Department of Justice serves subpoenas to Pebble mine developer and former chief executive Published February 5 Share on Facebook Print article The U.S. Department of Justice has issued a grand jury subpoena to the developer of the controversial proposed Pebble mine and the company’s former chief executive as part of an investigation involving already-disclosed private conversations about the project, according to a statement from the project’s parent company. The Pebble Limited Partnership and its former CEO, Tom Collier, have each been served with a subpoena issued by the U.S. Attorney’s Office for the District of Alaska, according to an online statement from Northern Dynasty Minerals, Pebble’s parent company on Friday.