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spontaneous combustion |
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Dealing with an Event |
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Dealing with an Event
There are a number of ways of dealing with a spontaneous combustion event, depending on the size and accessibility:
- If at the heating stage, increasing the
ventilation sufficiently to cool the site is an option. This can be a risky
process as there is a possibility of worsening the situation and, if the
ignition stage has been reached, increasing air flow will increase the size of
the fire.
- A small heating or even a fire in an
accessible location can be dealt with by digging out the heating material and
transporting it to a safe location, most probably surface. Care will be
required in handling hot/burning material (one does not want to create a fire
elsewhere) which may be giving off noxious gases.
- Normal fire fighting procedures can be used
for accessible locations. Care is required in poorly ventilated locations
because of the risk of the production of "water gas", a mixture largely of hydrogen and carbon
monoxide which is generated by quenching hot coal with water, a mixture which
is highly explosive.
- In areas which are not accessible it is
usually best to seal off the area quickly and allow the oxygen content at the
heating site to reduce as combustion takes place until the atmosphere will no
longer support combustion. Note that in mines prone to spontaneous combustion
it is normal practice to have seals around sections of the mine partly prepared
ready for rapid completion if required. Note also that the atmosphere within
the sealed off area is likely to pass through the explosive range, hence
evacuation of the mine will be necessary immediately following sealing until
such time as it can be ascertained that the atmosphere will not support an
explosion (typically 48 hours or more).
- The above process can be accelerated if
inert gases can be injected into the mine or part of mine. If this method is
used it is normal to inject nitrogen, supplied by road tankers, or by
generation of exhaust gases from combustion (a "Tomlinson" boiler or a jet
engine have been used.)
- If seam grades are suitable it may be
possible to flood the heating area and so exclude oxygen. Again the production
of water gas is a risk, and it is probable the area will need to remain flooded
to avoid the problem reoccurring.
U.S. Dept of Energy report on spon comb – general info & comments.
Paper on relationship between coal properties & spon comb parameters & Modelling spon comb of coal – 2 research papers on spon comb.
Influence of moisture on spon comb of coal – title self explanatory.
Case study of spon comb incident at Blair Athol – a particular case where open cut workings intersected u/g workings.
An expert system to predict spon comb potential of a mining operation – describes the basic system and provides contact details for the developer.
Mark Nelson's Research Interest: Spontaneous combustion – research carried out at UOW, largely on compost heaps but references to coal as well.
Spontaneous Combustion Expert System (SPONCOM) - OSHweb – access to the above doc on a NIOSH website
A novel method for the detection of spon comb – describes the use of "electronic noses" to detect odours from spon comb
ACARP publications – a list of ACARP publications, including work on fires, etc
The AusIMM - Publications - spon comb risk mgt in NSW coal mines – access to a risk management plan – not free info, payment required
Assesment of spon comb susceptibility by differential scanning calorimetry – paper on a method of testing on Indian coals
Design of enthalpy based fire sensing device for spontaneous heating – self explanatory
Coal mine gas emission assessment for sealed goaf area or abandoned mine – self explanatory
Journal of the Operational Research Society - Abstract of article: Algorithms for the Detection of Spontaneous Combustion in Coal Mines – not free info, subscription required
Coal oxidation at low temperatures, etc – a study of the spon comb process