We showcase the tools and techniques used by CSIRO's Coal Mining Research Program to numerically model groundwater flows around underground coal mines. Results quantifying the height of connective fracturing and its upscaling into a mining-induced permeability enhancement are presented. These results depend on overburden lithology and stratigraphy as well as mining parameters such as cutting height. The permeability enhancements have a great impact on water inflows to the mine operations. In contrast to many other groundwater settings, unsaturated flow is important around underground mines, and our open-source software package can simulate this efficiently. We present an example of a regional-scale groundwater model involving many mines that predicts impacts for centuries into the future.