The early numbers are stacking up on a $150 million reopening of a disused stretch of South West railway as a key piece of WA’s lithium industry.

Laid more than a century ago to support the State’s timber industry, the 82km line between Bunbury and Greenbushes has not operated since 2000.

However, industry and government are mulling the idea of reopening the stretch of rail to carry the increased volumes of lithium concentrate flowing from the $800 million-plus expansion of Talison Lithium’s mine at Greenbushes to Kemerton, Bunbury and Kwinana.

The alternative, and Talison’s current plan, is to continue to haul the concentrate out of Greenbushes by road but with the number of road-train trips to and from the mine more than trebling to 200 a day.

For towns and residents along the route on South Western Highway, that would equate to a truck rattling by every eight minutes.

Advocates of the rail option, including Greens South West MLC Diane Evers, worry that the increased mine traffic would heighten safety risks on the mostly one-lane highway, which passes through towns including Balingup and Donnybrook.

Talison, rail operator Arc Infrastructure (formerly Brookfield Rail) and the Government’s South West Development Commission have co-operated on a pre-feasibility study that looked at the reopening as part of a broader regional lithium supply chain upgrade.

The line will not return to operation unless Arc can make money on it.

However, the study, which has been forwarded to the State Government, has bolstered the case for a reopening by suggesting that the Greenbushes rail option could be financially competitive with road haulage.

Any redevelopment would be dependent on government help to offset the expected $150 million bill to cover the line’s return to service.

The Federal Government’s Infrastructure Australia looms as one likely source of funds.

The study envisaged “end to end connectivity on the South West main railway corridor” for Greenbushes’ lithium with new infrastructure at multiple locations.

That new infrastructure would include loading facilities at Bunbury port, with the added aim of attracting other users along the Greenbushes to Bunbury route to improve the viability of the reopening.

There would also be new loading facilities at the Greenbushes mine, an upgrade to the rail line between Greenbushes and Picton, just outside of Bunbury, a connection into the Kemerton industrial estate to feed US group Albemarle’s proposed new lithium hydroxide processing plant and transfer facilities to a similar plant being built by Tianqi Lithium in Kwinana.

Arc and Talison are now waiting on Government support for a more detailed assessment of the rail option.

WA Regional Development Minister Alannah MacTiernan said the Government intended to meet Arc and Talison in the next few weeks “to see how we may chart a way forward”.

“We do think it’s an issue that needs to be taken seriously,” she said.

But the Government isn’t committing to any financial support, at least not yet.

“We have to look at what the industry responsibility is here,” Ms McTiernan said.

“At the end of the day ... we don’t build the rail lines for BHP and Rio.

“We are not necessarily taking responsibility for the funding but we are doing the work.”

sean.smith@wanews.com.au