Filing Details

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. ___________)* Primero Mining Corp (Name of Issuer) Common, including purchase warrants (Title of Class of Securities) 74164W106, including 74164W171 (CUSIP Number) December 31, 2017 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [X ] Rule 13d-1(b) [ ] Rule 13d-1(c) [ ] Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). CUSIP No. 74164W106, including 74164W171

1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). Donald Smith & Co., Inc. 13-2807845 2. Check the Appropriate Box if a Member of a Group (See Instructions) (a) (b) [X] 3. SEC Use Only ......................................................... 4. Citizenship or Place of Organization A Delaware Corporation Number of 5. Sole Voting Power 12,527,131 shares Shares Beneficially 6. Shared Voting Power 0 Owned by Each Reporting 7. Sole Dispositive Power 19,095,894 shares Person With 8. Shared Dispositive Power 0 9.Aggregate Amount Beneficially Owned by Each Reporting Person 19,095,894 shares 10. Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) 11. Percent of Class Represented by Amount in Row (9) 9.85% 12. Type of Reporting Person (See Instructions) IA 1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). Donald and Paula Smith Family Foundation 22-3732524 2. Check the Appropriate Box if a Member of a Group (See Instructions) (a) (b) [X] 3. SEC Use Only ......................................................... 4. Citizenship or Place of Organization United States of America Number of 5. Sole Voting Power 202,000 shares Shares Beneficially 6. Shared Voting Power 0 Owned by Each Reporting 7. Sole Dispositive Power 19,095,894 shares Person With 8. Shared Dispositive Power 0 9.Aggregate Amount Beneficially Owned by Each Reporting Person 19,095,894 shares and warrants 10. Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) 11. Percent of Class Represented by Amount in Row (9)9.85% 12. Type of Reporting Person (See Instructions) OOItem 1. (a) Name of Issuer: Primero Mining Corp (b) Address of Issuer's Principal Executive Offices 79 Wellington Street West, Suite 2100 Toronto, Ontario A6 M5K 1H1 Item 2. (a) Name of Person Filing: Donald Smith & Co.,Inc. (b) Address of Principal Business Office: 152 West 57th Street New York, NY 10019 (c) Citizenship: A Delaware Corporation (d) Title of Class of Securities: Common (e) CUSIP Number: 74164W106, including 74164W171Item 3. This statement is filed pursuant to Section 240.13d-1(b), and the person filing is an investment advisor registered in accordance with Section 240.13d-1(b)(1)(ii)(E); Item 4. Ownership. Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1. (a) Amount beneficially owned: 19,095,894 (b) Percent of class: 9.85% (c) Number of shares as to which the person has: (i) SOLE POWER TO VOTE: 12,459,131 (ii) SHARED POWER TO VOTE: SEE ITEM 6 OF COVER PAGE (iii) SOLE POWER TO DISPOSE: 19,095,894 (iv) SHARED POWER TO DISPOSE: SEE ITEM 8 OF COVER PAGE Item 5. Ownership of Five Percent or Less is NOT APPLICABLE Item 6. Ownership of More than Five Percent on Behalf of Another Person: 1. Donald Smith & Co., Inc. does not serve as custodian of the assets of any of its clients; accordingly, in each instance only the client or the client?s custodian or trustee bank has the right to receive dividends paid with respect to, and proceeds from the sale of, such securities. The ultimate power to direct the receipt of dividends paid with respect to, and the proceeds from the sale of, such securities, is vested in the institutional clients which Donald Smith & Co., Inc. serves as investment advisor. Any and all discretionary authority which has been delegated to Donald Smith & Co., Inc. may be revoked in whole or in part at any time. To the knowledge of Donald Smith & Co., Inc., with respect to all securities reported in this schedule owned by advisory clients of Donald Smith & Co., Inc., not more than 5% of the class of such securities, including warrants, is owned by any one client. 2. With respect to the remaining securities and warrants owned, various persons have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Common Stock of Primero Mining Corp. No one person?s interest in the Common Stock and Warrants of Primero Mining Corp is more than five percent of the total outstanding Common Stock, including total warrants owned by Donald Smith & Co., Inc. Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company NOT APPLICABLE Item 8. Identification and Classification of Members of the Group See EXHIBIT A Item 9. Notice of Dissolution of Group NOT APPLICABLE Item 10. Certification (a) By signing below I certify that, to the best of my knowledge and belief, the securities and warrants referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. February 8, 2018 Date Donald G. Smith___________ Signature President_________________ Title SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b) RULE 13d-1(f)(1) EXHIBIT A: Donald Smith & Co., Inc. IA Donald & Paula Smith Family Foundation OO