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-
-
-
-
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2331484
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Patent number 2,331,484
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Issue date Oct 12, 1943
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E21 - EARTH DRILLING MINING
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2299214
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Patent number 2,299,214
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Issue date Oct 20, 1942
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E21 - EARTH DRILLING MINING
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1972352
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Patent number 1,972,352
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Issue date Sep 4, 1934
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E21 - EARTH DRILLING MINING
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1774203
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Patent number 1,774,203
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Issue date Aug 26, 1930
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E21 - EARTH DRILLING MINING
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1694780
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Patent number 1,694,780
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Issue date Dec 11, 1928
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E21 - EARTH DRILLING MINING
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1692260
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Patent number 1,692,260
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Issue date Nov 20, 1928
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E21 - EARTH DRILLING MINING
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1641862
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Patent number 1,641,862
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Issue date Sep 6, 1927
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E21 - EARTH DRILLING MINING
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1614033
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Patent number 1,614,033
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Issue date Jan 11, 1927
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E21 - EARTH DRILLING MINING
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1613106
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Patent number 1,613,106
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Issue date Jan 4, 1927
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E21 - EARTH DRILLING MINING
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1521037
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Patent number 1,521,037
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Issue date Dec 30, 1924
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E21 - EARTH DRILLING MINING
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1521049
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Patent number 1,521,049
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Issue date Dec 30, 1924
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E21 - EARTH DRILLING MINING
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1483053
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Patent number 1,483,053
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Issue date Feb 5, 1924
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E21 - EARTH DRILLING MINING
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1439020
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Patent number 1,439,020
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Issue date Dec 19, 1922
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E21 - EARTH DRILLING MINING
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1401759
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Patent number 1,401,759
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Issue date Dec 27, 1921
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E21 - EARTH DRILLING MINING
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1392836
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Patent number 1,392,836
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Issue date Oct 4, 1921
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E21 - EARTH DRILLING MINING
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1392835
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Patent number 1,392,835
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Issue date Oct 4, 1921
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E21 - EARTH DRILLING MINING
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1378813
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Patent number 1,378,813
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Issue date May 17, 1921
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E21 - EARTH DRILLING MINING
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1378819
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Patent number 1,378,819
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Issue date May 17, 1921
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E21 - EARTH DRILLING MINING
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1378358
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Patent number 1,378,358
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Issue date May 17, 1921
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E21 - EARTH DRILLING MINING
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1378812
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Patent number 1,378,812
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Issue date May 17, 1921
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E21 - EARTH DRILLING MINING
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1378816
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Patent number 1,378,816
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Issue date May 17, 1921
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E21 - EARTH DRILLING MINING
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1378815
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Patent number 1,378,815
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Issue date May 17, 1921
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E21 - EARTH DRILLING MINING
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1378809
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Patent number 1,378,809
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Issue date May 17, 1921
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E21 - EARTH DRILLING MINING
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1378817
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Patent number 1,378,817
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Issue date May 17, 1921
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E21 - EARTH DRILLING MINING
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1378810
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Patent number 1,378,810
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Issue date May 17, 1921
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E21 - EARTH DRILLING MINING