Coal Preparation

Economic Effect of Low Amounts of Non-Magnetics in the Correct Medium

Coal Preparation » Gravity Separation

Published: November 16Project Number: C23046

Get ReportAuthor: Michael O’Brien and Bruce Firth | CSIRO

This project has developed a methodology by which the economic loss incurred in a plant when processing a coal through a Dense Medium Cyclone (DMC), operating with a correct medium relative density less than 1.4, when the non-magnetics concentration in the correct medium is varied due to plant stoppages, feed changes, clay breakdown or bleed valve setting changes can be determined. The genesis for the project came from several previous ACARP projects which examined the effect of the non-magnetic material concentration in the magnetite medium. The results of those projects showed that instability can occur with mediums that contain less than 20% by weight of non-magnetic material with a particle size less than 0.200 mm and with a correct medium relative density (RD) below 1.4.

The concentration the of non-magnetics in the medium can depend on the feed rate to the plant, the amount of clays in the feed, the breakdown of particles in the DMC circuit and the setting of the bleed to the magnetic separator. Sherritt, in ACARP C20045, found that if everything else was held constant and the feed rate to the plant changed then the amount of non-magnetics in the correct medium is directly proportional to the feed rate.

The use of a model to describe the washability of a coal was considered for this project as it would allow a quantitative description of the washability with a limited number of variables and facilitate the calculation of coal recovery when a partition curve was applied to it. Washability curves relate the mass and ash value of a density separated coal fraction to the density at which the corresponding separation was made. Only two basic relationships are required to characterise washability, the first relates ash value to relative density, and the second defines the distribution by mass % of the relative density fractions.

Two models were developed that described the ash value to relative density relationship and the distribution by mass % of the relative density fractions for the 39 Australian washability's provided by Armstrong that covered the "good" the "bad" and the "ugly" range of washability's over six categories.

An e-newsletter has also been published for this project, highlighting its significance for the industry.


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