U.S. refiners and striking union workers are digging in for a protracted battle that could last through the spring. Even as the two sides returned to the bargaining table Wednesday for a new round of talks on salaries and safety, some refinery operators say they are training replacement employees to take over for union workers at their plants. A spokeswoman for Shell said discussions ended Wednesday with an agreement to resume talks next week. In a letter addressed to employees Tuesday, LyondellBasell Industries said it had filed a complaint with the National Labor Relations Board alleging the United Steelworkers has threatened and harassed people trying to cross picket lines. “We have been told of threats against returning employees, abusive language being used in texts and social media, and we have witnessed threatening behavior at the gates to the Houston Refinery as employees arrive for work,” the company said in […]