Mining Publication: Experimental Study on Foam Coverage on Simulated Longwall Roof

Original creation date: February 2018

Authors: W Reed, Y Zheng, S Klima, M Shahan, T Beck

Peer Reviewed Journal Article - February 2018

NIOSHTIC2 Number: 20054554

Trans Soc Min Metall Explor 2018 Feb; 342:72-82

Testing was conducted to determine the ability of foam to maintain roof coverage in a simulated longwall mining environment. Approximately 27 percent of respirable coal mine dust can be attributed to longwall shield movement, and developing controls for this dust source has been difficult. The application of foam is a possible dust control method for this source. Laboratory testing of two foam agents was conducted to determine the ability of the foam to adhere to a simulated longwall face roof surface. Two different foam generation methods were used: compressed air and blower air. Using a new imaging technology, image processing and analysis utilizing ImageJ software produced quantifiable results of foam roof coverage. For compressed air foam in 3.3 m/s (650 fpm) ventilation, 98 percent of agent A was intact while 95 percent of agent B was intact on the roof at three minutes after application. At 30 minutes after application, 94 percent of agent A was intact while only 20 percent of agent B remained. For blower air in 3.3 m/s (650 fpm) ventilation, the results were dependent upon nozzle type. Three different nozzles were tested. At 30 min after application, 74 to 92 percent of foam agent A remained, while 3 to 50 percent of foam agent B remained. Compressed air foam seems to remain intact for longer durations and is easier to apply than blower air foam. However, more water drained from the foam when using compressed air foam, which demonstrates that blower air foam retains more water at the roof surface. Agent A seemed to be the better performer as far as roof application is concerned. This testing demonstrates that roof application of foam is feasible and is able to withstand a typical face ventilation velocity, establishing this technique’s potential for longwall shield dust control.

First page of Experimental Study on Foam Coverage on Simulated Longwall Roof
Peer Reviewed Journal Article - February 2018

NIOSHTIC2 Number: 20054554

Trans Soc Min Metall Explor 2018 Feb; 342:72-82


Page last reviewed: 3/27/2019 Page last updated: 3/27/2019