The ETS (72 FR 28796) was initially issued May 22 of this year, and the extension to the comment period will close on January 18.

"[This] will provide commenters time to review and provide comments on the US Army Corps of Engineers' draft report, CFD [Computational Fluid Dynamics] Study and Structural Analysis of the Sago Mine Accident," MSHA noted.

The report, it explained, reviews preliminary results of the USACE study performed under contract for MSHA's Technical Support Directorate, also known as Technical Support.

"The USACE conducted research and testing from August 2006 to April 2007. The USACE provided a draft of the report of their findings to Technical Support in May of 2007," the agency said.

"The report details the USACE's efforts to mathematically model the methane explosion at the Sago Mine and potentially establish the seal overpressures."

MSHA noted the document was not finalised.

Additionally, the agency will hold a public hearing, in light of the new developments, on January 15 at its headquarters in Arlington, Virginia. The meeting will begin at 9am, and those who wish to speak should provide five days notice to the agency.

For those who still wish to make a statement regarding the ETS, only comments which encompass the report as it relates to the ETS' regulatory provisions will be accepted.

May's ETS, only the fourth in 30 years, included proposals for the improvement of the design, construction, maintenance and repair of seals and new requisites for the sampling of air behind seals and keeping it at controlled levels.

For the complete seals ETS, visit www.msha.gov/Seals/SealsSingleSource2007.asp.

The Army Corps report can be viewed at http://www.msha.gov/CFDSagoReport.pdf.