International mining consultancy MRM Mining Services (MRM), part of international mining software developer Runge Group, is implementing Runge's software system XPAC in local coal producer Exxaro Coal's mines. The software is providing washability results for several of Exxaro's collieries.

The software provides a mine scheduling capability that predicts the washed coal products during scheduled periods in the mining process. This allows for geologists, mining engineers and metallurgists to complete a comprehensive mining schedule, with the inclusion of geological criteria, that allows for detailed mine planning and scheduling alternatives.

Exxaro's Tshikondeni colliery produces high quality coking coal, which is used predominantly in the steel making process. The geological conditions at Tshikondeni are extremely complex, with multiple intrusive events coupled with extensive faulting. All related wash tables for the multiple seams are stored within the XPAC database.

Once the expected contamination / dilution has been accounted for, a composited wash table is created, which is then evaluated during the scheduling process to predict the final product. The completed schedules showing the expected qualities is then communicated to the plant manager, who in turn is able to set the plant parameters in anticipation of the planned run of mine coal produced.

This process allows optimisation of coal yields, and removes the uncertainty of the final product delivered. Supplying the mining schedule to the XERAS financial modeling system then completes the planning cycle. This system systematically applies costs to the related operations. The result is a detailed financial report accompanied by net present value analysis and indicators.

Tshikondeni technical services manager Anton Gregory says: "We went for the XPAC software because it was able to address all of our mining needs. Not only are we able to simulate our existing mining conditions, but we now also have a precise tool which allows us to accurately predict our washed product qualities."

At Grootegeluk mine, mining is carried out through conventional truck and shovel methods. The material from ten coal benches supply eight beneficiation plants with seven key products distributed to some 20 different clients. The Runge suite of software is used by management to evaluate "what if" scenarios.

All scenarios are costed by means of activity based costing and are compared within the XERAS environment, on the basis of cash flow, and other financial criteria. The XPAC design tool, and Intellicad is used to do the mine layouts, while the Talpac haulage fleet evaluation system supports the physical asset use process for truck and loader analysis.

XPAC provides the capability to schedule various product specifications, by using the wash table information within the original geological mode. It tests the effects of changes to the dense media separation plant.

The scheduled results are correlated with the operational standards to calibrate the model. The planning process requires detailed planning to consistently supply the necessary products to Grootegeluk's clients, such as the Matimba power station. This detailed day-to-day planning is successfully achieved using the XACT short term scheduling system.

The XPAC system is also used at the Leeuwpan openpit mine to accurately model the coal washing process, simulating the double stage wash process used at the mine. The XPAC and XACT mine planning software are used for pit sequencing and product planning, and assist in determining the life-of-mine, and medium and short term planning. The XPAC is useful for planning plant settings and optimising product specifications.

The Arnot colliery uses mechanised mining methods and the equipment is individually simulated within the XPAC system, allowing for variations in productivities based on prevailing mining conditions.

Completed work requires re-evaluation of the existing resource to produce a mineable reserve based on numerous physical and mining related restrictions. Once the mineable reserves are highlighted, layouts are done using the XPAC design module taking into account previously mined areas and future planned mining reserves. A condition based scheduling model is then created in XPAC resulting in the life-of-mine scheduling production plan.

MRM specialises in systematic and integrated mine planning and mine financial planning. The company was established in 1995 to service the African mining industry, and is based in Johannesburg and Witbank. The company provides comprehensive software support and solutions in mine planning, as well as expertise in project management, geological consulting and mine consulting. The Runge suite of software caters for all mining situations and commodities, and has a growing client base throughout Africa.

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