Stillwater Urges Shareholders to Vote the WHITE Proxy FOR Stillwater′s Director Nominees

Stillwater Mining Company (NYSE:SWC) (TSX:SWC.U) ('Stillwater? or the
'Company?) today announced that it has sent a letter to shareholders in
connection with the Company's 2013 Annual Shareholders Meeting, which
will be held on May 2, 2013.

The letter details Stillwater′s many concerns with the Clinton Group, a
1.3% shareholder, and its attempt to take control of the Company. In
particular, the Clinton Group offers no new strategy or detailed
operating plan and has shown through its communications that it does not
understand the Company′s business. Several of Clinton Group′s misguided
demands, the company believes, will be value-destructive for
Stillwater′s shareholders.

The letter exposes the fact that Clinton Group′s director nominees are
not qualified to oversee a U.S. public company, nor are they qualified
to oversee complex, PGM underground mining operations. Certain
individuals also have questionable professional backgrounds and
educational representations. The letter goes on to detail Clinton
Group′s poor investment track record and the significant value they have
destroyed at other companies.

All shareholders of record as of March 6, 2013 are entitled to vote at
the 2013 Annual Shareholders Meeting. Stillwater encourages all
shareholders to carefully review its definitive proxy filing and other
materials and vote only their WHITE proxy card. For more

information about Stillwater′s 2013 Annual Shareholders Meeting, please
visit www.supportstillwater.com.

The full text of the letter follows:

April 8, 2013

Dear Fellow Shareholder:

ENSURE THE CONTINUED SUCCESS OF STILLWATER ?

PLEASE VOTE
THE WHITE PROXY CARD TODAY

Since 2001, we have transformed Stillwater from a single low-volume,
high-cost mine into an integrated set of highly competitive,
industry-leading PGM operations and core growth prospects based in
Montana. We have managed to accomplish this despite extreme PGM price
volatility, critical auto contract expirations, ever deeper and receding
mine operations and an ore body weighted 3.4:1 toward lower-priced
palladium. Today, the outlook for Stillwater is better than it has ever
been and the Company is well positioned to take advantage of extremely
favorable PGM market fundamentals at a time when many of our peers face
significant operational and financial challenges.

DO NOT HALT THIS POSITIVE MOMENTUM ? CLINTON GROUP IS NOT THE ANSWER

We value the opinions of our investors and welcome feedback on a variety
of topics, as we have displayed openly in our meetings with many of you
over the years. However, in the case of Clinton Group, a hedge fund that
only recently acquired just 1.3% of the Company′s outstanding shares, we
believe they have a self-serving agenda, do not understand the Company′s
business, and pose a significant threat to the value of your investment
in Stillwater. They offer no new strategy or detailed operating plan and
have made several misguided demands that will, in our view, be
value-destructive for Stillwater′s shareholders.

CLINTON GROUP IS A SHORT-TERM FOCUSED TRADER WITH A POOR TRACK RECORD
AND NO RELEVANT

MINING EXPERIENCE

According to public filings, Clinton Group′s investment experience in
the mining industry includes only a few limited forays, none of them
PGM-focused, with an average holding period that suggests a significant
short-term bias. Further, despite Clinton Group′s promises, its record
in 'unlocking value for shareholders? is abysmal.

• Only holds its investments for nine months
  on average in all of its threatened or pursued proxy contests
  
• Failed to create valuein
  five out of seven situations where it gained board seats
  
• Averaged a 33% depreciation in value
  in the seven situations in which they procured board seats
  
• Had no publicly disclosed PGM investments
  prior to Stillwater
  

Indeed, Clinton Group failed to create value for itself or other
shareholders in four out of six situations where it gained board seats.
At Digital Generation, Clinton Group lost 41% for shareholders; at
Dillard′s, Clinton Group lost 77% for shareholders; Lenox Group lost an
astounding 99% of shareholder value during Clinton Group′s activism; and
Nutrisystem has dropped 26% since Clinton Group′s involvement.¹

CLINTON GROUP HAS PUT FORTH A SLATE OF UNQUALIFIED NOMINEES

WITH
QUESTIONABLE SKILLS AND BACKGROUNDS

Equally as worrisome as Clinton Group′s poor track record of value
creation are the issues associated with their slate of hand-picked
nominees. Clinton Group′s slate is not qualified to oversee a U.S.
public company, nor are they qualified to oversee complex, PGM
underground mining operations.

• 
  Seven of Clinton Group's eight nominees have NO
  direct PGM experience
• 
  Seven of Clinton Group's eight nominees have NEVER
  served on a U.S. public company Board

Furthermore, each of their nominees brings to bear significant concerns
regarding the adequacy of their qualifications and experience, which in
turn raises serious doubts as to the suitability of Clinton′s
hand-picked slate.

Brian Schweitzer ? It is peculiar that Dr. Schweitzer was a
staunch supporter of Stillwater while he was in office, but then only
weeks after he stepped down, aligned himself with the Clinton Group
seeking to disrupt our progress and growth in Montana.Furthermore,
we find it unconscionable that he can repeatedly make inaccurate and
inflammatory statements regarding Stillwater′s focus in, and commitment
to, its Montana operations and still purport to be a viable nominee for
Stillwater′s shareholders. Dr. Schweitzer would have you believe we have
taken our eye off Montana. Nothing could be further from the truth. (1)
98% of our workforce is based in Montana, (2) in conjunction with our
expanding operations, we have grown our Montana-based workforce 21% in
the past two years and plan to increase it another 9% by the end of
2013, and (3) we continue to allocate the overwhelming majority of our
capital expenditures to our Montana operations and growth projects
(i.e., 87% of our 2013 capital spending budget).

Charles R. Engles ? Dr. Engles abruptlytendered his
resignation as Chairman and CEO of Stillwater in 1997 at a time when the
Company struggled as a low-volume, high-cost producer with no clear
strategy for future growth or development in Montana. We believe our
shareholders should question Dr. Engles regarding his track record at
Stillwater and ask him to publicly discuss the reasons for his abrupt
resignation. Since then, Dr. Engles has been involved in a number of
failed ventures with questionable oversight, including Sundance Homes,
Catalytic Solutions and Cutanix Corporation. Furthermore, Dr Engles has
been out of the mining industry in any meaningful capacity for 15-plus
years.

John DeMichiei ? Mr. DeMichiei may be a coal mining professional,
but he has no PGM or related hard-rock mining experience and his track
record at coal producer Signal Peak Energy raises serious questions and
concerns. Under his leadership, Signal Peak has had significant labor,
safety and environmental issues. For example, Mr. DeMichiei took
coercive action and threatened employees with loss of wages and benefits
when they joined a union. Signal Peak′s Bull Mountain mine reported
seven roof falls between 2009 and 2012, compared to just one between
2003 and 2008, before Signal Peak took over the mine. Furthermore,
members of the Montana Board of Environmental Review have recently cited
'revisiting violations by Signal Peak on a repeated basis? and Signal
Peak′s 'historic? environmental issues. Separately, there appear to be
material inconsistencies in Mr. DeMichiei′s academic and employment
record. He claims to have a Bachelor of Science in Mining Engineering
from the University of Pittsburgh. The University of Pittsburgh could
only confirm attendance for one year, with no record of a degree. Mr.
DeMichiei also claims to have a Masters of Business Administration from
American University. American University was only able to confirm a
Masters of Public Administration.

Michael McMullen ? Mr. McMullen′s primary experience appears to
be limited to early-stage, non-producing and highly-speculative
exploration and development companies. He has no leadership experience
at a sizeable producing precious metals mining company like Stillwater.
Furthermore, for some reason, he has excluded in his bio his involvement
in West African Resources, which is an early stage gold explorer in
Burkina Faso.

Patrice E. Merrin ? Ms. Merrin was previously banned from the
U.S. for a period of time as a result of violations of the Helms-Burton
Act. Ms. Merrin engaged in the violations while an executive at the
Sherritt Corporation. The Sherritt Corporation jointly owns a zinc mine
in Cuba with the Cuban government, which had seized the mine from
Freeport McMoRan, a U.S. company, after Fidel Castro came to power.

Michael McNamara ? Mr. McNamara has less than 10 years of work
experience as a financial analyst, has been unemployed for the last
three years, and has had no mining, corporate management or public
company board experience whatsoever. Mr. McNamara is extremely
unqualified to serve on any public company Board.

Seth E. Gardner ? Mr. Gardner is another board nominee with
extremely limited experience. He does not appear to have any corporate
management experience of any kind and his board experience is limited to
Cerberus portfolio companies.

Gregory P. Taxin ? Mr. Taxin has no prior investment experience
in the PGM industry and little experience in mining. Furthermore, his
track record and qualifications as an investor are poor, aside from
taking aim at a wide variety of companies in various industries and very
publicly announcing change is needed. We believe this is reflective of
his short-term focus on investing and lack of understanding the
fundamental drivers of businesses he invests in. Ultimately, his poor
track record in other activist situations ? where in many cases he
caused significant value erosion due to ineffective and misguided
recommendations ? speaks for itself.

CLINTON GROUP CONTINUES TO SHOW A LACK OF UNDERSTANDING OF

STILLWATER′S
HISTORY AND BUSINESS

STILLWATER′S BOARD OF DIRECTORS ARE HIGHLY QUALIFIED

AND
SERVING YOUR BEST INTERESTS

Stillwater′s skilled and experienced director nominees are clearly best
suited to leverage the positive turnaround in palladium′s fundamentals
and continue building Stillwater as a leading PGM company. Our Directors
have experience in PGM, open-pit and underground mining, finance,
operations, and project development. The Board has proactively pursued
candidates with complementing existing skillsets on the Board and
recently added two new Directors. They are committed to the development
of the company′s PGM operations and growth programs and creating value
for ALL Stillwater shareholders. More detail on each of our Directors is
available in our 2013 proxy statement.

THE CHOICE IS CLEAR ? VOTE FOR THE
STILLWATER NOMINEES

ON THE WHITE
PROXY CARD TODAY

Protect the value of your investment. To supportyour Company′s
nominees, who are committed to looking after the best interests of ALL
Stillwater shareholders, please use your WHITE proxy card to vote TODAY?by
telephone, over the Internet, or by signing, dating and returning the WHITE
proxy card in the postage-paid envelope provided. You are urged to
discard any green proxy card sent to you by Clinton Group. Even a
protest vote against Clinton Group′s nominees on Clinton Group′s green
proxy card will cancel any previous proxy submitted by you in favor of
Stillwater. Please vote only the WHITE proxy card.

We appreciate all the positive feedback we have received from our
shareholders, and thank you for your support.

Best regards,

Francis R. McAllister

Chairman and Chief Executive Officer

Your Vote Is Important, No Matter How Many Or How Few Shares You Own

If you would like to obtain copies of the Company′s proxy materials or
have questions about how to vote your shares, or need additional
assistance, please contact the firm assisting us in the solicitation of
proxies:

INNISFREE M&A INCORPORATED

Shareholders Call
Toll-Free: (877) 825-8906

Banks and Brokers Call Collect:
(212) 750-5833

REMEMBER:

We urge you NOT to vote using any green proxy card
sent to you by

the Clinton Group, as doing so will revoke your vote
on the WHITE proxy card.

¹ Source: 13D Monitor, Capital IQ, Company filings, and
FactSet as of 4/1/2013. At Nutrisystem, proxy fight was avoided based on
a settlement reached to add an independent director. Returns calculated
from first public filing to best available exit date or 4/1/13.

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 2011 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 CONTACTS:

Mike Beckstead, 406-373-8971

or

Innisfree
M&A Incorporated

Arthur Crozier / Jennifer Shotwell / Scott
Winter

212-750-5833

or

MEDIA CONTACTS:

Sard
Verbinnen & Co

Dan Gagnier / Michael Henson

212-687-8080