Divisions based on groundwater chemical characteristics and discrimination of water inrush sources in the Pingdingshan coalfield

Within the Pingdingshan coalfield, the spatial distribution characteristics of key groundwater chemical components were studied in four aquifers that influence coal-mining operations. Thirty-six water samples were collected from the four aquifers, which were divided into smaller units. Discriminant models of mine-water inrush sources were developed for the three divisions I, II_I, and II_II, and engineering verification was conducted. The results showed that the main indices influencing groundwater chemical characteristics were Na⁺+K⁺, Ca²⁺, Mg²⁺, Cl⁻, SO₄ ²⁻, and HCO³⁻ in the Pingdingshan coalfield with regional variations according to faults and synclines. The Guodishan fault was the primary groundwater chemical division structure, which divides the Pingdingshan coalfield into two primary groundwater chemically characteristic units, divisions I and II. The Likou syncline was the secondary groundwater chemically characteristic structure, which divides division II into two secondary groundwater chemically characteristic units: divisions II_I and II_II. Discriminant models of water inrush sources in divisions I, II_I, and II_II (12 discriminant functions) were developed, and engineering verification showed that discrimination accuracy for 16 groundwater samples in four aquifers of three divisions was 93.75 %.