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Dynamics of autonomous rock electromagnetic radiation measurement instrumentation

Mydlikowski Remigiusz, Maniak Krzysztof

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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Vol. 69, nr 5

art. no. e138567

EN

The paper analyzes the operation of innovative composite measurement instrumentation for spontaneous electromagnetic emission. The designed receiver measures and records both components of the EM field emitted by rocks subjected to increased mechanical stress. The range of signals transmitted by the receiver system and its dynamics were determined. A receiver was used to observe electromagnetic signals generated during a hard coal sample crushing in laboratory conditions. Test results confirmed the high dynamic range of the system at 98 dB and the ability to observe signals over a range of frequencies up to 50 kHz. The experimental results confirm the signal bandwidth characteristic of coal mine EM field emission obtained in earlier studies. The constructed autonomous receiver can be used in mine workings as a complementary warning system for emerging mine hazards.

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Experimental Verification of Standard Recommendations for Estimating the Load-carrying Capacity of Undercut Anchors in Rock Material

Jonak Józef, Karpiński Robert, Siegmund Michał, Machrowska Anna, Prostański Dariusz

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 1

230--244

EN

The recommendations put forward in the International Standards for anchorage in concrete concerning the assessment of the load-carrying capacity of anchors (the pull-out force) embedded in natural rock material were verified. Regarding the predicted extent of surface failure we have shown, in earlier studies, substantial discrepancies between the strength test results for anchorages in the rock mass and the established standard recommendations for anchorages in concrete. As regards the industrial practice and the goals of the reported project, simplified calculation procedures that will facilitate the selection of optimal configurations for the layout of anchor holes, while being computationally effective and applicable under the industry-specific conditions are sought.

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Stress-strain characteristics as a source of information on the destruction of rocks under the influence of load

Bogusz A., Bukowska M.

Journal of Sustainable Mining

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2015

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Vol. 14, iss. 1

46--54

EN

This paper presents the problems associated with the complete stress-strain characteristics of the destruction of rocks under load, in the full range of their strain. The most important factors influencing the course of a stress-strain curve are discussed, i.e.: the shape and size of samples and the conditions experienced when conducting the experiment in a testing machine. Presented mechanical and energy parameters were obtained in laboratory tests carried out by loading rock samples in a servo controlled testing machine as well as some indices devised on the basis of these parameters. The interpretation of complete stress-strain characteristics allow solve various issues connected with underground mining, especially assessing natural hazards which are common in underground mining for minerals, as well as designing and managing mining works within underground workings.