Bootu Creek Mine operators plead guilty after Craig Butler’s death

Workers watched helplessly as a beloved supervisor tried to flee as 48,000 cubic metres of rock fell down in a ‘catastrophic’ wall failure. Now the mine operator has pleaded guilty to its role in the workplace tragedy.

A Territory mine owner risked the lives of its workers by allowing them to enter an ‘aggressively’ designed open-cut pit, despite warning signs in the hours leading up to a ‘catastrophic’ wall failure.

Four years ago, Bootu Creek Mine workers were forced to watch helplessly as a beloved supervisor tried to flee a tsunami of 48,000 cubic metres of rock, mud and dirt during a horror mine incident.

Darwin Local Court heard 59-year-old Craig Butler was engulfed by debris during a fatal worksite incident at the OM Manganese-owned mine, 110km north of Tennant Creek on August 24, 2019.

On Monday, OM Manganese pleaded guilty to failing to comply with its workplace safety duty and exposing the nine workers in the Tourag pit to the risk of death or serious injury.

Craig Butler, 59, was buried alive after a wall collapsed at a Territory mine site.

The court heard workers raised the alarm over dangerous conditions in the pit days before the catastrophic slip, including reporting rock tumbling down the slope and catch berms starting to lose structure, crack and give way.

WorkSafe NT barrister Duncan McConnel SC said the company had faced a balancing act when designing the ramps and walls of the nearly 100m deep pit — choosing between “economic viability” and worker safety — and had gone for an “aggressive” strategy.

“A steeper pit design has a commercial benefit to a mining company … (and a) heightened prospect of pit slope failure,” Mr McConnel said.

He said the mine had a “batter angle” of 60 degrees, five degrees steeper than an engineer consultant’s recommendation, and did not implement expert advice for additional measures to detect early signs of slope movement.

Mr McConnell said eight months before Mr Butler’s death there was another major slide in the Tourag pit, three months before there was a slide in part of the mine, and just days before, monitoring data showed “significant” movement on the unstable slope.

A different pit wall collapse at Bootu Creek mine in the months prior to Mr Butler’s death.

“The pit should have been closed and additional monitoring measures put in place to ascertain the extent of movement of the hanging wall before work could safely resume,” Mr McConnel said.

Instead, the mining firm allowed Carl Barber, Hung Nguyen, Justice Carew, Leslie Clarke, Simon Galway, Darren McMahon, Brenda Perez and Gina Rata alongside supervisor Mr Butler to enter the pit on August 24, 2019.

The court heard Mr Butler and chief operations officer Trevor Cook went into the pit after reports of rock movement, but concluded it was not an early sign of danger.

But soon after Mr Cook left the pit, miners were left to watch in horror as a section of the pit wall 94m above the ground began to fail. 

Mr Butler started to run but was “engulfed” in 48,000 cubic metres of rock, with an 80m wide slurry of deep mud and debris narrowly avoiding two other workers.

It took 11 days for his body to be recovered.

Bootu Creek pit wall image attached. To be credited to the Department of Primary Industry and Resources (DPIR),

Mr McConnel said it was a “systemic failing” by OMM to manage the “ever present risk of pit slope failure”.

A statement from the mining firm said Mr Butler’s death “acted as a catalyst” for an overhaul of mine safety and operations.

“It should not have taken that catastrophic incident for the company to implement best practice standards,” it said.

“From the bottom of our hearts we are very sorry and we will never let this happen again.

“(But) an apology does not make up for our failures to Craig.”

Bootu Creek Mine operator OM Manganese representative Andre de Villiers (left) speaks with lawyer James Stuchbery outside the Darwin Local Court on Monday after the company pleaded guilty to failing to comply with a health and safety duty following a fatal pit wall collapse in 2019. Picture: Jason Walls

Barrister Mary Chalmers SC said the company now had the “gold standard” of safety measures, while a memorial to Mr Butler remained on site “as a daily visual reminder” of the tragedy.

Ms Chalmers argued the warning signs in the days and hours leading up to the collapse were not “ignored”, and it was unfair to claim the “catastrophic” incident was foreseeable.

Judge Thomasin Opie adjourned the matter for sentence on October 11.