May 17, 2020

Stillwater Mining: Only US Producer of Platinum Group Metals (PGM's)

Stillwater Mining
Canadian Mining
J-M Reef
6 min
Stillwater Mining: Only US Producer of Platinum Group Metals (PGM's)
Mining Global takes a look at Stillwater Mining Company

About Stillwater Mining:Only US Producer of Platinum Group Metals (PGM's)

Stillwater Minin...

Mining Global takes a look at Stillwater Mining Company

About Stillwater Mining: Only US Producer of Platinum Group Metals (PGM's)

Stillwater Mining Company is the only U.S. producer of platinum group metals (PGMs) and the largest primary producer of PGMs outside of South Africa and the Russian Federation. PGMs are rare precious metals used in a wide variety of applications, including auto catalysts, fuel cells, hydrogen purification, electronics, jewelry, dentistry, medicine and coinage. Stillwater Mining Company is engaged in the development, extraction, processing, smelting and refining of PGMs from a geological formation in southern Montana known as the J-M Reef and from the recycling of spent catalytic converters. The J-M Reef is the only known significant source of PGMs in the United States and the highest-grade PGM resource in the world.

The Company conducts mining operations at its Stillwater and East Boulder mines in southern Montana. Concentrating plants are located at both mines to upgrade ore to a concentrate. The Company operates a smelter, refinery and laboratory at Columbus, Montana to further upgrade the concentrate to a PGM-rich filter cake. Another key segment of the Company’s operations is the recycling of spent catalyst material to recover PGMs.

The Company owns the Marathon PGM-copper deposit in Ontario, Canada, and the Altar porphyry copper-gold deposit located in the San Juan province of Argentina.

Stillwater Mining Company’s current mining operations are in south-central Montana where it operates two underground mines along the J-M Reef, the world’s richest known deposit of platinum group metals (PGMs).

The Stillwater Complex, which hosts the J-M Reef ore deposit, is located in the Beartooth Mountains in south-central Montana. It is situated along the northern edge of the Beartooth Uplift and Plateau, which rise to elevations in excess of 10,000 feet above sea level. The plateau and Stillwater Complex have been deeply incised by the major drainages and tributaries of the Stillwater and Boulder Rivers down to elevations at the valley floor of approximately 5,000 feet.

Geologically, the Stillwater Layered Igneous Complex is composed of a succession of ultramafic to mafic rocks derived from a large complex magma body emplaced deep in the Earth’s crust an estimated 2.7 billion years ago. The molten mass was sufficiently large and fluid at the time of emplacement to allow its chemical constituents to crystallize slowly and sequentially, with the heavier mafic minerals settling more rapidly toward the base of the cooling complex. The lighter, more siliceous suites crystallized more slowly and also settled into layered successions of norite, gabbroic and anorthosite suites. This systematic process resulted in mineral segregations being deposited into extensive and uniform layers of varied mineral concentrations.

The uniquely PGM-enriched J-M Reef and its characteristic host rock package represent one such layered sequence. The geosciences community believes that the PGM-enriched suite and other minerals characterizing the J-M Reef accumulated at the same time and by the same mechanisms of formation as the rocks enclosing them. Over time, the orientation of a portion of the original horizontal reef and layered igneous complex was faulted an estimated 20,000 feet to the northeast and was tilted upward at angles of 45 to 90 degrees to the north by the Beartooth Uplift. Localized faulting and intrusive mafic dikes are also evident along the 28-mile strike length of exposed Stillwater Complex. The upper portion and exposed edge of the reef complex were eroded, forming the lenticular-shaped surface exposure of the Stillwater Complex and J-M Reef package evident today.

The J-M Reef package has been traced at its predictable geologic position and with unusual overall uniformity over considerable distances within the Stillwater Complex. The surface outcrops of the reef have been examined, mapped and sampled for approximately 28 miles along its east-southeasterly course and over a known expression of over 8,200 feet vertically. That predictability of the J-M Reef has been further confirmed in subsurface mine workings of the Stillwater and East Boulder Mines and by over 38,000 drill hole penetrations.

The PGMs in the J-M Reef consist primarily of palladium, platinum and a minor amount of rhodium. The reef also contains significant amounts of iron, copper and nickel, and trace amounts of gold and silver.

Stillwater Management Team

Michael J. McMullen - President and Chief Executive Officer

Mick McMullen is President and Chief Executive Officer and a member of the Board of Directors. Mr. McMullen was elected to the Board on May 2, 2013 and appointed President and Chief Executive Officer on December 3, 2013. Previously, Mr. McMullen served in a variety of senior executive and directorship positions, most recently as a Principal at MRI Advisory AG, a private company focusing on the development of metal and minerals projects in the Americas, Europe and Africa. Over the course of his 21-year career, Mr. McMullen has been responsible for the development of several large open pit and underground mines in Australia, Europe and Latin America. He has had detailed involvement in all aspects of the mining business, including exploration, permitting, mine development, financing, operations, product sales, and asset acquisition and divestments, as well as the debt and equity markets. He has managed multiple operations across several jurisdictions, working with large work forces and unions in culturally diverse and environmentally sensitive areas. His experience covers a range of commodities including copper, gold, iron ore and PGM’s. Mr. McMullen holds a Bachelor of Science degree in Geology from Newcastle University in New South Wales and pursued graduate studies in Mineral Economics at Western Australian School of Mines.

Dee L. Bray - Vice President, Mine Operations

Dee L. Bray was appointed Vice President of Mine Operations effective March 2015. Mr. Bray joined Stillwater Mining Company in 1994. While working at each of the Company’s Montana Mines, (Stillwater Mine, 12 years and East Boulder Mine, 6 years) he gained experience in engineering, operations, maintenance and safety. He held various engineering and operations positions of increasing responsibility, including Production General Foreman, Safety Manager, Maintenance Superintendent, Production Superintendent and Mine Manager. Prior to his current role, Mr. Bray served as the Manager of Operations, Montana Mines since 2013. 

Mr. Bray began his career with Consolidation Coal Company, working in engineering and operations roles at two underground mines. He has over 27 years of experience in the mining industry, including coal and hard rock.

Mr. Bray earned a Bachelor of Science degree in Mining Engineering from the Montana College of Mineral Science & Technology. He has been a Certified Mine Safety Professional since 2009.

Gregory K. RosetVice President and General Manager, Smelting and Recycling Operations

Gregory K. Roset was appointed Vice President, Smelting and Recycling Operations, effective August of 2010. He has been the General Manager of Smelting since 2001. Mr. Roset joined the Company in 1988 as Concentrator Metallurgical Engineer at the Stillwater Mine, prior to being assigned to the smelter design, permitting and commissioning team in 1989. He has held various technical and managerial positions of increasing responsibility in the smelting operations since 1990. Prior to joining Stillwater, Mr. Roset held various metallurgical and supervisory positions with ASARCO and Kennecott from 1982 to 1988. Mr. Roset is Chairman of the Board of Governors for the Center for Advanced Metals and Minerals Processing at Montana Tech in Butte, Montana. Mr. Roset received both Bachelor of Science and Master of Science degrees in Metallurgical Engineering from the Montana College of Mineral Science & Technology.

Stillwater Mining Company’s corporate office is located in Denver, Colorado.

Source: Stillwater Mining Website -

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