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Of all the underground occupations, roof bolting is one of the most dangerous. The job is less routine than operating a continu- ous miner or a shuttle car. The miners are exposed to unsupported top, albeit at a dis- tance, and they have to work with a num- ber of components, including the drilling machine (roof bolter), drill steels and bits, resin cartridges, the bolts themselves and the bearing plates. When they encounter difficult conditions, such as poor roof geol- ogy or water (or both), the situation becomes risky for them and everyone else traveling under those supports. In addition to being an arduous task, roof bolting is often considered the slow point for contin- uous mining operations. Several of the suppliers who service this aspect of underground coal mining are looking at ways to improve safety as well as the performance of the ground control tools. Some changes include modifications to hardware as well as improvement for the tools and machines used to install these anchoring systems. While many of these improvements appear to be common sense approaches, the reality is that a substantial amount of R&D; has been invested in these advancements. At the end of the shift, the goal is to ade- quately support the top safely for the amount of time miners will be traveling beneath it. The object is to get it right the first time. These suppliers are working to make sure the miners reach those objectives. Jennmar Invests in R&D; While a family company, Jennmar's role in coal is global; it has developed and manufactured ground control products for more than 40 years. Its engineering staff has also been focusing strongly on R&D; and has recently unveiled several new products to its line. The first is the JM Cable Fully Grouted Cable Bolt (FGCB), which was developed by affiliate KMS (Keystone Mining Services) and Jennmar after compiling key customer input and extensive lab and field testing. Using the FGCB, a standard cable bolt can be fully encapsulated during installa- tion or post-installation with polyurethane, or PUR; when fully encapsulated, a cable bolt is better protected than a traditional bolt from corrosive elements potentially present in the mine roof, which could affect the bolt's structural properties, especially over prolonged periods of time. FGCB is available as a non-tensioned (FGNT) and INSTáL Tensionable Cable Bolt (CB) and (CC) models. "Although [it was] initially developed for corrosion protection, field trials demonstrated that the FGCB can act as a traditional PUR injectable bolt for strata stabilization," said Dr. John C. Stankus, KMS president; KMS is the Jennmar arm that oversees the research and develop- ment of new products. "The FGCB has proven to be a very versatile roof support system due to its ability to control many different ground conditions, from increasing the lifespan of standard cable- bolt supports in long-term main entry systems to stopping the ingress of water and allowing access to previously unattainable reserves." It is ideal for use in areas where a cable support is needed, including fractured and laminated conditions, outby/inby and in old works. It also can be applied in belt entries and for belt rehabilitations, for intersection support, at intersections for pillar recovery, in longwall recovery and setup entries, and in longwall headgate entries. Jennmar cited a case study with one of its U.S. customer mines where supplemental r o o f b o lt i n g B Y D O N N A S C H M I D T , F I E L D E D I T O R 54 www.coalage.com April 2014 Roof Bolting Tools The latest technology – and some long-recognized mainstays – for every operation's key locations A mine's initial support plan before revision. A close-up view of polyurethane injection. CA_pg54-59_V3_CA_pg46-47 4/14/14 1:27 PM Page 54