Newest landfill at Mount Isa Mines complying with contemporary best practice
A new landfill site has been constructed at Mount Isa Mines in order to manage waste generated within the mine site internally, without requiring it to be taken to the city council’s landfill. It is located on the Kennedy Siltstone Open Cut (KSOC) overburden stockpile to the north of the current landfill.
This new landfill has been designed and constructed to the highest standards as stipulated by the Environmental Authority.
The landfill site expands over a footprint of 32,000 square meters and is estimated to occupy 184,000 cubic meters of waste generated from within the mine site.
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Phase 1 landfill from the north.
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Phase 1 landfill from above.
Key project works include bulk earthworks for foundation preparation, bearing layer construction, installation of liner and construction of leachate collection system.
This system consists of network of primary and secondary perforated pipes embedded in a layer of gravel.
The project also features a use of geo-grid for controlling possible settlement of the foundation.
The leachate barrier for the landfill is formed of composite liner profile, comprising of compacted clay liner, geosynthetic clay liner and high-density Polyethylene Geomembrane (HDPG).
Installation of geogrid.
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HDPE liner testing and welding.
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Geosynthetic clay liner installation.
This composite liner profile will collect all the seepage generated from the landfill operation and direct it to the collection sumps, preventing any leakage of leachate to the receiving environment.
The landfill site is comprised of four different cells with two leachate collection sumps. Each sump has an automated pump with hybrid system that runs with diesel and solar.
The pumps transfer leachate generated within the cells to a separate leachate pond located near KSOC pit. This pond has the capacity to hold up to five million litres of leachate and acts as an evaporation pond where the leachate will dry out.