The union had earlier asked the company to negotiate by 10:00 a.m. local time but said in a statement later on Monday that it had begun preparing for a strike.
Pan Global’s subsidiary Minera Águilas has received the necessary permits to start its exploration campaign on the first two sections of the Águilas project.
EU antitrust regulators on Wednesday voiced concerns about German Wieland's bid for copper smelter Aurubis' flat-rolled products business, saying the deal may hurt competition.