Each file contains one mining step. The user must construct a number of files to simulate the excavation sequence. There are capabilities in the program for looking at differential stresses, displacements, and energy, between files. There is no limitation as to the number of elements used to construct your boundary element mesh. There's no built in limitation to the number of elements or nodes that can be solved. In the past, there was a difficulty with versions prior to 4.098, where the maximum file size in MS Windows (2GB) caused problems with the swap file thus limiting to the maximum number of nodes to ~7500. This has since been fixed, so be sure you have the latest update from our website. You must also have adequate hard disk space to solve these large models, so in fact you are limited by the size of your hard disk. Use the Compute3d Stats option in the Analysis Param menu to see the size needed to solve the model. To calculate the required amount of disk space you can also used the following equation: **D=N*N*9*4**- where,

**D** = Disk space required in Bytes.

**N** = Number of Nodes in your problem. This is the number displayed in the lower right corner of the Modeler window beside the ND.