Abstract:The underground brine resources in Laizhou Bay have declined significantly after nearly 20 years of intensive mining. It is very urgent to explore its sustainable mining model. The coastal underground brine can be recharged by various salt sources and has the potential for sustainable mining. Clarifying main sources of salt in underground brine and the change law of salt composition affected by human activities can help to standardize sustainable mining mode of underground brine. This research is carried out based on the results of groundwater level monitoring and groundwater sample chemical analysis during the underground brine mining and stoppage periods. The research results show that the underground brine in Laizhou Bay is mainly affected by seawater, evaporative salt or salt rock dissolution. Although the annual underground brine salt composition variation rule is consistent at different distances from the shore, there are differences in controlling factors. The salt recharged to underground brine during the mining period is mainly the salt evaporated and concentrated in the intertidal sediments. During the stoppage period, the evaporative salt or the salt dissolved from the salt rock is the main salt source of the underground brine. The type of water body (sea water or fresh water) that is easy to affect the underground brine storage area, and the working state (mining or stoping mining) of the underground brine mining area are main factors affecting the salt composition of the underground brine.
