Control of Spontaneous Combustion in a Pillar Using a ... - SME
Control of Spontaneous Combustion in a Pillar Using a ... - SME
Control of Spontaneous Combustion in a Pillar Using a ... - SME
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D. Chalmers<br />
A. Lim, E. Baume & P. Holt
• Self heat<strong>in</strong>g <strong>of</strong> coal<br />
• Develops as a result <strong>of</strong> oxidation on exposure<br />
to air.<br />
• Ideal conditions<br />
• Sufficient supply <strong>of</strong> air<br />
• Insufficient airflow to remove heat<br />
• Some coals are more prone than others.
INHERENT<br />
• Rank<br />
• Porosity<br />
• Pyrites<br />
• Moisture<br />
• Petrology<br />
MINING RELATED<br />
• Low air velocity<br />
• Moderate differential<br />
pressures<br />
• Broken coal<br />
• M<strong>in</strong><strong>in</strong>g method
• Rout<strong>in</strong>e shutdown <strong>of</strong> the m<strong>in</strong>e<br />
• M<strong>in</strong>e deputy patroll<strong>in</strong>g the conveyor belt <strong>in</strong> C<br />
head<strong>in</strong>g<br />
• noticed that the rib just <strong>in</strong>bye n<strong>in</strong>e cut through<br />
was glow<strong>in</strong>g orange.<br />
• Senior management was alerted<br />
• procedures were implemented to br<strong>in</strong>g this<br />
under control
MEASURES TAKEN<br />
• Bore holes and <strong>in</strong>ject<br />
water to cool it<br />
• Spray it with shotcrete<br />
• Lower Fan pressure by<br />
shutt<strong>in</strong>g down one unit.<br />
EFFECTIVENESS<br />
• Good, but messy<br />
• Worked for a while then<br />
failed<br />
• Good but damag<strong>in</strong>g<br />
bottom l<strong>in</strong>e
• How much grout would be needed to <strong>in</strong>ject<br />
<strong>in</strong>to pillar to prevent Spon Comb reoccurr<strong>in</strong>g?<br />
• Sought help from consultants<br />
• Attended Australian M<strong>in</strong>e Ventilation Conference,<br />
UNSW<br />
• Discussed solution with several presenters<br />
• Lateral Th<strong>in</strong>k<strong>in</strong>g was required
• Problem<br />
• Only one return<br />
• Belt road has drive head –INTAKE AIR
SMH.com.au<br />
Annie Leibovitz<br />
Maggie Mastricola
• A. wrapp<strong>in</strong>g pillar <strong>in</strong> Plastic<br />
• B. Form a balance chamber by runn<strong>in</strong>g a<br />
membrane along return side <strong>of</strong> pillar<br />
• This drops the Pressure across the pillar<br />
• Keeps return open for ventilation<br />
• Reduces leakage through pillar<br />
• Spon comb under control
900Pa<br />
25Pa<br />
Door<br />
Stopp<strong>in</strong>g<br />
Membrane stopp<strong>in</strong>g
• Leakage through the door provides <strong>in</strong>take<br />
pressure to both sides <strong>of</strong> pillar<br />
• Pressure dropped from 900 Pa to 25 Pa
• flexible membrane as a means to provide a<br />
balance chamber -successful.<br />
• The spontaneous combustion event under<br />
control<br />
• Chamber has provided long-term solution
• clean up floor before <strong>in</strong>stallation<br />
• brief<strong>in</strong>g <strong>of</strong> m<strong>in</strong>e personnel how membranes<br />
work<br />
• modification <strong>of</strong> reta<strong>in</strong><strong>in</strong>g washers<br />
• <strong>in</strong>jection <strong>of</strong> grout <strong>in</strong> floor and ro<strong>of</strong> where<br />
applicable