Hundreds of BHP workers look set to walk off the job at Port Hedland next week in what would be the Western Australian mining industry's most significant industrial action for a quarter of a century.It comes after talks between the mining giant and unions aimed at improving workers' pay and conditions failed to reach a result.The unions, which represent almost 400 workers at the mining giant's Port Hedland operations, said they had given BHP the required five days' notice to strike.The dispute at the port, Australia's largest export facility, stands to threaten $120 million in revenue a day for the company and $6.85m in royalty payments to the WA government, according to the latest available data.Operations at BHP's iron ore port in Port Hedland (ABC News: Charlie Mills)The combined ports unions — the Western Mine Worker's Alliance, the Australian Manufacturing Worker's Union, and the Electrical Trades Union — indicated they would down tools next Thursday for eight hours.The latest round of negotiations between unions and the mining giant wrapped up on Tuesday without a definitive outcome.ETU WA Secretary Adam Woodage said BHP had failed to negotiate in good faith."This is nobody's preferred way forward, but when it is our only way forward we will take it," he said."I hope this sharpens the minds of BHP workers, and shareholders, on the importance of negotiating a fair, safe and productive iron ore industry."The stoppage will impact the miner's facilities at the bulk export terminal in Port Hedland. (ABC Pilbara: Kimberley Putland)BHP previously said its focus remained on securing an outcome that maintained "industry leading pay and conditions" for its workforce."In the event of union disruption at our sites, we have strong contingency plans in place to protect our people and ensure safe, reliable operations can continue," a spokesperson said.Industrial landscape shiftingUnions have steadily been regaining their foothold in the Pilbara since the Albanese government's changes to industrial relations in 2022.It has sparked criticism from mining companies and Western Australia's Chamber of Minerals and Energy, who have argued any increase in industrial activity across the region threatened the national economy.But the workers were backed by WA Premier Roger Cook and Federal Resources Minister Madeline King, who criticised the industry's response."It seems to be a particular aversion to modern unionism in the Pilbara and it's difficult to understand sometimes," Ms King said last month."It is hard sometimes to understand why they object to EBA's in the Pilbara, but nonetheless, that is a matter for BHP and union representatives to work out."Workers at the miner's South Flank and Mining Area C endorsed a new bargaining agreement last week, covering more than 1,800 staff, despite unions campaigning against it.The agreement was endorsed by 58 per cent of the vote.