-
Mining apparatus and method
-
Patent number 4,082,360
-
Issue date Apr 4, 1978
-
Peabody Coal Company
-
John A. L. Campbell
-
E21 - EARTH DRILLING MINING
-
-
3915500
-
Patent number 3,915,500
-
Issue date Oct 28, 1975
-
E21 - EARTH DRILLING MINING
-
3896626
-
Patent number 3,896,626
-
Issue date Jul 29, 1975
-
E21 - EARTH DRILLING MINING
-
3874734
-
Patent number 3,874,734
-
Issue date Apr 1, 1975
-
E21 - EARTH DRILLING MINING
-
3842966
-
Patent number 3,842,966
-
Issue date Oct 22, 1974
-
E21 - EARTH DRILLING MINING
-
3739586
-
Patent number 3,739,586
-
Issue date Jun 19, 1973
-
E21 - EARTH DRILLING MINING
-
3471201
-
Patent number 3,471,201
-
Issue date Oct 7, 1969
-
E21 - EARTH DRILLING MINING
-
3357742
-
Patent number 3,357,742
-
Issue date Dec 12, 1967
-
E21 - EARTH DRILLING MINING