PolyMet Project Update at Shareholders’ Meeting

Shareholders Elect Two Veteran Copper Mining Executives to
Nine-Member Board

ST. PAUL, Minn.–(BUSINESS WIRE)–PolyMet Mining Corp. (“PolyMet” or the “Company”) TSX: POM; NYSE MKT:
PLM – is pleased to report 67.28% of the eligible shares were
represented at its Annual General Meeting of Shareholders held on July
19, 2017 in Toronto, Ontario, and all motions put forward by the Company
were passed at the meeting.

The number of directors of the Company was fixed at nine and the
following persons were elected as directors of the Company to hold
office until the next annual general meeting. The voting results are
shown below:

Joining the PolyMet board are veteran copper mining executives Dennis
Bartlett and Mike Ciricillo.

Mr. Bartlett is executive director and a founding partner in Cupric
Canyon Capital, a private company that is developing a large copper mine
in Botswana. His mining career spans more than 40 years, where he began
as a mining engineer for Phelps Dodge Mining Company in 1977. He served
in various planning, operations, construction, start-up and leadership
capacities at large copper mining operations in Chile, Peru, New Mexico
and Arizona, eventually leading all of the company’s North and South
American mining operations as senior vice president, mining operations.
He later served as senior vice president, development, for Phelps Dodge
and, subsequently, Freeport-McMoRan Mining Company. He had instrumental
leadership roles in the expansion of the Cerro Verde copper mine in
Peru, construction of a new copper mine in Safford, Arizona, and initial
development of the Tenke Fungarume copper mine in Africa. Mr. Bartlett
holds a bachelor’s degree in mining engineering from the University of
Arizona and a Master of Business Administration from Western New Mexico
University.

Mr. Ciricillo began his career at INCO Ltd in Ontario Canada, later
joining Phelps Dodge Mining Company, which was subsequently acquired by
Freeport-McMoRan, where he served in various operations positions of
increasing responsibility in the U.S., Chile, The Netherlands and
Democratic Republic of Congo. He served as director of project
development (Africa), general manager of Miami Operations (Arizona), and
president of Freeport McMoRan Africa before joining Glencore in 2014 as
head of copper operations in Peru. He is currently responsible for
Glencore’s copper smelting and refining operations. Mr. Ciricillo holds
a bachelor of engineering degree from McGill University (Quebec, Canada)
and an MBA from Western New Mexico University.

“Dennis and Mike bring a level and depth of mining knowledge and
experience to the PolyMet board that is without parallel,” said Jon
Cherry, president and CEO. “They have operated and had executive
oversight over some of the largest and most successful mining and
processing operations in the world. They will be a tremendous asset as
we navigate through financing, the final stages of permitting, then
construction and operations of the mine.”

In other board action, PricewaterhouseCoopers LLP was re-appointed as
auditors of the Company and the board is authorized to fix the
remuneration to be paid to the auditors.

Following the meeting, Mr. Cherry gave a presentation on achievements of
the past year and goals for the future. Key achievements include:

• All permit applications submitted as of November 2016 and subsequently
  are under review by the reviewing agencies;
• The U.S. Forest Service issued its Final Record of Decision on the
  NorthMet Project and Land Exchange in January 2017;
• All six draft permits (major) for water appropriations and both dam
  safety permits completed local units of government and tribal review
  in May and June, respectively;
• Significant progress continues to be made on draft permits with the
  Minnesota Department of Natural Resources and Pollution Control Agency;
• Project engineering work continues to progress commensurate with
  permitting.

Key objectives include completing the land exchange via administrative
or Congressional process before the end of 2017; seeing draft permits
out for public comment in late summer and continuing into fall with
final permit decisions beginning in late 2017 and continuing through
early 2018; updating the Definitive Feasibility Study and 43-101
technical report consistent with draft and final permits; advancing
engineering on long-lead items to prepare for order placement; and,
beginning plant rehabilitation work as allowed by permit.

About PolyMet

PolyMet Mining Corp. (www.polymetmining.com)
is a publicly-traded mine development company that owns 100 percent of
Poly Met Mining, Inc., a Minnesota corporation that controls 100 percent
of the NorthMet copper-nickel-precious metals ore body through a
long-term lease and owns 100 percent of the Erie Plant, a large
processing facility located approximately six miles from the ore body in
the established mining district of the Mesabi Iron Range in northeastern
Minnesota. Poly Met Mining, Inc. has completed its Definitive
Feasibility Study. The NorthMet Final EIS was published in November
2015, preparing the way for decisions on permit applications. NorthMet
is expected to require approximately two million hours of construction
labor, creating approximately 360 long-term jobs, a level of activity
that will have a significant multiplier effect in the local economy.

PolyMet Disclosures

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 the ability to receive
environmental and operating permits, job creation, and the effect on the
local economy, 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.

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
Information Form for the fiscal year ended January 31, 2017 and in other
filings with Canadian securities authorities and the U.S. Securities and
Exchange Commission, including the Company’s Form 6-K providing
information with respect to operations for the three months ended April
30, 2017, for a discussion of some of the risk factors and other
considerations underlying forward-looking statements. The Annual
Information Form contains the Company’s mineral resource and other data
as required under National Instrument 43-101.

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

Click
here to subscribe to Mobile Alerts for PolyMet Mining Corp.

Contacts

PolyMet Mining Corp.
Media
Bruce Richardson, +1
651-389-4111
Corporate Communications
[email protected]
or
Investor
Relations
Jenny Knudson, +1 651-389-4110
Investor Relations
[email protected]