Table 04. Number of
HOURS WORKED at Anthracite Mines in the United States,
by Primary Activity,
1978-2007
|
Year
|
Underground
Mines
|
Surface
Mines
|
|
|
Underground
|
Surf
at UG
|
Total
|
Strip
|
Auger
|
Culm
Bank
|
Dredge
|
Total
|
|
1978
|
558,726
|
98,293
|
657,019
|
1,654,513
|
-
|
213,479
|
11,110
|
1,879,102
|
|
1979
|
527,592
|
74,026
|
601,618
|
1,725,213
|
-
|
255,727
|
9,672
|
1,990,612
|
|
1980
|
579,369
|
81,842
|
661,211
|
2,406,968
|
-
|
246,033
|
10,540
|
2,663,541
|
|
1981
|
629,242
|
104,386
|
733,628
|
2,539,566
|
-
|
231,181
|
13,311
|
2,784,058
|
|
1982
|
687,717
|
111,971
|
799,688
|
2,465,404
|
-
|
236,306
|
16,537
|
2,718,247
|
|
19831
|
563,168
|
100,113
|
663,281
|
1,808,340
|
-
|
233,166
|
17,068
|
2,058,574
|
|
1984
|
604,214
|
119,145
|
723,359
|
1,775,315
|
-
|
240,431
|
18,357
|
2,034,103
|
|
1985
|
586,909
|
126,599
|
713,508
|
1,505,021
|
-
|
259,912
|
12,879
|
1,777,812
|
|
1986
|
661,682
|
156,109
|
817,791
|
1,694,776
|
-
|
332,931
|
13,326
|
2,041,033
|
|
1987
|
515,001
|
157,666
|
672,667
|
1,156,455
|
-
|
318,529
|
6,538
|
1,481,522
|
|
1988
|
482,136
|
161,204
|
643,340
|
1,060,923
|
-
|
237,948
|
4,357
|
1,303,228
|
|
1989
|
442,919
|
139,985
|
582,904
|
1,172,247
|
-
|
250,117
|
5,615
|
1,427,979
|
|
1990
|
394,939
|
123,144
|
518,083
|
1,318,132
|
-
|
387,092
|
3,135
|
1,708,359
|
|
1991
|
354,168
|
108,207
|
462,375
|
1,174,713
|
-
|
389,374
|
5,200
|
1,569,287
|
|
1992
|
336,142
|
116,282
|
452,424
|
1,154,779
|
-
|
491,207
|
4,378
|
1,650,364
|
|
1993
|
294,225
|
96,603
|
390,828
|
949,750
|
-
|
658,822
|
4,838
|
1,613,410
|
|
1994
|
271,744
|
83,030
|
354,774
|
1,002,527
|
-
|
505,007
|
6,340
|
1,513,874
|
|
1995
|
291,758
|
90,431
|
322,189
|
965,144
|
-
|
548,490
|
4,340
|
1,517,974
|
|
1996
|
281,344
|
73,351
|
354,695
|
1,045,895
|
-
|
548,079
|
2,690
|
1,596,664
|
|
1997
|
261,742
|
87,096
|
348,838
|
1,182,054
|
-
|
492,529
|
2,340
|
1,676,923
|
|
1998
|
255,240
|
88,748
|
343,988
|
1,167,802
|
-
|
430,399
|
-
|
1,598,201
|
|
1999
|
216,290
|
81,515
|
297,805
|
1,154,187
|
-
|
292,852
|
| |