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Standardization of Operator Enclosure Air Quality - Bulldozers working on burning coal piles

On a warm June day, my truck pulled up to the gate at a large coal mine in northeastern Colombia, South America. We were there to evaluate the air quality in a large bulldozer cab. The concern for air quality increases when conditions external to the cab deteriorate due to extreme heat, fire, and dust which is the case when operating on the mountainous coal piles, which have the unusual habit of spontaneously combusting. We drove miles into the coal mine, passing cavernous, canyon-like surface excavations and haul trucks lining up to receive four hundred tons of coal from the largest dragline buckets in the world. It was a privilege to experience this unique world of massive machines run by committed coal miners.

Excavator working on a burning coal seam. Photo By TripodStories- AB - Own work, CC BY-SA 4.0,

We approached the smoking coal pile, bulldozers crisscrossing its volcanic-like surface with flames jumping up all over the pile. I hopped out of the truck with my air quality test belt and made tracks to the bulldozer that was just pulling up in preparation for our visit. The operator hopped out, and I placed the test instruments on the back of his seat, signaled the operator it was ready, and got back into the truck. With little concern, the operator turned the bulldozer toward the burning coal pile and put the machine into gear.

There was a time when technology could not protect mining machine operators from harmful cab environments. Today, thanks to the collaboration between stakeholders, a consensus standard addresses cab air quality. ISO 23875 was published in February of 2021 and amended in 2022 and is the only ISO cab standard focused on operator enclosure air quality.

Why has all of this happened? Because machine cabs are part of a safe work environment.

Check out the ISEEE online course on implementing ISO 23875 with Amendment 1. This course will accelerate your understanding of the standard and provide time-saving templates for the required maintenance manual and performance tests.


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