Multinational mining giant Rio Tinto has been accused of "putting production over safety" at a Northern Territory mine site by the Australian Manufacturing Workers' Union (AMWU) and employees.

Key points: Rio Tinto has defended its safety record after the AMWU raised concerns

Rio Tinto has defended its safety record after the AMWU raised concerns Production at Gove Operations has ramped up 35 per cent in recent years, but workforce numbers have remained "relatively unchanged"

Production at Gove Operations has ramped up 35 per cent in recent years, but workforce numbers have remained "relatively unchanged" The safety claims coincide with the snap departure of general manager Linda Murry

Documents show production at Rio Tinto's Gove Operations in East Arnhem Land has been ramped up by 35 per cent in the past two years, which the union said had led to the company "cutting corners" with safety.

AMWU NT organiser Lloyd Pumpa said union members had been reporting a "steady decline" in safety standards at the site.

He said the union was also receiving a surge in membership numbers from Gove Operations, including from supervisory staff.

"That's not very usual … they're also very concerned at the way that senior management has been pressurising them to cut corners, increase production level targets and meet target levels that they think [are] unacceptable," he said.

One Rio Tinto employee at the mine, who could not be named due to the possibility of his employment being terminated, echoed the fears that compromises were being made on safety.

"I always worry about safety onsite," he said.

Rio Tinto have upped their Gove bauxite production and export levels significantly in recent years. ( ABC News: Zoe Walker )

"We've had a bad year.

"There's a pretty strong feeling that they put production over safety. Although they'll certainly tell you that they don't."

Despite the concerns, NT Worksafe said it had received just three incident reports from the mine during the past two years, including "a collision between a dump truck and a light vehicle" and "an electric shock while welding".

No injuries were reported.

Company defends safety record

In a statement, Rio Tinto confirmed the dump truck collision was "classified as a 'potential fatal injury' in accordance with our global health, safety and environment standards".

"Rio Tinto has a rigorous process in place to investigate any incidents that occur across its operations and has implemented the critical lessons learnt from this incident," the company said.

It also defended its handling of safety and said they took "any issues raised regarding the health and safety of our personnel seriously".

"Gove Operations has rigorous processes in place to manage health and safety and investigate and learn from any incidents that occur across its operations," it said.

Tight-lipped over boss's departure

The claims come as Rio Tinto remained tight-lipped over the reasons behind the snap departure of an executive from its East Arnhem Land operations last week.

The resignation of Linda Murry, the general manager of the Northern Territory's Gove Operations, was announced in just a two-line statement from the company.

Linda Murry, centre, made a snap departure from Rio Tinto last week. ( Source: Rio Tinto )

"Rio Tinto confirms that Linda Murry has resigned from her position," it said.

"Troy McNamara will act in the role until a permanent replacement is identified."

Worker and union sources have told the ABC they were questioning whether the end of Ms Murry's tenure, which started in late 2017, related to issues regarding safety at the remote site.

When asked to confirm or deny this, Rio Tinto did not directly respond and declined to comment further on Ms Murry's departure, and have reportedly not briefed employees further than the two lines sent to the ABC.

Production increased 35pc

A flyer handed out at a 2018 community meeting, shown to the ABC, said Gove Operations had reached a record production level of 12.5 million tonnes of bauxite mined for export in 2018, up 12 per cent from 2017.

On top of that, a 2017 annual report showed an enormous production increase of 23 per cent on the year prior, amounting to a total of a 35 per cent increased production over the past two years.

Despite the increase in production, Rio Tinto confirmed that during the past 12 months, "workforce numbers have remained relatively unchanged".

Gove refinery was mothballed in 2014, but Rio Tinto's mine operation is still running. ( ABC News: Matt Garrick )

"In 2018, Gove Operations' workforce consisted of approximately 300 employees and a further 150 contractors," the company said.

Most of these employees work at the operation's bauxite mine, while a handful of staff remained employed at East Arnhem Land's decommissioned alumina refinery.

Darryl Manderson lost his life in a workplace incident at Gove Operations in 2014. ( Source: Facebook )

During Mr Pumpa's most recent visit to Gove three weeks ago, he said Rio Tinto workers were reporting feeling "overarching … un-confidence in senior management in the way that they are pursuing these goals".

"We understand that people have to pursue targets and make the business profitable … [but] let's just bring it back a little bit and ensure that the safety levels are maintained," he said.

Safety has come into question at Rio Tinto's Gove Operations in the past.

The Gove refinery was the site of a fatal accident in 2014 when employee Darryl Manderson was crushed to death while completing maintenance work.

Another worker lost his life in a fatal fall at the site in 2007, when the refinery was operated by former owner Alcan.

Weipa boss to take over operations

Mr McNamara, currently the manager of Rio Tinto's Weipa operation in Far North Queensland, now steps into the difficult position of overseeing the dismantling of a nearly-50-year old alumina refinery.

The Gove refinery was mothballed in 2014 after a long, failed bid to pipe gas to the region to provide a cheaper fuel source to run the operation.

Protests were held in Gove in 2013 against the impending closure of the town's alumina refinery. ( ABC News: Matt Garrick )

More than 1,000 employees were made redundant, and the refinery was placed into "care and maintenance mode".

Last year, Ms Murry announced the refinery would never be reopened, sparking the beginning of a lengthy, costly and environmentally risky dismantling process.

Ms Murry was contacted for comment.