Spontaneous Combustion Testing for Hazard Management Planning Dr B Basil Beamish MAusIMM CP (Min) RPEQ Technical Director CB3 Mine Services Pty Ltd 3/20

Spontaneous Combustion Testingfor Hazard Management Planning

Dr B Basil Beamish MAusIMM CP (Min) RPEQTechnical Director

CB3 Mine Services Pty Ltd3/20 Archerfield Road, Darra Qld 4076

T: +61 7 33754100M: +61 488 708 949

[email protected] Conference and Exhibition on Occupational Health and Safety in Mines -

Istanbul December 2014

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

Sponcom process(Moreby and Chalmers, 2006)

International Conference and Exhibition on Occupational Health and Safety in Mines -


RETAINED LOST

Intrinsic and extrinsic factors determine reaction rate

Coal + O2 CO, CO2, and H2O + HEAT

CONVECTION

CONDUCTION

EVAPORATION

INCREASES REACTION RATE

INCREASES COAL TEMPERATURE

Balance determines

developmentof event

Incubation period is the time taken for coal to reach thermal runaway with given intrinsic and extrinsic factors.

• 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 avoid controls

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 Occupational Health and Safety in Mines -


http://www.resourcesandenergy.nsw.gov.au/__data/assets/pdf_file/0007/419515/MDG-1006.pdf

http://www.resourcesandenergy.nsw.gov.au/__data/assets/pdf_file/0007/419515/MDG-1006.pdf


Common Sponcom tests used bythe Australian Coal Mining Industry

• 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.


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


Example of repeat R70 testing fora Newcastle high volatile bituminous

coal

20

40

60

80

100

120

140

160

0 1 2 3 4 5 6 7 8 9 10

Tem

per

atu

re (

oC

)

Time (hours)LAB A (Oven 1) LAB A (Oven 1)

R70 = 4.73 oC/h

R70 = 4.90 oC/h


Example of repeat R70 testing foran Australian sub-bituminous coal

20

40

60

80

100

120

140

160

0.0 0.5 1.0 1.5 2.0

Tem

per

atu

re (

oC

)

Time (hours)LAB A (Oven 1) LAB A (Oven 1)

R70 = 33.42 oC/h

R70 = 34.27 oC/h


Intrinsic Spontaneous Combustion Propensity classification (ISCP) based on Qld and NSW coal conditions

(Beamish and Beamish, 2012)

Queensland New South Wales

ISCPClass

Propensity ratingR70 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


New South Wales intrinsic spontaneous combustion propensity plot

0

1

2

3

4

5

6

7

8

0 5 10 15 20 25 30 35 40 45 50

R7

0(o

C/h

, db

)

Ash content (%, db)

Illawarra 1 Illawarra 2 Hunter Valley Upper Hunter

Newcastle Western San Juan Spring Creek

Low

Low - Medium

Medium

High


Examples of SponComSIM™ testing to establish time to thermal runaway

20

40

60

80

100

120

140

160

0 10 20 30 40 50 60 70 80 90 100 110 120

Tem

per

atu

re (

oC

)

Time (hours)

Kideco Spring Creek Illawarra (Bulli)

Newcastle A LW3A LW3B40

-60

day

s

10-1

5 d

ays


Example of recent Queensland case study

20

40

60

80

100

120

140

160

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140

Tem

per

atu

re (

oC

)

Time (hours)

Kideco Spring Creek K4E Low Ash (35C) K4E Low Ash (40C)

40

-60

da

ys

10

-15

da

ys

67

-100

da

ys


Quantification of reactive pyrite effect

20

40

60

80

100

120

140

160

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Tem

per

atu

re (

oC

)

Time (hours)R70 SponComSIM

R70 = 1.73 oC/h

RIT = 149 oC


Effect of increasing amounts of reactive pyrite

(Beamish, Lin and Beamish, 2012)

20

40

60

80

100

120

140

160

0 10 20 30 40 50 60 70 80 90

Time (hours)

Tem

per

atu

re (

oC

)

Kideco Spring Creek BBHVB03 BBHVB06 BBHVB13 BBHVB01

40-6

0 d

ays

10-1

5 d

ays


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


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


Individual gas evolution results forArea A of a New South Wales mine

0

1

2

3

4

0.000

0.005

0.010

0.015

0.020

40 60 80 100 120 140 160 180 200

Hyd

roge

n, E

thyl

ene,

Eth

ane,

Met

hane

(%)

Temperature (°C) Hydrogen Ethylene Ethane Methane Carbon Monoxide Carbon Dioxide

Carb

on M

onox

ide,

Car

bon

Dio

xide

(%)

Carb

on M

onox

ide,

Car

bon

Dio

xide

(%)


Individual gas evolution results forArea B of a New South Wales mine

0

1

2

3

4

0.000

0.005

0.010

0.015

0.020

40 60 80 100 120 140 160 180 200

Hyd

roge

n, E

thyl

ene,

Eth

ane,

Met

hane

(%)

Temperature (°C) Hydrogen Ethylene Ethane Methane Carbon Monoxide Carbon Dioxide

Carb

on M

onox

ide,

Car

bon

Dio

xide

(%)

Carb

on M

onox

ide,

Car

bon

Dio

xide

(%)


Graham’s ratio trend with increasing coal temperature for

Area A

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

20 40 60 80 100 120 140 160 180 200

Gra

ham

's R

atio

(%)

Temperature (°C)

Measured GRExtrapolated GR


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.


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.


Questions?

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Spontaneous Combustion Testing for Hazard Management Planning Dr B Basil Beamish MAusIMM CP (Min) RPEQ Technical Director CB3 Mine Services Pty Ltd 3/20