Underground Mine Sensor Networks

World economies that are involved in mining activities are highly motivated to develop sensor networks that are able to send early warning signals to reduce the number of accidents, especially those that involve human injuries or deaths. The factors with greatest impact in the cause of accidents in underground mines are the presence of pit gas, landslides and lack of information about the exact location of personnel in the event of a disaster. The development of sensor networks capable of measuring variables of interest related to the factors mentioned in real time, adding wireless communication capabilities for easy deployment and robustness, promises to be of great impact on safety for the mining industry. In this publication the main causes of accidents for underground coal mines are established, based on existing worldwide reports. Variables (temperature, gas, structural faults, fires and/or combustion engine machine effects presence) that can be related to the most frequent causes of disaster and its relevant measuring range are then presented. Sensor technology to measure these variables is also analyzed, taking into account operational principles, measurement range, precision, accuracy, linearity, sturdiness, sampling rate and then related to wireless sensor networks technology energy saving requirements. This publication focuses on coal mines, because these are the most accident prone underground mining environments. However, application of these results to copper mining activities is considered as well.