PolyMet Form 20-F Availability

HOYT LAKES, MINNESOTA -- (Marketwire) -- 06/28/12 -- PolyMet Mining Corp. (TSX: POM)(NYSE MKT: PLM)(NYSE Amex: PLM) ("PolyMet" or the "Company") today confirmed that its Form 20-F for the fiscal year ended January 31, 2012 is available to shareholders in hard copy, free of charge, by sending a request to info@polymetmining.com.

The Company's Form 20-F, with audited financial statements for the fiscal year ended January 31, 2012, was filed with the United States Securities and Exchange Commission ("SEC") on May 1, 2012. An electronic copy of the Form 20-F is available on the Company's website, www.polymetmining.com, on EDGAR at www.sec.gov and on SEDAR at www.sedar.com.

About PolyMet

PolyMet Mining Corp. (www.polymetmining.com) is a publicly-traded mine development company that controls 100% of the NorthMet copper-nickel-precious metals ore body through a long-term lease and owns 100% of the Erie Plant, a large processing facility located approximately six miles from the ore body in the established mining district of the Mesabi Range in northeastern Minnesota. PolyMet Mining Corp. has completed its Definitive Feasibility Study and is seeking environmental and operating permits to enable it to commence production. The NorthMet project is expected to require approximately one-and-a-quarter million hours of construction labor and create approximately 360 long-term jobs, a level of activity that will have a significant multiplier effect in the local economy.

POLYMET MINING CORP.

Joe Scipioni, CEO

This news release contains certain forward-looking statements concerning anticipated developments in PolyMet's operations in the future. Forward-looking statements are frequently, but not always, identified by words such as "expects," "anticipates," "believes," "intends," "estimates," "potential," "possible," "projects," "plans," and similar expressions, or statements that events, conditions or results "will," "may," "could," or "should" occur or be achieved or their negatives or other comparable words. These forward-looking statements may include statements regarding our beliefs related to exploration results and budgets, reserve estimates, mineral resource estimates, work programs, capital expenditures, actions by government authorities, including changes in government regulation, the market price of natural resources, costs, ability to receive environmental and operating permits, job creation, or other statements that are not a statement of fact. Forward-looking statements address future events and conditions and therefore involve inherent known and unknown risks and uncertainties. Actual results may differ materially from those in the forward-looking statements due to risks facing PolyMet or due to actual facts differing from the assumptions underlying its predictions.

In connection with the forward-looking information contained in this news release, PolyMet has made numerous assumptions, regarding, among other things: the geological, metallurgical, engineering, financial and economic advice that PolyMet has received is reliable, and is based upon practices and methodologies which are consistent with industry standards. While PolyMet considers these assumptions to be reasonable, these assumptions are inherently subject to significant uncertainties and contingencies.

PolyMet's forward-looking statements are based on the beliefs, expectations and opinions of management on the date the statements are made, and PolyMet does not assume any obligation to update forward-looking statements if circumstances or management's beliefs, expectations and opinions should change.

Specific reference is made to PolyMet's most recent Annual Report on Form 20-F for the fiscal year ended January 31, 2012 and in our other filings with Canadian securities authorities and the U.S. Securities and Exchange Commission, including our Report on Form 6-K providing information with respect to our operations for the three months ended April 30, 2012 for a discussion of some of the risk factors and other considerations underlying forward-looking statements.

The TSX has not reviewed and does not accept responsibility for the adequacy or accuracy of this release.

Contacts:

Corporate

PolyMet Mining Corp.

Douglas Newby

Chief Financial Officer

+1 (212) 867-1834
dnewby@polymetmining.com


Media

PolyMet Mining Corp.

LaTisha Gietzen, VP Public, Gov't & Environmental Affairs

+1 (218) 225-4417
lgietzen@polymetmining.com
www.polymetmining.com