11. Application of Models for Reactive Mass Transport at Mining Sites

Christoph Klinger, Michael Eckart
Minimum 5, maximum 20 delegates
Regular € 290/310, Students € 200/220

At some point, a mine’s deposit is depleted and dewatering is stopped for each mine. With the rising water, manifold chemical processes between water, water constituents and the rocks are initiated. The water formed during the flooding differs almost always substantially from the water previously pumped in the active mine. Therefore, the knowledge of future quantity and composition is a prerequisite for the approval procedure of the mine decommissioning and, if necessary, the planning of a suitable water treatment. So far, there are no internationally accepted standards or guidelines on how to conduct such a mine water forecast. This course offers a methodology, which is already routinely used in many mining companies and ensures an effective and qualitatively consistent project processing.

The short course will include a presentation of the geochemical and hydraulic basics as well as work with the participants in the respective tasks by means of examples. The required input data will be developed as well as their transformation and implementation for a model tool. Mine specific geochemical processes and the requirements for proper model setup and calibration are discussed.

Programme

1. Introduction into the model concept
­ Setting of a mine site and requirements for a model
­ Limitations and possibilities
­ Development of a 3-dimensional flow and mass transport model for mining
­ Source terms: Consideration of natural inflows and mining-related sources
­ transport units, special transport units such as suspended matter
­ Transport influencing factors (process description an model implementation): sedimentation rates, sorption, microbial catalyzed processes
­ Void space: Spatial consideration of void space allocation and drifts
­ Flow paths: hydraulic connections, in particular time-dependent hydraulic properties in hard coal mining and turbulent flow laws in galleries and boreholes
­ Water level-dependent time-varying hydraulic boundary conditions
2. Model setup
­ Introduction into the user surface of ReacFlow3D
­ CAD-construction of the basic model
­ Implementation of a CAD-based model in an executable flow and mass transport model
­ Documentation of hydraulic situation: Water tree as basis for quality and flow rate calibration
­ Interfering factors in the assessment of water quality
­ Source term evaluation for reproduction / calibration of mobilization processes (e.g. oxidation products, salts, operating fluids…)
3. Model calculations
­ Calibration of flooding events (e.g. plausibility control)
­ Implementation of the planned flooding scenario
­ Forecast calculations for future decommissioning activities
­ Interpretation of model results

Christoph Klinger: chemical basics, aspects of mine water management and model input data, calibration and process control

Michael Eckart: model description (geochemistry and hydraulics), model setup, implementation of the input data, model application.

This short course is intended to provide a introduction to the application of mining compatible models with a practical orientation. Beyond the hydraulic and geochemical understanding, possibilities for the model transformation of real mining sites and the spatially differentiated processes are conveyed. Common understanding of the fundamentals / basic data for a mine water quality forecast, the methods of processing the basic data and appropriate software tools for processing.

This course is for representatives of mining companies, engineering consultants and authorities Documentation of a basic examle; proposal for a standard-methothology will be handed out to the attendees.