Lerchs & Grossmann (LG)

Lerchs & Grossmann allows the user to consider multiple rock types, multiple processes and multiple products to produce multiple nested pit shells. An interactive and easy to use interface allows an easy input of all the parameters for the optimisation. A powerful set of analysis tools allows easy construction of charts and reports directly into Excel® giving the freedom of easy formatting for publishing.

Multiple subregions can be used to define different slope angles, depending on the geomechanical properties of each rock type. Subregions can have any 3D shape. Regular or sub-blocked models are allowed. The values are directly read from and written to the block models. No intermediate files are required.

Several options are available for sensitivity analysis during optimisation. These options allow the engineer to evaluate breakpoints in different parameters such as costs and prices. These tools can also be used to produce nested pit that can be used as their basis for conceptual mining phases.

Grade variables are read in the original units. Several different grade and mass units are supported, including metric, avoirdupois, troy and Japanese units. In addition, the economic value of each block can be read directly from the block model if it was calculated with a user defined method, for which powerful calculation functions and scripting languages are available. The use of evaluated models still gives the user two options for sensitivity analysis and for producing nested pits.

Resulting nested pits can be displayed as contours or 3D surfaces. Reports can be easily defined by simply activating the columns to report. All Excel® standard charts are configured from within Vulcan for easy reproduction of charts and reports.

Two modules are available that use the LG algorithm:

• LG - Single Product and Process
• LG - Multiple Product and Process

The Single and Multiple product and process modules differ only in the ability to work with more than one product/process. In both versions the option to read the economic value from the block model is available.