LaModel Software
The LaModel program was developed by Dr.Keith A. Heasley in 1996. It is used to model the stresses and displacements on thin tabular deposits such as coal seams. It uses the displacement-discontinuity (DD) variation of the boundary-element method and because of this formulation, it is able to analyze large areas of single or multiple-seam coal mines (Heasley, 1998). What makes LaModel unique among boundary element codes is that the overburden material includes laminations which give the model a very accurate flexibility for stratified sedimentary geologies and multiple-seam mines. Using LaModel, the total vertical stresses and displacements in the coal seam are calculated; and also, the individual effects of multiple-seam stress interactions and topographic relief can be separated and analyzed individually.
Since LaModel’s original introduction in 1996, it has continually been upgraded and modernized as operating systems and programming languages have changed. The present program is written in Microsoft Visual C++ and runs in the windows operating system. It can be used to calculate convergence, vertical stress, overburden stress, pillar safety factors, intra-seam subsidence, etc. on single and multiple seams with complex geometries and variable topography. Presently, the program can analyze a 2000 x 2000 grid with 6 different material models and 52 different individual in-seam materials. It uses a forms-based system for inputting model parameters and a graphical interface for creating the mine grid. Also, it includes a number of wizards for:
- Calculating the lamination thickness based on the extent of abutment loading
- Calculating coal material properties based on a Mark-Bienawski pillar strength
- Calculating gob properties based on expected gob loading, and
Recently, the LaModel program has been interfaced with AutoCAD—taking an AutoCAD map of the pillar plan, overburden and automatically convert these into the appropriate seam and overburden grids. The output from LaModel can be downloaded into AutoCAD and overlain on the mine map for enhanced analysis and graphical display (Heasley, 2008).