MODFLOW-USG: the New Possibilities in Mine Hydrogeology Modelling (or What is Not Written in the Manuals)

Geological heterogeneity associated with layers, open mine voids, tectonic faults and fractures can all make modelling difficult, particularly for mine dewatering. This heterogeneity is difficult to represent with the traditional MODFLOW structured grid. A new version of MODFLOW, called MODFLOW-USG (for UnStructured Grid), supports a wide variety of structured and unstructured grid types (Panday et al. in MODFLOW-USG version 1: an unstructured grid version of MODFLOW for simulating groundwater flow and tightly coupled processes using a control volume finite-difference formulation. USGS, Reston, 2013) that provide flexibility for modelling difficult geologic structures. This communication compares aspects of MODFLOW and MODFLOW-USG, and uses the Gbely lignite deposit as an example of a situation for which MODFLOW-USG could be applied.