Wyniki wyszukiwania - Biblioteka Nauki

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Application of composite materials in underground mining industry – fore-shaft closing platform

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Kamiński P. , Niedbalski Z. , Małkowski P. , Bozic D.

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2022

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tom vol. 40, iss. 1

19--31

EN

According to Polish law regulations, fore-shaft in underground mines in process of its liquidation must be either filled with bulk material or closed with double-deck platform on its top. As liquidation by closing is cheaper and easier than filling, steel closing platforms are typically used for this purpose. However, steel price fluctuations due to COVID-19 pandemic together with rapid development of composite materials, make application of composite structure a tempting direction. The article presents a design of composite double-deck closing platform for fore-shaft liquidation in one of the collieries located in the eastern area of Silesian Coal Basin. Presented solution was thoroughly calculated and tested and then assembled in the mine. The aim of the research was to prove applicability of composite structures in underground mines with maintaining proper level of safety.

2

The effect of temperature on the mechanical properties and workability of rock salt

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Małkowski P. , Bednarek Ł. , Kotwica K. , Stopka G.

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tom Vol. 2, Iss. 1

384--393

EN

Underground salt mining accounts for about 16 percent of the total salt production worldwide. When excavating salt rock, the cutters of the road header come into contact with the rock. This produces friction and, consequently, a rise in temperature. Generally, as temperature increases, salt gradually loses its plasticity. The extent of these alterations depends on the presence of other minerals in the rock. This paper presents the results of laboratory tests on regularly shaped samples of salt. An analysis was performed of the results of compressive, tensile and induced-shear strength, and of Young's modulus, Poisson's ratio, cuttability index and side chipping angle. The testing was conducted on samples with a temperature of about 20°C and samples heated to 50°C and 80°C. The tests showed that as temperature increased, so did compressive and tensile strength, and longitudinal and transverse strain of salt. The temperature increase caused, however, a decrease in shear strength. The cuttability index and the side chipping angle also decreased when the heated samples were being cut. The percentage changes in the parameters within the 60-degree temperature range were as high as several dozen percent.

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Automatyczny system monitoringu stateczności wyrobisk korytarzowych

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Małkowski P. , Niedbalski Z. , Bednarek Ł. , Pytlik M. , Frymarkiewicz A. , Filipowicz K.

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tom T. 77, nr 7-9

9--23

PL

Zapewnienie stateczności wyrobisk jest kluczową sprawą dla prawidłowego funkcjonowania kopalni podziemnej. Dla danych warunków geologiczno-górniczych, w celu zachowania wymaganych gabarytów wyrobiska, dobierany jest odpowiedni schemat obudowy. Po wykonaniu projektu taki powinien jednak zostać zweryfikowany na podstawie pomiarów dołowych. Badania te powinny dotyczyć zarówno górotworu, jak i obudowy i stać się następnie podstawą kalibracji przyjętych modeli obliczeniowych oraz parametrów warunku wytrzymałościowego dla skał. W artykule przedstawiono opracowany system zintegrowanego automatycznego monitoringu wyrobiska przyścianowego oraz podano przykładowe wyniki pomiarów. Urządzenia elektroniczne zabudowane w wyrobisku pozwoliły na pomiar rozwarstwień stropu, obciążenie obudowy podporowej, obciążenie obudowy kotwiowej oraz na pomiar zmian naprężeń w górotworze. Ponieważ wyrobisko było utrzymywane w części przyzrobowej, wykonywano także pomiar obciążeń kasztów. Wszystkie urządzenia podpięte były do rejestratorów, które mogły gromadzić bezobsługowo dane przez dłuższy okres czasu. Uzyskane doświadczenia pokazują, że opracowany system można zastosować w innych wyrobiskach, gdzie dostęp jest utrudniony lub np. drążony w samodzielnej obudowie kotwowej.

EN

Ensuring mining workings stability is the key problem for the proper underground mine activity. The support passport of any working is designed for the common mining and geological conditions and should guarantee the required working dimensions for the specific range of time. However, after the support execution, the project should be then verified by the underground measurements. These measurements should concern both rock mass and support control and they should serve as the calibration of the rock mass model assumptions and the failure criterion. The integrated automatic monitoring system for the gate stability control and exemplary results are presented in the paper. Electronic devices installed in the working allowed to measure the roof rocks separation, a load on support frame, a load along the rock bolt and a change of stress in the rock mass. As the gate was maintained behind the longwall face the load on wooden box cribs was controlled as well. All the devices were connected to dataloggers, which could collected data unattended for a long time. The experience gained shows, that designed system can be applied in other underground workings, especially there, where the access is limited or e.g. where only roofbolting is applied.