Mining Contract: Dispersibility Testing of Dried Wet and Foam Rock Dust

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Contract #	200-2016-90152
Start Date	9/15/2016
End Date	9/14/2018
Research Concept	Rock dust helps to impede the propagation of explosions in coal mines. However, the mining industry has requested new, equally effective wet and foamed rock dust products that do not contribute to respirable dust measurements and can withstand the challenges of a moisture-rich environment. With the closure of NIOSH’s Lake Lynn Laboratory in December 2012, all full-scale explosion propagation testing—which included tests incorporating various levels and types of rock dust—halted. The closure has impeded the coal industry from developing and testing new products.

Contract Status & Impact

This contract is complete. To receive a copy of the final report, send a request to mining@cdc.gov.

Explosible coal dust is continually generated at the coal cutting face, therefore mine workers apply rock dust—typically pulverized limestone—to all mine surfaces. During the application of rock dust with dusting machines, large amounts of this pulverized limestone dust are suspended in the ventilating air, which can be both a nuisance and contribute to the respirable dust measurements of workers downstream. Fresh rock dust is applied periodically as machine movement and foot traffic may disturb and thin out this protective dust, so the issue of airborne dust recurs frequently.

To help the industry counter these health and safety concerns, new methods of applying rock dust are being developed and must be tested. Without an appropriate testing facility at the National Institute for Occupational Safety and Health’s Pittsburgh facility, alternate sites and facilities must be employed.

Using a new test facility at the Colorado School of Mines, researchers will evaluate the dispersibility of conventional dry-applied rock dust versus new wet and foam rock dusts and aid rock dust suppliers and equipment manufacturers with development of new wet and foam rock dusts that—when dried—disperse similarly to conventional rock dust.