Mine Illumination and Solid-State Lighting

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Mine Illumination and Solid-State Lighting
Dr. John J. Sammarco NIOSHPittsburgh Research
Laboratory
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Agenda

• Why is lighting important?
• Age and vision
• History of lighting
• Lighting safety accidents
• High brightness light emitting diodes (HB LEDs)
• NIOSH lighting research

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Why look at mine lighting?

• Miningthe most difficult lighting environment
  in the world
• Illumination Engineering Society of North
  America, 2003.

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Why look at mine lighting?

• Miners depend heavily on visual cues to spot
  hazards
• Aging workforce
• Accidents

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Age Effects on Vision

• Night vision decreases with age
• Smaller pupil
• Eye less able to adapt to light
• Fewer rod receptors
• Cloudy eye lens

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Age Effects on Vision
Yellowing of Lens(age in years)
Degradation of lens decreases effective light
level and effective contrast (due to scatter)
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Why look at mine lighting?

• Improved lighting may help miners avoid
  accidents
• Slip/trip/falls
• Falls of ground
• Striking/pinning
• An MSHA study of metal/nonmetal mining concluded
  that current lighting systems are inadequate.

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Safety Lighting
The percentage of accidents declines as
illuminance is increased in industrial
(non-mining) work areas Source (Walton et al.,
2005)
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A Brief History of Lighting
Candle holders with candles
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Oil Lamps
Photos Royal BC Museum, British Columbia,
Canada, http//www.royalbcmuseum.bc.ca/
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Carbide lamps
Photo Royal BC Museum, British Columbia, Canada,
http//www.royalbcmuseum.bc.ca/ Quotation Where
the Sun Never Shines, Priscilla Long, Paragon
House, New York, 1989.
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Incandescent Lights
Photos Royal BC Museum, British Columbia,
Canada, http//www.royalbcmuseum.bc.ca/, Cape
Breton Mine Museum, www.minersmuseum.com
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What is light?
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What is light?Electromagnetic radiation
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(No Transcript)
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Light Spectrum

• White light from LEDs
• Shorter wavelenghts
• Bluish-white light
• Better depth perception
• Better color rendering
• Better visual performance

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Spectral Power Distribution
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Lighting technologies
Type Life (hrs) Cost Specular color temp. Efficiency (lumens/watt) Shock proof
Incandescent 1,500 7 2800oK 14 no
Halogen 2,500 6 3200oK 24 no
HID 10,000 20 4000oK 80 no
Solid-state LED 50,000 8 5500oK 70 (prototypes _at_ 110) yes

• Lower specular color temperatures indicate a
  yellowish light
• higher temperatures indicate a whiter light.

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Light Emitting Diodes (LEDs)
LEDs are semi-conductors they don't have a
filament that will burn out. They are illuminate
by the movement of electrons in a semiconductor.
Luminaires
LEDs
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Light Emitting Diodes (LEDs)

• Advantages
• Lower power requirements
• Long Life (gt50,000 hours)
• Small size
• Sturdy
• White, shorter wavelength light

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NIOSH Mine Lighting Research
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Reducing underground mining mishaps by improving
mine illumination
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Project Scope

• Underground lighting
• Cap lamp (coal)
• Preblast lighting (metal/nonmetal)
• Machine lighting (coal)

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Cap Lamps
Additional Personal lighting
LED Cap Lamp2 lb. battery, 5 year LED life
5 lb. battery
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Machine Lighting
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Preblast Lighting

• inspect roof back
• loading of explosives

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Specific aim summary

• Does the color (spectral power distribution) from
  white LEDs
• Improve visual performance?
• Reduce glare?
• Can advantages of LEDs (small, robust, high
  efficiency, etc) enable new designs to
• Improve visual performance?
• Reduce glare?
• Realize new safety applications?

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NIOSHMine Illumination Lab
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Glare tests
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Peripheral motion detection
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Slip/trip/fall hazards
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Mean time to detect an objectIncandescent cap
lamp was slowest
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Lighting prototypes
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Questions