The Aboriginal elder who signed off on landmark agreements with BHP that underpin the company’s iron ore operations has lashed out at the mining giant for taking five months and counting to investigate the cause of damage to a culturally important cave.

The blast from Banjima elder Slim Parker comes as Indigenous leaders set the scene for a bitter showdown with the resources sector and the West Australian government over whether they should have a veto over mining development in the minerals-rich state.