It has been another tough session for 29Metals Ltd (ASX: 29M) shares.

At one stage today, the ASX All Ords stock was down as much as 36% to 54 cents.

The copper miner's shares have recovered a touch since then but remain down 25% to 40.5 cents in afternoon trade.

This latest decline means that 29Metals shares are now down 65% over the last 12 months.

Investors have been heading to the exits on Tuesday after the company revealed that it has suspended operations at Capricorn Copper.

This is a big blow given that the company has been working very hard to restart production at Capricorn Copper following extreme weather a year ago.

According to the release, the ASX All Ords stock made the move following an extended period of rainfall between late January and mid-March. This rainfall resulted in a steady accumulation of water in regulated structures on site to levels now similar to those following the March 2023 extreme weather event.

Management advised that with water at these levels, the dewatering of Esperanza South underground mine (ESS) cannot continue which, in turn, delays the restart of mining as part of the Capricorn Copper Recovery Plan.

The ASX All Ords stock's managing director and CEO, Peter Albert, said:

The decision to suspend operations has not been taken lightly, particularly because of the impact it will have on our team at Capricorn Copper who have worked tirelessly following the extreme weather event in March 2023, as well as the local community, our contractors, and the businesses across the region and the state of Queensland that support the site.

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.

As things stand, the duration of the suspension is unknown. It will be dependent on a number of factors, including reducing the water levels held on site and securing the regulatory approvals required to set Capricorn Copper on a sustainable footing.