No, they're not. They've been bought out by other mining companies, which bought those out.  Those giant mining conglomerates have teams of lawyers that work day and night to try to ensure that the modern conglomerates aren't responsible for the activities of their forebears.  For instance, the San Juan Corporation is the current owner of the Gold King mine.  Yet the taxpayers are responsible for that cleanup, not the company that bought the company that bought the company that mined the Gold King site.