title: Novel approach for extinguishing large-scale coal fires using gas-liquid foams in open pit mines.
abstract: Coal fires are a serious threat to the workers' security and safe production in open pit mines. The coal fire source is hidden and innumerable, and the large-area cavity is prevalent in the coal seam after the coal burned, causing the conventional extinguishment technology difficult to work. Foams are considered as an efficient means of fire extinguishment in these large-scale workplaces. A noble foam preparation method is introduced, and an original design of cavitation jet device is proposed to add foaming agent stably. The jet cavitation occurs when the water flow rate and pressure ratio reach specified values. Through self-building foaming system, the high performance foams are produced and then infused into the blast drilling holes at a large flow. Without complicated operation, this system is found to be very suitable for extinguishing large-scale coal fires. Field application shows that foam generation adopting the proposed key technology makes a good fire extinguishment effect. The temperature reduction using foams is 6-7 times higher than water, and CO concentration is reduced from 9.43 to 0.092‰ in the drilling hole. The coal fires are controlled successfully in open pit mines, ensuring the normal production as well as the security of personnel and equipment.
authors.affiliation: School of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116, China. luxinxiao123@163.com.|State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou, 221116, China. luxinxiao123@163.com.|Key Laboratory of Gas and Fire Control for Coal Mines of Ministry of Education, China University of Mining and Technology, Xuzhou, 221116, China. luxinxiao123@163.com.
authors.forename: Xinxiao
authors.initials: X
authors.lastname: Lu
authors.affiliation: School of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116, China. wdmcumt@gmail.com.|State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou, 221116, China. wdmcumt@gmail.com.|Key Laboratory of Gas and Fire Control for Coal Mines of Ministry of Education, China University of Mining and Technology, Xuzhou, 221116, China. wdmcumt@gmail.com.
authors.forename: Deming
authors.initials: D
authors.lastname: Wang
authors.affiliation: School of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116, China.|State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou, 221116, China.|Key Laboratory of Gas and Fire Control for Coal Mines of Ministry of Education, China University of Mining and Technology, Xuzhou, 221116, China.
authors.forename: Botao
authors.initials: B
authors.lastname: Qin
authors.affiliation: School of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116, China.
authors.forename: Fuchao
authors.initials: F
authors.lastname: Tian
authors.affiliation: School of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116, China.
authors.forename: Guangyi
authors.initials: G
authors.lastname: Shi
authors.affiliation: School of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116, China.
authors.forename: Shuaijun
authors.initials: S
authors.lastname: Dong
mesh_terms: D003031:Coal / Q000032:analysis*; D003032:Coal Mining / Q000379:methods*; D005390:Fires / Q000517:prevention & control*
chemical_list: D003031:Coal
keywords: Coal fire; Fire extinguishment; Foam preparation; Foaming; Jet