Mining and Ground Control Engineers at WIPP discovered Jan. 15 that a portion of the ceiling in the Panel 3 access drift had fallen in a restricted access area.
The roof fall was discovered during routine ground control and bulkhead inspections conducted by WIPP geotechnical staff, and the section that fell was estimated to be approximately 8’ long by 8’wide and 24” thick. Access to this area has been restricted since November 2014 due to ground control concerns, and no WIPP personnel were present at the time of the fall. The area where the fall occurred is also known to contain low levels of radioactive contamination as a result of the Feb. 14, 2014, radiological release.
This event highlights the need to continue prioritizing roof bolting and ground control in both the contaminated and uncontaminated areas of the WIPP underground facility in order to ensure safety and habitability in the underground. This area was originally scheduled to be re-bolted during the annual outage in February 2014. The outage was suspended as a result of the fire and radiological incidents, and the bolting was not performed.
WIPP geotechnical inspections conducted in November 2014 identified seven areas in the underground facility where access was restricted due to significant bolt loss. Barriers and signs were installed to identify these restricted areas, and workers are reminded of these restrictions as part of daily pre-job briefings before entering the underground facility. The area where the roof fall occurred was one of the seven locations previously identified.
Roof bolting resumed in mid-November of 2014, and ground control engineers have indicated that the area where the roof fall occurred can be re-bolted and recovered. The map to the right identifies the areas where progress has been made to catch up on the backlog of ground control and maintenance activities, as well as areas where access is restricted until bolting activities can be completed.