The Ellton Group designed and installed a 2km coal conveyor system for Rio Tinto Coal Australia’s Coal and Allied Hunter Valley Operations.
Combining engineering innovation and efficiency with built-in safety and environmental excellence, the 1400mm belt conveyor system rated at 2400 TH and driven by ground-mounted Bonfiglioli Power Pack drives includes an overland conveyor and a skyline stacker conveyor system that eliminates the need for heavy trucks to transfer coal from another load-out facility during peak production.
The unique conveyor design also overcomes numerous environmental and structural challenges as it traverses reclaimed and subsidence-prone land to deliver high volumes of coal to an existing stockpile facility through a cost-efficient design that incorporates recycled previous structures.
Managing Director of the Ellton Group, Mr Mark Elliott explained one of the many unique aspects of the design was the complete incorporation of an existing skyline gantry system contained within the new structure. The old gantry had a tripper running through it. The new, higher capacity structure is built around the existing tripper gantry, running the conveyor in the opposite direction but sharing a radically improved and strengthened structure that easily and safely handles higher conveyor loadings but is designed to minimise additional mass and wind loadings.
Working in consultation with Rio Tinto’s operations staff and their consultants, the Ellton Group evolved numerous options that made good use of existing infrastructure while observing their rigorous safety and environmental standards. One of their winning edges was the ability to introduce fresh thinking to issues facing mine operators.
Examples of design, safety and environmental initiatives introduced on the project:
To ensure safe and efficient design of the trestle structures carrying the overland conveyor above extensive areas of reclaimed and previously mined land that is prone to subsidence, the Ellton Group’s solution included trestle structures and roof sections that were not only structurally independent of each other, but also independently adjustable in three dimensions.
Sound economics as well as a focus on environmental results meant that maximum utilisation of existing infrastructure was a prime objective. Incorporating existing structures in the final design that were not originally rated for the revised duty was only part of the design challenge. The upgrade works had to be executed while the existing plant continued to operate; the new design therefore had to be suitable for construction in and around equipment that could not be stopped or demolished.
Minimised additional wind and mass loading on the existing structure was achieved by adopting a ‘wraparound’ gantry design to support the new conveyor and tripper. The gantry design had to be as light as possible and still allow the existing tripper to operate inside the old gantry both during and following construction.
In addition to full coverage of the conveyed load to minimise spillage and dust, the areas traversed by the overland conveyor are protected by civil works including bunding, side dish drains, channelling and settlement ponds. These works separate and redirect clean water run-off from surrounding landscape to avoid possible contamination, capture water emanating from the conveyor path and direct it to one of several dirty water settlement ponds constructed along the route. By containing run-off and run-on, recycling is optimised and contamination of the environment is avoided.
The Ellton Group also recovered and re-used old gantry structures, which were stripped, refurbished, painted and refitted to new standard and incorporated into the elevated stages of the overland conveyor. In addition to saving money and avoiding waste, the refurbishment and reuse cleaned up the entire site where they were previously located. The fully enclosed tipper feed structure now spans a busy local road, removing the need for trucking by providing a clean and safe alternative.
The Ellton Group also used innovative Bonfiglioli Power Pack heavy duty fully coupled drive combinations, engineered by Bonfiglioli for optimum ease of installation, rugged service and low maintenance in materials handling and process applications.
Mounting of the drives and take-ups at ground level, rather than with elevated drives and vertical take-ups ensured ease and safety of maintenance. The on-ground concept ensures simple and safe de-tensioning of the belt and removal of stored energy, thus enhancing safety. The design not only eliminates the hazards associated with isolating suspended gravity weights but also reflects the Ellton Group’s experience in underground mining while providing better and quicker access for maintenance.