The Coppabella Mine, located in central Queensland, is an open-cut mine that produces low-volatile pulverised coal injection (PCI) coal.
One of its run of mine (ROM) walls has been in service for over a decade and over time the steel facing panels of the wall had deteriorated, requiring repairs to maintain serviceability. Access to repair this area was limited due to the operational and production requirements of the mine.
The mine required a solution to repair this area without affecting the safety of coal mine workers or coal production.
Mainmark collaborated with Peabody Projects, Coppabella Mine and a local engineering company, Field Engineers, to develop and deliver a fit for purpose solution that could be implemented without affecting coal production and would provide an assurance that the repairs would be long-lasting and durable.
The end result was a complete engineered solution that fixed the ROM wall safely, without causing unplanned down-time or production loss
Mainmark needed to repair the ROM wall by filling the voids, agglomerating loose materials and providing support behind the steel half-pipe wall face. Anchor points then needed to be installed to further strengthen the wall and extend the design life.
Mainmark had to ensure that all works were carried out in a safe and tidy manner in compliance with mine safety standards. This was all the more important as the works were to be conducted in areas with limited accessibility.
The project was required to be completed without taking the ROM bin offline, and had to have zero impact on the surrounding operations of the mine.
Mainmark used a combination of our proprietary Teretek® engineered resin solution, modified lightweight cementitious Terefil® grout, a Hollow Bar Anchor System, and shotcrete to complete the project.
The wall was injected with a combination of Teretek® and modified Terefil® to fill the voids, agglomerate the loose material and support the wall. Mainmark installed Hollow Bar Anchors, which were drilled and grouted in place at up to 20m deep and five degrees off horizontal into the ROM rammed earth platform (REP). This provided a mass anchoring, with the anchors tensioned to 30kN.
A layer of mesh and baseplates was installed across the face, creating footings, and a specialised formula of shotcrete at 150mm thick was applied. This was followed by a second layer of mesh and a second layer of shotcrete, again at 150mm thick, for a total thickness of 300mm.
The project management portion of the job included managing a small team of professionals with expertise in specific fields. This required many hours of work to manage the labour force, hire equipment, materials and preparation.
Mainmark and Peabody also facilitated and managed the process of having personnel and equipment inducted and signed-off to work within the mine, which included liaising with people spread over three states and from four different companies.
Mainmark’s extensive experience and know-how combined with the Peabody Project Team’s commitment to safety and success meant that this process ran smoothly and the project was completed in a short timeframe.
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