Quarry Pit Optimization of Operations

Quarry pit optimization of operations for an opencast mine using computer modeling is an essential technique to determine budget figures. This post is a follow-up from the previous post regarding “Quarry Blast Fragmentation Critical Factor for Pit Operations“.

PGSurvey Planning

PGSurvey once again had the opportunity to complete a long-term plan for a new chromite operation. The plan is based on the current costs and revenue per ton of chromite. Various project scheduling have been completed for various scenarios. The waste dump planning was done to establish when backfilling should be done in order to have sufficient dumping space.

Some time ago we prepared a Pre-Feasibility Report, which investigated the potential to develop this chromite quarry to its full extent. By using drill results that we have done in 2012, the Pre-Feasibility Report describe how the outline of the opencast pit was derived.

By using the industry budget figures for opencast mining, a computer model was developed to determine the optimal pit high-wall. The waste parting between the MG3 and MG2, is approximately 17.7m wide, this study was therefore done as two separate mines. The MG4 & MG3 could optimally be mined to a 29 meter high-wall, while MG2 and MG1 could optimally be mined to a 24 meter high-wall. Attention to the geological fault has been given, which has displaced (down-through) all the reefs by 2.5 metre on the western side of the fault.

Computer Modeling

Based on several input parameters PGSurvey has developed this model on the following:

• Dip of the seam, high-wall dip -61 degrees from crest to toe position, seam widths for each seam, expected MCF and geological recovery for each seam, SG of chrome, revenue per ton and costs

The program produces a graph for various heights of the high-wall