From the last company update, investigation teams comprising of government and Massey Energy specialists are continuing to re-establish power underground.

Teams are also continuing track rehabilitation, along with mapping, while some photographs were recently taken at undisclosed locations in the mine.

Company board members are not typically part of such efforts, but Massey chief operating officer Chris Adkins led company teams there last month according to Associated Press.

He reportedly became a certified mine rescue team member in late May.

Massey is challenging a US Mine Safety and Health Administration order limiting the scope of its permitted investigation activity.

The company said the MSHA order prohibited its internal investigators from utilizing “basic investigative tools” including cameras, electronic mapping and coal dust analysis.

The cause of the disaster is not yet known but government officials suspect methane and coal dust fuelled the explosion due to its magnitude.