Note – Basic information in this lecture was drawn from the Note – Basic information in this lecture was drawn from the Code of Federal Regulations, the Federal Register, the Code of Federal Regulations, the Federal Register, the
MSHA website, and Historical compilations and reports of MSHA website, and Historical compilations and reports of accidents from the U.S. Bureau of Mines and MSHAaccidents from the U.S. Bureau of Mines and MSHA
Underground Coal MinesUnderground Coal Mines
Major ObjectivesMajor Objectives Provide for escape in the event of a fireProvide for escape in the event of a fire Limit exposure to dust and methaneLimit exposure to dust and methane
Main ApproachMain Approach Specify air velocities and volumes to areas of Specify air velocities and volumes to areas of
the minethe mine Specify any reuse of airSpecify any reuse of air Require approved mine ventilation plansRequire approved mine ventilation plans
Have to have an approved ventilation planHave to have an approved ventilation plan New Plans or Changes must be shown to New Plans or Changes must be shown to
the representative of the minersthe representative of the miners Plans must be posted on the bulletin boardPlans must be posted on the bulletin board MSHA has to review each mines MSHA has to review each mines
ventilation plan every 6 months to make ventilation plan every 6 months to make sure it still fits conditionssure it still fits conditions
Ventilation plans can usually adapt fixed Ventilation plans can usually adapt fixed rules of the regulations to individual minerules of the regulations to individual mine
Ventilation Plan ContentsVentilation Plan Contents(30 CFR 75.371)(30 CFR 75.371)
Company InformationCompany Information Name and location of companyName and location of company Name, Location and MSHA number of mineName, Location and MSHA number of mine Name of individual submitting planName of individual submitting plan
Main Mine Fan InformationMain Mine Fan Information Only Anthracite coal mines are allowed booster fans Only Anthracite coal mines are allowed booster fans
underground underground (30 CFR 75.302)(30 CFR 75.302) Main mine fans have to be monitored continuously Main mine fans have to be monitored continuously
with at least a pressure recording device and a with at least a pressure recording device and a person on the surfaceperson on the surface
• Person must have two way communications to working areasPerson must have two way communications to working areas Mine fans need an independent power supply from Mine fans need an independent power supply from
the rest of the mine (separate circuit)the rest of the mine (separate circuit) (30 CFR 75.310)(30 CFR 75.310)
Things Regs will look for in Things Regs will look for in Main Mine FansMain Mine Fans
Have to be 15 ft offside from openingHave to be 15 ft offside from opening Have to have weak stopping or explosion Have to have weak stopping or explosion
door to protectdoor to protect Have to be located away from surface Have to be located away from surface
combustiblescombustibles Have to have doors that can close if Have to have doors that can close if
ventilation air could conceivably reverseventilation air could conceivably reverse
Required Operation of Mine Fans Required Operation of Mine Fans (30 CFR 75.311)(30 CFR 75.311)
Fans must run at all timesFans must run at all times If not run have to shut down machinery, If not run have to shut down machinery,
limit people underground to servicing limit people underground to servicing things requiring shut-down, turn off power things requiring shut-down, turn off power to underground circuits unless have some to underground circuits unless have some sort back-up fansort back-up fan
Monitoring and Inspection of Mine Monitoring and Inspection of Mine FansFans
Fans need daily inspection unless full monitoring Fans need daily inspection unless full monitoring system is installedsystem is installed Then monitor record must be checked daily and the Then monitor record must be checked daily and the
monitor performance checked every 7 daysmonitor performance checked every 7 days
Fan must be stopped and checked every 31 Fan must be stopped and checked every 31 daysdays Need to restart in 15 minutes or have to shut down Need to restart in 15 minutes or have to shut down
circuits to underground and safety inspect before any circuits to underground and safety inspect before any re-entryre-entry
15 minutes is the time allowed to restart fan before 15 minutes is the time allowed to restart fan before mine has to be evacuatedmine has to be evacuated
Allowed Supplements to Main Mine Allowed Supplements to Main Mine FanFan
Can have tubing and fans to help with face Can have tubing and fans to help with face ventilationventilation Motors have to have auto shut-down if 1% Motors have to have auto shut-down if 1%
methane is detected (1% methane shuts methane is detected (1% methane shuts down the universe underground)down the universe underground)
Can have diffusers and scrubbers on the Can have diffusers and scrubbers on the mining equipmentmining equipment
Regs are silent on things like regulators Regs are silent on things like regulators (passive controls for ventilation)(passive controls for ventilation)
Mine Ventilation Plans Must Mine Ventilation Plans Must Specify how Air Quality is to be Specify how Air Quality is to be
MaintainedMaintained Traditional method is dilutionTraditional method is dilution
Still the method of choice for dust and Still the method of choice for dust and methanemethane• Regulations have default air quantities for the Regulations have default air quantities for the
purposepurpose
Event of diesel equipment underground Event of diesel equipment underground plus issues of silica and asbestos creating plus issues of silica and asbestos creating another fieldanother field Control by scrubbing systems, intrinsic Control by scrubbing systems, intrinsic
cleanliness and personal protection cleanliness and personal protection equipmentequipment
The Default Dilution QuantitiesThe Default Dilution Quantities
Bituminous and Lignite mines (Sub-bituminous Bituminous and Lignite mines (Sub-bituminous covered with Bituminous – Anthracite is an covered with Bituminous – Anthracite is an exception)exception) Last Open Cross Cut needs 9,000 cfm at the intake Last Open Cross Cut needs 9,000 cfm at the intake
entryentry• All working sections or sections that could work simply by All working sections or sections that could work simply by
starting equipmentstarting equipment• As with all reg specific quantities ventilation plans can As with all reg specific quantities ventilation plans can
changechange May require more if not getting air dilutedMay require more if not getting air diluted May get less if you can demonstrate job getting doneMay get less if you can demonstrate job getting done
• (30 CFR 75.325 (b))(30 CFR 75.325 (b))
Bituminous and Lignite Dilution Bituminous and Lignite Dilution QuantitiesQuantities
3,000 cfm to each working face measured at last 3,000 cfm to each working face measured at last row of permanent support on room and pillarrow of permanent support on room and pillar (30 (30 CFR 75.325 (a))CFR 75.325 (a)) 60 fpm min velocity60 fpm min velocity (30 CFR 75.326)(30 CFR 75.326)
Longwall and Shortwall systems need 30,000 Longwall and Shortwall systems need 30,000 cfm with at least 50 fpm but not more than 100 cfm with at least 50 fpm but not more than 100 fpm of velocityfpm of velocity (30 CFR 75.325 (c))(30 CFR 75.325 (c)) Must control dust and methaneMust control dust and methane
• 100 fpm limit can in fact constrain production rate100 fpm limit can in fact constrain production rate
Quantities must be sustained during installation Quantities must be sustained during installation and removal of equipmentand removal of equipment (30 CFR 75.325 (d))(30 CFR 75.325 (d))
Can put scrubbers and diffuser fans on mining Can put scrubbers and diffuser fans on mining machinesmachines Must be specified in Ventilation PlanMust be specified in Ventilation Plan
Diesel Equipment RulesDiesel Equipment Rules There are rules and cleanliness of equipment itself There are rules and cleanliness of equipment itself
(covered under separate lecture series)(covered under separate lecture series) Engines have nameplate air requirements that must Engines have nameplate air requirements that must
be metbe met• Add up all equipment on face (may form an over-riding air Add up all equipment on face (may form an over-riding air
quantity) that is operated any time during shiftquantity) that is operated any time during shift• Diesel also imposes the air requirements outby and in entries Diesel also imposes the air requirements outby and in entries
and travel-waysand travel-ways (30 CFR 75.325 (f))(30 CFR 75.325 (f))
Exceptions to Diesel Air AdditionsExceptions to Diesel Air Additions
If diesel discharges into a return air course If diesel discharges into a return air course or an air supply going directly to a return or an air supply going directly to a return air courseair course
Getting Air to the FacesGetting Air to the Faces
Air Supplied must be freshAir Supplied must be fresh Any area were equipment is working must Any area were equipment is working must
have a separate split of airhave a separate split of air Supersections must have fresh split of air for Supersections must have fresh split of air for
each equipment set (unless only run one at a each equipment set (unless only run one at a time)time)
Air supplied must not have passed by or Air supplied must not have passed by or through any uninspected areas or through any uninspected areas or secondary mined areassecondary mined areas
(30 CFR 75.332)(30 CFR 75.332)
Keeping Air Supplies SeparateKeeping Air Supplies Separate
Must maintain permanent stopings of Must maintain permanent stopings of incombustible material to within 3 cross-cuts incombustible material to within 3 cross-cuts outby of working faceoutby of working face
Stoping must separate intake and return air Stoping must separate intake and return air courses from each other and from the beltwaycourses from each other and from the beltway This requirement for beltway to be a neutral has now This requirement for beltway to be a neutral has now
been changedbeen changed Primary escapeway must be separated from belt Primary escapeway must be separated from belt
or trolley entriesor trolley entries (30 CFR 75.333)(30 CFR 75.333)
The Practical Need to Go Between The Practical Need to Go Between Air CoursesAir Courses
Personal doorsPersonal doors Need every 300 ft if under 4 ft coalNeed every 300 ft if under 4 ft coal Need every 600 ft if over 4 ft coalNeed every 600 ft if over 4 ft coal
• Obviously takes longer to move in low coalObviously takes longer to move in low coal
Equipment needs to moveEquipment needs to move Door have to be a double door airlock – only Door have to be a double door airlock – only
one side open at a timeone side open at a time Over and Undercasts of masonary or steel Over and Undercasts of masonary or steel
– no aluminum (toxic in fire)– no aluminum (toxic in fire)
The Fate of Worked Out AreasThe Fate of Worked Out Areas
If no secondary mining then sweep with If no secondary mining then sweep with return air to avoid methane and noxious return air to avoid methane and noxious gas build-upsgas build-ups Alternative often taken is to sealAlternative often taken is to seal
Secondary mined areas require a bleeder Secondary mined areas require a bleeder around edge to sweep with return airaround edge to sweep with return air Plans must include keeping bleeders open Plans must include keeping bleeders open
from roof falls or from flooding out with waterfrom roof falls or from flooding out with water Again alternative is to sealAgain alternative is to seal
(30 CFR 75.334)(30 CFR 75.334)
MSHA’s Concerns About Sealed MSHA’s Concerns About Sealed AreasAreas
Practice of sealing became widespread after Practice of sealing became widespread after 1992 when ventilation sweep problems at South 1992 when ventilation sweep problems at South Mountain caused explosion killing 8 peopleMountain caused explosion killing 8 people
Events behind the sealsEvents behind the seals Without ventilation oxygen depletes reacting with coal Without ventilation oxygen depletes reacting with coal
to form CO and CO2to form CO and CO2 Methane emits and is not dispersedMethane emits and is not dispersed Interesting when we did fill in an old 1950s panel at Interesting when we did fill in an old 1950s panel at
Peabody #10 temp almost 90 (coal oxidation)Peabody #10 temp almost 90 (coal oxidation)
Explosibility of MethaneExplosibility of MethaneAdding 5% methane to airBecomes explosive(lower limit of explosibility)
Over 15% methane in airDisplaces so muchOxygen an explosion is notSustainable.
Of course in sealed areaOxygen is dropping so theExplosibility range isNarrowing. Below 12% O2Methane is not regardedAs explosive
If methane comes up fastAnd oxygen goes down slowYou get explosive mixtures
How Dangerous?How Dangerous?
Mine Explosions are usually dangerousMine Explosions are usually dangerous It is theoretically possible to get an explosive mixture It is theoretically possible to get an explosive mixture
behind a sealbehind a seal Still need an ignition sourceStill need an ignition source Most ignition sources are human activities and they are sealed Most ignition sources are human activities and they are sealed
on the other sideon the other side Roof falls seem capable of sparking in most event casesRoof falls seem capable of sparking in most event cases
Since 1992 have had 13 explosions behind sealsSince 1992 have had 13 explosions behind seals 2 didn’t do any damage at all2 didn’t do any damage at all 6 did minor damage to seals6 did minor damage to seals 3 were exciting and could have been killers if people had been in 3 were exciting and could have been killers if people had been in
the wrong place at the wrong timethe wrong place at the wrong time Sago and Darby in 2006 were both killer disastersSago and Darby in 2006 were both killer disasters
A Look at AlternativesA Look at Alternatives Alternative is to leave area openAlternative is to leave area open
Today have to sweep area and send it to the returnsToday have to sweep area and send it to the returns Area must be inspectedArea must be inspected If area is pillared and GOBed must leave entries open If area is pillared and GOBed must leave entries open
around the edge and sweep themaround the edge and sweep them• This air must also be run to the returnsThis air must also be run to the returns
Today cannot put equipment and haulage in the Today cannot put equipment and haulage in the returnsreturns
• Haulage is either neutral or an intakeHaulage is either neutral or an intake• Returns are pretty much emptyReturns are pretty much empty
I don’t have non-fatal or even non disaster data I don’t have non-fatal or even non disaster data but old workings and GOBS caused 36 major but old workings and GOBS caused 36 major killer explosionskiller explosions
What Can Be Learned?What Can Be Learned? Old Practice just let the GOBs sitOld Practice just let the GOBs sit
8 explosions killing 400 people methane accumulated in 8 explosions killing 400 people methane accumulated in abandoned workings and then drifted out into active workingsabandoned workings and then drifted out into active workings
• Rules today requiring regular sweeping of these areas would have Rules today requiring regular sweeping of these areas would have stopped these disastersstopped these disasters
6 explosions killing 84 people involved people going into old 6 explosions killing 84 people involved people going into old uninspected workingsuninspected workings
• With sweeping some of these areas might not have had methane With sweeping some of these areas might not have had methane pocketspockets
• Inspection might have helped but we don’t preshift abandoned Inspection might have helped but we don’t preshift abandoned working all the timeworking all the time
• Proper safety lamps would have also helpedProper safety lamps would have also helped 6 explosions killing 49 people roof falls in abandoned areas 6 explosions killing 49 people roof falls in abandoned areas
pushed bursts of methane into active workingspushed bursts of methane into active workings• Sweeping might have helped but methane bursts can still be a Sweeping might have helped but methane bursts can still be a
problem (Grundy in 1981)problem (Grundy in 1981) Sealing Would Have Stopped All of TheseSealing Would Have Stopped All of These
Lessons and PreventionLessons and Prevention
3 Explosions killing 64 people involved taking vent air 3 Explosions killing 64 people involved taking vent air from abandoned areas and circulating into active areasfrom abandoned areas and circulating into active areas
Clearly illegal and would be prevented by todays regsClearly illegal and would be prevented by todays regs Of course sealing would also have stoppedOf course sealing would also have stopped
2 Explosions killing 145 people the methane was vented 2 Explosions killing 145 people the methane was vented into the returns but the mine had the haulage and into the returns but the mine had the haulage and support system in the returnssupport system in the returns
Todays regs putting haulage in an intake or neutral would have Todays regs putting haulage in an intake or neutral would have prevented theseprevented these
Of course sealing would have stoppedOf course sealing would have stopped 2 Explosions killing 94 people originated in and occurred 2 Explosions killing 94 people originated in and occurred
in an isolated abandoned areain an isolated abandoned area Doubtful vent sweep or seals would have stopped theseDoubtful vent sweep or seals would have stopped these
System FailuresSystem Failures
Cases were venting mistakes or mishaps Cases were venting mistakes or mishaps caused explosions – 5 Explosions killing 56 caused explosions – 5 Explosions killing 56 peoplepeople Sealing would have stopped theseSealing would have stopped these Not making mistakes would have had ventilation Not making mistakes would have had ventilation
avoidedavoided Defective Seals (some of these are old cases Defective Seals (some of these are old cases
where a seal was a plywood door)where a seal was a plywood door) 4 Explosions killing 95 people4 Explosions killing 95 people 3 seals were not even a joke for sealing requirements3 seals were not even a joke for sealing requirements 1 was an improperly constructed new seal Darby1 was an improperly constructed new seal Darby
Those Who Don’t Learn from the Past are Those Who Don’t Learn from the Past are Doomed to Repeat ItDoomed to Repeat It
Mines Vented abandoned area sweep air into return that Mines Vented abandoned area sweep air into return that were actively used for haulagewere actively used for haulage
Barrackville 1925 (33-34 dead) Barrackville 1925 (33-34 dead) Same Thing in 1951 at Orient #2 (119 dead)Same Thing in 1951 at Orient #2 (119 dead)
Explosions starting in the abandoned workingsExplosions starting in the abandoned workings #16 1930 (82 dead) left a hot trolly line in an abandoned area #16 1930 (82 dead) left a hot trolly line in an abandoned area
roof fall arced it across a railroof fall arced it across a rail Sago 2006 (12 dead) a line left running to an old pump in a Sago 2006 (12 dead) a line left running to an old pump in a
sealed work acted as an antenna and generated electricity from sealed work acted as an antenna and generated electricity from a lightning strikea lightning strike
Poorly Designed Seals Leak into active areasPoorly Designed Seals Leak into active areas Moweaque 1932 (54 dead) seals leaked no one checked open Moweaque 1932 (54 dead) seals leaked no one checked open
man trip light lit itman trip light lit it Darby 2006 (5 dead) seals not tight men lit up a cutting torch Darby 2006 (5 dead) seals not tight men lit up a cutting torch
right outside leak without checking for methane (even though right outside leak without checking for methane (even though they had meters in their pocket)they had meters in their pocket)
To Vent or Not To Vent?To Vent or Not To Vent? Review of past suggests that sealing would have Review of past suggests that sealing would have
avoided more disasters than ventilationavoided more disasters than ventilation Sealing is simpleSealing is simple
Ventilation requires entry maintenance and inspectionsVentilation requires entry maintenance and inspections Many roof falls are cumulative roof effectsMany roof falls are cumulative roof effects
EconomicsEconomics Seals involve an up front capital costSeals involve an up front capital cost Ventilation involves a distributed costVentilation involves a distributed cost
• If loss of ventilation air limits production then cost is hugeIf loss of ventilation air limits production then cost is huge MSHA under pressureMSHA under pressure
Two killer blasts in within a few months blew seals out from Two killer blasts in within a few months blew seals out from explosive voids behindexplosive voids behind
MSHA’s political pressureMSHA’s political pressure• Regulatory changes have always come in response to disasterRegulatory changes have always come in response to disaster• MSHA being viewed as failurMSHA being viewed as failur
MSHAs New Seal StandardMSHAs New Seal Standard
Old Standard was seal had to be solid concrete Old Standard was seal had to be solid concrete block and take a horizontal load of 20 psiblock and take a horizontal load of 20 psi Allowed alternate materials – Omega blocks at SagoAllowed alternate materials – Omega blocks at Sago Standard was based on a 1971 report by Bureau of Standard was based on a 1971 report by Bureau of
Mines on designing bulkheadsMines on designing bulkheads
MSHA used a 2007 Niosh report for new MSHA used a 2007 Niosh report for new standardstandard NIOSH reviewed practices around the worldNIOSH reviewed practices around the world Then ran computer simulated blasts to see what kind Then ran computer simulated blasts to see what kind
of pressure pulse and duration could be expectedof pressure pulse and duration could be expected
The StandardThe Standard
After May 22, 2007 new seals must withstand 50 After May 22, 2007 new seals must withstand 50 psipsi 50 psi seal is equivalent to a 3.5 foot thick concrete 50 psi seal is equivalent to a 3.5 foot thick concrete
plug anchored into coalplug anchored into coal Seals must be monitored by running a pipe into area Seals must be monitored by running a pipe into area
15 feet (air right against the seal is dead and might 15 feet (air right against the seal is dead and might not have rep composition)not have rep composition)
Also requires a pipe into first cross-cutAlso requires a pipe into first cross-cut• Sounds a little like the electrical antenna at SagoSounds a little like the electrical antenna at Sago• Atmosphere must be inertAtmosphere must be inert
Can do things to make inert – Australian nitrogen floodingCan do things to make inert – Australian nitrogen flooding Or naturally inert (non-explosive)Or naturally inert (non-explosive)
More StandardMore Standard
Seal of 120 psi if operator does not monitor and Seal of 120 psi if operator does not monitor and or inert the atmosphereor inert the atmosphere 120 psi seal is equivalent to 2 foot thick reinforced 120 psi seal is equivalent to 2 foot thick reinforced
concrete sealconcrete seal Has a section for very homogeneous methane Has a section for very homogeneous methane
atmospheres that can pressure pile and atmospheres that can pressure pile and detonatedetonate Requires air be compressed ahead of flame front (at Requires air be compressed ahead of flame front (at
45 psi precompression can get 300 psi overpressure)45 psi precompression can get 300 psi overpressure) Mine operator has to provide full analysis under these Mine operator has to provide full analysis under these
conditionsconditions
Other Aspects of Seal DesignOther Aspects of Seal Design Seals need a drainages system so they don’t impound Seals need a drainages system so they don’t impound
waterwater Seal designs must be approvedSeal designs must be approved
MSHA keeps a data base of approved designsMSHA keeps a data base of approved designs Designs required certified engineering studiesDesigns required certified engineering studies Seals must be certified appropriate by a PESeals must be certified appropriate by a PE Seals must be part of ventilation planSeals must be part of ventilation plan MSHA must be given notice of seal construction so they can MSHA must be given notice of seal construction so they can
observe the constructionobserve the construction People monitoring or constructing seals must be trainedPeople monitoring or constructing seals must be trained
MSHA anticipates most of these seal projects will go to MSHA anticipates most of these seal projects will go to specialized contractors – not done in housespecialized contractors – not done in house
Estimate that seals will cost at least 40 million a year Estimate that seals will cost at least 40 million a year more than current practicemore than current practice
MSHA assumed no one would go back to ventilating old MSHA assumed no one would go back to ventilating old workingsworkings
Old SealsOld Seals
Rule required outgas samples from Rule required outgas samples from existing seals to see what was behind existing seals to see what was behind themthem
MSHA decided not to require replacement MSHA decided not to require replacement or a 2or a 2ndnd layer seal because of feeling that layer seal because of feeling that reopening areas would create extra reopening areas would create extra dangerdanger
Ventilation for Electrical AreaVentilation for Electrical Area Include things like substations and battery barnsInclude things like substations and battery barns
It is not minor electrical equipment such as pumpsIt is not minor electrical equipment such as pumps Need to be built of incombustible materialsNeed to be built of incombustible materials Need to be ventilated with intake air fed directly Need to be ventilated with intake air fed directly
to the returnsto the returns No quantity specified in regs, though build-up is No quantity specified in regs, though build-up is
obviously part of the intentobviously part of the intent Sensors need to shut off power and close doors Sensors need to shut off power and close doors
if wrong gas or particularly heat combination if wrong gas or particularly heat combination shows upshows up
(30 CFR 75.340)(30 CFR 75.340) Shops have same basic requirementsShops have same basic requirements
ExaminationsExaminations
All entries and production work places must be “pre-All entries and production work places must be “pre-shifted” within three hours before the start of the shiftshifted” within three hours before the start of the shift
The examiner must be certified for the workThe examiner must be certified for the work Checks for hazardous conditions, methane, oxygen, and dust Checks for hazardous conditions, methane, oxygen, and dust
levelslevels Checks the seals for leakageChecks the seals for leakage Has to certify reportsHas to certify reports
Worked out areas or bleeders need weekly inspectionWorked out areas or bleeders need weekly inspection Listed Separately but normally done with pre-shift is Listed Separately but normally done with pre-shift is
checking beltwayschecking beltways Isolated pump areas ect can be checked by the worker if Isolated pump areas ect can be checked by the worker if
he has training and certification – doesn’t have to have he has training and certification – doesn’t have to have full inspectors papersfull inspectors papers
Expressed in Mine Ventilation Expressed in Mine Ventilation PlansPlans
Plan needs to identify areas where more than Plan needs to identify areas where more than 3,000 cfm are needed3,000 cfm are needed
Any area where a minimum quantity is specified.Any area where a minimum quantity is specified. Volumes of air at last open cross-cut if more Volumes of air at last open cross-cut if more
than 9,000 cfmthan 9,000 cfm Any exceptions to keeping permanent Any exceptions to keeping permanent
separation of intakes and returns to within 3 separation of intakes and returns to within 3 cross-cuts of facecross-cuts of face
Any exceptions on Longwall or Shortwall air Any exceptions on Longwall or Shortwall air quantitiesquantities
More Ventilation PlansMore Ventilation Plans
Plans spell out equipment used to monitor air Plans spell out equipment used to monitor air quality, where and when it will be usedquality, where and when it will be used
Locations of stopings regulators bleeders etcLocations of stopings regulators bleeders etc Method to be used to keep bleeder entries clearMethod to be used to keep bleeder entries clear Location of degasification and methane drainage Location of degasification and methane drainage
holes (short horizontal drainage holes don’t have holes (short horizontal drainage holes don’t have to be shown)to be shown)
Air Quantities for Diesel EquipmentAir Quantities for Diesel Equipment Locations for CO and NOx monitoringLocations for CO and NOx monitoring
A Proposed Change in RulesA Proposed Change in Rules
Current Rules require that belt air be Current Rules require that belt air be separated from intakes, returns and separated from intakes, returns and primary escapeway.primary escapeway. (Main affected (Main affected Section is 30 CFR 75.350)Section is 30 CFR 75.350) Air quantity must be limited to that needed to Air quantity must be limited to that needed to
dilute methane (and dust) to keep ventilation dilute methane (and dust) to keep ventilation downdown
Things the Current Rule DoesThings the Current Rule Does
Main idea is belt entry fire would pump Main idea is belt entry fire would pump fumes right onto the working areasfumes right onto the working areas
Limiting belt entry air was intended to Limiting belt entry air was intended to avoid fanning flames and stimulating fireavoid fanning flames and stimulating fire It also limited cooling effects and made fires It also limited cooling effects and made fires
get hotterget hotter It also created dustier conditions in beltwaysIt also created dustier conditions in beltways Low air velocity resulted in higher pressures Low air velocity resulted in higher pressures
drops potentially pressurizing a fire area into drops potentially pressurizing a fire area into the intakes and the escapewaysthe intakes and the escapeways
New RuleNew Rule
Belt entry air can be used to ventilate Belt entry air can be used to ventilate working sections butworking sections but Must install Automatic atmospheric monitoring Must install Automatic atmospheric monitoring
with early alarm triggers and train miners in with early alarm triggers and train miners in use under part 48 traininguse under part 48 training
Dust levels would have to be the same as Dust levels would have to be the same as for intake airfor intake air Mines before 1970 could and do use intake Mines before 1970 could and do use intake
air without monitoring requirementsair without monitoring requirements• Rule would eliminate the exemptionRule would eliminate the exemption
More Proposal SummaryMore Proposal Summary
The primary escapeway must still be kept The primary escapeway must still be kept separate from the belt entryseparate from the belt entry
Had to provide life lines in the primary Had to provide life lines in the primary escapeway to protect miners from black escapeway to protect miners from black out conditions in a fire.out conditions in a fire.
IssueIssue
Sweep of CO directly to the face in the Sweep of CO directly to the face in the event of a belt fireevent of a belt fire Alma Mine Belt fire of Jan 2006Alma Mine Belt fire of Jan 2006
• Mine had a crew of 12 on a face ventilated from Mine had a crew of 12 on a face ventilated from the belt entry that cought firethe belt entry that cought fire
• 10 miners got SCSRs on – met another crew and 10 miners got SCSRs on – met another crew and took a mantrip outtook a mantrip out
• 2 may have had trouble with their SCSRs and 2 may have had trouble with their SCSRs and were overcome while trying to evacuate.were overcome while trying to evacuate.
