JM Steel

Combination Bolt

JENNMAR offers the industry’s most proven combination bolt system in the mining industry. The Combination Bolt is a two-piece bolt. The upper piece, available in additional combinations, consists of JENNMAR’s exclusive J-BAR® for better mixing, stronger threads, and greater anchorage capacity. The lower piece (a headed smooth bar) is connected to the top bolt by a coupler. The Combination Bolt provides ultimate tension in weak strata. The top portion (J-BAR) is encapsulated with resin, while the lower anchor is tensioned to the roof with our bearing plate.

Advantages

• The ultimate tension resin system for all seam heights

• No need to bend for insertion

• Proven Shear Pin system with coupler

• Proven usage in longwall headgate and tailgate entries as supplemental or primary support

• Prevent roof sag and lateral roof movement