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Thursday, July 18, 2013

#133 - Breathing Air in Mine Shafts – Part 1

Some mine shafts extend deep into the earth where the conditions are hazardous and the temperatures are high enough to be life threatening. For example, the TauTona Gold Mine in South Africa is currently the deepest mining operation in the world at 3.9km (2.4mi) deep. The rock face temperature in that mine can reach 60C (140F). 

We recently had a call from another gold mining operation in North America. The hazard of concern in this case was with the availability of fresh breathing air.

No doubt you have heard references to the ‘canary in a coal mine’. This expression is derived from the historical practice of taking caged canaries into mines. The canary has a small body and rapid breathing rate and metabolism. It will succumb to the effects of carbon monoxide or methane much sooner than an adult human. It therefore provided a portable early warning of life-threatening changes in the mine atmosphere.

In the North American gold mine application mentioned above, the issue of atmosphere concern originated not from mine itself, but from activity at the top level of the mine. Mines have air handling systems that are designed to supply breathable air and manage the temperature. Typically, a large fan and louver system draws fresh air from ground level and pumps it down into the mine. If the ground level areas surrounding the fan intake have a lot of vehicular traffic or other combustion processes, the baseline air being pulled into the mine may have an elevated level of carbon monoxide (CO). Vehicles and various engines in the mine will also contribute to the total CO in the mine atmosphere.




To ensure a safe baseline air input into the mine, a continuous CO monitor can be installed in the air flow after the fan. The monitor should be ranged for ppm analysis because the Permissible Exposure Limit of CO gas is currently 50 ppm over 8 hrs.* The monitor should have alarm set points with relay contacts to provide warning and allow automated controls to be initiated.




For this purpose, we have sold the Model 580 shown in our catalog here.

We have also provided engine exhaust analyzers for use in mines. See this post for more info. The picture and comments about the facility located somewhere in the Tien Shan Mountains in the Kyrgyz Republic (Kyrgyzstan) was a mining project that needed engine exhaust analysis for tuning the numerous small engines located throughout the mine.

There is a part 2 to this post here.

For information on these and other gas analyzer systems, give Mike or Dave at Nova a call, or send us an e-mail.
1-800-295-3771
sales at nova-gas dot com
websales at nova-gas dot com
http://www.nova-gas.com/

* PEL as established by US OSHA, by Time-Weighted Average


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