ROOF BOLTER NOISE SOURCE IDENTIFICATION PROJECT

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ROOF BOLTERNOISE SOURCE IDENTIFICATION PROJECT
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ROOF BOLTER TEAM
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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)

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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.
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Noise Generated while Drilling Holes
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Noise Generated while Drilling Holes
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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

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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, DONT use machine as heater

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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 MANUFACTURERS SETTINGS
  
  
  
  
  ON ROTATION SPEED AND THRUST
  NIOSH has conducted test comparing different
  rotational speeds

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RECOMMENDED NOISE 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

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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)

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RECOMMENDED NOISE 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)

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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)