Groundwater serves as an important water source for residents in and around mining areas. To achieve scientific planning and efficient utilization of water resources in mining areas, it is essential to figure out the chemical formation process and the ground water sulfur cycle that transpire after the coal mining activities. Based on studies of hydrochemistry and D,¹⁸O-H₂O,³⁴S-SO₄ isotopes, this study applied principal component analysis, ion ratio and other methods in its attempts to reveal the hydrogeochemical action and sulfur cycle in the subsidence area of Pingyu mining area. The study discovered that, in the studied area, precipitation provides the major supply of groundwater and the main water chemistry effects are dominated by oxidation dissolution of sulfide minerals as well as the dissolution of carbonate and silicate rocks. The sulfate in groundwater primarily originates from oxidation and dissolution of sulfide minerals in coal-bearing strata and human activities. The mixed sulfate formed by the oxidation of sulfide minerals and by human activities continuously recharges the groundwater, promoting the dissolution of carbonate rock and silicate rock in the process.

The compilation of serial maps of karst geology in China and Southeast Asia is a project under the “One Belt One Road” geological survey plan granted by China Geological Survey. This paper summarized the research trend of geoscientific mapping in China and Southeast Asia and introduced the significance,contents,technical routes,operating methods and progress of the project. Through bilateral and multilateral cooperation,this project builded an international cooperation platform for mapping and completes the preliminary compilation of related karst geological maps in China and Southeast Asia,thus filling up the blank of karst geological maps in this region.