Production by Mining Method (Thousand Short Tons)
| Year | Surface Mining | Underground Mining | Total | |||||
| Auger | Strip | Total | Cont. Miner | Longwall | Other | Total | ||
| 2008 | 249 | 7,884 | 8,133 | 13,018 | 3,019 | 0 | 16,037 | 24,170 |
| 2007 | 197 | 8,685 | 8,882 | 13,675 | 2,348 | 0 | 16,023 | 24,905 |
| 2006 | 716 | 9,827 | 10,543 | 14,457 | 4,429 | 0 | 18,886 | 29,429 |
| 2005 | 355 | 10,073 | 10,428 | 13,915 | 2,594 | 0 | 16,509 | 26,937 |
| 2004 | 405 | 9,617 | 10,022 | 15,322 | 5,142 | 0 | 20,464 | 30,486 |
| 2003 | 312 | 9,961 | 10,273 | 115,417 | 5,755 | 0 | 21,172 | 31,445 |
| 2002 | 417 | 8,432 | 8,849 | 17,556 | 5,341 | 0 | 22,897 | 31,746 |
| 2001 | 526 | 9,407 | 9,933 | 15,885 | 6,782 | 0 | 22,667 | 32,600 |
| 2000 | 1,782 | 7,859 | 9,633 | 17,825 | 5,752 | 0 | 23,577 | 33,210 |
| 1999 | 530 | 8,629 | 9,159 | 17,843 | 5,192 | 60 | 23,095 | 32,254 |
| 1998 | 385 | 7,657 | 8,042 | 19,238 | 6,359 | 363 | 25,960 | 34,002 |
| 1997 | 406 | 8,495 | 8,900 | 21,096 | 6,801 | 91 | 27,989 | 36,889 |
| 1996 | 308 | 9,294 | 9,602 | 22,133 | 4,913 | 134 | 27,180 | 36,782 |
| 1995 | 205 | 8,704 | 8,909 | 21,002 | 5,936 | 71 | 27,008 | 35,917 |
| 1994 | 332 | 9,039 | 9,371 | 21,271 | 7,317 | 846 | 29,435 | 38,805 |
| 1993 | 464 | 9,079 | 9,543 | 23,124 | 7,247 | 177 | 30,548 | 40,091 |
| 1992 | 320 | 7,852 | 8,173 | 24,549 | 9,322 | 518 | 34,389 | 42,562 |
| 1991 | 321 | 7,767 | 8,087 | 25,023 | 8,303 | 922 | 34,249 | 42,336 |
| 1990 | 157 | 7,488 | 7,646 | 27,339 | 9,998 | 1,518 | 38,854 | 46,500 |
Source: