Introducing Footprint Finder for Sub-Level Caving

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For decades, mining companies have trusted GEOVA PCBC’s footprint finder application to quickly and effectively evaluate the footprint of block cave operations. Now PCSLC (for sub-level caving) has its own tool to rapidly evaluate sub-level cave scenarios to determine which option will be most attractive and robust.

Quickly Create and Evaluate SLC Scenarios

Footprint Finder for SLC (FFSLC) has been designed to quickly evaluate sub-level caving scenarios using minimal inputs for simplicity. The application converts a column of blocks above a level into “rings”, and evaluates the economic footprint for each SLC level. Extraction percentages can be set to defaults or can be optimized using the Footprint Finder application.

A basic face shape can be set by azimuth, and a rate of face advance used to determine the sequence of mining. These parameters are easily modified so that multiple SLC scenarios and strategies can be modelled and compared.

Extraction Percentage Optimization

The FFSLC determines the economic footprint within a clipping boundary and applies the extraction percentage profile based on the number of levels (blocks/rings) that are above the current level. In the image below, blocks on the first level are all colored in blue, these blocks are all given an extraction percentage of 60% from the excel extraction profile input because there are no rings above these blocks. On the level below, there are both green and blue blocks.

The green blocks sit directly below the first level, and will be given the extraction percentage of 80%, while the blue blocks on the second level have no blocks/rings above and will be given the extraction percentage of 60%. Thus FFSLC is able to quickly model a desired extraction percentage profile.

Futhermore, the FFSLC is able to optimize the extraction percentage profile by using the minimum and maximum extraction percentages suggested to run multiple iterations and return best result. The aim of the FFSLC is to achieve the highest value which it accomplishes by minimizing dilution and maximizing ore recovery. It is able to do this by adjusting the extraction percentage of each column of blocks to match the shape and grade distribution of the orebody.

Below are images of four sample columns of blocks/rings, on the left shows the typical extraction profile and the optimized profile shown on the right. These results can then be fed back into PCSLC to optimize the draw stragery of an SLC.

Level Input and Sequencing

The level spacing can be quickly modified and tested for sensitivity as the minimum and maximum elevation for each level can be easily set within excel.

Mining levels are designated with the type M, while block rings and external material use the designation B and X respectively. The results can be displayed graphically with X, Y and Z offsets so that levels can be shown side by side.

Grade elements are used for tracking Primary, Secondary, Tertiary and Quaternary material movement. These grade elements can be plotted to see where material is coming from on each level. Individual clipping boundaries can be used for each level to further restrict to footprint shape as desired.

The sequence is easily controlled by integers set within the sectors attribute of the block model. The desired face shape can be created as an XY Curve and these curves can be applied to each sector at a specified azimuth.

The table sheet (example below) controls the period, target tons, max active levels, and the maximum advance distance for a given period. These all combine to produce a production schedule for the desired SLC scenario.

Sample Production Schedule:

In conclusion, the FFSLC is exciting new tool which can be used to rapidly evaluate and analyze a wide variety of sub level caving scenarios, quickly and efficiently.

If you’d like more information on any of the above features, please contact us at GEOVIA.Info@3ds.com. You may also be interested in reading about the PCBC Undercut Modeling Tool.

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Christina Ludwicki

Christina Ludwicki

GEOVIA CBU Senior Application Consultant at Dassault Systèmes
Having joined the GEOVIA Caving Business Unit in 2014, Christina is focused on solution implementations at client sites and software training. She has worked on many different block caving projects, from order of magnitude to feasibility studies, to sub-level caving projects and software development testing. Christina is based in Vancouver, Canada.