Eye to the future as Lady Loretta winds down

Glencore’s Lady Loretta zinc mine is continuing to advance progressive rehabilitation work as the operation draws to a close. The Lady Loretta site, north of Mount Isa, is proposed to be used for native vegetation habitat as well as grazing land after the scheduled end of mine life in 2025. A key part of the rehabilitation process is the construction of a modern engineered waste rock emplacement facility, which has been in the works since 2012. Its purpose is to manage reactive potential acid-forming rock and mineral waste, which is produced by the mining operations. Lady Loretta senior environmental advisor Joe Kaspar said the facility had been constructed with a low permeability foundation and drainage infrastructure that directed contaminated water (including the acid mine drainage), to a lined containment dam. “Additionally, upstream of the facility, drains have been constructed to divert clean water away from the facility as much as possible to prevent the unnecessary contamination of clean water,” he said. “Further, in 2022 we consolidated historic acid-forming waste stockpiles which means that only one waste rock emplacement facility will require rehabilitation. “Current upgrades to the emplacement facility have also made the progressive installation of a permanent cover system possible. “An updated closure options analysis was also recently undertaken for the waste rock emplacement, and included a detailed analysis of the various options to determine the optimal final landform cover and was supported by findings from studies undertaken at our other operations.” He said a bituminous geomembrane (BGM) cover was determined to be preferred for the crest, to provide chemical and physical stabilisation of the waste material in the storage facility. Glencore’s annual report, released this month, showed a drop in zinc production across its Australian operations to 564,000 tonnes in 2022. This was 45,400 tonnes (7 per cent) lower than 2021, mostly related to lower volume and grade at Lady Loretta, reflecting reserves depletion as the mine approaches end of life. Lead production of 165,900 tonnes was 22,200 tonnes (12 per cent) down on 2021, for the same reasons. IMAGE at top of page: The waste rock emplacement at Glencore's Lady Loretta mine. The pink colouring on this aerial orthophoto shows the form of the Waste Rock Emplacement as of October 2021. The yellow colouring here shows the new waste rock emplacement formation that is being shaped in 2023.

Eye to the future as Lady Loretta winds down

Industry Queensland

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