-
-
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3712679
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Patent number 3,712,679
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Issue date Jan 23, 1973
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E21 - EARTH DRILLING MINING
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3494668
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Patent number 3,494,668
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Issue date Feb 10, 1970
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E21 - EARTH DRILLING MINING
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2764396
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Patent number 2,764,396
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Issue date Sep 25, 1956
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E21 - EARTH DRILLING MINING
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2684235
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Patent number 2,684,235
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Issue date Jul 20, 1954
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E21 - EARTH DRILLING MINING
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2630308
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Patent number 2,630,308
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Issue date Mar 3, 1953
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E21 - EARTH DRILLING MINING
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2608400
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Patent number 2,608,400
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Issue date Aug 26, 1952
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E21 - EARTH DRILLING MINING
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2425108
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Patent number 2,425,108
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Issue date Aug 5, 1947
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E21 - EARTH DRILLING MINING
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2399074
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Patent number 2,399,074
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Issue date Apr 23, 1946
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E21 - EARTH DRILLING MINING
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2281503
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Patent number 2,281,503
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Issue date Apr 28, 1942
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E21 - EARTH DRILLING MINING
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2253941
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Patent number 2,253,941
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Issue date Aug 26, 1941
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E21 - EARTH DRILLING MINING
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2182127
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Patent number 2,182,127
-
Issue date Dec 5, 1939
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E21 - EARTH DRILLING MINING
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2176885
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Patent number 2,176,885
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Issue date Oct 24, 1939
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E21 - EARTH DRILLING MINING
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2148495
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Patent number 2,148,495
-
Issue date Feb 28, 1939
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E21 - EARTH DRILLING MINING
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2093476
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Patent number 2,093,476
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Issue date Sep 21, 1937
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E21 - EARTH DRILLING MINING
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2089944
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Patent number 2,089,944
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Issue date Aug 17, 1937
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E21 - EARTH DRILLING MINING
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1824727
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Patent number 1,824,727
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Issue date Sep 22, 1931
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E21 - EARTH DRILLING MINING
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1809283
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Patent number 1,809,283
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Issue date Jun 9, 1931
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E21 - EARTH DRILLING MINING
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1809307
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Patent number 1,809,307
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Issue date Jun 9, 1931
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E21 - EARTH DRILLING MINING
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1809282
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Patent number 1,809,282
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Issue date Jun 9, 1931
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E21 - EARTH DRILLING MINING
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1808858
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Patent number 1,808,858
-
Issue date Jun 9, 1931
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E21 - EARTH DRILLING MINING
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1808649
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Patent number 1,808,649
-
Issue date Jun 2, 1931
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E21 - EARTH DRILLING MINING
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1784156
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Patent number 1,784,156
-
Issue date Dec 9, 1930
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E21 - EARTH DRILLING MINING
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1783443
-
Patent number 1,783,443
-
Issue date Dec 2, 1930
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E21 - EARTH DRILLING MINING
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1778295
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Patent number 1,778,295
-
Issue date Oct 14, 1930
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E21 - EARTH DRILLING MINING
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1755331
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Patent number 1,755,331
-
Issue date Apr 22, 1930
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E21 - EARTH DRILLING MINING
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1741714
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Patent number 1,741,714
-
Issue date Dec 31, 1929
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E21 - EARTH DRILLING MINING
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1726891
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Patent number 1,726,891
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Issue date Sep 3, 1929
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E21 - EARTH DRILLING MINING
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1682296
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Patent number 1,682,296
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Issue date Aug 28, 1928
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E21 - EARTH DRILLING MINING