A three-stage approach is proposed and is centred on the use of concepts like risk Identification, sensing, spotting, monitoring, control and stockpile management. In summary, this methodology will ensure that coal in the stockyard is used in the Most efficient and effective manner, concentrating effort on areas where large scope of Improvement exist.
MITIGATING THE EFFECTS OF FACTORS RESPONSIBLE FOR THE AUGMENTATION OF SPONTANEOUS COMBUSTION OF COAL:
- Proper selection of particle size distribution. If the stockpile is of mainly medium to fine particle then making it finer or adding fines will help. If the pile consists of coarse particles of relatively low reactivity then removing the finer material will help.
- Avoiding segregation. Improper stacking might result in segregation of stockpiles and hence increase propensity to oxidation.
- Proper attention must be given to the preparation and maintenance of the stockpile. Pile maintenance might be crucial in avoiding channels where air can easily creep into the dump.
- Proper compaction. Air circulating within the stockpile should be restricted by proper compacting and dozing off.
- Moisture contributes the spontaneous combustion as it aids in the oxidation process. Moisture content should be limited to about 3% to avoid enhanced oxidation. Measures must be taken to keep stored coal from being exposed to moisture.
- Dimensions of stockpile. Size and area of stockpile should be based not only on estimated tonnage but also on design principles of Stockpile management. Proper dimensioning of stockpiles helps negate weathering of coal. Just dumping the coal in a big pile Might lead to problems. Rather coal should be packed in horizontal layers of about 1.3 to 3.0 feet high followed by levelling and Compaction by dozers.
- Use of protective covering: Inert covering material such as tarpaulin sheets with sufficient heat resistivity can be used to cover the Cover the openly kept stockpile to reduce the loss of calorific value and further oxidation of coal. It helps in cutting off oxygen to come In contact with coal.