Table
01. Number of Coal Operations in the United States, by Primary Activity,
1978-2006
|
Year
|
Underground
Mines
|
Surface
Mines
|
|
|
Underground
|
Surf at UG
|
Total
|
Strip
|
Auger
|
Culm Bank
|
Dredge
|
Total
|
|
1978
|
2,537
|
155
|
2,692
|
3,176
|
53
|
61
|
3
|
3,293
|
|
1979
|
2,371
|
175
|
2,546
|
2,893
|
32
|
55
|
8
|
2,988
|
|
1980
|
2,407
|
303
|
2,710
|
2,783
|
30
|
58
|
12
|
2,883
|
|
1981
|
2,448
|
374
|
2,822
|
2,880
|
32
|
59
|
15
|
2,986
|
|
1982
|
2,468
|
259
|
2,727
|
2,790
|
39
|
54
|
18
|
2,901
|
|
1983
|
2,129
|
44
|
2,173
|
2,256
|
36
|
50
|
20
|
2,362
|
|
1984
|
2,184
|
31
|
2,215
|
2,259
|
50
|
53
|
19
|
2,381
|
|
1985
|
2,073
|
30
|
2,103
|
2,125
|
52
|
54
|
18
|
2,249
|
|
1986
|
2,026
|
39
|
2,065
|
2,032
|
52
|
66
|
18
|
2,168
|
|
1987
|
1,969
|
40
|
2,009
|
1,918
|
71
|
55
|
22
|
2,066
|
|
1988
|
1,854
|
59
|
1,913
|
1,776
|
90
|
56
|
24
|
1,946
|
|
1989
|
1,739
|
42
|
1,781
|
1,665
|
90
|
57
|
25
|
1,837
|
|
1990
|
1,735
|
42
|
1,777
|
1,603
|
92
|
67
|
20
|
1,782
|
|
1991
|
1,558
|
47
|
1,605
|
1,515
|
82
|
72
|
24
|
1,693
|
|
1992
|
1,415
|
40
|
1,455
|
1,380
|
80
|
64
|
19
|
1,543
|
|
1993
|
1,272
|
51
|
1,323
|
1,258
|
83
|
73
|
15
|
1,429
|
|
1994
|
1,207
|
49
|
1,256
|
1,176
|
97
|
80
|
19
|
1,372
|
|
1995
|
1,049
|
32
|
1,081
|
1,086
|
96
|
77
|
16
|
1,275
|
|
1996
|
940
|
41
|
981
|
954
|
103
|
77
|
18
|
1,152
|
|
1997
|
940
|
28
|
968
|
929
|
94
|
77
|
17
|
1,117
|
|
1998
|
883
|
27
|
910
|
882
|
94
|
74
|
19
|
1,069
|
|
1999
|
792
|
25
|
817
|
828
|
104
|
63
|
16
|
1,011
|
|
2000
|
752
|
19
|
771
|
747
|
84
|
73
|
16
|
920
|
|
2001
|
754
|
23
|
777
|
754
|
95
|
73
|
15
|
937
|
|
2002
|
693
|
18
|
711
|
761
|
81
|
68
|
11
|
921
|
|
2003
|
622
|
21
|
|
