April 05, 2012 at 11:42 AM

Perfect Earth was employed to provide a trial on a coal mine site where spontaneous combustion had occurred

The situation:

Due to wet weather, spontaneous combustion had occurred in the mine site spoil, forcing the mine to close due to gases being released into the atmosphere. The mine was concerned, if left untreated, that the combustion would spread to the coal seam. Perfect Earth was requested to provide a trial to suppress and extinguish the combustion process and to reduce the possibility of further spontaneous combustion. 

Filling the vents:

The initial job was to fill the vents where excessive heat had worked to the surface. Venting is caused by the fire at the base of the stockpile thus creating a vent from the combustion site with a depth of up to 300 metres to the surface. Combustion was still taking place during the filling of the vents. By filling the vents with non combustible material, the oxygen starved the combustion site, thereby reducing one of the three fuels. 

Temperature readings of 500 degrees Celsius were recorded during the installation period. Health and safety was highest on the agenda as gases were released from the spoil. Gas masks and gas monitors were worn should there be any concern of exceeding the limitations of PPE.

A special mix of fire resistant products designed by Perfect Earth was used and pumped through our hydromulch unit via hose into the voids. By doing this we were able to fill the void and cap the vent. 

Compaction of the surface:

Upon completion of void filling, compaction of the upper spoil surface is required. By providing this, water and air are less able to penetrate the surface. 

Capping the surface:

Applying a second mix of products, Perfect Earth was able to starve oxygen from moving into the spoil by capping the surface of the spoil. Temperatures were reduced from 500 degrees Celsius to 40 degrees Celsius within 1 day. This second mix, being able to flex once dried, provided an ideal cap, totally sealing the surface area

Outcome:

Both products provide long term sealing of vents and continue to provide successful outcomes. Perfect Earth is now employed to provide this service to mines where spontaneous combustion occurs, or may occur.

Once combustion is no longer a concern, Perfect Earth will be providing re-vegetation of areas affected by spontaneous combustion. Cost effective spontaneous combustion controlled by Perfect Earth.

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