(a) When rock bolts and accessories addressed in ASTM F432-83,
"Standard Specification for Roof and Rock Bolts and Accessories", are used
for ground support, the mine operator shall--
(1) Obtain a manufacturer's certification that the
material was manufactured and tested in accordance with the specifications of
ASTM F432-83; and,
(2) Make this certification available to an authorized
representative of the Secretary.
(b) Fixtures and accessories not addressed in ASTM F432-83 may be
used for ground support provided they--
(1) Have been successful in supporting the ground in an
area with similar strata, opening dimensions and ground stresses in any mine;
or
(2) Have been tested and shown to be effective in
supporting ground in an area of the affected mine which has similar strata,
opening dimensions, and ground stresses as the area where the fixtures are
expected to be used. During the test process, access to the test area shall
be limited to persons necessary to conduct the test.
(c) Bearing plates shall be used with fixtures when necessary for
effective ground support.
(d) The diameter of finishing bits shall be within a tolerance of
plus or minus 0.030 inch of the manufacturer's recommended hole diameter for
the anchor used. When separate finishing bits are used, they shall be
distinguishable from other bits.
(e) Damaged or deteriorated cartridges of grouting material shall not
be used.
(f) When rock bolts tensioned by torquing are used as a means of
ground support,
(1) Selected tension level shall be--
(i) At least 50 percent of either the yield point of the
bolt or anchorage capacity of the rock, whichever is less; and
(ii) No greater than the yield point of the bolt or
anchorage capacity of the rock.
(2) The torque of the first bolt, every tenth bolt, and
the last bolt installed in each work area during the shift shall be
accurately determined immediately after installation. If the torque of any
fixture tested does not fall within the installation torque range, corrective
action shall be taken.
(g) When grouted fixtures can be tested by applying torque, the first
fixture installed in each work place shall be tested to withstand 150
foot-pounds of torque. Should it rotate in the hole, a second fixture shall
be tested in the same manner. If the second fixture also turns, corrective
action shall be taken.
(h) When other tensioned and nontensioned fixtures are used, test
methods shall be established and used to verify their effectiveness.
(i) The mine operator shall certify that tests were conducted and
make the certification available to an authorized representative of the
Secretary.
[51 FR 36198, Oct. 8, 1986, as amended at 51 FR 36804, Oct. 16, 1986]
