Coupled simulation–optimization model for draining confined aquifer via underground boreholes to prevent water inrush of coal mines

Mechanical Analysis of the Failure Characteristics of Stope Floor Induced by Mining and Confined Aquifer

“…Water inrush has become the second most serious disaster after gas [3][4][5]. It not only causes heavy casualties and property losses but also severely damages local groundwater resources [6][7][8].…”

Development of a combined mining technique to protect the underground workspace above confined aquifer from water inrush disaster

“…The surroundings of underground coal mining are complex and the lower and upper strata close to the coal seams might have rich water, so there is a potential risk of floor water inrush when mining coal resources above confined aquifer especially when there is an obvious failure depth of seam floor (Guo et al 2018;Ma et al 2013Ma et al , 2015Malkowski et al 2014Malkowski et al , 2017Wu and Wang 2006). For instance, a maximum water inrush flow rate of 34.22 m 3 /s occurred in the Fangezhuang coal mine of Kailuan, China, causing an economic loss of up to 500 million yuan (Meng et al 2012;Meng et al 2018). In Zhaogezhuang coal mine as well, groundwater burst along the fault zone around tram rail and ventilating way, indicating that the fault zone played an important role in inducing the groundwater bursting (Wu et al 2004).…”

“…Then how to treat the loss of coal resource and repair the generated seam floor failure becomes the next question. Accordingly, during or after coal mining, there are some primary remedial engineering measures used to prevent water inrush from confined aquifers underlying coal seams (Cai et al 2019;Junthong et al 2019;Meng et al 2018;Niedbalski et al 2018;Palarski et al 2011Palarski et al , 2014Strozik 2017). One measure is draining the aquifer to lower the pressure on the aquiclude, but the aquifer is usually so thick that the aquifer is usually overdrained over long period without knowing how much water should be drained, which leads to many environmental problems (Meng et al 2018).…”

“…Accordingly, during or after coal mining, there are some primary remedial engineering measures used to prevent water inrush from confined aquifers underlying coal seams (Cai et al 2019;Junthong et al 2019;Meng et al 2018;Niedbalski et al 2018;Palarski et al 2011Palarski et al , 2014Strozik 2017). One measure is draining the aquifer to lower the pressure on the aquiclude, but the aquifer is usually so thick that the aquifer is usually overdrained over long period without knowing how much water should be drained, which leads to many environmental problems (Meng et al 2018). The other measure is grouting to block fractures in the aquifer, which also strengthens the waterresisting ability of the aquiclude, while the method of excavating strip coal pillars using caving zone backfill technology is evolving based on this aforesaid thought (Meng et al 2018;Zhu et al 2018b).…”

“…One measure is draining the aquifer to lower the pressure on the aquiclude, but the aquifer is usually so thick that the aquifer is usually overdrained over long period without knowing how much water should be drained, which leads to many environmental problems (Meng et al 2018). The other measure is grouting to block fractures in the aquifer, which also strengthens the waterresisting ability of the aquiclude, while the method of excavating strip coal pillars using caving zone backfill technology is evolving based on this aforesaid thought (Meng et al 2018;Zhu et al 2018b). As for the caving zone backfill technology, the slurry is grouted into goaf rather than aquifer or aquiclude to limit the damage of seam floor from its upward side.…”