Transcript Spontaneous Combustion Testing for Hazard Management

Spontaneous Combustion Testing
for Hazard Management Planning
Dr B Basil Beamish MAusIMM CP (Min) RPEQ
Technical Director
CB3 Mine Services Pty Ltd
3/20 Archerfield Road, Darra Qld 4076
T: +61 7 33754100
M: +61 488 708 949
[email protected]
International Conference and Exhibition on
Occupational Health and Safety in Mines Istanbul December 2014
Presentation outline
• The Sponcom process and requirements for a
Principal Hazard Management Plan
• Assessment of self-heating propensity in
Australia
• Examples of spontaneous combustion testing
results and interpretation for mine planning
• Conclusions
International Conference and Exhibition on
Occupational Health and Safety in Mines Istanbul December 2014
Sponcom process
(Moreby and Chalmers, 2006)
Coal + O2
 CO,
CO2, and H2O + HEAT
Intrinsic and extrinsic
factors determine
reaction rate
INCREASES REACTION RATE
INCREASES COAL
TEMPERATURE
RETAINED
Incubation period is the time taken for
coal to reach thermal runaway with
given intrinsic and extrinsic factors.
LOST
Balance
determines
development
of event
CONVECTION
CONDUCTION
EVAPORATION
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•
•
•
•
Oxidation rate doubles for each 10⁰C rise in temperature, once the coal temperature exceeds
70⁰C
Coal is a good insulator and can retain heat for years
Coal can retain elevated activity for years
Incubation periods can range from weeks to years
Never use incubation period to International
avoid controls
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MDG1006 Spontaneous Combustion
Management Guideline
• Updated by the NSW Mine Safety Operations Branch in
February, 2011 released in May 2011
• www.resourcesandenergy.nsw.gov.au/__data/assets/pdf
_file/0007/419515/MDG-1006.pdf
• The intent of this guideline is to provide assistance to
mines in the development and implementation of a
Principal Hazard Management Plan (PHMP) for
Spontaneous Combustion.
• Spontaneous combustion testing information is required
to assess propensity to self-heat and to obtain data on
gas evolution associated with coal temperature increase.
International Conference and Exhibition on
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Common Sponcom tests used by
the Australian Coal Mining Industry
•
•
•
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Common tests measure the intrinsic spontaneous combustion
propensity under set conditions with no indication of time to thermal
runaway. Assessment is based on a rating scheme compared against
previous coal histories.
Crossing Point Temperature (CPT) and Relative Ignition Temperature
(RIT) are high temperature index tests and do not provide any
measure of the coal self-heating at low ambient temperature. They
are also measured by force heating the coal in an oven.
Minimum Self-heating Temperature (SHT) and R70 self-heating rate
are low temperature index tests and provide a measure of the coal
self-heating at low ambient temperature. They are measured in an
adiabatic oven that allows the coal to heat itself, although SHT is now
calculated from the oxygen content of the coal.
New SponComSIM™ testing provides additional data on the time
taken to reach thermal runaway using site boundary conditions and is
benchmarked against coals with known self-heating performance.
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Sampling strategies for
Sponcom assessment of a longwall mine
• Site specific and tailored to suit project objectives
• Top, middle and bottom of seam, plus any rider seams
likely to fall into the goaf or floor coal left behind
• Minimum 800g required per sample (25cm of HQ core)
• Longwall operations tested every longwall panel
• Fresh face lumps just as good as core
• R70 testing of all samples for assessing intrinsic
spontaneous combustion propensity
• SponComSIM™ testing of specific samples for
benchmarking thermal runaway timeframe
• SponComGAS™ testing for evaluating gas evolution
trends in support of TARPs
International Conference and Exhibition on
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Example of repeat R70 testing for
a Newcastle high volatile bituminous coal
160
Temperature (oC)
140
120
100
R70 = 4.90 oC/h
80
R70 = 4.73 oC/h
60
40
20
0
1
2
3
4
5
6
Time (hours)
LAB A (Oven 1)
LAB A (Oven 1)
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7
8
9
10
Example of repeat R70 testing for
an Australian sub-bituminous coal
160
Temperature (oC)
140
120
100
R70 = 34.27 oC/h
80
R70 = 33.42 oC/h
60
40
20
0.0
0.5
1.0
Time (hours)
LAB A (Oven 1)
LAB A (Oven 1)
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1.5
2.0
Intrinsic Spontaneous Combustion Propensity classification
(ISCP) based on Qld and NSW coal conditions
(Beamish and Beamish, 2012)
Queensland
New South Wales
ISCP
Class
Propensity rating
R70 value
(°C/h)
R70 value
(°C/h)
I
low (L)
R70 < 0.5
R70 < 1
II
low-medium (LM)
0.5  R70 < 1
1  R70 < 2
III
medium (M)
1  R70 < 2
2  R70 < 4
IV
high (H)
2  R70 < 4
4  R70 < 8
V
very high (VH)
4  R70 < 8
8  R70 < 16
VI
ultra high (UH)
8  R70 < 16
16  R70 < 32
VII
extremely high (EH)
R70  16
R70  32
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New South Wales intrinsic spontaneous
combustion propensity plot
8
7
High
R70 (oC/h, db)
6
5
4
3
Medium
2
Low - Medium
1
Low
0
0
5
10
15
20
25
30
35
Ash content (%, db)
Illawarra 1
Illawarra 2
Hunter Valley
Upper Hunter
Newcastle
Western
San Juan
Spring Creek
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40
45
50
Examples of SponComSIM™ testing
to establish time to thermal runaway
160
40-60 days
10-15 days
Temperature (oC)
140
120
100
80
60
40
20
0
10
20
30
40
50
60
70
80
90
100
Time (hours)
Kideco
Newcastle A
Spring Creek
LW3A
Illawarra (Bulli)
LW3B
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110
120
Example of recent Queensland case study
160
120
100
67-100 days
40-60 days
10-15 days
Temperature (oC)
140
80
60
40
20
0
10
20
30
40
50
60
70
80
90
100
110
120
Time (hours)
Kideco
Spring Creek
K4E Low Ash (35C)
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K4E Low Ash (40C)
130
140
Quantification of reactive pyrite effect
160
RIT = 149 oC
Temperature (oC)
140
120
100
80
R70 = 1.73 oC/h
60
40
20
0
2
4
6
8
10
12
14
16
18
Time (hours)
R70
SponComSIM
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20
22
24
26
28
30
Effect of increasing amounts of reactive pyrite
(Beamish, Lin and Beamish, 2012)
160
40-60 days
10-15 days
Temperature (oC)
140
120
100
80
60
40
20
0
10
20
30
40
50
60
70
80
Time (hours)
Kideco
Spring Creek
BBHVB03
BBHVB06
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BBHVB13
BBHVB01
90
Trigger Action Response Plan (TARP)
setting for underground mines
• Identification of most appropriate
indicator gases and ratios
– Initially based on gas evolution testing of the coal
– TARP trigger levels set at logically determined values that
are site specific (internal standard)
– Refined as part of the review process with mine site
experience
– Possibility of differing geological domains influencing TARP
trigger levels
International Conference and Exhibition on
Occupational Health and Safety in Mines Istanbul December 2014
Small-scale gas evolution testing
• Characterises the gas evolution trend that occurs in
response to coal self-heating as the temperature of
the coal increases
• Results are evaluated for the specific trends of
individual gases and gas ratios
• The information can be used to identify key
indicator gases and ratios for use in TARPs and to
support the alarm limits set in the TARP
• Coal is step heated up to approximately 180°C and
gases analysed by GC include: O2, N2, CH4, CO2, CO,
H2, C2H6, C2H4
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0.020
4
0.015
3
0.010
2
0.005
1
0.000
0
40
Hydrogen
60
80
Ethylene
100
Ethane
120
140
160
Temperature (°C)
Methane
Carbon Monoxide
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180
200
Carbon Dioxide
Carbon Monoxide, Carbon Dioxide (%)
Hydrogen, Ethylene, Ethane, Methane (%)
Individual gas evolution results for
Area A of a New South Wales mine
0.020
4
0.015
3
0.010
2
0.005
1
0.000
0
40
Hydrogen
60
80
Ethylene
100
Ethane
120
140
160
Temperature (°C)
Methane
Carbon Monoxide
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180
200
Carbon Dioxide
Carbon Monoxide, Carbon Dioxide (%)
Hydrogen, Ethylene, Ethane, Methane (%)
Individual gas evolution results for
Area B of a New South Wales mine
Graham’s ratio trend with increasing
coal temperature for Area A
5.5
5.0
4.5
Graham's Ratio (%)
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
Measured GR
Extrapolated GR
0.0
20
40
60
80
100
120
140
Temperature (°C)
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160
180
200
Conclusions
• Reliable and accurate results with appropriate
interpretation are required by industry for
Spontaneous Combustion Principal Hazard
Management Planning.
• Relevant laboratory spontaneous combustion
testing is required to evaluate the risk of
developing an event under the site specific
conditions of each mine and within different
areas of the mine.
• Gas evolution testing provides support for the
selection of appropriate indicator gases and
ratios used in TARPs.
International Conference and Exhibition on
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References
• Beamish, B and Beamish, R, 2012. Testing and sampling
requirements for input to spontaneous combustion risk
assessment, in Proceedings of the Australian Mine Ventilation
Conference, B Beamish and D Chalmers (eds), pp 15-21 (The
Australasian Institute of Mining and Metallurgy: Melbourne).
• Beamish, B, Lin, Z and Beamish, R, 2012. Investigating the
influence of reactive pyrite on coal self-heating, in
Proceedings 12th Coal Operators’ Conference, N Aziz (ed), pp
295-300 (University of Wollongong and The Australasian
Institute of Mining and Metallurgy).
• Moreby, R and Chalmers, D, 2006. Mine ventilation course
notes, Mining Education Australia.
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Questions?
International Conference and Exhibition on
Occupational Health and Safety in Mines Istanbul December 2014