a. The rock immediately above a coal seam. It is commonly a shale and is often carbonaceous in character and softer than similar rocks higher up in the roof strata. The roof shale may contain streaks and wisps of coaly material, which tends to weaken the deposit. Roof in coal mining corresponds to hanging wall in metal mining. See also: roof stone Nelson
b. In mine timbering there are two classifications of roof, the immediate roof and the main roof. The immediate roof lies directly over the coal and may be a single layer or several layers of rock material of the same, or different consistencies, and from a few inches to several feet in thickness. This roof requires timbering to support it as the coal is removed. The main roof is the roof above the immediate top, and may vary from a few feet to several hundred, or even thousands of feet in thickness. This roof is generally controlled by leaving pillars of solid coal that will support its weight. Kentucky
c. The country rock bordering the upper surface of an igneous intrusion. CF: floor
Source: Dictionary of Mining, Mineral, and Related Terms












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