MSHA - Directorate of Technical Support A Troubleshooting Guide for
Roof Support Systems


Fully Grouted Bolts

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NO SHOW OF GROUT

Possible Cause Solution
B.7 Hole Too Long Hole length should be 1" longer than the bolt length
B.8 Hole Diameter Too Large Replace bits
B.9 Cracks In Roof Increase the grout volume to make up for lost grout
B.3 Improper Grout Cartridge Follow manufacturer's recommendation for the grout
B.4 Improper Hole-Deformed Bar Size Do not exceed the manufacturer's recommended grout annulus

NOTCHED BOLT BREAKS WHEN STRAIGHTENED

Possible Cause Solution
B.12 Excessive Bolt Bending Instruct operator not to bend bolts more than 60 degrees and never more than 90 degrees
B.2 Defective Bolts Replace bolts

POOR ANCHORAGE

Possible Cause Solution
B.4 Improper Hole/Deformed Bar Size Do not exceed the manufacturer's grout annulus
B.5 Improper Mixing Instruct operator in proper installation procedure
B.3 Improper Grout Cartridge Follow the grout manufacturer's recommendations
B.1 Defective Grout Replace grout
B.15 Smooth Hole Change bits or vary the drilling parameters

GROUT CARTRIDGE HARD

Possible Cause Solution
B.16 Shelf Life Exceeded Replace grout
B.17 Storage Temperature Too Hot Move grout to a cooler location and contact manufacturer to evaluate grout before using
B.1 Defective Grout Replace grout

BOLT HEAD HOT DURING MIXING

Possible Cause Solution
B.18 Bolter On Drilling Settings Instruct operator to switch the settings for installation
B.11 Excessive Thrust During Mixing Reset bolter thrust and instruct the operator in the proper installation procedure

GROUT WILL NOT SET

Possible Cause Solution
B.4 Improper Hole/Deformed Bar Size Do not exceed manufacturer's recommended grout annulus
B.5 Improper Mixing Instruct operator in proper installation procedure
B.6 Temperature Too Cold Pre-warm cartridges prior to use or increase mix time
B.1 Defective Grout Replace grout

BOLTING MACHINE STALLS DURING MIXING

Possible Cause Solution
B.10 Excessive Rotation During Insertion Instruct operator to limit rotation during insertion
B.6 Temperature Too Hot Use a slower curing grout
B.5 Improper Mixing Instruct operator in proper installation procedure

BOLT BREAKS ON INSTALLATION

Possible Cause Solution
B.10 Excessive Rotation During Insertion Instruct operator to limit rotation during insertion or use slower curing grout
B.2 Defective Bolt Replace bolts
B.6 Temperature Too Hot Use slower curing grout
B.5 Improper Mixing Instruct operator in proper installation procedure

BOLT CANNOT BE TOTALLY INSERTED

Possible Cause Solution
B.10 Excess Rotation During Insertion Instruct operator to limit rotation during insertion
B.7 Hole Too Short Hole length should be 1" longer than the bolt length
B.16 Shelf Life Exceeded Replace grout
B.6 Temperature Too Hot Limit rotation during insertion or use slower setting grout
B.6 Temperature Too Cold Pre-warm cartridges prior to use
B.8 Hole Diameter Too Small Replace bits
B.14 Crooked Hole Instruct operator in proper drill alignment while drilling
B.1 Defective Grout Replace grout

HEAD ROTATES DURING TORQUE TEST

Possible Cause Solution
B.13 Excessive Torque Applied Apply no more than 150 ft.-lbs.
B.4 Improper Hole-Deformed Bar Size Do not exceed manufacturer's recommended grout annulus
B.5 Improper Mixing Instruct operator in proper installation procedure
B.6 Temperature Too Cold Pre-warm cartridges prior to use or increase mix time
B.8 Hole Diameter Too Large Replace bits
B.3 Improper Grout Cartridge Follow manufacturer's recommendations for grout cartridge
B.16 Shelf Life Exceeded Replace grout cartridge
B.1 Defective Grout Replace grout cartridge