The U.S. Department of Labor's Mine Safety and Health Administration (MSHA) has announced plans to hold a briefing on June 29 to share with the public information gathered during the investigation of the explosion at the Upper Big Branch Mine in Raleigh County, W.Va.

The briefing, which will be held at the National Mine Health and Safety Academy in Beckley, W.Va., will coincide with the one-year anniversary of the start of the underground investigation. “Although the underground investigation and interviews are still ongoing, MSHA investigators will be able to compile additional relevant evidence by June in order to provide a substantive presentation to the public,” according to a DOL press release.

MSHA has already met with the families of the victims and shared details of the investigation with them. Information has also been released via the agency's "Upper Big Branch Mine-South Massey Energy Co. Single Source Page" available at www.msha.gov.

During the June briefing, MSHA says it will provide an overview of the physical evidence gathered so far, as well as summaries of other evidence obtained by investigators. Due to the ongoing U.S. Department of Justice (DOJ) criminal investigation and requests by federal prosecutors to MSHA to limit the public release of evidence relevant to potential prosecutions, some information will not be disclosed to the public. The MSHA says that President Obama has instructed both agencies to conduct thorough investigations into the tragedy, and “to ensure that those responsible are brought to justice.”

"We take very seriously the need to keep the public informed as to what we're learning and when we're learning it," said Joseph A. Main, assistant secretary of labor for mine safety and health. "We also take seriously the efforts of the FBI and the U.S. attorney to bring to justice those who may have broken the law. Throughout this investigation, we've worked hard to balance those important goals."

MSHA indicated that it will continue to make publicly available relevant information that will not compromise its own investigation or the ongoing criminal investigation.