Transcript Sec_7_UG_Mining_Methods_and_Sources_of_Dust.ppt

Control of Airborne
Respirable Dust Hazards:
A Training Program for
Underground Coal Miners
Penn State
The Penn State
Miner Training Program
University Park, PA 16802
March 31, 2003
Raja V. Ramani, Ph.D., P.E, C.M.S.P.
Mark C. Radomsky, Ph.D. MPA, C.M.S.P.
Joseph P. Flick, M.S., C.M.S.P.
CENTERS FOR DISEASE CONTROL
AND PREVENTION
NATIONAL INSTITUTE FOR
OCUPATIONAL SAFETY AND HEALTH
GENERIC MINERAL TECHNOLOGY
CENTER ON RESPIRABLE DUST
PENNSYLVANIA BUREAU
OF DEEP MINE SAFETY
RESPIRABLE DUST
TRAINING PROGRAM
Section 7
UNDERGROUND MINING
METHODS
AND
SOURCES OF DUST
Mining Process and Environment
 The working environment in underground coal
mining is completely enclosed by the geological
medium consisting of the coal seam, and the strata
above and below the coal seam.
 Mining process consists of two kinds of operations:
1. Unit operations
2. Auxiliary operations
Mining Process and Environment
 Unit operations are repeated in a cycle to extract
coal, and develop the mine and mine the coal seam
 Unit Operations – cutting, drilling, blasting, loading,
hauling and roof bolting
 Unit operations are repeated in the face areas and
all unit operations produce dust
Mining Process and Environment
 Auxiliary operations provide the support services
necessary for the unit operations to function
effectively.
 Auxiliary Operations – ventilation, ground
control, drainage, power, main haulage,
communications and lighting.
 Auxiliary operations can produce dust.
Ventilation is a major dust control auxiliary
operation.
Underground Coal Mining Methods
There are two major U.S. underground coal
mining methods with several sub-classes:
 Room and Pillar Methods – common methods
 Conventional Mining Method
 Continuous Mining Method
 Longwall Methods – common methods
 Longwall Retreating Method with Shearers
 Longwall Retreating Method with Ploughs
Coal Production Per Mining Method
U.S. Underground Coal Mine Production Distribution
in year 2000 [Total : 374 million tons]
Room and pillar conventional mining 2.4 million tons
Room and pillar continuous mining
178.6 million tons
Longwall retreating (shearers)
189.0 million tons
Other underground methods
4.0 million tons
Projection of a Hypothetical Mine Showing
the First Two Years of Development
Distribution of Broken Material by
Respirable, Airborne and Large Particle
Size
Mining Sequence in 7-Entry Development
for a Conventional Mining Section
Sources of Dust in Mines
Conventional Mining Section
 Kerf Cutting by the Coal Cutter
 Drilling of the Blast Holes in the Face
 Blasting of the Coal
 Loading of Coal to Shuttle Cars
 Drilling for Roof Bolt Holes
 Feeder Breaker at the Dump Point
 Panel Conveyor
 Contamination of Intake Airways
Mining Sequence in 5-Entry Development
for a Continuous Mining Section
Sources of Dust in Mines
Continuous Mining Section
 Coal/Rock Cutting by Continuous Miner [CM]
 Coal/Rock Falling to the Ground
 Gathering and Loading of the Coal by CM
 Loading the Coal on to Shuttle Cars
 Drilling for Roof Bolting
 Feeder Breaker at the Dump Point
 Panel Belt Conveyor
 Contamination of Intake Air
Dust Sources in a Continuous Miner
Section
Typical Longwall Section
Stage loader
Roof supports
Shearer
Conveyor
Gob
Sources of Dust in Mines
Longwall Mining Section
 Coal/Rock Cutting by Longwall Shearer
 Advance of the Shield Supports
 Breaking of Coal at Stageloader/Crusher
 Panel Belt Conveyor
 Contamination of Intake Air
Dust Sources in a Longwall Section
Longwall Equipment Parameters
Current
Projected
900 kW
?
Cut width
Conveyor speed/
power
Shield width/
capacity
Face voltage/
total power
1m
1.5 m/s
1,800 kW
1.5 m /
900 t
4,160 V
3,900 kW
1.13 m
1.5 m/s
2,700 kW
2.0m /
>900 t
Panel belt width
1.4 m
---
Main belt width
1.8 m
---
Production/8 hr. machine shift
8,000 t
---
Shearer cutting power
---
Typical Longwall Panel Parameters
Current
Projected
2.0
---
330.0
420.0
3,000.0
5,500.0
3 or 4
2 or 3
% Dev. coal
10 to 15
Under 10%
Cut width (m)
0.9 to 1.2
>1.2
Seam height (m)
Face width (m)
Panel length (m)
No. of entries
Sources of Dusts in Mines
 Primary Sources – These are sources in which the
dust produced primarily from breaking the coal or rock
from the seam or strata. Examples include: continuous
miners, longwall shearers, roof bolting machines, and
blasting.
 Secondary Sources – These are sources in which
the dust is produced from secondary breaking arising
from loading, transferring and transporting the coal.
Examples include loading machines,
stageloader/crusher, conveyor, and reentrainment of
settled dust.
Sources of Dusts in Mines
 The above two sources can be further broken down into
major, minor and negligible sources on the basis of their
contribution to the overall dust load in the mines.
 Major sources include continuous miner,
longwall shearer, and roof bolting machines
 Minor sources include loaders and roof bolters
 Negligible sources include conveyors, and
reentrainment
Sources of Dust in Mines
Conventional Mining
Mining
Method
Conventional
Mining
Equipment
Operation
Primary
Source
Coal cutter/coal cutting
Major
Coal driller/coal drilling
Major
Blasting
Major
Load & transfer to shuttle
car
Rock drill/roof bolt
drilling
Feeder-breaker
Conveyor
Secondary
Source
Quartz
Source
Major
Minor
Minor
Negligible
Major
Negligible
Negligible
Minor
Sources of Dust in Mines
Continuous Mining
Mining
Method
Equipment
Operation
Continuous miner/coal
cutting
Continuous
Mining
Primary
Source
Secondary
Source
Major
Quartz
Source
Major
Falling of broken material
to ground
Minor
Gathering arm
Minor
Transfer to shuttle car
Minor
Rock drill/drilling
Minor
Major
Negligible
Minor
Feeder-breaker
Conveyor
Negligible
Negligible
Sources of Dust in Mines
Longwall Mining
Mining
Method
Equipment
Operation
Shearer/coal cutting
Longwall
Mining
Primary
Source
Secondary
Source
Major
Roof support movement
Minor
Minor
Stage-loader-crusher
Conveyor
Negligible
Quartz
Source
Negligible
Minor
Proceed to Section 8
Longwall Dust Control Methods