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ROOF BOLTER NOISE SOURCE IDENTIFICATION PROJECT. ROOF BOLTER TEAM. FIELD STUDY AREAS. SINGLE and TWIN HEAD BOLTERS COAL and METAL/NONMETAL MINES DRY DUST COLLECTION and WET DRILLING FLETCHER, FMC, JOY, LONG-AIRDOX, EIMCO
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FIELD STUDY AREAS • SINGLE and TWIN HEAD BOLTERS • COAL and METAL/NONMETAL MINES • DRY DUST COLLECTION and WET DRILLING • FLETCHER, FMC, JOY, LONG-AIRDOX, EIMCO • SANDSTONE, SHALE, LIMESTONE, TRONA, VARIOUS LAMINATES • DRILL BITS (CARBIDE & CERAMIC) and DRILL STEEL (ROUND, HEX & CONSTRAINED LAYER DAMPING) • INITIAL and FOLLOW-UP SURVEYS (STRAPS, CHANNELS, WORN HEADS, WATER BOXES)
TWIN HEAD ROOF BOLTER Q-300 RESULTS WET DRILLING -vs- DRY DRILLING SAME SEAM/SAME GEOLOGY/SAME HEIGHT ISLAND CREEK 003 Right Side ISLAND CREEK 003 Left Side CONSOL 005/006 Right Side CONSOL 005/006 Left Side * Worked as Cont. Miner Operator for 2 hours.
Noise Generation Sources Drilling Holes (2 - 4k Hz range) Intentionally Penetrating Roof Straps (14 Gauge) Accidental Metal to Metal contact while drilling, (Channels & 14 Gauge Straps) Vacuum at the Drill Pot without Drill Steel Inserted (Drill Pot Whistle in extreme situations) Dust Collection Systems and Hydraulic Motors Miscellaneous: Supply Loading and Unloading, Unstopping Plugged Steel, etc. Background (Cont. Miner, Cont. Haulage, etc.) MANTRIPS
TRAINING/WORK PRACTICES • TRAIN ROOF BOLTER OPERATORS IN “NOISE REDUCTION TECHNIQUES” - • 1- Align Hole/Drill Straight Hole = 3-10 dBA drop • 2- Minimize Crowding Steel at End of Drill Cycle (last 3 seconds of cycle = 3-5 dBA increase) • 3- Minimize Metal to Metal Contacts (Hammering Drill Steel, Dropping Materials, Penetrating Straps,etc.) • 4- Emphasis Identification/Repair of Worn Equip. (Bits,Steel,Drill Pots,Chuck Inserts, etc.) • CUT OFF MACHINE WHEN NOT IN USE - if cold, put on a jacket, DON’T use machine as heater
ROOF BOLTER MAINTENANCE • INCORPORATE A NOISE CHECK LIST WITH THE ONSHIFT EXAM FOR DUST CONTROL PARAMETERS (LOOK/LISTEN FOR DAMAGED MUFFLERS, POT WHISTLES, BENT LEVELLING ARMS, WORN HEADS, LOOSE CHUCK INSERTS, BENT STEEL, etc.) • MAINTAIN PROPER TRAM CHAIN TENSION • TIGHTEN ATRS PADS (LOOSE PADS CREATE NOISE DURING TRAMMING) • MAINTAIN MANUFACTURER’S SETTINGS ON *ROTATION SPEED AND THRUST *NIOSH has conducted test comparing different rotational speeds
RECOMMENDEDNOISE CONTROLS • USE *DRILL STEEL THAT REDUCES SIDE HOLE RUBBING (NOT BENT OR DAMAGED) AND USE STARTER STEEL IF A STAIGHT HOLE CAN NOT BE DRILLED WITH ONE PIECE STEEL (STARTER STEEL HELPS CONTROL ALIGNMENT - MINIMIZING SIDE HOLE RUBBING) • * NIOSH has conducted comparisons of various drill steels and drill bits • USE SHARP *DRILL BITS TO REDUCE LATERAL DRIFT OF THE HOLE (CURVED HOLE),SIDE HOLE RUBBING AND DRILLING TIME (LENGTH OF EXPOSURE) • * NIOSH has conducted comparisons of various drill steels and drill bits
RECOMMENDED NOISE CONTROLS • USE THE RECOMMENDED MUFFLER AND INSTALL A WATER BOX AS A BACKUP SYSTEM (Approx. 1 dBA Drop at Head & 3-8 dBA at Bumper - Surveyed both the Baffle System and the Bubble Flow Through System) • USE DAMPING MATERIALS IN STORAGE AREAS, ON TOP OF THE MACHINE AND SEPARATIONS IN THE TOOL TRAY (FOR DRILL STEEL, TORQUE WRENCH, BOLT SUPPLIES)
RECOMMENDEDNOISE CONTROLS • REDUCE MANTRIP NOISE (UNCOVERED, DIESEL, TRACK TRIPS WERE FOUND TO BE THE HIGHEST EXPOSURES - these cases between 1/3 and 1/2 of Dose was accumulated on the Mantrips) • IF YOU HAVE TRIED EVERYTHING ELSE AND • STILL HAVE A NOISE PROBLEM WITH ROOF BOLTER - INSTALL A WET DRILLING SYSTEM (WATER WORKS AS LUBRICANT MINIMIZING THE EFFECTS OF SIDE HOLE RUBBING) (3 - 10 dBA Drop)
CONTROLS UNDER STUDY • STRAPS AND CHANNELS (WAYS TO DAMPEN) - (Currently working with Shamrock Coal - April) • MANTRIP NOISE (esp. DIESEL,TRACK,UNCOVER) - (Currently working with Cave Spur - March) • CONTINUE WITH OUR FOLLOW-UP SURVEYS (STRAPS, MANTRIPS, WORN HEAD)- (Currently working with Coastal Coal in identifying bolter maintenance problems that result in noise sources - 2nd follow-up survey in April) • MORE “TAKING CARE OF THE DRILL POT” - (FEEDBACK SYSTEM Monterey - March, HOTL, THICK WALL STEEL Coastal Wet Drilling- March, MIST DRILLING, DRILL STEEL GUIDE CLAMP)