Double verification and quantitative traceability: A solution for mixed mine water sources

Accurate identification of mine water sources is one of the keys to safe coal mining. However, conventional water source identification methods rely on groundwater-level responses and hydrochemical characteristics. The identification results often have multiple interpretations, lack verification of the actual situation, and cannot trace source quantitatively for mixed water sources. In this paper, we propose a new double verification and quantitative traceability (DV-QT) method. The double verification consists of verification and the consistency of water source identification results based on conventional methods and verification of the rationality of both the water source identification results and the inrushing water channel results. When the verification fails, the groundwater-level or hydrochemical data shall be analyzed in depth, or the hydraulic connection between groundwater in the channel and water source needs to be determined. The quantitative traceability includes the multivariate mixing and mass balance calculations (M3) that calculate the proportion of water sources. Through an example application, the proposed method identified the causes of the identification error of the traditional hydrochemical characteristic analysis method, that is, the hydrochemical evolution process during water inrush cannot be ignored, and allowed for accurate water source identification and quantitative mine water traceability. The new approach is especially useful for mixed water sources and in mines with complicated hydrogeological conditions.