Mining Groundwater Model and Drainhole Well for groundwater Depressurization

[Hafids Galant A]

Hello everyone,
I have a question regarding the groundwater model for mining and pumping areas. I have simulated mine-out conditions using a steady-state simulation on a regional scale. The results indicate that a drawdown in the groundwater table is necessary to prevent the mine slopes from becoming saturated. However, when I ran a simulation of pumping and vertical drainholes using transient-simulated drain boundary conditions, it did not produce any changes. and in the pumping simulation, the model did not show a cone of depression, and the drawdown observed in the model does not match the actual field conditions (a drawdown of approximately 25–30 m). I performed the simulation using Visual ModFlow Flex 9 with the NWT solver.

Based on this case, should I change my model area from regional to focus solely on the mining pit? Or should I adjust my input parameters again?

I would greatly appreciate any answers to this issue so that I can gain a different perspective on modeling, especially in mining areas

Thank you
Best regards

Hafids Galant