Study on chemical characteristics and evolution law of groundwater in Taigemiao Mining Area

Taigemiao Mining Area is rich in coal resources, but water resources are scarce and the ecological environment is fragile, and the use of hydrogeochemical methods to carry out research on the chemical characteristics and evolution law of groundwater in the whole basin of mining areas can provide scientific support for green mining in mining areas. Piper three-line diagram was used to analyze the types of Cretaceous groundwater, Jurassic groundwater, river water and lake water, and the water chemical characteristics met the characteristics of lake water mixed by river water and evolving groundwater; through Gibbs diagram analysis, it is concluded that the Cretaceous and Jurassic groundwater in the cyclic evolution process It is controlled by rock and evaporation; the ion ratio endmember method further shows that the Cretaceous and Jurassic groundwater is dominated by silicate rock salt and rock salt, accompanied by ion exchange; finally, the mass balance simulation shows that the Cretaceous groundwater circulation During the evolution process, dolomite, gypsum, and rock salt minerals are dissolved, CO₂ is absorbed, and calcite is precipitated. With ion exchange, it can be mixed with different proportions of river water to form lake water, but Jurassic groundwater can only be mixed with a small amount of river water or not mixed with river water. The river water accounts for 83% of the water supply of Hongjiannao Lake. Jurassic groundwater cannot be the main source of water supply. The main sources of water in Hongjiannao Lake are Cretaceous groundwater and river water. Combined with the hydrogeological conditions of the mining area, the groundwater flow system of the mining area is divided into the Cretaceous groundwater flow system in the south, the Cretaceous groundwater flow system in the north and the Jurassic groundwater flow system in the deep. Coal mining directly affects the Jurassic groundwater flow system. On the premise of ensuring that the two Cretaceous groundwater flow systems are not damaged, when coal mining drainage only captures the outflow water from the Jurassic boundary or a small amount of Jurassic replenishment to Hongjiannao, coal mining will affect Hongjiannao and surrounding rivers. impact is minimized.