A secretive facility more than a century old has been approved for expansion, to meet increased demand from Australia's mining industry.

The Bajool Explosives Reserve, one of four state government-owned reserves, has expanded by more than 600 hectares since 2022 and will soon begin increasing its output.

"It's quite an important reserve for not just Queensland, but for the rest of Australia as well," said Rob White, Resources Safety and Health Queensland (RSHQ) explosives director.

"It's the gateway down to New South Wales and across to Western Australia as well."

The site, about 30 kilometres south of Rockhampton in Central Queensland, is used to store, manufacture and dispose of explosives mostly for the mining industry.

Mr White confirmed among the materials stored at the high-security centre, were tonnes of ammonium nitrate, which can be made into ammonium nitrate emulsion, to be sent to mines around the country.

The exact amount of explosives and the security measures around them could not be confirmed, due to commercial in confidence and security concerns.

The facility also provides space for items including seized illegal fireworks, out-of-date ammunition and flares, to be safely destroyed inside large incinerators.

"It's about safe and secure explosives [that are] heavily regulated and secure to the community," Mr White said.

With its proximity to the Rockhampton Port, also known as Port Alma, the country's highest-volume licensed explosives port, precise operations inside the Bajool reserve have long been shrouded in secrecy.

History and expansion plans

In addition to the Bajool site, the government has explosives reserves at White Rock near Cairns, Helidon near Brisbane and Brookhill near Townsville.

Bajool was originally gazetted for explosives purposes in the late 1800s and the site's first magazine, a structure designed to safely store or detonate explosives, was built in 1913.

In its infancy it was primarily used for the gold mine in Mount Morgan, about 60km away, and coal mine Blair Athol, more than 400km from the facility.

"Bajool has played an important part moving forward in history for the mining industry," Mr White said.

In 2022 the high-security site grew from 300 hectares to more than 900, using land to the north of the site to build more infrastructure.

As well as growing its physical size, in recent months it also received state government approval to increase operations.

It is the first major expansion of the reserve since it was established. 

Mr White said the need for expansion was driven by increasing demand from the mining industry.

"We realised a number of years ago that we were running at capacity," he said.

"We can now bring industry in very shortly to then [see] at least a prospective site for manufacture and storage of ammonia nitrate."

CQ University resources engineering lecturer Xiaohan Yang agreed demand for more mining explosives was increasing.

"The upgrade [seems to be] not just for immediate demand, for also for future planning," Dr Yang said.

"Because of the need for the critical minerals and also the strategy for critical minerals from the Queensland government," he said.

Initial work at the expanded section will start early next year and it is expected to be fully operational by 2030.

With roughly 120 employees on site usually, the reserve's upgrade was expected to create an extra 50 to 70 direct jobs once operational, Mr White said.

"Then it could be anything up to 120 or more indirect jobs within the logistics chain itself, [such as] truck drivers," he said.

The facility has also previously been touted by a group of Central Queensland councils as one of the reasons the region was suitable for increased Australian Defence Force (ADF) infrastructure.

Mr White said though the reserve had stored for the ADF during past exercises, its focus remained on the mining industry.