Coal Preparation

Working Effectively with Saline Water in Coal Preparation - Report and Handbook

Coal Preparation » Environmental Improvement

Published: December 09Project Number: C17046

Get ReportAuthor: P. Ofori, B. Firth, C. McNally, A. Nguyen | CSIRO Energy Technology, University of Queensland, Chemical Engineering

A Handbook is provided with this report.  


This study was undertaken to identify the impacts of using saline mine water as coal preparation process water and the reuse of plant water as a means of reducing fresh water use and approaches to maintaining optimum plant efficiency. It examined the interaction between dissolved electrolytes, hydrophobic and hydrophilic solids and air bubbles and how they impact on coal preparation unit operations.


Availability of good quality water in sufficient quantities is seen as an emerging issue in the Australian coal industry. Potential approaches to meet this challenge are to reduce water consumption in coal preparation, increase recycling or use saline mine water if it is available on the minesite. With the last two options, the impact of dissolved salt build up on plant product quality and the efficiency of separation processes need to be understood.


The aim of the work was the establishment of the important physical forces which control the behavior of solids, liquid and air bubbles in CHPP separation processes and linking these with process performance in an environment of changing water quality. This new understanding allows the manipulation of these surface forces in a manner that mitigate negative effects of saline water use and thus maintain optimum process efficiencies.


This project studied the coal preparation processes that are impacted by salinity including flotation, filtration and sedimentation to clarify the effect of salt on these processes. This information was combined with the insight gained from basic surface chemistry studies, including particle-particle interaction forces by Atomic Force microscopy to understand how these processes are affected by salinity. This connection between practical impacts and the underlying surface forces controlling these effects is being used to formulate systematic approaches to mitigate any negative impacts and exploit positive effects to operational advantage. Operational guidelines for coping with the negative effects and enhancing any positive effects are provided.


From the process point of view, saline water has a positive impact in terms of improved flotation recovery or conversely reduced flotation reagents consumption especially when high concentrations of divalent cations such as Mg+2 and Ca+2 and divalent anions such as SO4-2 are present. The extent of this effect depends on the type of coal. For filtration and sedimentation rates, the impact of saline water is negative in the absence of flocculant addition, contrary to what may be expected from the Double Layer theory. Fortunately the use of flocculants has such an overwhelming positive impact on filtration and sedimentation rates that it overshadows the effect due to the salts and in that situation, the presence of the salts in most cases results in clearer sedimentation overflow with less residual solids.


The information acquired is presented in this report and a handbook linking the science to potential operational issues in a comprehensible manner that will provide plant operators with the capacity to determine unfavorable conditions and how best to deal with the situation. The benefit to the industry of is the improved management of coal preparation plants in an environment of changing water quality. Fresh water importation would be reduced as more mine water is used and recycled, contributing to corporate sustainable development goals.




Health and safety, productivity and environment initiatives.

Recently Completed Projects

C26061The Young’S Moduli, Poisson’S Ratios And Poroelastic Coefficients Of Coals

This report describes the measurement of coal (and rock) properties ...

C24015 Assessment Of Convergence Based Roof Support Design For Longwall Abutment Loads

The aim of Stage two of project C24015 was to develop a roof support...

C25072New Approaches To Mine Gas Analysis And Ratios

The spontaneous combustion of coal remains a hazard in underground c...


Open Cut

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

Recently Completed Projects

C26022Real-Time Prediction Of Coal Top Through Guided Borehole Radar Wave Imaging For Open Cut Blast-Hole Drilling

Damage to the tops of coal seams caused by incorrect blast stand-off...

C26027Using An Ecotoxicological Approach To Validate The DGT Technique For The Measurement Of Bioavailable Metal Concentrations

This project builds on the opportunity identified through Project C2...

C25039Prediction Of Long-Term Salt Generation From Coal Spoils

The release of salts from spoil piles has the potential to affect su...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C250083D Flotation Of Fine Particles

In this project a process for the continuous, selective agglomeratio...

C20052Full Scale Gravity - Desliming Using Cascading REFLUX Classifiers

Considerable quantities of fine coal are disposed of as part of the ...

C26007 Revised Dustiness And DEM Test Method (Update Of AS4156.6) Part 2:Preparation

In 2015 project C23054 investigated and reviewed the Australian Stan...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C25045Stage Two - Assessment Of In Situ High-Temperature Strength Of Cokes

Stage I of this project established a reliable and repeatable proces...

C27003Review Of ACARP Research To Support Marketing Of Australian Thermal Coal

In this project, researchers pinpointed issues relating to the use o...

C25044Trace Elements In Coal; Status Of Test Methods In Use And Their Applicability


The key objectives of this stage...

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C27008Selective Absorption Of Methane By Ionic Liquids

The connection of a ventilation air methane (VAM) abatement plant di...

C24061Proof-Of-Concept Photocatalytic Destruction Of Methane For Coal Mining Fugitive Emissions Abatement

Australia's fugitive emissions in 2015 were 41 Mt CO2-e (representin...

C23052Novel Stone Dust Looping Process For Ventilation Air Methane Abatement - Phase 3

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