More often than not, mining operations need water - and lots of it!
The availability of adequate, sustainable and suitable water supplies
is crucial, whether it be for drilling, ore processing or dust settlement.
As mining operations are frequently located in isolated areas with little
available surface water, mine managers and engineers are increasingly
looking for ways to incorporate groundwater resources into their mining
and ore-processing operations. In fact, sometimes the overall economic
viability of a mine will be based solely on the availability of suitable
On the other hand, activities associated with mining, including excavation
of huge voids, dewatering, and contamination, can cause major disruptions
to surface water and groundwater systems. Regulatory authorities often
require the assessment of a mine's possible impacts upon groundwater
systems. Information provided by such assessments will allow appropriate
mitigation procedures to be employed, controlling the extent of any
possible deleterious impacts upon the natural and human environment.
C. M. Jewell & Associates Pty Ltd (CMJA) has considerable depth
of expertise in all facets of hydrogeological assessments related to
mining activities. We use a range of innovative investigative tools,
including electromagnetic, aeromagnetic and DC groundwater geophysics,
aerial-photograph and remotely sensed image analysis, soil/subsoil surveys,
drilling investigations and specialised water sampling methods. The
analysis of field data is planned at a level appropriate to the project
goals, but may include estimation of infiltration rates, calculation
of groundwater velocities, calculation of contaminant mass balances,
geographic analysis (using digital GIS technology), groundwater modelling
or contaminant transport modelling.
Perhaps you require suitable groundwater resources to support mining
operations; perhaps you need to assess the impact of mining/quarrying
operations on underlying groundwater resources; perhaps you need someone
to design a groundwater monitoring program. Whatever your need in this
area, CMJA has the experience, knowledge and technology to help. Each
project is tailored to the requirements of the client, and to the need
to provide supporting information to regulatory authorities or operational
Included below are some interesting examples of CMJA's hydrogeological
investigations in the mining sector.
Identifying groundwater resources for mining prospects
The availability of suitable groundwater resources may be a significant
factor in the decision to progress a mineral deposit from the
prospect stage into an operating mine. CMJA has conducted hydrogeological
investigations for Peak Hill Gold Mine, Golden Cross Resources
NL (Cargo gold prospect and Kempfields silver/barite prospect)
and David Mitchell-Melcann Pty Ltd (Attunga limestone quarry)
to identify suitable groundwater resources for mining and ore-processing
operations. This usually requires a multi-phase approach, involving
review and assessment of existing geological and hydrogeological
data sets, structural interpretation of aerial photographs and
remotely sensed images, geophysical surveys (preferably using
electromagnetic techniques), and good geological instinct.
Assessing the potential impact of mining operations upon groundwater
Before consenting to the development and/or expansion of a mining
operation, the regulatory authority usually requires an assessment
of that operation's impact on groundwater conditions and resources.
Frequently, when mining is to proceed below the water table, the
assessment must take into account impacts of dewatering and depressurisation.
Similarly, the potential impact of an open-cut or underground
mine on natural surface water and groundwater flow systems must
be assessed. Alternatively, risk-based assessments of the potential
for aquifer contamination, or to identify contaminant migration
pathways, may be required.
CMJA has conducted many such assessments. Our clients have included
Enhance Place Pty Ltd (Enhance Place Colliery near Lithgow, NSW),
David Mitchell Pty Ltd (Sulcor limestone mine and Attunga limestone
quarry, both near Tamworth), Concrite Quarries Pty Ltd (Exeter
Basalt Extraction Area, Southern Tablelands, NSW), ACI Industrial
Minerals (silica sand mining at Tanilba Northern Dune, Port Stephens,
NSW), Chadcole Pty Ltd (Kempsey Clay operations, north coast,
NSW) and Calga Sands/Rocla (Calga, Central Coast, NSW).
Typically, we approach impact assessments in a staged fashion.
First, potential aquifers that may be at risk must be identified
by review and assessment of existing geological and hydrogeological
data sets. Secondly, it is necessary to deduce or estimate the
baseline hydrogeological properties of the aquifers and surrounding
geological medium. These include hydraulic conductivity, porosity,
lateral and vertical hydraulic gradients, and groundwater geochemistry.
Finally, having reviewed and interpreted all relevant information
sets, we can assess the impact of a particular mining operation.
Such assessments can be qualitative and/or quantitative, depending
upon the requirements of the client.
Acid generation at McKinnons Gold Mine, Cobar, NSW
In order to meet the requirements of regulatory authorities, Burdekin
Resources NL commissioned CMJA to conduct a preliminary study
to estimate the final open-pit water chemistry following closure
of the mine. Hydrogeochemical speciation modelling using MODPHRQ,
a development of the well-established code PHREEQC, was used to
model the hydrogeochemical processes controlling the geochemical
evolution of groundwater. This allowed predictions of the final
open-pit water quality.
Development of a groundwater monitoring plan, Sulcor Limestone
So that David Mitchell Pty Ltd could comply with licensing requirements,
CMJA was commissioned to design a full groundwater monitoring
plan. This plan included design and construction specifications
for the required groundwater monitoring network in addition to
a groundwater sampling and groundwater level measurement plan
specifying monitoring schedules and analytical suites, standard
operating procedures for collecting measurements, sampling, sample
handling and documentation, quality assurance/quality control
procedures and reporting schedules.
|Development of a post-closure groundwater
monitoring system, Kelian Gold Mine, East Kalimantan, Indonesia
CMJA reviewed all the hydrogeological and geotechnical data available
for the site, identified key areas of potential impact, then designed
and installed a monitoring network of 24 wells subsequently, reactive
transport modelling to simulate metal transport to the nearby Kelian
River was carried out.
How CMJA can help you
We have the expert capability to help you with groundwater issues related
to the mining industry. Whether you need to unravel complicated hydrogeological
settings, locate groundwater resources, make reliable predictions of
water quality impacts, or assess the impact of mining operations on
groundwater systems or vice versa, we can meet your needs. We also offer
a full-service consultancy in this field, from water sampling to expert