EXHIBIT 99.7

CERTIFICATION

Pursuant to 18 United States Code § 1350

As Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002

Pursuant to Section 1350 of Chapter 63 of Title 18 of the United States Code (18 U.S.C. Section 1350), as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, each of the undersigned officers hereby certify that the Annual Report on Form 40-F for the fiscal year ended December 31, 2021 of PolyMet Mining Corp. (the "Company") filed with the Securities and Exchange Commission on the date hereof fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended, and that the information contained in such report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: March 17, 2022	/s/ Jonathan Cherry
	Name: Jonathan Cherry
	Title: Chief Executive Officer (Principal Executive Officer)

Date: March 17, 2022	/s/ Patrick Keenan
	Name: Patrick Keenan
	Title: Chief Financial Officer (Principal Financial Officer)