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David K. IngramDavid K. Ingram
Mining Hearing Loss Prevention WorkshopMining Hearing Loss Prevention WorkshopJune 21June 21--22, 200522, 2005
Pittsburgh Research LaboratoryPittsburgh Research Laboratory
Development and Assessment of Controls
Session
Surface Drill Rigs
Development and Assessment of Controls
Session
Surface Drill Rigs
Rubber Tire RigsRubber Tire RigsRubber Tire Rigs
Track Mounted RigsTrack Mounted Rigs
Examples: Examples: Air Rotary AAir Rotary A--weighted Sound Levels weighted Sound Levels
112
92
100
107 106
101
70
75
80
85
90
95
100
105
110
115
120
Hole In-cab Dust Collector Fan Exhaust Compressor
Microphone Location
Soun
d Le
vel d
B(A
)
Engineering Controls forEngineering Controls forTwo Types of Air Rotary RigsTwo Types of Air Rotary Rigs
1) Cab Mounted Rigs 2) Non-Cab Mounted Rigs
What can be done to make the What can be done to make the Cabs Quieter?Cabs Quieter?
• Install sound proofing material
• Replace worn out door or window seals
• Replace broken, cracked or missing glass
• Repair the air conditioner or heater
• Encourage the operator to close the door
• Make sure the cab’s mounting brackets prevent structural vibration
• Isolate the hydraulic control lines from the control panel
How do we isolate How do we isolate hydraulic control valves?hydraulic control valves?
No way! It’s not
practical!
(Photo Source: Wilkes & McLean Ltd. internet webpage)
PossibleSolution
Hydraulic Muffler
Solution to Hydraulic Line Solution to Hydraulic Line VibrationVibration
Installed Hydraulic Mufflers:
Idle:91 86 dB(A)
Drilling:98 94 dB(A)
What About Rigs Without What About Rigs Without Cabs?Cabs?
As Designed in AutoCAD
In Use at Drilling SitePartial Cab Partial Cab Design to Design to
CompletionCompletion
Sound Level Measurements: Partial Cab Engaged Sound Level Measurements: Partial Cab Engaged vsvs DisengagedDisengaged
Disengaged
Engaged
Stop
1/3-Octave Band Center Frequency (Hz)
50
55
60
65
70
75
80
85
90
95
100
A-w
tdSo
und
Pres
sure
Lev
el, d
B(A
)
1001251602002503154005006308001000125016002000250031504000500063008000
63 80
Disengaged, 104 dB(A)Engaged, 96 dB(A)
8 dB(A) Reduction with the Partial Cab
Driller’s Comments: Partial CabDriller’s Comments: Partial Cab
•• DesignDesign•• “Looked better than expected”“Looked better than expected”•• UsabilityUsability•• “Cab blocks dirt when setting the surface.” “Cab blocks dirt when setting the surface.”
The driller said he would have a hard time The driller said he would have a hard time staying/seeing/breathing at the control panel staying/seeing/breathing at the control panel during this process. The cab blocks the dirt during this process. The cab blocks the dirt coming directly at him during the initial drilling coming directly at him during the initial drilling into the surface. into the surface.
•• Problems with CabProblems with Cab•• Around midday there is glare off the window Around midday there is glare off the window
panels and he can’t see the drill steel because of panels and he can’t see the drill steel because of the control panel reflection. the control panel reflection.
Driller’s Comments Driller’s Comments -- Cont.Cont.
•• Cleaning the Partial Cab Window PanelsCleaning the Partial Cab Window Panels•• Used the air line to blow off the dirt from the Used the air line to blow off the dirt from the
window panels. window panels. •• Changes in rig soundsChanges in rig sounds•• “Can’t hear the drill steel sounds behind the cab. “Can’t hear the drill steel sounds behind the cab.
Rig sounds different”. We talked about how he Rig sounds different”. We talked about how he would get used to the sound changes, similar to would get used to the sound changes, similar to the changes when wearing the changes when wearing HPDsHPDs. .
•• Overall thoughtsOverall thoughts•• “I like it. Other drill operators will want it “I like it. Other drill operators will want it
(the partial cab) as well”(the partial cab) as well”
For more informationFor more information
David K. IngramDavid K. Ingram
Phone: 412Phone: 412--386386--6547 Fax: 4126547 Fax: [email protected]@cdc.gov
www.cdc.gov/niosh/miningwww.cdc.gov/niosh/mining
Pittsburgh Research LaboratoryPittsburgh Research Laboratory
