This 1944 painting entitled Mine America's Coal by Norman Rockwell appeared in the National Portrait Gallery. It belongs to the Normal Rockwell Museum in Stockbridge, Massachusetts.
Norman Rockwell painted this smiling coal miner for a poster published by the War Manpower Commission, encouraging Americans to support the country and its energy needs through the commission's efforts. The text on the poster reads: “Mine America's Coal. We'll make it hot for the enemy! See your United States Employment Service.” By portraying a middle-aged man, Rockwell emphasized that workers of all ages could be American heroes. The red, white, and blue pin with two stars indicates that this coal miner has two sons serving in the military. Conveying pride and confidence, his smile suggests a bright future made possible through hard work and patriotism. -- NPG
Wikimedia has this copy of the poster which ultimately came from the National Archives and Records Administration.
Mine America's Coal
“... we'll make it hot
for the enemy!”
See Your United States Employment Service
War Manpower Commission