Parallel coal seams

Sun, PD Three-dimensional numerical simulation of coupled gas leak flow and coal-rock deformation in parallel coal seams, this volume, 2004. 

VISUAL NUMERICAL SIMULATION OF COUPLED GAS LEAK FLOW AND COAL-ROCK DEFORMATION IN PARALLEL COAL SEAMS... 

The SIP methods by Stone (1986) for the gas leak flow equations and the rock mass deformation equations for double parallel coal seams have been developed by Sun (1998,2002) with Microsoft Visual C+-I- 6.0 under Windows2000 on a Pentium rv rc. The program is suitable for isotropic heterogeneous coal seams with irregular shapes as well as anisotropic heterogeneous coal seams. The systems with the first or the second boundary conditions as well as the hybrid boundary conditions can all be solved. The overview of the numerical implementations of the SIP methods for the solid-gas coupled mathematical model for double parallel coal seams is described as follows. 

The above steps are performed iteratively along the time axis to simulate the interaction between the gas leak flow and the coal/rock mass deformations in double parallel coal seams. The spatial precision (i.e. the sizes of grids for describing the coal seam planes) as well as the time precision (i.e. the time increment value) for numerical simulations is determined by practical engineering requirements. 

In this paper, a mathematical model for coupled coal/rock mass deformations and gas leak flow in parallel coal seams is presented from a new viewpoint of solid-gas interaction. It consists of equations for the gas leak flow, equations for coal/rock mass deformation and the... 

In the longwalt system, which originated in Europe, two parallel entries arc excavated from the main mine entry directly into the coal seam. The parallel entries, which may he as much as 750 feet (365 meters) apart or more, arc then joined together at their far end by a crosscut. The coal face that is furmed at the crosscut is called the longwall."... 

Liang Baoxia Pan Yishan 2006. Analysis of Plane-Parallel Flow Model for Water Injection in Thin Coal Seams with High gas Content. Journal of Mining and Safty Engineering 23(2) 206-209, 214. 

In coal seams, igneous rock is commonly seen as a dike, which is a nearly vertical tabular mass cutting across the bedding of the sediments. If a zone of weakness exists between the bedding planes, the molten material may have been forced to spread as a broad sheet parallel to the bedding plane to form a sill. 

This particular method for the recovery of coal was developed mainly in the period following World War II. An attractive aspect of the method is the relatively low cost of the equipment since the technique essentially involves boring a series of parallel horizontal holes into a coal seam. 

The stream method can be applied generally to steeply pitched coal beds inclined galleries following the dip of the coal seam are constructed parallel to each other and are connected at the bottom by a horizontal gallery or fire drift (Figure 21.29). 

Shale parting (shale break) Typically a layer of shale in a coal seam that runs parallel to the bedding plane of the seam. 

Black Beauty and Maitland Samples. Approximately three miles northwest of Walsenburg, Colo., coal beds of the Vermejo formation are cut by a northeast-trending. nearly vertical dike which is approximately 25 feet thick. Fortunately, at this locality two coal mines have operated—one on either side of the dike. Both mines have been developed by drifting in from the outcrop of the seam. The Black Beauty mine on the south side of the dike has developed down dip more or less parallel to the strike of the dike. The main slope of the Maitland No. 2 mine on the north side has developed down dip and... 

The best known (sometimes infamous) method of surface mining is strip mining, in which strips of overburden are removed by draglines and other heavy earth-moving equipment to expose seams of coal, phosphate rock, or other materials. Heavy equipment is used to remove a strip of overburden, and the exposed mineral resource is removed and hauled away. Overburden from a parallel strip is then removed and placed over the previously mined strip, and the procedure is repeated numerous times. Older practices left the replaced overburden as relatively steep erosion-prone banks. On highly sloping terrain, overburden is removed on progres-... 

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