It Happened...
On December 12, 1994, an electrical fault in the transformer windings caused a fire in a 1500 KVA load center. A CO sensor three crosscuts outby the fire went into alarm and was subsequently investigated. The fire was contained within the load center and put out with fire extinguishers.
On May 5, 1995, a belt fire occurred due to friction against the belt structure. Brattice cloth and material under the belt caught fire. The fire was detected by a CO monitoring system and prompt response by mine personnel prevented the fire from burning out of control.
On January 3, 1998, following two ten hour production shifts, a belt fire occurred when the belt was stopped. An idler roller failed causing frictional heating from metal to metal contact. The fire was discovered after activation of the audible alarm on the surface by the CO monitoring system.
Example carbon monoxide sensor installation
FIRE DETECTION SYSTEMS vary in their design and application. Different types of detectors look for different products generated by the fire. Some detectors look for heat, some look for specific gases such as carbon monoxide (CO), some look for smoke, and some look for light produced by a flame. With advances in technology, its is possible to have different combinations of detection to monitor a wider spectrum of fire conditions.
LOCATIONS
Belt drives Unattended electrical equipment
Bleeder entries Beginning and end of belt flights
Idle areas
• ALWAYS investigate fire alarms immediately. Treat an alarm as if a fire exists until proven otherwise.
• ALWAYS determine the causes of nuisance alarms and correct the problem.
• ALWAYS keep sensors clean and dry and maintain them in working order.
• ALWAYS report fire detection system problems to mine management.
• ALWAYS test the sensors in a fire area as soon as possible after the fire is extinguished.
• ALWAYS replace sensors that show signs of fire damage.
• ALWAYS connect sensors together using MSHA approved flame -resistant cable that also meets the specifications of the detection system manufacturer.
• ALWAYS monitor your detection systems from one central location.
• ALWAYS consider the use of infrared or thermal imaging systems for detecting hot spots.
• NEVER rely only on your of smell to warn you of a fire.
• NEVER make field repairs to faulty sensors, replace them with approved new ones.