The U.S. Mine Safety and Health Administration has offered a quick update on its investigation of the Upper Big Branch Mine Disaster, posting the following highlights to its Web site:

— To date, 197 interviews have been conducted, with approximately 50 more planned.

— Mapping teams have completed about 90 percent of the mine mapping. Once water is pumped from the headgate 22 section, the mapping crews will be able to complete the mapping. Pumping is likely to begin later this week.

— Investigation teams plan to revisit the longwall face to search for evidence that may be under sloughed or fallen material. The second remote control for the shearer has not been located, nor have any additional methane detectors been found.

— Testing continues on the handheld detectors that have been collected.

— To date, 260 pieces of evidence have been collected.

— Investigators have gathered 183 separate documents (not counting record books and individual data sheets obtained from the mine)

— MSHA investigators have taken more than 3,000 photographs.

— The flame and forces team continues to conduct its underground investigation.

— Electrical testing continues on electrical components of the longwall shearer and cable.

— Testing of 1,800 rock dust samples has been completed. Additional rock dust samples will be taken when the water is pumped from the headgate 22 and tailgate 22 sections.