Minedw - Version 3.0 - Three-Dimensional (3D), Finite-Element, Groundwater Flow Program Software

MINEDW is a three-dimensional (3D), finite-element, groundwater flow program that was developed specifically for mining applications. MINEDW is used worldwide to design dewatering or depressurization systems, predict local and regional environmental impacts of mine dewatering, assist in the design of water-supply systems, simulate the infilling of a “pit lake” after mining ceases, and estimate pore-pressure distributions within highwalls for geotechnical design purposes. Its user friendly graphical interface with pre- and post-processing functionality provides a powerful numerical modeling environment.
 

Software Overview

MINEDW is used at more than 50 mines throughout the world for mining-related applications in diverse hydrogeologic and climatic conditions.

Developed from , MINEDW was validated by Sandia National Laboratories in 1998 and has been used at more than 50 mines world wide in diverse hydrogeologic and climatic conditions.

• Used at more than 50 mines throughout the world for mining-related issues in diverse hydrogeologic and climatic conditions
• Simulates open-pit and underground mining for dewatering design and input to slope-stability analysis;
• 3-D graphic representations of geology, model domain, pit geometry, groundwater heads, and pore pressures;
• Simulates excavation and subsequent pit-lake infilling to represent different mining schedules; and
• Simulates interaction between groundwater and surface water.

System Requirements in MINEDW

To install and operate MINEDW, your computer must meet the following minimum requirements:

• Processor – A processor with a minimum clock speed of 2 GHz is recommended. The speed of calculation for a MINEDW model is directly related to the processor’s speed; therefore, the selection of a high-speed processor is key to improving computational efficiency.
• Hard Drive – At least 150 MB of hard disk space must be available to install MINEDW. In addition, a minimum of 200 MB disk space should be available in order to save model files.
• RAM - The minimum amount of RAM that is required to load MINEDW is 4 GB.Generally, the combined RAM needed by MINEDW and its model storage should leave 0.5 to 1 GB for Windows operations. Windows applications that run simultaneously with MINEDW will reduce its calculation speed.
• Display – To achieve best performance, a discrete video card, a screen resolution of 1024 × 768 pixels, and a 16-bit color palette are recommended.
• Operating System – MINEDW is available as a 64-bit native Windows application. MINEDW running on Vista x64 and Windows 7 are also currently supported by Itasca.
• Output Device – By default, plots from MINEDW are sent directly to the Windows native printer. Plots can also be directed to bitmap formats (PNG or BMP).

Features in MINEDW

Finite-Element Grid

The grid is specified in terms of triangular prisms and facilitates representation of complex geometries and highly-variable spatial discretization, which is particularly useful for mining applications with complex geologic structures and steep hydraulic gradients.

Progressive Geometry

The elevation of nodes of the finite-element grid can be defined to vary through time. This enables more accurate representation of the underground workings and open pits according to the mine schedules being evaluated.

Saturated/Unsaturated Flow

The finite-element grid can remain fixed through time (with the exception of excavations), and the saturated flow domain can change through time in accordance with changes in the water table, further facilitating representation of the spatial hydrogeologic variability of the groundwater system without additional computational overhead of solving unsaturated flow equations.

3D Graphics
Represent geology, model domain, pit geometry, groundwater heads, and pore pressures in 3D.

Flexible Boundary Conditions
Boundary conditions can be represented as specified-head, specified-flux, and internal source-sink terms (each of which can be variant or invariant with time), or as variable-flux boundaries that simulate time-variant fluxes in response to changing boundary heads and an infinite aquifer.

Very Transmissive Zones
By defining links between specific node pairs with enhanced conductivity, very transmissive zones can be used to accurately represent tunnels, underground workings, declines, conductive faults, wells pumping from multiple layers, etc.

Groundwater/Surface-Water Interaction
Streams are simulated as river networks of hydraulic compartmentalization and the model simulates river depletions and additions from exchange with groundwater.

Evaporation/Evapotranspiration
Loss of water from bare/vegetated soils can be simulated and is proportional to the distance between the ground surface and water table, with maximum evaporation rate and extinction depth as constraints.

Pit Lakes
Excavation and pit-lake infilling of multiple pits can be simulated within the same model domain and their respective mining schedules represented simultaneously. The model also provides node-bynode fluxes into/out of the pit lake, evaporation and precipitation on the lake surface, and predictions of lake stages as a function of time, which can readily be used to predict detailed hydrodynamic and geochemical pit-lake conditions and to predict pit-wall seepage during mining.

Time-Variant Conductivity
Can be used to represent the zone of relaxation around excavations, backfilling operations, longwall and room-and-pillar coal mining, freeze-thaw conditions, or other scenarios where hydraulic conductivity may change during the simulation period.

Numerically Stable
Due in part to the finite element grid and the numerical methods applied in the model, MINEDW is typically very stable numerically. This is particularly important in cases where there is a high degree of hydraulic compartmentalization with steep hydraulic gradients.

MINEDW Applications

Mine Dewatering Planning

• Prediction of inflow to underground mine workings and open pits
• Prediction of requirements and schedule of dewatering wells and drainage galleries

Environmental Impact Assessment

• Drawdown predictions
• Assessments of impacts on surface water
• Pit-lake infilling simulations

Pore-Pressure Analysis

• As an input to ground-stability analysis
• Assessments of effectiveness of various pore-pressure reduction schemes