NT government-appointed independent monitor David Browne said while there had been a substantial improvement in the mine’s environmental performance over the last five years, there remained plenty of risks.
“A key issue for the site is managing the waste rock and tailings and the open pit in terms of the end of
mine life pit will be important,” he told reporters from News Limited.
“That and seepage from the tailing facility will always be issues that need to be managed at the site.”
The mine’s “stakeholders” had not understood the rocks they were mining and the risks of releasing acid and metals before they started, he said.
It was being managed better now with trials of geo-synthetic liner covers due to start, Mr Browne said.
Seepage from tailings has been blamed for elevated lead levels in fish in Barney Creek and dust at the mine’s crushing plant on the coast has contaminated local air and water.
In its’ latest report the Independent Monitor said notable improvements included:
• Improved handling and compaction of clays, significantly reducing the number of compaction tests not meeting the specification.
• Completing construction and commissioning of the western perimeter runoff dam (WPROD).
• Testing of tailings deposited at the tailings storage facility (TSF), which has confirmed the lack of oxidation of tailings.
• Improving groundwater monitoring at the McArthur River Mine and Bing Bong Loading Facility by installing new monitoring bores and loggers.
• Commissioning a new computerised network for monitoring and reporting of site water management operations in real time (e.g., pond water levels and water transfers).
• Successfully managing the high rainfall of January 2018 with no uncontrolled releases from any runoff dam or the TSF.
• Developing and implementing an Air Quality Management Plan for the mine site and Bing Bong Loading Facility.
• Refining monitoring sites for the Annual Marine Monitoring Program to better understand contaminants in the study area.
• Planting 84,000 seedlings in 2017, with nearly all grown in the onsite nursery.
• Successfully eradicating weed infestations of neem tree at Bing Bong Loading Facility and devil’s claw at the McArthur River floodplain.
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