Basics of Coal Dust Particle Suppression by Sprinkler Water

Nozzle Location

• Among the many considerations when implementing a dust suppression program is nozzle location. Dust occurs at several points during the coal mining and processing operation and must be controlled at all times. Locate nozzles wherever front-loaders pick up and drop off coal. Coal placed in bins or hoppers as well as coal traveling along conveyor belts needs to be sprayed to prevent dust from escaping.

Droplet Size

• Consider the relationship between water droplet size and coal dust particle size when implementing a suppression system. If spray nozzles release droplets that are larger than the dust particles, the particles will follow the air-stream around the water droplet and will not be captured. Droplets that are too small will evaporate before they reach the ground, releasing captured dust particles back into the air. Nozzle type and positioning are used to control water droplet size.

Nozzle Type

• The smallest water droplets are produced by utilizing atomized air. Atomization is achieved by either forcing air through a nozzle at high pressure or by adding compressed air to a low-flow nozzle. Compressed air systems are more effective, but they are expensive to maintain. Good results are also achieved using high-pressure, hydraulic systems as a less expensive alternative to compressed air. Small water droplets do not travel as far as larger droplets, so nozzle placement is critical to successful suppression.

Dangers of Coal Dust

• Coal dust is a health hazard and, according to OSHA, is flammable. For these reasons dust suppression is important to successful mining operations. Continued exposure to coal dust can result in a condition known as coal worker's pneumoconiosis, or black lung disease. The most common symptoms of black lung disease are coughing and shortness of breath. Although it is rarely fatal, black lung disease can cause life-threatening complications, such as chronic bronchitis, chronic obstructive pulmonary disease, heart failure and respiratory failure. If you are exposed to coal dust, OSHA recommends removing contaminated clothing and washing your arms, face and hands. Workers experiencing coughing, wheezing or shortness of breath should be removed from the facility and seek medical attention.