COAL DUST HAZARD MITIGATION

Coal mining poses to explosion hazard due to coal dust. In several coal mining fields, collected coal from site are taken to the collecting field by truck. An underground construction is made for the conveyor to run under this coal stack. Buldozer pushes the coal to the hole on the tunnel concrete ceiling below,so the coal will fall onto the top belt of the running conveyor. This will safe more time than using an an excavator to upload to the truck bin to take to the river or dock.

Narrow passage with entrance just at both ends. The construction in picture - 1 has 300 meters long, it is at South Kalimantan. As coal dust may accumulated in along the conveyor frame and roller, the roller bearing sometimes might build up the heat and reach the flash point of the coal dust. When this happens, an explosion may occur.

Fixed-spot type heat detector is not appropriate for this application as heat may build anywhere along the conveyor length. Protectowire Heat Sensor Cable can solve the problem. Having construction like a cable which the detection point is continuously along its long body. The linear heat sensor can be installed on both sides of the conveyor near the roller bearing or on the center top above the upper belt. Most cases the fire coming from the jammed bearing that become hotter.

The problem when the sensor installed near the roller bearing , unaccidentally acts may cause the sensor broken or short. This short in the sensor cable body will cause a false alarm. To overcome this problem, Protectowire has CTI (Confirmed Temperature Initiation) technology. With CTI model, a short can be differentiated between actual fire or mechanical faults.

To mitigate the coal dust hazard, electrically-actuated deluge water spray system shall be employed. The solenoid used shall be of explosion - proof type as the system may operate in hazardous atmosphere. In the Picture-03, the linear heat sensor cable were run at the water spray pipe line above the conveyor.