EMBRACING tech
Gas Sensing Technology Improves Mine Safety
Gas in Mines : an Omnipresent Hazard An underground mine is an inhospitable place in which to work . Gas poisoning and explosion is a major hazard , with many different types of gas commonly present in mines . Black damp , a mixture of carbon dioxide and nitrogen , is formed as the result of corrosion in enclosed spaces so removing oxygen from the atmosphere and potentially causing suffocation . Fire damp mainly consists of methane , a highly ammable gas that explodes at concentrations between 5 % and 15 % or , if it does not explode , at 25 % concentration it causes asphyxiation . Methane ignition can trigger the much more dangerous coal dust explosions because the shock wave raises coal dust from the oor of the mine galleries to make an explosive mixture that is highly susceptible to spontaneous combustion . Stink damp , so called because of the rotten egg smell of the hydrogen sulphide gas , can explode and is also very toxic . Carbon monoxide , toxic even at low concentrations , is another major hazard . Gas sensors are the critical operating component of all gas detection instruments . �ey transform a gaseous concentration , typically measured in ppm , into a change in electrical voltage or current that provides a reliable , stable and repeatable input for the detection instrument . With so many different gaseous hazards potentially present , effective gas detection is critical in protecting life and equipment underground . Apart from gas-related hazards , underground mining dangers include suffocation , gas poisoning , roof collapse and gas explosions , while open cut hazards are principally mine wall failures and vehicle collisions . Most risks are greatly reduced in modern mines , and multiple fatality incidents are now rare in most parts of the developed world . However , according to the Bureau of Labour Statistics , mining remains the second most dangerous occupation in America , with 30 deaths in a typical year due to mine accidents .
� e B e n e c i a l I m p a c t o f M o d e r n Technology on Fatality Rates Modern technology employed in mines throughout the developed world , has dramatically improved safety . Improvements in mining methods such as automated longwall mining , effective hazardous gas monitoring , gas drainage , better electrical equipment and improved ventilation have reduced many of the risks of rock falls , explosions , and unhealthy air quality . In less developed and developing countries , many more miners continue to die annually , either directly as the result of accidents in mines , or indirectly as the result of illnesses contracted from working under poor conditions .
� e C h a l l enges Fa c i ng G a s S ensor Manufacturers In deep coalmines , extreme temperature changes , rapid humidity variations and signi cant pressure changes are experienced as miners travel down from the surface . In both deep and open cast coal mines methane gas is an ever-present hazard . Speci c regional issues are a further complication , for example , in South African mines , hydrogen cross-
Page36 | Jan - Feb 2016
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