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Substantiating and Assessing the Stability of the Underground System Parameters for the Sawn Limestone Mining: Case Study of the Nova Odesa Deposit, Ukraine

Petlovanyi Mykhailo, Saik Pavlo, Lozynskyi Vasyl, Sai Kateryna, Cherniaiev Oleksii

Inżynieria Mineralna

2023

no. 1

79--89

Due to the russian federation aggression against Ukraine, the infrastructure of many settlements has undergone significant destruction, so in the post-war period, limestone can become a reliable and useful resource for its reconstruction. A significant number of limestone deposits in southern Ukraine are suitable for the production of wall (block) stone, but the geotechnical conditions of many mining sites require the use of an underground mining method. To study the mining system parameters of the Nova Odesa sawn limestone deposit, analytical and calculation methods are used based on known and proven hypotheses of stable spans and pillars, as well as verification by numerical modeling based on the finite element method in the SolidWorks software package. It has been determined that with a change in the ceiling thickness by 50% (from 0.8 to 1.2 m), the safe width of the chamber in the absence tensile stresses in the sawn limestone roof, under given mining-geological and mining-technical conditions of mining operations, increases by 22%. It has been revealed that the area of 25.0 m2 corresponds to the required safety factor of the square-shaped supporting pillar. It has been shown by numerical modeling that under the conditions of the Nova Odesa deposit, the load on a 5×5 m supporting pillar will reach 26% of its load-bearing capacity, and the extraction chamber ceiling is in a stable state without the formation of tensile stresses. The research results are useful for substantiating and assessing the stability of the room-and-pillar mining system elements with supporting pillars in the underground mining of sawn limestone or other mineral deposits.

W wyniku agresji federacji rosyjskiej na Ukrainę infrastruktura wielu osiedli uległa znacznemu zniszczeniu, dlatego w okresie powojennym wapień może stać się niezawodnym i użytecznym surowcem do jej odbudowy. Znaczna liczba złóż wapienia na południowej Ukrainie nadaje się do produkcji kamienia ściennego (blokowego), jednak warunki geotechniczne wielu miejsc wydobywczych wymagają zastosowania metody urabiania podziemnego. Do badania parametrów systemu wydobywczego złoża wapienia Nowa Odessa stosowane są metody analityczne i obliczeniowe oparte na znanych i sprawdzonych hipotezach stabilnych przęseł i filarów oraz weryfikacja poprzez modelowanie numeryczne w oparciu o metodę elementów skończonych w pakiecie oprogramowania SolidWorks. Stwierdzono, że przy zmianie grubości stropu o 50% (z 0,8 na 1,2 m) bezpieczna szerokość komory przy braku naprężeń rozciągających w stropie, w danych warunkach górniczo-geologicznych i górniczo-technicznych działalności wydobywczej wzrasta o 22%. Stwierdzono, że powierzchnia 25,0 m2 odpowiada wymaganemu współczynnikowi bezpieczeństwa kwadratowego słupa nośnego. Modelowanie numeryczne wykazało, że w warunkach złoża Nova Odesa obciążenie filaru nośnego o wymiarach 5m×5m osiągnie 26% jego nośności, a strop komory wydobywczej jest w stanie stabilnym bez powstawanie naprężeń rozciągających. Wyniki badań są przydatne do uzasadnienia i oceny stateczności elementów systemu urabiania komorowo-filarowego wraz z filarami oporowymi w podziemnym wydobyciu wapienia lub innych złóż kopalin.

Reducing wear of the mine ropeways components basing upon the studies - of their contact interaction

Haddad Jamil Sami, Denyshchenko Oleksandr, Kolosov Dmytro, Bartashevskyi Stanislav, Rastsvietaiev Valerii, Cherniaiev Oleksii

Archives of Mining Sciences

2021

Vol. 66, no. 4

579--594

To improve the durability of the rollers of supporting and guiding devices as well as traction ropes of ropeway facilities based upon the analysis of their contact interaction. Theoretical studies of a mathematical model of contact interaction of mine ropeway components to determine regularities of the formation of dynamic efforts within the contact area and experimental studies of the plant under mine conditions. Based upon a mathematical model, contact stresses within the zone of contact of traction rope with guiding rollers and drive sheaves of mine ropeways under real operating conditions have been determined. The obtained results are validated experimentally under mine conditions. Innovative patent-protected design solutions have been proposed; the solutions make it possible to considerably increase the durability of the ropeway components. It has been determined that methods of surface increase in the strengthening of a roller working surface do not have proper effect as the strengthened layer on a soft base cracks and delaminates due to high contact loads; maximum angle of rope bending on rollers of supporting devices (6º – in operation manual; 15º – in safety rules) recommended for GRW is overstated. It shouldn’t be more than 1.5º in terms of values of contact stresses for standard plants; development of prestressed compression state in the material of elastic lining of a drive friction sheave allows increasing considerably (by two times and more) its service life. Ropes with reduced diameters of external layer wires (Ukraine’s regulatory document – DST 2688) being used currently on mine ropeways do not meet the operating conditions and have a short period of service life due to their corrosive and fatigue breaking. To lengthen the service life of GRW traction ropes, it is required to change for the ropes with increased diameters of the external layer wires with preliminarily clamped strands.