Abstract
Caving process is a complex dynamic phenomenon influences safety and productivity of coal longwall mining. It improves safety due to reduction of load on support, face convergence and abutment stresses. Proper caving with respect to the quality and time of occurrence ensures continuity of operation and subsequently, the productivity of coal extraction. Therefore, a reliable prediction of strata behaviour and its caving potential are imperative in design of longwall projects. This paper presents a hybrid probabilistically qualitative–quantitative model to evaluate cavability of immediate roof and to estimate main caving span in longwall mining by combining empirical model and numerical solution. For this purpose, numerical simulation was incorporated to Roof Strata Cavability index (RSCi) as summation of ratings for nine significant parameters. Distinct element code was used to simulate numerically main caving span corresponding to various RSCi classes probabilistically. T
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CONSOL Energy Inc. (CEIX) has reported financial and operating results for 4Q20 and fiscal year ended 31 December 2020.
4Q20 highlights:
Consummated the CONSOL Coal Resources (CCR) merger transaction with strong shareholder support.
Net income and net income attributable to CONSOL Energy Inc. Shareholders of US$14.7 million and US$13.1 million, respectively.
Cash and cash equivalents of US$50.9 million as of 31 December 2020.
Gross payments on total debt of US$26 million during the quarter.
Coal shipments recover to 5.9 million t compared to 4.5 million t in 3Q20 and 2.3 million t in 2Q20.
Net leverage ratio1 of 2.5 x as of 31 December 2020.
Net cash provided by operating activities of US$66.9 million.