Mine dewatering design
KLM Consulting Services has led the groundwater profession in Southern Africa in providing comprehensive hydrogeological and dewatering consulting services to major Mining Houses. Open pit and underground mines require dewatering and depressurisation to ensure high-wall stability and pit floor workability. It is important to maintain the water table below the mine sump and to lower the pore pressures in the slopes. To obtain background data on water levels and pore pressures and calculate the effectiveness of the dewatering system that will be used, dewatering has to begin before the onset of mining.
Our areas of mine dewatering design and depressurisation expertise include the following:
- Structural mapping and inflow plotting;
- Testing the hydraulic properties of rocks;
- Installation of monitoring networks and the data base set up;
- Numerical modelling of water inflow and dewatering schemes;
- Layout of drainage galleries or drain holes;
- Design of dewatering and supply boreholes;
- Supervision of construction and test pumping of boreholes and drain holes;
- Design and operation of groundwater monitoring and remediation systems;
- Mine-Waste Impact Assessments and Management;
- Modelling of post mining pit chemistry and mine closure.
All mines that are excavated below the water table need some form of dewatering. The scale of the dewatering effort is dependent upon the following factors:
- The hydrogeological characteristics of the rock mass in which the excavation takes place.
- The depth of the excavation below the water table.
- The strength of the materials making up the pit slopes.
Groundwater resource development and management
Groundwater supply in Southern Africa accounts for 50% to 85% of the domestic supply in rural areas. Due to declining rainfall, demand for groundwater is increasing. Municipalities and private companies need to ensure the most efficient use of existing resources.
Over the past thirty years, KLM Consulting Services has identified, developed and implemented large scale wellfields (6Mm/yr to 12Mm /yr) and designed their management programmes. KLMCS understands it is important that for future generations, these resources are managed sustainably and effectively.
We also have expertise in:
- Groundwater exploration and hydrocensus
- Groundwater exploration programmes using remote sensing and geophysical methods
- Down-hole geophysical logging surveys
- Preparation of terms of references (scope of work) for drilling and pumping test activities
- Supervision of drilling and pump testing of water supply boreholes
- Design of boreholes and supervision of construction
- Design and implementation of aquifer pumping tests
- Analysis of aquifer testing and evaluation
- Groundwater sampling according to internationally acceptable protocols
- Water quality assessment
- Numerical modelling of groundwater flow and solute transport
- Aquifer monitoring and water management strategy
- Licensing with authorities and compliance with stock exchange regulations
- Artificial recharge programs
- Management, development and monitoring of well fields and major aquifers
- Writing and review of Bankable Feasibility studies
- Reducing water costs to businesses.
Environmental impact assessment and environmental management reports.
Government, lenders and stock exchange regulations impose environmental liability on past, current and future land users. Before inception of any project, an environmental impact assessment study has to be conducted to determine potential effects on the environment and possible mitigation.
Groundwater can be contaminated from urban waste, industrial effluent, diffuse source or mine tailings. Prevention and control require effective containment and management techniques.
KLMCS has expertise in:
- Sampling of soil and groundwater for contaminants (including volatile organics such as chlorinated hydrocarbons)
- Geophysical surveys to determine preferential groundwater flow paths and tracing of pollution plumes
- Installation of monitoring networks
- Satellite and air photo interpretation to locate seepage and sub-surface flow from waste disposal facilities
- Tier 1 and 2 site assessments in accordance with the Risk Based Corrective Action (RBCA) approach
- Health based risk assessment according to the US EPA protocol
- Modelling of contaminants (including hydrocarbon and chlorinated hydrocarbon) transport and degradation
- Writing of Environmental Management Program Reports (EMPRs) and Environmental Impact Assessments (EIAs)
- Expert testimony
- Review of EIA’s and EMPR’s.
- Development of conceptual and numerical models
- Groundwater models are valuable tools in determining and simulating ground movement of water and contaminants. The initial step in setting up a mathematical model is the development of a conceptual model, which is then coded using an appropriate software programme such as MODFLOW, FEFLOW, MINEDW (through HCItasca USA), PHREEQC, BIOCHLOR, SEQUENCE, RBCA and others, depending on the applicability to the project.
KLMCS areas of expertise include:
- Collection and processing of pump testing, hydrogeological and geochemical data
- Preparation of data plots, cross sections, contour diagrams, geostatistical analysis
- Aquifer simulation to determine drawdown, wellfield design and dewatering requirements
- Solute transport and flow path modelling for environmental studies
- Simulated aquifer clean up, protection and management
- • Risk analysis and cost benefit evaluation
Cost effective and successful remediation design and technologies are currently being researched in order to offer our clients a solution to groundwater contamination problems. We assist clients not only in the evaluation, but also in the design and implementation of remedial and groundwater control systems.
KLMCS areas of expertise are:
- Conventional excavation and disposal;
- Monitored natural attenuation (MNA);
- Enhanced biodegradation and bioremediation (both in-situ and ex-situ);
- Groundwater pump and treat systems;
- Groundwater hydrodynamic control systems (gradient reversals);
- Scavenger systems and recycling
In addition we utilise a network of qualified contractors to implement the following aspects:
- Soil remediation systems;
- Air sparging;
- Soil vapour extraction;
- Surface/subsurface geotechnical structures;
- Water treatment and disposal systems;
- Underground storage tank removals.
Courses are given each year by the staff of KLM Consulting Services and its associates. The courses are designed for managers, engineers and geologists working in a mine environment, where groundwater, (either too much or too little) needs to be managed. The emphasis is balanced between hard mining issues, such as the prediction, occurrence and removal of groundwater, as well as the environmental considerations and reduction in pollution. Professionals who manage groundwater projects also benefit from the courses.
The skills gained from the courses are:
- A thorough understanding of groundwater occurrence and movement;
- An understanding of different mine dewatering techniques;
- The ability to manage groundwater projects and optimise returns;
- The ability to identify potential sources of pollution.
- Geographical Information Systems (GIS)
We offer a wide spectrum of GIS services which include:
- GIS programming, solutions design and implementation
- Spatial Database setup, programming and maintenance
- Web Based GIS programming and configuration
- GIS hosting and virtualised GIS server setup
- Spatial Analysis
- Gap Analysis
- Spatial Data Maintenance and Data Migration
- Cartography and Customised mapping
- Differential GPS Survey and GPS Data Analysis
- Rapid point survey data collection
- Utilities Mapping
- GIS Support, Implemented Systems Documentation and Training
KLMCS has been contracted to work on mines dealing in coal, base metals, gold, kimberlite, platinum, uranium and industrial minerals.
Our Clients include:
- AB Global Mining
- Akanani Mining
- Amplats Ltd
- Anglo American Corporation of South Africa
- Anglogold Free State
- Anglogold Vaal River Operations
- Anglogold West Wits Mines
- Anglovaal Ltd
- Aviva Corporation, Australia
- Barplats Ltd
- BHP Billiton Ltd. (MAC)
- Boteti Mining Company and Lundin Group (AK6, Karowe)
- Botswana Department of Water Affairs
- CIC Energy
- De Beers Consolidated Mines (Finsch, Premier/Cullinan, Kimberley mines, Koignaas, The Oaks, Williamson and Venetia)
- Debswana mines (Orapa, Jwaneng, Damtshaa and Letlhakane)
- Discovery Metals Ltd, Australia
- Equinox Minerals Limited Australia
- Gautrain Bombela Consortium
- Gem Diamonds
- Gibb (Arcus Gibb)
- Goldfields Ltd
- Highland Mining Corporation Limited
- Impala Platinum Ltd
- Industrial Development Corporation of South Africa
- Ingwe Ltd
- International Mining Consultants (World Bank) JCI projects
- Kamoto Mines
- Lumwana Mining Corporation
- Malawi Department of Water Irrigation and Development
- Mining Plus
- Mocambique Department of Water (DNA)
- Murray and Roberts
- National Union of Mineworkers
- Noventa Pty Ltd
- Oppenheimer & Sons
- Paradigm Project Management
- Parsons Brinckerhof ( PB Power)
- Price Forbes Control Risk Management (Lloyds of London)
- Rio Tinto Ltd
- Rossing Uranium
- Snowden Consulting
- South African Department of Environmental water
- Southern Era Resources (Klipspringer) Toronto
- SRK Consulting Services
- Sulzer Pumps
- Teal Mining Pty Ltd
- UNESCO (Ramsar Convention)
- Vedanta Resources PLC
- The University of the Witwatersrand