Mining Publication: MULSIM/NL Application and Practitioner's Manual

• Coal mining
• Computer simulation
• Convergence
• Rock mechanics

MULSIM/NL (multiple seams, nonlinear) is a new U.S. Bureau of Mines boundary-element-method (BEM) program for calculating stresses and displacements (i.e., convergence) in coal mines or thin, tabular metalliferous veins. This manual gives detailed operating instructions for MULSIM/NL and illustrates its use with several practical examples. While this manual concentrates on the practical aspects of actually running and using MULSIM/NL, another companion report titled "MULSIM/NL-Theoretical and Programmer's Manual" provides mathematical and programming details to those engineers and programmers who need to fully understand the FORTRAN program or desire to alter and enhance it. MULSIM/NL analyzes one to four parallel seams that have any orientation with respect to the Earth's surface. Three main features distinguish MULSIM/NL from its predecessors: (1) nonlinear material modes, (2) multiple mining steps, and (3) comprehensive energy release and strain energy computations. MULSIM/NL has six material models for the in-seam material including (1) linear elastic for coal, (2) strain softening, (3) elastic plastic, (4) bilinear hardening, (5) strain hardening, and (6) linear elastic for gob. The multiple mining step capability enables the user to simulate a changing mine geometry. Finally, MULSIM/NL performs comprehensive energy release rate calculations.