Operations at the Capricorn copper mine, in Queensland, will be suspended and the headcount of the mine will be significantly reduced, ASX-listed 29Metals said on Tuesday.

The decision comes as a response to an extended period of rainfall spanning late January to mid-March, exacerbated by successive tropical cyclones in the region.

The prolonged precipitation has led to a gradual build-up of water in regulated structures on-site, reaching levels akin to those witnessed during the extreme weather event of March last year.

The accumulation hampered the dewatering of Esperanza South underground mine (ESS), consequently stalling the planned resumption of mining activities at ESS as outlined in the Capricorn Copper recovery plan.

“Unfortunately, the combination of elevated water levels at the beginning of the wet season (as a result of the event a year ago) and the sustained rainfall since late January this year has more than offset our successes reducing water levels through mechanical evaporation and authorised releases of treated water within prescribed limits,” said outgoing MD and CEO Peter Albert.

He stated that the duration of the suspension would depend on several factors, including reducing water levels held on site and securing regulatory approvals required to set Capricorn Copper on a sustainable footing.

“29Metals’ objective will be to ensure the period of suspension is as short as possible. Planning for the restart will start almost immediately and we will use this pause in operations to build back stronger and set Capricorn Copper up for the future,” said Albert.

During the suspension, 29Metals will undertake targeted exploration activity to test new mineralised zones identified last year east of the Mammoth orebody and evaluate the potential to produce a cobalt byproduct.

Capricorn Copper has a substantial mineral endowment of nearly 65-million tonnes in mineral resources, 19-million tonnes in ore reserves at 1.7% copper, supporting an estimated mine life of at least ten years.

Last year, the Queensland government conferred ‘prescribed project’ status on Capricorn Copper, in a bid to support recovery activities following the extreme weather events of last March.

The company in July launched Phase 1 of the restart operations, which saw the restart of mining activities at the Mammoth and Greenstone deposits. Phase 2 of the restart strategy would have focused on the ESS operations, with dewatering and rehabilitation efforts at the mine to be undertaken during Phase 1 to enable full recovery operations during Phase 2.