2.0 Features of MINEDW
======================

The **MINEDW** software includes special features that facilitate
the 3-D simulation of dewatering operations in open-pit and underground
mines. Some of these features are as follows:

-  The progressive excavation of an open pit can be simulated in the
   model by changing the elevation of the nodes affected by mining over
   time.

-  A groundwater flow problem is simulated as saturated-unsaturated
   groundwater flow. This allows the finite-element mesh to remain fixed
   with time (except for excavations) and the saturated flow domain to
   adjust with time in accordance with changes in the position of the
   water table. The fixed mesh, in contrast to a deforming mesh,
   facilitates the representation of the spatial hydrogeologic
   variability of a groundwater system by the finite-element mesh.

-  **MINEDW** provides 3-D graphic representations of geology, model
   domain, pit geometry, groundwater heads, groundwater flux, recharge
   and evaporation zones, particle tracking, and pore pressures.

-  Specified-head boundary conditions can be imposed using heads that
   are either invariable with time or variable with time. In the latter
   case, the boundary heads are specified in terms of tables
   representing a hydrograph of the heads.

-  Specified-flux boundary conditions and internal source-sink terms are
   defined by a group of data sets that can be combined in different
   configurations for each time step.

-  Variable-flux boundary conditions can be imposed to simulate
   time-variant boundary fluxes in response to changing boundary heads.
   This boundary condi­tion allows the finite volume of the modeled flow
   domain to be “extended” to infinity by “attaching” the analytical
   solution for a semi-infinite, linear aquifer to the boundary of the
   flow domain. [II]_

-  The interaction between the groundwater system and river networks can
   be realistically simulated. Streams are simulated as a river network
   (or networks) that consists of a main river channel and tributary
   channels. The model accounts for streamflow depletions or additions
   by simulating the exchange of water between the stream and the
   groundwater system.

-  In addition, evapotranspiration of groundwater from vegetated areas
   or evaporation from bare-soil areas can be simulated. The
   evapotranspiration rate is assumed to be inversely proportional to
   the depth from the ground surface to the water table elevation.
   **MINEDW** uses the maximum evaporation rate and the extinction
   depth as constraints.

-  Spatial and temporal variation in precipitation across the model
   domain can be simulated. In areas with steep relief, **MINEDW** has
   the capability to simulate orographically controlled precipitation.

-  Open-pit excavation, open-pit backfilling, and pit-lake formation can
   be efficiently simulated within a **MINEDW** model.

-  **MINEDW** can efficiently simulate the formation of a zone of
   relaxation (ZOR) around a pit excavation or underground mining
   operation through time according to the mining schedule.

-  Outputs of pore-pressure distribution can be seamlessly used in both
   two-dimensional (2-D) and 3-D geomechanical models using Itasca’s
   geomechanical codes.