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| Patents for E21C 39 - Devices for testing in situ the hardness or other properties of minerals, e.g. for giving information as to the selection of suitable mining tools (220) |
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| 10/16/1990 | US4962668 Material stress monitor | | 01/18/1990 | DE3823495A1 Hydraulische gesteinzerklueftende bohrlochsonde und verfahren zu ihrer anwendung Hydraulic gesteinzerklueftende borehole probe and method for their application | | 12/06/1989 | EP0344926A1 Material stress monitor | | 11/16/1988 | CN87214063U Twin-arm full cross-section automatic sampling machine | | 09/27/1988 | US4774470 Shield tunneling system capable of electromagnetically detecting and displaying conditions of ground therearound | | 04/15/1987 | CN86200855U Coal sampler | | 04/07/1987 | US4655082 Mining machine having vibration sensor | | 07/30/1985 | US4531403 Method and apparatus for fracturation detection | | 06/04/1985 | CA1188364A1 Method of and apparatus for mining analysis | | 01/29/1985 | US4495804 Method of and apparatus for mining analysis | | 04/10/1984 | US4441616 Process for sorting coarse to fine materials according to their chemical composition | | 06/29/1983 | EP0024418B1 Process for sorting coarse-to-fine material according to the chemical composition thereof | | 01/18/1983 | US4368919 Holder assemblies for sensitized cutter tools on mining machines | | 01/11/1983 | US4367899 Holder assemblies for sensitized cutter tools on mining machines | | 09/14/1982 | CA1131463A1 Method of fracturation detection | | 03/09/1982 | US4318302 Method of determining mine roof stability | | 02/10/1982 | EP0045607A2 Method and apparatus of fracturation detection | | 11/17/1981 | US4300397 Device and method for determining material strength in situ | | 03/11/1981 | EP0024418A1 Process for sorting coarse-to-fine material according to the chemical composition thereof. | | 09/04/1980 | WO1980001837A1 Process for sorting coarse-to-fine material according to the chemical composition thereof |
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