UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number:001-34743 “COAL KEEPS YOUR LIGHTS ON” “COAL KEEPS YOUR LIGHTS ON” HALLADOR ENERGY COMPANY (www.halladorenergy.com) Colorado 84-1014610 (State of incorporation) (IRS Employer Ide ...