Stillwater Reports on First Quarter 2013 Production Results and Montana Expansion Projects

STILLWATER MINING COMPANY (NYSE:SWC) announced today that its
mined production of palladium and platinum totaled 127,100 ounces for
the first quarter of 2013, exceeding the Company′s plan for the quarter.
The Company reiterated its 2013 annual guidance of 500,000 ounces of
mined production. For the first quarter of 2012, the Company′s combined
mine production of palladium and platinum totaled 120,800 ounces,
including 87,700 ounces from the Stillwater Mine and 33,100 ounces from
the East Boulder Mine.

The Company′s recycled volume of palladium, platinum and rhodium
(including tolled ounces) in the first quarter 2013 totaled 154,200
ounces, a Company record by a significant margin. This compares to
107,300 ounces recycled during the first quarter of 2012. New suppliers
account for the bulk of the surge in recycling volume, although higher
PGM prices were also a factor.

First quarter 2013 total cash costs per mined ounce are expected to be
approximately $523, up from the $514 recorded for the first quarter of
2012 but below 2013 annual cash cost guidance of $560. (Total cash cost
per ounce is a non-GAAP measure defined in the Company's regular filings
with the U.S. Securities and Exchange Commission.) The first quarter
2013 total cash cost estimate is still subject to review by the
Company′s independent auditors. The expected increase from last year is
primarily the result of our ever-expanding underground mining
operations, general wage and other cost inflation and the priority given
to our new-miner training programs.

Commenting on the first quarter results, Frank McAllister, the Company's
chairman and CEO, stated, 'We are very pleased to report excellent mine
production and recycling results during the first quarter of 2013, as
well as the good progress on our Montana development projects. In our
view, the Company currently is positioned as well now, both
operationally and financially, as at any time in its history. This is a
direct result of the long-term planning and investment the Company has
made in Montana. As we target increased PGM production in this complex
ore body, it is also important to highlight the investment we have made
in our workforce, and their safety, to achieve these goals.?

Added McAllister, 'Importantly, even in the face of recent lower PGM
prices, we still enjoy the flexibility to move our growth projects
forward at a time when other mining companies are struggling to meet
consistent levels of production or raise project financing. We continue
to believe the fundamentals for our primary product, palladium, are
extremely robust.?

Montana Development Projects

The Graham Creek project's 8,200-foot excavation, utilizing a tunnel
boring machine (TBM), remains on track and is scheduled to be finished
in early May. Through the end of the first quarter of 2013, the TBM has
completed nearly 8,000 feet of total advance. During the first quarter,
work began on the first of two ventilation raises to surface that will
be completed as part of the project. The second ventilation raise will
begin when the TBM drive and necessary infrastructure development is
completed. Both ventilation raises to surface are scheduled to be
completed over the next 18 months. It is anticipated that initial
production from the Graham Creek project will begin in late 2014 with
about 30,000 of annual incremental PGM production expected by 2015.

The Company's new Far West project, now underway, was first identified
in last year's mine planning process and is situated in an area of
relatively high PGM grades between the 3500 and 5000 levels at the
western end of the Stillwater Mine. Work on the extension of the 3500
west rail level and supporting infrastructure is proceeding. The Company
anticipates the Far West project will take about three years to fully
develop with initial production expected during 2016. The project is
expected to provide approximately 20,000 ounces of incremental PGM
production in 2016 and 45,000 ounces per year thereafter. The Far West
represents an acceleration of incremental production made feasible by
the Company's ongoing development of the Blitz project. Because the Far
West project is situated within the existing envelope of the Stillwater
Mine, the development efforts there will benefit from the existing major
infrastructure of the mine.

The Blitz project includes a TBM drive that ultimately will extend about
23,000 feet to the east from the existing Stillwater Mine
infrastructure, a second conventional drift parallel to the TBM drive
and about 600 feet above it, and a proposed new surface portal and
decline to be located about four miles to the east of the existing
Stillwater Mine facilities. Through the first quarter, the TBM has
advanced about 1,300 feet and the conventional drift has driven nearly
1,800 feet of ramp and infrastructure development. As these drives
continue to advance, definitional and probe drilling will be performed
to further enhance the understanding of the geology in this area. Once
in production, the Blitz project is expected to replace gradually
declining production in other areas of the Stillwater Mine and add
approximately 25,000 ounces of annual incremental PGM production.

Marathon

The Company's principal asset at Marathon is a large PGM-copper
development project located just north of the town of Marathon, Ontario
on the north shore of Lake Superior. It holds a highly attractive
palladium deposit of scale. The copper aspect presents opportunity at
time of production to lower cost and increase leverage to palladium. The
Company has completed and submitted an Environmental Impact Statement
for the Marathon project to the appropriate Canadian authorities and has
received comments and information requests as a result of the
submission. The Company is in the process of responding to these
requests.

The Company is engaged in completing the engineering design as well as
an updated economic assessment for the feasibility update which it
expects to complete during the second half of 2013. Recent findings from
the EIS process now take into consideration project design for tailings,
waste rock and water management. Early indications from engineering work
to date suggest the project remains economically viable with the
expected adjustments to grade and the previously updated capital
spending projections. Of note, in March 2012 Mitsubishi purchased a 25%
interest for $81 million (implied valuation of $325 million representing
an 87% premium to the price paid by Stillwater). Mitsubishi′s
involvement reduces Stillwater′s capital requirement and project
financing risk.

Altar

The Company′s Altar copper-gold project in the San Juan Province of
Argentina is an advanced stage exploration property with a substantial
drill-indicated resource that is emerging as a large porphyry
copper-gold deposit and adjacent satellitic gold deposit. The Company
believes the Altar project is a low-cost option on copper-gold with
significant resource potential upside. Stillwater has reduced spending
significantly at Altar in 2013, and a limited drilling program at Altar
for the 2013 season has now been completed successfully approximately
one month earlier than planned. For the first quarter of 2013,
exploration and administrative expenses at Altar totaled $6.7 million;
this compares to a total of $12 million for the first quarter of 2012.
The recently completed drilling season included 20 drill holes (16 new
drill holes and 4 extensions) totaling 11,100 meters. This compares to
the 70 drill holes totaling 27,280 meters completed during the 2012
drilling season. Drill results since acquisition at Altar have been
favorable.

About Stillwater Mining Company

Stillwater Mining Company is the only U.S. producer of palladium and
platinum and is the largest primary producer of platinum group metals
outside of South Africa and the Russian Federation. The Company′s shares
are traded on the New York Stock Exchange under the symbol SWC and on
the Toronto Stock Exchange under the symbol SWC.U. Information on
Stillwater Mining Company can be found at its website: www.stillwatermining.com.

Some statements contained in this news release are forward-looking
statements within the meaning of Section 27A of the Securities Act of
1933, as amended, and Section 21E of the Securities Exchange Act of
1934, as amended, and, therefore, involve uncertainties or risks that
could cause actual results to differ materially. These statements may
contain words such as 'believes,' 'anticipates,' 'plans,' 'expects,'
'intends,' 'projects?, 'estimates,' 'forecast,' 'guidance,' or similar
expressions. These statements are not guarantees of the Company's future
performance and are subject to risks, uncertainties and other important
factors that could cause our actual performance or achievements to
differ materially from those expressed or implied by these
forward-looking statements. Such statements include, but are not limited
to, comments regarding expansion plans, costs, grade, production and
recovery rates, permitting, financing needs, the terms of future credit
facilities and capital expenditures, increases in processing capacity,
cost reduction measures, safety, timing for engineering studies, and
environmental permitting and compliance, litigation, labor matters and
the palladium and platinum market. Additional information regarding
factors, which could cause results to differ materially from
management's expectations, is found in the section entitled 'Risk
Factors' in the Company's 2012 Annual Report on Form 10-K and in
subsequent filings with the United States Securities & Exchange
Commission. The Company intends that the forward-looking statements
contained herein be subject to the above-mentioned statutory safe
harbors. Investors are cautioned not to rely on forward-looking
statements. The Company disclaims any obligation to update
forward-looking statements.

Investor:

Mike Beckstead, 406-373-8971

or

Innisfree M&A
Incorporated

Arthur Crozier / Jennifer Shotwell / Scott Winter,
212-750-5833

or

Media:

Sard Verbinnen & Co

Dan
Gagnier / Michael Henson, 212-687-8080