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.


Open Cut

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

Recently Completed Projects

C19024Establishing Ecologically Sustainable Mine Water Release Criteria In Seasonally Flowing Streams

Extreme rainfall conditions in the Fitzroy Catchment over an approxi...

C25030Coal Mine Open Pit Final Void Closure And Relinquishment - Addressing Uncertainty In Coal Mine Environmental Planning

This report addresses uncertainties faced by coal mine operators whe...

C27046Estimation Of True Deformation Vector From Slope Radar Monitoring

Slope deformation radar monitors are now widely used in open cut coa...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C27004Improving Coal Flotation With Oscillatory Air Supply

This report provides detailed information on coal flotation with os...

C25018Improving Solids Recovery And Moisture Reduction In Ultrafine Coal Dewatering

This report provides detailed information on fine coal dewatering in...

C27028Lab Froth Flotation Testing Guide With Coal Quality

Correct outcomes from laboratory froth flotation testing in coal bor...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C26039Nanoporosity In Cokes: Their Origin, Control And Influence On CO2 Reactivity

This project using the outcomes of previous project C24060, examine...

C28063A Comprehensive Technical Review Of High-Efficiency Low-Emission (HELE) Pulverised Coal Combustion Technologies For Power Generation

Research and development has been undertaken worldwide to realise co...

C28064Carbon Structure Transformation During Coking Of Australian Coking Coals: Better Understanding The Coke Formation

Carbon structures of coke that are formed during the plastic layer a...

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) - Phase 2 Demonstration In A Packed Bed Reactor

An alternative approach to high temperature oxidation of ventilation...

C26004CFD Modelling Of Reverse Thermal Oxidisers For VAM Abatement - CFD Modelling Of Fixed-Bed RTO Devices

The project is part of a larger multi‐phase program of study a...

C27058Technological Assessment Of A Recycle Reactor For VAM Abatement

Underground coal mining emits high volumes of methane, diluted in ve...

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