The sheer size of the storage bunker constructed for the Limpopo-based Grootegeluk Medupi Expansion Project (GMEP), owned and operated by coal and heavy minerals mining company Exxaro Resources, posed a daunting challenge for engineers and contractors in terms of design and construction, reports materials handling consultancy LSL Consulting.

The company is involved in the development of materials handling facilities for the GMEP, from in-pit crushing plants to screening and conveying, as well as the stacking and reclaiming of material, to the point where coal is handed over to State-owned power utility Eskom.

LSL MD Dimitri Simigiannis explains that several aspects of the storage bunker had to be re-engineered to construct the 50 000 t unit. “We based a lot of our initial estimations on the construction of a 15 000 t bunker, which is the typical size of bunkers that have recently been constructed.”

Simigiannis adds that, in scaling up from 15 000 t to 50 000 t, the complexity of the work required to complete the construction of the bunker in time was not fully contemplated.

This had a serious knock-on effect on several other aspects of the project, such as cost and time, as well as frustration experienced by on-site personnel.

“To our benefit, we were involved in all the stages of the construction process, from the concept, prefeasibility and feasibility stages to detailed engineering,” notes Simigiannis.

Developing the bunker required LSL’s continuous involvement and fine-tuning capabilities as construction of the bunker progressed. “We used the large bunker solution for run-of-mine storage, owing to space limitations between two existing dumps.

Conveyor System Recognised

LSL Consulting has been involved with materials handling consulting at Grootegeluk mine since the 1980s.

During an official event earlier this month, Exxaro presented LSL Consulting with an award for its innovative design of the coal dispatch systems at GMEP.

“Our vast experience at the mine enabled us to significantly improve the current safety requirements for the GMEP,” says Simigiannis.

“For the conveyors on the backfill portion, our designs can compensate for a certain level of settlement – owing to fresh fills on which we had to build – before the conveyor system requires lifting and realignment to compensate for longer term settlements,” he explains.

Meanwhile, LSL Consulting is nearing the end of its contract at GMEP and has downscaled its on-site staff complement. At the peak of the GMEP, LSL had up to 40 engineers and draughtspeople working on the project.