SANTIAGO (Reuters) - A strike at mining giant BHP's huge Escondida mine in Chile entered its third day on Thursday, bolstering global copper prices as an ongoing standoff between the company and workers starts to spread worries about supply of the red metal.

BHP and the worker union held an initial meeting on Wednesday in a bid to defuse the strike but failed to make a breakthrough that would allow the restart of formal talks, with miners digging in as they seek a larger share of profits.

Benchmark three-month copper on the London Metal Exchange was up over 2.2% to $9,169 per metric ton on Thursday, and various mining shares like Rio Tinto, Southern Copper and Freeport-McMoRan ( FCX ) rose as well.

Escondida is the world's largest copper mine, accounting for nearly 5% of global supply in 2023, and the union on strike has in past years forced the firm to halt operations and declare force majeure, meaning it can't fulfill its contracts.

On Wednesday, BHP said operations were continuing under a contingency plan while the union said the strike was keeping the Los Colorados concentration and electrowinning plants offline.

The two sides have both signaled a willingness to returning to formal talks but remain at loggerheads over the conditions. BHP had asked the union to pause its strike to resume negotiations, a demand the union refused.

Hundreds of workers have also set up camp at Puerto Coloso, BHP's exclusive port, which also houses its desalination plants.