes in the mining plan.

(1) Ton (or short ton) is the weight measure used in US reporting. It equals 907 .18 kg.
(2)  Expressed as palladium plus platinum in-situ ounces at a ratio of around 3.57 parts Pd to 1 part Pt.

Stillwater Mining Company mined PGM production history (on a 100% basis)