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