Abstract: There are three conventional ways to forecast the maximum water inflow in mine pits: diagram method, least-squares analysis，and linear regression analysis.These methods are all based on experiment data, which involve a quantitative forecast based on the mathematical statistical principle, many conditions and a bothersome process.The method proposed in this paper, based on the principle of conservation of energy and the equivalent undamped passage, summarizes the movement law of underground water inrush in mine pits and sets up an equation for the water inflow between rise and fall, which requires only simple conditions and is easy to solve with an accurate result.

Key words: Dynamic steady water level, Static steady water level, Maximum water inflow, Runoff passage, Mine pit, Vertical upcast movement