Open Cut

Reducing Analytical and Water Quality Monitoring Costs using Diffusive Gradients in Thin Films (DGT) Technique

Open Cut » Environment

Published: May 16Project Number: C23027

Get ReportAuthor: Trang Huynh and Sue Vink | The University of Queensland

Release of mine water into streams in the Fitzroy catchment to remove surplus water accumulated during extreme wet seasons raised concerns about the impacts of releases on aquatic biota. The regulator has subsequently imposed stringent monitoring conditions that include a suite of 17 metals and arsenic. In many cases metal concentrations have been close to or below the analytical detection limit and well below guideline trigger values. In some cases elevated metal concentrations occur at upstream and downstream sampling sites due to natural processes. In other instances it is difficult to know whether a spike in the concentration of a single metal is due to natural or anthropogenic causes or simply contamination during sampling.


This study investigated the use of a novel in-situ method for determining metal and metalloid concentrations. The method, called Diffusive Gradients in Thin Film technique, measures metal and metalloid concentrations by uptake onto a resin. The units were tested in both laboratory and field trials. The metals and metalloids chosen for analysis in this work were based on a review of water quality data obtained from the Fitzroy Partnership for River Health. The laboratory trials exposed DGT units to filtered river water for a week. This solution was periodically spiked and diluted to imitate mine water releases and runoff events. Comparison of the DGT concentrations with the dissolved concentrations showed that the concentrations of each metal determined by DGT was usually lower than the average dissolved concentration. The relative proportion of DGT determined metals compared to dissolved concentrations varied between metals. This variation likely represents differences in the elemental properties of each metal.


In the field trials DGT units were deployed at four REMP monitoring sites in the Isaac River catchment and in two mine water dams. The sites were chosen to take advantage of several years of water quality monitoring undertaken as part of the EA conditions. The DGT units were deployed to capture metals and arsenic concentrations during periods with and without mine water releases. The concentration of metals and metalloids in the mine water dams were generally higher than in the rivers corresponding with higher salinity.  Results showed that the concentration of Ag, Cd, Co, Cr, Pb, V and Mo were below the LOR for grab samples and DGT in-situ measurements at all sites. Of the remaining metals and metalloids the bioavailable concentrations of most of metals in this study were significantly lower than the respective dissolved concentrations with clear differences in these relationships depending on the metal/metalloid. Results from the river trial also showed that most of the As and Zn concentrations determined by grab samples were below the LOR. By virtue of the integrative nature of the DGT technique the bioavailable concentrations of these metals could be determined. The concentration of all metals and metalloids using the DGT technique were all less than the guideline trigger values for these sites.


By design, the units provide an average concentration integrated over the period of deployment. Thus, one DGT unit could potentially replace numerous water samples and will provide a far more representative view of in stream concentrations over a deployment period. In addition, the uptake of metals and arsenic on the gel is known to mimic biological uptake of these constituents thereby providing a more robust indication of toxicity to aquatic organisms. The in-situ gel capture of metals and arsenic also reduces the possibility of contamination of water samples during collection that can easily occur in low concentrations. Because the units can remain in-situ during high stream flow periods and are deployed and recovered during low stream flow, the method can provide metal concentrations during high stream-flow periods without compromising the safety of personnel required to undertake water monitoring.


A period of longer deployments and manual water sampling across a wider range of water quality is recommended to better calibrate the DGT method against dissolved concentrations. Once fully calibrated, we expect that this technique could replace a considerable amount of the manual water sampling for metals and metalloids in routine compliance and other monitoring. In addition, incorporation of DGT units in standardised toxicity tests with a variety of taxa could provide insights into developing trigger values for bioavailable metal and metalloid fractions.


Health and safety, productivity and environment initiatives.

Recently Completed Projects

C27045Assessment Of Longwall Mining Induced Connective Fracturing

In underground mines the mining induced permeability change in the o...

C29007Innovative Coal Burst System To Investigate The Influence Of Confinement Loss And Pre-Conditioning On Coal Burst Mechanism

The challenges associated with designing and operating a safe and pr...

C28009Advanced Fracture Propagation Testing Of Coal Measure Rocks Under Dynamic Loading To Replicate Coal Burst Scenario

This project is aimed to address critical challenges regarding enhan...


Open Cut

Safety, productivity and the right to operate are priorities for open cut mine research.

Recently Completed Projects

C28035Topsoil Deficits In Site Rehabilitation Accelerated Transformation Of Spoils To Functional Soils

The incorporation of commercial biological amendments (compost, worm...

C34036Tyre Handler Testing Rig Stage 2: Lifting Trials

Tyre handling is a major source of risk in surface mining operations...

C29052Autonomous Water Pressure Sensors For Spoil Dumps And Dams

The geotechnical integrity and stability of a mine spoil dump or tai...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C33048Capability For Dewatered Tailings (DT) And Mixed Plant Rejects (MPR) Testing In Support Of A Critical State Soil Mechanics Framework For Potential Liquefaction Assessment

Testing of fine coal materials in the unsaturated state, such as dew...

C28062Improving Operation And Control Of Centrifugal Dewatering Using A Novel Online Tool

Centrifugal dewatering is one of the main processes used for fine an...

C23045Full Scale Trial Of The REFLUX™ Flotation Cell

A 2 m diameter REFLUX Flotation Cell™ (RFC™) was install...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C34060In-Situ Investigation Of Coke Structure Formation Under Stamp Charged Coking Conditions

Stamp charged cokemaking has emerged as an effective technique to im...

C34062Improving The Classification Of Microstructure Distribution In Coke CT Images Using Deep Learning And Lineal Path Calculations

This project builds on a number of earlier projects that have helped...

C29071Source Of Variability Of Reactivity Of Coke In The CSR Test

The Coke Strength after Reaction (CSR) test is used worldwide to det...

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C28076Selective Absorption Of Methane By Ionic Liquids (SAMIL)

This third and final stage of this project was the culmination of a ...

C29069Low-Cost Catalyst Materials For Effective VAM Catalytic Oxidation

Application of ventilation air methane (VAM) thermal oxidiser requir...

C23052Novel Stone Dust Looping Process For Ventilation Air Methane Abatement

This multi‐phase project is concerned with the mitigation of m...

Mine Site Greenhouse Gas Mitigation

Low Emission Coal Use

Step-change technologies aimed at reducing greenhouse gas emissions.

Recently Completed Projects

C17060BGasification Of Australian Coals

Four Australian coals were trialled in the Siemens 5 MWth pilot scale ga...

C17060AOxyfuel Technology For Carbon Capture And Storage Critical Clean Coal Technology - Interim Support

The status of oxy-fuel technology for first-generation plant is indicate...

C18007Review Of Underground Coal Gasification

This report consists of a broad review of underground coal gasification,...

Low Emission Coal Use

Mining And The Community

The relationship between mines and the local community.

Recently Completed Projects

C16027Assessing Housing And Labour Market Impacts Of Mining Developments In Bowen Basin Communities

The focus of this ACARP-funded project has been to identify a number...

C22029Understanding And Managing Cumulative Impacts Of Coal Mining And Other Land Uses In Regions With Diversified Economies

The coal industry operates in the context of competing land-uses that sh...

C23016Approval And Planning Assessment Of Black Coal Mines In NSW And Qld: A Review Of Economic Assessment Techniques

This reports on issues surrounding economic assessment and analysis ...

Mining And The Community


National Energy Research,Development & Demonstration Council (NERDDC) reports - pre 1992.

Recently Completed Projects

1609-C1609Self Heating of Spoil Piles from Open Cut Coal Mines

Self Heating of Spoil Piles from Open Cut Coal Mines

1301-C1301Stress Control Methods for Optimised Development...

Stress Control Methods for Optimised Development and Extraction Operations

0033-C1356Commissioned Report: Australian Thermal Coals...

Commissioned Report: Australian Thermal Coals - An Industry Handbook