Independent Review of MSHA's Actions at Crandall Canyon Mine

Research Engineer of the NIOSH Pittsburgh Research Laboratory, and an internationally
recognized expert on standing roof supports, for his recommendation for a support system.
Barczak recommended the use of Rocprops for the conditions encountered.
Billy Owens, District 9 Roof Control Branch Supervisor, had extensive experience in the use of
Rocprops. However, he stated that he was not consulted or involved in any way with the
support selection used during the rescue effort at the Crandall Canyon Mine. He further
stated that he had seen individual Rocprops dislodged as the result of a bounce at the
Aberdeen Mine. From this experience, he knew the importance of the wire ropes being
wrapped around the pillars or securely anchored by bolting to the roof. At Aberdeen, even
though individual Rocprops were dislodged, they were restrained from further movement
because both ends of the wire rope were secured. At Crandall Canyon, the wire ropes were
not anchored as they were at the Aberdeen Mine. Owens stated that the inby end of the wire
ropes could have been “bolted to the roof”.
During interviews, several of the MSHA inspectors who were monitoring the underground
work stated that they had concerns over the adequacy of the Rocprops providing protection
from a future bounce. They were confident in the Rocprop as vertical roof support, but
questioned its ability to withstand lateral forces resulting from a bounce. Inspectors stated
that they had seen Rocprops dislodged at the Aberdeen Mine. Allyn Davis, District 9
Manager, stated that he had heard that Rocprops had failed at Aberdeen Mine and that was
one of the reasons for requiring three wire ropes instead of one.
Several Rocprops were dislodged during the rescue effort by a shuttle car negotiating the
turn from the No. 1 entry into the belt entry. One inspector documented in his notes,
following a bounce that occurred on August 15 th , that it appeared the tops and bottoms of the
Rocprops had moved, and he questioned their ability to provide support. Another inspector
stated that he thought that the bottoms of some of the Rocprops in the No. 1 entry had been
pushed toward the center of the entry after material had accumulated behind the chain link
fencing that was attached behind the props. These inspectors also stated that their input was
never solicited in the decision to use or evaluation of Rocprops during the rescue effort.
One inspector stated that he was aware of an angled-base bracket that could be used with two
Rocprops to provide additional lateral support. He had observed this device at other mines
and was aware of its ability to withstand lateral forces. The base plate had two sockets for the
placement of the Rocprops, one near-vertical and one angled at approximately 60-degrees.
Two spikes, approximately two inches long, were welded to the bottom of the base plate to
penetrate the mine floor and resist movement. One Rocprop would be pressurized against
the roof, just off of vertical, and the second Rocprop would be pressurized between roof and
floor at an angle, which would wedge the support in tighter if lateral forces were exerted. The
photos below show the angled-base bracket and its installation at another mine.
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