Research on Temporal Patterns of Water–Rock Interaction in the Coal Mine Underground Reservoir Based on the Dynamic Simulation Test

Abstract

The temporal pattern of water−rock interaction is significant in predicting the ion concentration of the effluent in coal mine underground reservoirs. This study used the roof-caved rock samples and main incoming water (mine water and fissure water) of the Daliuta coal underground reservoir as the research object and designed four groups of dynamic simulation experiments of the water−rock interaction. Based on the main ion concentrations in the water sample at different reaction times, Q-type hierarchical cluster analysis (HCA) was used to classify the stages of water− rock interaction. The types and intensities of water−rock interaction in each stage were identified by combining the ion ratio and principal component analysis (PCA). Q-type HCA shows that the dynamic simulation experimental water samples can be divided into three categories according to the reaction time, representing the early, middle, and late stages of the water−rock interaction process. The influence of water quality on the division of the water−rock interaction stage is greater than that of rock characteristics. The ion ratio and PCA show that the dissolution of pyrite minerals, cation exchange reaction, and mineral adsorption mainly occur in the early stage of water−rock interaction, in which the cation exchange reaction plays a leading role in the change of ions in water. In the middle stage, the cation exchange reaction and the dissolution of carbonate minerals, such as calcite and dolomite, mainly occur, in which mineral dissolution is the main. In the late stage, the water−rock interaction is relatively weak, and the change of ion concentration in water is not obvious. This study proves the temporal patterns of water−rock interaction between caved rock and mine water (or fissure water) and differences in the types and intensities of water−rock interaction in each stage. The results can provide a theoretical basis for the optimization of the operation cycle of coal mine underground reservoirs and the prediction of effluent ion concentration.

Water Quality Characteristics and Water–Rock Interaction Mechanisms of Coal Mine Underground Reservoirs

“…Additionally, fine sandstone presented a relatively high content of Ca, specifically 6.20%, while the concentrations of K and Mg in both rock samples exceeded 1%. Based on this mineral chemical composition analysis, silicates or aluminosilicates may constitute the primary minerals present in these two rock samples, along with common-coal-seam associated minerals such as carbonates, gypsum, and pyrite. , …”

“…Based on this mineral chemical composition analysis, silicates or aluminosilicates may constitute the primary minerals present in these two rock samples, along with common-coal-seam associated minerals such as carbonates, gypsum, and pyrite. 11 , 26 …”

Study on the Interaction Mechanism between Residual Coal and Mine Water in Goaf of Coal Mine Underground Reservoir

“…Daliuta coal mine is divided into the 2 −2 and 5 −2 coal seams. The No.1, No.2, and No.3 reservoirs have been built in the mined 2 −2 coal seam, and two water recycling chambers have been built in the goaf of the 5 −2 coal seam [13,14]. According to statistics, the total water storage of the three reservoirs is 7.105 million m 3 , the amount of sewage recharge is 9780 m 3 /d, and the underground and surface water consumption is 12,420 m 3 /d [15].…”

The Microbial Community Composition and Nitrogen Cycling Metabolic Potential of an Underground Reservoir in Rizhao, Shandong Province, China

“…However, the rapid pace of economic growth has exacerbated the issues of water shortage and environmental deterioration [3]. The construction of underground reservoirs has emerged as a crucial strategy to alleviate these constraints, optimize water resource allocation, and achieve sustainable development [4]. To ensure water use safety in coastal areas and maximize water resource utilization, a construction scheme for underground reservoirs has been proposed.…”