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 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)

ISLAND CREEK 003 Right Side TWIN HEAD ROOF BOLTER Q-300 RESULTS WET DRILLING -vs- DRY DRILLING SAME SEAM/SAME GEOLOGY/SAME HEIGHT CONSOL 005/006 Right SideCONSOL 005/006 Left Side ISLAND CREEK 003 Left Side * Worked as Cont. Miner Operator for 2 hours.

*Noise Generated while Drilling Holes

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

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.) TRAINING/WORK PRACTICES 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

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 RECOMMENDED NOISE CONTROLS 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)

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) RECOMMENDED NOISE CONTROLS 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) ( 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)