During boom times miners worked in shifts
around the clock. Some of the shifts were given names. Midnight to morning work
was called the "night-owl" shift. This photo is from the late 1940s.
Among the bituminous coal producing states, Pennsylvania far surpassed the others. The following chart lists production, in million tons, of the leading bituminous coal producing states.
| 1889 | 1909 | 1919 | 1929 | |
| Pennsylvania | 81,719 | 255,481 | 325,089 | 144,111 |
| West Virginia | 6,232 | 137,305 | 150,030 | 139,031 |
| Kentucky | 2,400 | 10,651 | 29,426 | 60,894 |
| Illinois | 12,404 | 50,898 | 60,331 | 60,705 |
| Ohio | 9,977 | 27,863 | 24,091 | 35,141 |
Photo: courtesy of Archives Department, Rochester and Pittsburgh
Coal Company Records, Indiana University of Pennsylvania
Kentucky Coal Councils Coal Education Web Site. 2001. <http://www.coaleducation.org/default.htm>
(26 November 2001).