Main objectives underlying mathematical model of powered support unit operation in terms of its working capacity

Abstract

This study synthesizes the operating data of a longwall system to determine the impacts of time, compressive strength of roof rock strata, rate of face advance, and distance between the cross bar in a roof support from the side wall on the value of the actual working capacity of powered supports. The analyses of the general linear models are supported by the Statistica program. Criteria imposed on the input data lead to the development of models of the powered support unit (shield) operation yielding corrected value of the coefficient R2 (0.11-0.42), rendering the models statistically significant. For the investigated longwall panel, the minimal bearing capacity of the powered support obtained by several methods is compared with the actual bearing capacity of the powered support units. Mathematical models were recalled to obtain the pressure value that can be used in the further procedure as: - pressure in a shield leg required to obtain the load-bearing capacity of a hydraulic leg in response to the load applied to the powered support, - pressure exerted by rock strata on the longwall excavation, which is utilized to determine the real load acting on the powered support unit. In the context of these two objectives, the roof stability factor was obtained accordingly, revealing excellent support-strata interactions under the specified geological and mining conditions.