Abstract
Strip mining is the key technology to solve the problem of coal mining under water, so mastering the law of overburden load transfer in strip mining is the key to safe production in working face. We studied it in the context of the shallow seam No. 3 in the Shanghe Coal Mine (northern Shaanxi Province, China) through similarity simulation and field measurement analysis. A theoretical analysis, based on the concept of pressure arch, allowed the establishment of a continuous arch theoretical model for the strip coal pillars (or filling bodies) of the mine. A similar simulation study on strip filling and staged mining has previously shown that, in a first stage, the overlying strata load is mainly transferred to the remaining strip coal pillars; in a second stage, this load is mainly sustained by the odd-numbered strip coal pillars; finally, in a third stage, this load is mainly sustained by the first-stage strip filling body, while the third-stage filling body is not loaded. Our theoretical analysis showed that, during the first stage, the overlying rock load outside the arch was mainly sustained by the arch structure, while that inside of the arch was sustained by the filling body; in the second stage, the arch structure lost stability during the recovery of the even-numbered coal pillars and the arch axis developed upward, leading to the formation of a new arch with an odd number of coal pillars as the arch foot; in the third stage, after the recovery of the odd-numbered coal pillars, a new arch was formed. The arch foot of the new supporting structure was represented by the first-stage filling body; moreover, the load was mainly borne by the second-stage filling body, ensuring the stability of the overburden rock after mining. The theoretical analysis revealed that the pillar or filling body only bears part of the overburden load in strip filling mining. The pillar (filling body) load in correspondence of working face 3216 during each stage of filling was measured and analyzed, proving a continuous arch structure transformation between the pillar and the filling body. Finally, we verified the reliability of the proposed theoretical model.
Highlights
The Yushen mining area is located at the border between the Maowusu Desert and the Loess Plateau, within a shallow seam mining area
Based on the pressure arch and key stratum theories (Li et al 2017; Yang et al 2016; Yu and Ma 2019; Huang et al 2017), we studied the application of solid coal paste filling mining to the Shanghe Coal Mine, which is located in a shallow coal seam area of the northern Shaanxi Province
The staged mining and filling methods were adopted for the similar simulation experiment on the mining and filling process, in order to reconstruct a slow transit of the overlying rock load onto the filling body
Summary
The Yushen mining area (northern Shaanxi Province, China) is located at the border between the Maowusu Desert and the Loess Plateau, within a shallow seam mining area. Du et al (Du et al 2019b) proposed the principle of direct roof control in strip structure filling (e.g., “water-retaining and water-storing” coal mining) by applying the finite-length beam model to an elastic foundation. We analyzed the load transfer of the overlying strata during the strip filling mining process through similarity simulation and theoretical analysis. The Shanghe Coal mine is located in the northeast of Yuyang District, Yulin City and belongs to “coal mining with water conservation” area Since it was built and put into operation in 1994, the room-pillar mining method has been used for a long time. The ratio of the filling body for the similar simulation experiment on the Shanghe Coal Mine was determined to be sand:gypsum:calcium carbonate = 3.12:0.21:0.35. A total of 22 load sensors were set up at the site, one for each strip during filling (Fig. 3)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
