** Shares of Australia's Mineral Resources MIN.AX fall 12.6% to A$21.72, set for their weakest trading session since February 19, if losses hold

** The lithium miner says it has temporarily paused haulage from its Onslow Iron project in Western Australia following a road train accident earlier this week

** Delays in ramping up Onslow project and increased development costs have raised concerns about the company's operational efficiency and future profitability

** Says haulage is continuing through contractor vehicles using alternative routes, while the cause of the incident is under internal investigation, the miner said

** Stock down 31.2% YTD

(Reporting by Rishav Chatterjee in Bengaluru)

((Rishav.Chatterjee@thomsonreuters.com;))