Convergence at the faces of development workings
Since 1963 we have been carrying out investigations in pits of the Pechora coalfield to establish the general laws of roof-floor convergence in the face areas of development workings and their role in gas bursts. We also considered how various methods of working on the seam influence the amount of type of convergence. The observations were made in 20 workings in five pits of Vorkutaugol Group, cut by cutter-loaders and by drilling and blasting at depths between 350 and 600 m; the cross-sectional areas of the workings ranged frm 3.7 to 12.0 m/sup 2/. The aggregated data on daily convergence values was analyzed by the multiple correlation method with the aid of a computer. The aim of the analysis was to elucidate the influence of six factors on the daily convergence values: the depth below the surface, the corrected seam strength, the cross-sectional area of the working, the initial distance from the face to the measurement prop, the daily advance, and the thickness of the seam. The combined correlation coefficient was rather low - 0.49 with a reliability of 9.13. The greatest influence on the convergence values is exerted by the cross-sectional area and by the distance from the face (the partial correlation coefficients being 0.281 and 0.310, respectively), and lesser influences are exerted by the depth below the surface and by the corrected strength of the seam (partial correlationcoefficients 0.164 and 0.178); the influences of seam thickness and daily face advance are very slight. The multiple correlation results indicate that a very great influence is exerted by disregarded factors, among which the most important are undoubtedly the properties of the surrounding rocks.
- Research Organization:
- Pechora Scientific-Research Planning Inst., Vorkuta, USSR
- OSTI ID:
- 5518114
- Journal Information:
- Sov. Min. Sci. (Engl. Transl.); (United States), Vol. 13:4; Other Information: Translated from Fiz.-Tekh. Probl. Razrab. Polezn. Iskop.; 13: No. 4, 24-29(Jul 1977)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Thin, level and steep seam equipment used in the donets basin
Toward a method of quantitative assessment of the cuttability of coals