Stillwater Mining Company has an extensive history with roots that can be traced back to the late 19th century. Early exploration along the Stillwater Complex in south-central Montana focused on chromium, copper and nickel. Later, the focus shifted to platinum group metals (PGMs) and the discovery of the J-M Reef, which is the richest known deposit of PGMs in the world. Today, Stillwater operates two underground mines along the J-M Reef.
Early Mining Exploration
Mining in the Stillwater Complex began not with platinum group metals, but with chromite, copper and nickel. Since the late 1800s, the Stillwater Complex and adjacent rocks were known to contain chromite, copper and nickel.
In 1883 Jack Nye and brothers Jimmy and Jonas Hedges found sulfide-rich rocks in the areas of Mountain View, Benbow and Initial Creek. Nye traveled to Minneapolis, Minnesota, and submitted his report. On the basis of those findings, the original Stillwater Mining Company was formed in the summer of 1884, and a mining project commenced in 1885.
In 1885 construction of Nye City began, located just west of the American Chrome Company hospital building. By 1887, a small smelter had been assembled and the town grew to a peak population of 300 to 400 people, and included, at one time, six saloons, a store, a commissary, a boarding house and an assay office.
An unexpected discovery brought things to an abrupt end. A government survey of the Stillwater basin revealed that Nye City was not part of the Federal domain included in Gallatin County, but was actually on Crow Indian Reservation lands. Because such exploitation of tribal lands was prohibited by law, the mining operation had to be dismantled and removed. In 1890, the Crow Indians ceded the land, which reopened the Stillwater basin to mining and claim-staking.
In the early years of the 20th Century a group of prospectors banded together for a trial shipment of ore. Smelting, however, revealed that the value of the ore did not warrant production. Little more was done on the claims until William M. “Bill” Mouat, a nephew of the president of the Minneapolis Mining and Smelting Company, became interested in the claims around World War I. He hired Otto W. Miller, a Columbus, Montana, resident with mining experience, to redeem the claims. This started a new episode of development.
The Mouat property was brought to the attention of the Anaconda Minerals Company in the early 1920s. In a 1925 report by Vincent D. Perry, later president of the Anaconda Minerals Company, preliminary sampling results included the first geologic maps of the property. In 1940 and 1941, the U.S. Bureau of Mines conducted exploration with 5,981 feet of drilling in eight holes, then sampling and metallurgic testing of the results. This provided data for the considerable mapping work that was conducted throughout the 1940s. This map served as the fundamental source of information for this area for many years.
Exploration for PGMs
In 1961, H.K. Conn of the Johns-Manville Corporation (“Manville”) attended the Commonwealth Mining Congress in South Africa and visited the Rustenburg platinum mines on one of his tours. This visit sparked his imagination that there might be a zone similar to the Merensky Reef in the Stillwater Complex because he was already familiar with the complex. In 1967 E.L. Mann and S.G. Ellingwood visited the Stillwater Complex and initiated a modest program of soil sampling and reconnaissance mapping. Results were generally disappointing, and Manville might well have walked away from the area after the first summer, were it not for one set of samples displaying weak platinum, palladium and other mineral values. Field exploration continued each year, with only minimal encouragement until 1973, when Manville geologists discovered the major Stillwater PGM zone, commonly referred to today as the J-M Reef.
PGM Mining Operations Begin
In 1979, a Manville subsidiary entered into a partnership agreement with Chevron U.S.A. Inc. (“Chevron”) to develop PGMs discovered in the J-M Reef. Manville and Chevron explored and developed the Stillwater property and commenced underground mining in 1986.
Stillwater Mining Company was incorporated in 1992, and in October 1993, Chevron and Manville transferred substantially all assets at the Stillwater property to the Company. Chevron and Manville each received a 50 percent ownership interest in Stillwater’s stock. In September 1994, the Company redeemed Chevron’s entire 50 percent ownership. Stillwater Mining Company completed an initial public offering in December 1994, and Manville sold a portion of its shares through the offering, reducing its ownership percentage to approximately 27 percent.
In 1995 Manville sold its remaining ownership interest in the Company to institutional investors. On June 23, 2003, a stock purchase transaction was undertaken with MMC Norilsk Nickel (“Norilsk Nickel”), whereby a subsidiary of Norilsk Nickel became a majority stockholder of Stillwater. In 2010 Norilsk Nickel disposed of its entire ownership interest through a secondary offering of Stillwater shares in the public market. Today, the Company’s common stock is publicly traded on the New York Stock Exchange (NYSE) under the symbol SWC.
|1973||—||Johns-Manville Corporation geologists discover the Stillwater Platinum Group Elements (PGE) Zone which later becomes known as the J-M Reef|
|1979||—||A partnership is formed between a Johns-Manville Corporation subsidiary and Chevron USA to develop PGMs at the J-M Reef|
|1982||—||Exploration work and development of the Minneapolis Adit (5150 level) is performed in the Stillwater River Valley|
|1985||—||An Environmental Impact Statement is completed for the Stillwater Mine|
|1986||—||Production begins at the Stillwater Mine|
|1990||—||A smelter is commissioned with 30 tons per day capacity|
|1992||—||Stillwater Mining Company is incorporated in the state of Delaware|
|1993||—||Chevron & Manville complete the transfer of assets, liabilities, & operations to Stillwater Mining Company|
|1994||—||Stillwater Mining Company completes its initial public stock offering; the stock is listed on the New York Stock Exchange (NYSE)|
|1994||—||Construction begins on a 1,950-foot shaft project at Stillwater Mine (commissioned in 1996)|
|1996||—||The Base Metals Refinery is commissioned|
|1997||—||The sampling facility is commissioned and recycling commences at the Columbus metallurgical complex|
|1997||—||Work begins on the East Boulder mining project|
|1998||—||The paste backfill plant is commissioned at the Stillwater Mine|
|1998||—||A Tunnel-Boring Machine (TBM) begins operation at the East Boulder Mine|
|1999||—||A new smelter is commissioned with 100 tons per day capacity|
|1999||—||Development of the East Boulder Mine begins|
|2000||—||Base metal refinery copper electrowinning circuit commissioned|
|2000||—||The Hertzler tailings impoundment is commissioned at the Stillwater Mine|
|2001||—||Base metal refinery nickel crystallization circuit commissioned|
|2002||—||Production begins at the East Boulder Mine|
|2003||—||A stock purchase transaction is completed with MMC Norilsk Nickel, resulting in a subsidiary of Norilsk becoming a majority shareholder of Stillwater Mining Company|
|2009||—||A second furnace is commissioned with 150 tons per day capacity|
|2010||—||Expansion of the recycling/sampling plant is completed|
|2010||—||The Blitz and Graham Creek projects begin|
|2010||—||Stillwater acquires the Marathon PGM-Copper Project in Ontario, Canada|
|2010||—||MMC Norilsk Nickel sells its entire interest in Stillwater Mining Company to institutional investors through a secondary stock offering|
|2011||—||Kiruna electric trucks are commissioned at the Stillwater Mine|
|2011||—||A sampling/X-ray definition automated assay laboratory is commissioned at Columbus metallurgical complex for recycling business|
|2011||—||Stillwater acquires Peregrine Metals Ltd., including the Altar porphyry copper-gold deposit located in the San Juan province of Argentina|
|2012||—||The Blitz project TBM is commissioned at the Stillwater Mine|
|2014||—||The Graham Creek project at the East Boulder Mine is completed|