WASHINGTON — The House Education and Labor Committee subpoenaed Labor Secretary Elaine Chao Monday, seeking key internal communications documents for its investigation into the Crandall Canyon Mine accident.

Committee Chairman George Miller, D-Calif., requested numerous documents just after the Aug. 6 accident that killed six miners and a later incident that killed three rescue workers, but the committee has not received them. He used the subpoena "as a last resort," according to the committee, which released a copy of it late Monday.

Communications director Tom Kiley said the department has produced some of the requested documents, but it still is missing communications records.

"Those communications are vital to the committee's investigation," Kiley said. "The committee would prefer to work cooperatively with the Labor Department to secure this information, but by failing to cooperate with us, the Labor Department has left us no choice but to subpoena the information.

"The committee intends to conduct a comprehensive, independent investigation of the tragedy so that we can help learn what steps we can take to prevent future tragedies."

Miller's subpoena demands any communication between the department and Murray Energy, including CEO Bob Murray, as well as internal department communication and anything with other federal agencies or with the committee's investigation into the accident.

It specifically asks for all communication from Jan. 29, 2001, through today between Murray and Chao, Acting Deputy Secretary of Labor Howard Radzely, Acting Solicitor of Labor Jonathan Snare or Mine Safety and Health Administration head Richard Stickler.

Chao has until Oct. 9 to produce the documents. The committee — of which Rep. Rob Bishop, R-Utah, is a member — has a hearing planned for Oct. 3 to examine what happened at the mine, but the investigation does not stop with that hearing, according to the committee. A thorough investigation will take place, which can include additional hearings if needed, according to the committee.

Interviews have taken place at the MSHA office in Denver, and investigators from the committee were at the mine site from Aug. 20 through Aug. 25, according to the committee.

Meanwhile the Senate Health, Education, Labor and Pensions Committee has a hearing planned for Oct. 2. Chairman Edward Kennedy, D-Mass., also has requested numerous documents from the department. Kennedy, Sen. Orrin Hatch, R-Utah, and other senators wrote Labor Department Inspector General Gordon Heddell last week asking for an expedited review.