ACARP ACARP ACARP ACARP
Coal Preparation

Gravity Concentrator Expert Control System

Coal Preparation » Process Control

Published: November 13Project Number: C20048

Get ReportAuthor: Bob Drummond | QCC Resources

Currently there are over approximately 30 gravity concentrators comprising both the Advanced Separation Engineering TBS design and the FLSmidth, Reflux Classifier design installed and operating in Australian CPP's treating raw coal plant fines.

It is well established that both the effective Gravity Concentrator cutpoint and efficiency are related to both the selected operating variables, namely the bed density setpoint and the fluidising water flowrate, as well as the feed coal quality and how well the Gravity Concentrator units are maintained. Incorrect selection of these process settings by poorly trained operators may lead to less than optimal fine coal circuit metallurgical performance.

It is proposed that a range of point density readings at different elevations within the gravity concentrator sorting column be measured (rather than a single point density as is currently the case), and the resulting density profile or gradient be utilised to provide a usable correlation with respect to the unit processing cutpoint and processing efficiency. Further, if a usable correlation exists an expert control system can be developed to optimise the operation of the Gravity Concentrator by automatically adjusting the bed density setpoint and fluidising water rate to match an "optimum" density gradient profile.

The first phase of this project focussed on determining whether a usable correlation exists between the measured density profile within the gravity concentrator sorting column and measured processing efficiency of the unit.

A custom density probe was designed and fabricated through a collaborative effort between Burkert Fluid Controls and Quality Coal Consulting. This custom density probe included 10 probe sensors equispaced at 150mm centres so that the density profile within the sorting column of the Gravity Concentrator could be measured to a depth of approximately 1400mm.

The most recent TBS installation at Drayton CTU was used as a reference site for the site testing program. The coarse 2.4m diameter TBS which processes the nominal -2.2w/w+0.6mm fines was selected on which to undertake the sampling and density profile mapping.

A sampling campaign of 16 runs was devised and undertaken through November 2011 where the bed density setpoint and fluidising water rate were adjusted to manipulate the processing cutpoint and efficiency of the TBS.

During each 20 minute test run the TBS feed, overflow product and underflow reject were sampled and the sorting column bed density profile via the new multipoint density probe was logged.

Washability testing was carried out on the -2.2w/w+0.5mm sample composites and partition curves for each run were developed using a new curve fitting procedure. The new curve fitting procedure uses the standard Whiten with bypass approach but fits 2 separate curves to the raw washability partition data: a curve segment fitted to the low density data points and a different curve segment fitted to the high density data points. Constraints were developed to ensure that the individual curve segments were continuous and smooth at the transition point. This procedure resulted in a significant improvement in matching a "best fit" partition curve to the raw washability data.

Efficiency parameters such as Ep, cutpoint, low and high density bypass and combustibles recovery were derived from the laboratory data and fitted partition curves.

The density gradient data was analysed over each sampling period and a density gradient or density profile curve was fitted to the average point density data. The modified Hoerl equation (which has the general power function form) was found to provide the best fit of the average point density data.

The washability partition curve data and the measured point density data was examined and sampling runs which corresponded to poor TBS operation were discounted and removed from the final data set.

The three curve fitting parameters from the density gradient curves of best fit were correlated against the measured efficiency data derived from the TBS sampling testwork.

The shape and form of the density gradient curves were very similar for the data sets examined and although a few minor relationships (between the TBS efficiency data and the density gradient curve fitting parameters) were observed, the correlations were very poor and would not form a suitable basis to develop a workable control strategy to optimise TBS performance.

Considerable variation in the raw coal feed quality and the fine coal circuit operation (flooding sieve bends) which possibly impacted on the TBS metallurgical performance, may have also masked any correlations between the data sets.

Accordingly it is recommended that the second stage of this work (to develop an expert control system for Gravity Concentrators based on optimising the sorting column density profile) be not pursued.

Underground

Health and safety, productivity and environment initiatives.

Recently Completed Projects

C34019Longwall Bretby Cable Handling Monitoring With Fibre Optics

This project examined the potential of using fibre optic sensing tec...

C27049Mine Machine Radar Sensor Integration

The aim of this project was to develop an integrated radar sensor an...

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...

Underground

Open Cut

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

Recently Completed Projects

C33035High Water Recovery, Low Cost Desalination Using PV-Powered Membrane Capacitive Deionisation (Mcdi)

Capacitive deionization is a robust, energy efficient and cost effec...

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...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

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

NERDDC

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

NERDDC