Abstract
The water quality of mine water is obviously improved after being stored in underground reservoir, but the process of water-rock interaction and the purification mechanism of mine water quality are not clear. In this study, the water samples and rock samples collected in the underground reservoir of Daliuta coal mine were taken as the research object. Based on the analysis of the hydrochemical characteristics of the reservoir water samples and the characterization of the rock samples, combined with PHREEQC analysis, the mechanism of water quality purification of mine water was discussed. The results showed that the rocks in the underground reservoir had layered silicate structure and flaky kaolinite structure, with some irregular edges and microcracks, and higher specific surface area and total pore volume. These characteristics made the rocks have a certain adsorption and removal capacity for heavy metal ions and other pollutants in the mine water. The water-rock interaction, such as the dissolution of albite and halite, the precipitation of gypsum and kaolinite, and the cation exchange, resulted in the increase of the concentration of Na+ and the decrease of the concentration of Ca2+, Mg2+, and TDS in the outlet water, and the hydrochemical type changed from SO42--Cl-/Ca2+ type to SO42--Cl-/Na+ type. Moreover, this study shows that PHREEQC analysis can be used to analyze the water-rock interaction of coal mine underground reservoir and can obtain more detailed information; therefore, it may have the potential ability to help assess the migration and transformation of pollutants during the storage process of mine water in underground reservoirs.
Highlights
The severe shortage of water has seriously hindered the development of the energy industry in many coal-producing areas (Chen et al, 2016; Rathi et al, 2017), especially in the Shendong Mining Area (Ma et al, 2013), located in the arid and semi-arid areas of northwest China but with rich coal reserves (Chen, 2016)
This paper reveals the process of water rock interaction in coal mine underground reservoir and the purification mechanism of mine water quality, which provides theoretical support and reference for the future application of PHREEQC software to simulate the process of water rock interaction in coal mine underground reservoir and the efficient utilization of reservoir water
The results showed that the dissolution of Na+ occurred in the coal mine underground reservoir and mainly from silicate minerals like sodium feldspar was consistent with the mineral composition analysis of rock
Summary
The severe shortage of water has seriously hindered the development of the energy industry in many coal-producing areas (Chen et al, 2016; Rathi et al, 2017), especially in the Shendong Mining Area (Ma et al, 2013), located in the arid and semi-arid areas of northwest China but with rich coal reserves (Chen, 2016). In view of the above problems, Gu (Gu, 2015) put forward and successfully developed the coal mine underground reservoir technology using the cavity between the broken rock bodies in the mined space area formed after coal mining (Shi, 2021). The technology solves both the mine water disaster problem and realizes the efficient recycling of the mine water resources (Gu et al, 2016), providing more than 95% of the water use (Chen et al, 2016), which largely solves the production and domestic water problem in the mining area. The purification mechanism of mine water in the process of water rock interaction between mine water and rock in reservoir storage stage is not clear
Sign-in/Register to view highlights & summary 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.
