Nova Analytical Systems: #134 - Breathing Air in Mine Shafts

Last post we talked about CO analysis of mine shaft input air. That application required a continuous monitor to be installed just after the air intake fans.

Even more recently, we had an inquiry about oxygen (O2) monitoring in a mine in India.

An intermittent-use portable instrument was required in this case. They wanted to measure the O2 levels in the mine and then progressively evaluate any variations detected throughout the mine. This could include variations between locations in the mine or variations over time.

The mine staff were also interested in using a portable instrument to check for O2 deficiency in enclosed spaces. For example, prior to cleaning a large tank, it is important to determine if there is sufficient oxygen present before entering the space.

Other gases in this particular mine are typically carbon monoxide and methane (CO & CH4). According to the current site information available, the CH4 is in the range of 0.3 to 0.5 % by vol and CO is in the range of 100 to 300 ppm. (That CO level seems high in our estimation. Levels over 100ppm are dangerous to human health. According to OSHA, the Permissible Exposure Limit of CO gas is currently 50 ppm over 8 hrs.) The temperature, pressure, and moisture were generally representative of ambient breathable air in a mine.

The Nova model requested was from the 600 Series. The ranges available are:

0-25.0% O2

0-200 PPM CO

This instrument has a built in sample pump and a separate display for each gas. Communication options include:

4-20mA outputs; one per gas; for connection to customer's data collection system.
An optional detachable data logger can be supplied with the analyzer. The analyzer writes to the data logger via the 4-20mA outputs and can later be uploaded to your personal computer for trending and analysis.
Alternatively, a serial output and data-logging software can be supplied. This option allows the analyzer to be directly connected to a computer during air analysis. (We don't sell computers; the customer uses their own.)