1 煤炭生产量1999年美国煤炭总产量为9923Mt，比1998年降低21%,主要原因有2个：（1）由于核能发电大幅度增长,造成发电用煤量减少；（2）煤炭出口量大幅度下降。因为多数的核能发电厂座落在密西西比河东岸，大部分出口煤炭也来源于东部的煤田(主要分布在西弗吉尼亚州、弗吉 1 Coal Production The total output of coal in the United States in 1999 was 992.3Mt, a decrease of 21% over 1998. There were two main reasons for this: (1) the coal consumption for power generation decreased due to the substantial increase of nuclear power generation; (2) Coal exports dropped significantly. Because most of the nuclear power plants are located on the east bank of the Mississippi River, most of the coal exported is also from the eastern coalfields (mainly in West Virginia,