Coal Preparation

Best Practice Guide to Dense Medium Cyclone Sampling and Analysis

The Australian coal industry has been progressively adopting dense medium cyclone (DMC) processing technology for the last 40 years. By the late 1970’s the use of 710 mm diameter units was very common, while since the mid 1990’s large diameter (1000 mm diameter and larger) ....  read more

Commercial Laboratory Scale Float-Sink Testing Using Stabilised Suspension

The objective of this project was to carry out commercial lab scale float-sink testing using the stabilised suspension of submicron zirconium dioxide developed in ACARP project C15057.

A float-sink separator has been developed for carrying out float-sink testing using ....  read more

CPP Feed Washability Prediction from Small Top Size Samples

Coal Grain Analysis (CGA) characterisation by size and RD provides an amazing insight as to the nature of each particular coal type.

Maceral analysis quantifies a coal in terms of its coal matter components and mineral matter. From that point of view it provides an absolute theoretical ....  read more

Delineation Of Large Diameter Dense Medium Cyclone Performance

This project evaluated the performance of a large diameter (1450mm cyclone diameter) high capacity (362mm equivalent inlet diameter) dense medium cyclone, treating a full size range of -50+1.4wwmm at cut-points in the range 1.60-1.70RD and 10-15% NG (+/-0.1RD). Under the broad range of ....  read more

Dense Medium Cyclone Forum Meeting Report

An ACARP Dense Medium Cyclone (DMC) Forum was held on 26th September, 2005 in which eminent Australian Coal Preparation professionals addressed issues identified by ACARP as important to the future direction of DMC R&D. Major findings were:

1. Behaviour of

Dense Medium Cyclone Handbook

This handbook is intended as neither an introductory text, nor as a manual for detailed design. Rather it seeks to provide guidance for experienced circuit operators who are already familiar with coal-washing dense medium cyclones and their ancillary devices, circuitry and control systems.

Development of a Dense Medium Separation Process for Fine Coal Based on the Use of a Teetered Bed Separator

The agreed ACARP objectives of this study were:-

• To develop a cheaper alternative to dense-medium cyclone technology for the treatment of –0.5 mm coal
• To evaluate alternative to magnetite as a potential dense-medium
• To provide data on the fundamental

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

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 ....  read more

Effect of g Force on Banana Screen Efficiency

Multi-slope (Banana) screen failures have been prevalent in the coal industry since the introduction of this type of screen in the 1980s. Increasing the size of these screens while benefitting the industry in terms of plant capacity and production has resulted in an increasing failure ....  read more

Effect of Particle Crowding at the Vortex Finder and Spigot on Dense Medium Cyclone Operation

This project addresses the priority of metallurgical efficiency improvements with respect to the operation of the Dense Medium Cyclone (DMC) and in particular the effect of crowding of the vortex finder and spigots on DMC operational efficiency. Coal preparation researchers and experts over ....  read more

Estimation of Steady State and Dynamic Dense Medium Cyclone Performance

As part of a longer term thrust, this project has developed a framework for the development of a fundamentally based mathematical description of dense medium cyclones (DMCs). The dynamics of multiphase flow through dense medium cyclones have been derived from first principles utilising ....  read more

Estimation of Steady State and Dynamic Dense Medium Cyclone Performance

Please note that the simulator that forms part of this report is no longer available - Should you choose to continue with the purchase of this report we are not in a position to provide the simulation tool referenced and referred to within the report.

Evaluation of In-Line Pressure Jig

The Gekko Systems In-Line Pressure Jig is a mature technology that has been successfully used in the metalliferous industry for over ten years, but has not been systematically tested in the coal industry. It has the potential to efficiently process coal over a very broad range of sizes (30 – ....  read more

Evaluation of Long Bodied Dense Medium Cyclones in an Operating Coal Preparation Plant

This investigation was carried out under an ACARP grant with additional support provided through BHP's sponsorship of AMIRA Coal Preparation project 239A. This allowed JKMRC to provide technical advice and assistance throughout the trial.

Field Testing of a Zero Offset Dense Medium Separator

Approximately sixty percent of Australian Coal is washed in dense medium cyclones, yet instantaneous module efficiencies always indicate a higher plant yield than that obtained in practice. This difference is extremely significant - experienced coal ....  read more

Field Testing of Short Spiral Separators

The objectives of this project were to:

• Compare the performance of shortened spirals with conventional spirals.
• Identify any areas of reduced metallurgical performance in the shortened spirals.
• Determine whether two stage spirals offer any significant

Full Plant Fly Ash Magnetite for Dense Medium Separation

This project involved confirming the properties and behaviour of fly ash magnetite (FAM) in full scale plant trials at Oaky Creek and Burton Coal and two pilot plant trials at ACIRL, Maitland. The FAM used in the project was derived from fly ash produced from coal burnt at the Callide ....  read more

g-Force Reduction and Monitoring of Multi-sloped Screens

Screen failures are a major issue in the coal preparation industry, and a failure can result in considerable lost product time and damage screen structures such as supports and feed and discharge boxes. The g-force at which these screens operate is typically in the range from 4g to 5g and ....  read more

Gravity Separation and Desliming of Fine Coal

Experiments were performed to test whether two Reflux Classifier units in series are able to effectively clean a feed containing -2.0mm coal. The first unit, called the "gravity unit", used narrow 6mm wide channels to perform a density separation. The overflow from this unit contained ....  read more

Gravity Separation of Ultrafine Coal using Centrifugal Forces

A new separator suitable for recovering ultrafine feed, less than 0.2 mm, by gravity separation was investigated. The separator consists of a fluidized bed mounted within a high speed centrifuge, utilizing fluidization water to suspend the particles against the high G forces. Further, the ....  read more

Improved Control of Dense Medium Cyclones

The project aimed to improve the control of dense medium cyclone operations in coal preparation plants through evaluation of the feasibility of on-line measurement of dense medium cyclone efficiency via ....  read more

Industrial Study of a Novel Dense Medium Cyclone at Gregory CHPP

Following the development of a novel dense medium cyclone at a pilot scale at the JKMRC, a 1000mm diameter large dense medium cyclone was designed and fabricated. The cyclone, called JKDMC, was tested at the Gregory Coal Handling and Preparation Plant over the period between 28 July and 29 ....  read more

Industrial Trials of Novel Cyclones

Industrial trials of two JK cyclones – a 1000mm large JK dense medium cyclone (JKDMC) and a 375mm JK classifying cyclone (JKCC) – were conducted at Dartbrook CHPP and Integra CHPP respectively in the second half of 2006. They were compared with a 1000mm Multotec DMC (M-DMC) ....  read more

Influencing Factors for Dense Medium Cyclones

The project objective was to quantify the changes in DMC operational conditions with respect to medium stability and particle crowding .

The project had two main components:

· A pilot scale DMC (150mm) was employed to investigate medium stability and particle crowding in ....  read more

Investigation of Misplaced Material in Large Dense Medium Cyclones

This report considers the reasons for the existence of low density tails that have recently been measured with alarming regularity in the Australian coal preparation plants employing large diameter dense medium cyclones. Two aspects of the issue are addressed: precision of partition ....  read more

Investigation of the Graviton Separator at Pilot Scale

Vast quantities of fine coal, worth hundreds of millions of dollars, are disposed as tailings from many coal preparation plants. Often this coal has not responded well to flotation and may have suffered oxidation. Or, the cost of installing flotation is prohibitive. Gravity separation exploits ....  read more

Joint Evaluation of Monitoring Instruments for Dense Medium Cyclones

The objective of this project was to bring together at a single site the two research groups involved in dense medium cyclone (DMC) instrumentation and software development to demonstrate:

• A comprehensive DMC monitoring and measurement reporting capability; and
• The

Large Diameter Dense Medium Cyclone Performance In Low Density/High Near Gravity Environment

This project evaluated the performance of a large diameter (1450mm cyclone diameter) high capacity dense medium cyclone, treating a full size range of -50+1.4wwmm at cut-points in the range 1.42-1.51RD and 17-45% NG (+/-0.1RD). A range of feed solids loading / M:C ratios (3:1 to 6:1), and feed ....  read more

Large Diameter DM Cyclone Operating Data

The use of large diameter (greater than 1 m) dense medium cyclones has become widespread in the Australian coal industry, and in the future is likely to be the dominant processing unit. There is little readily available data on ....  read more

Large Diameter DM Cyclone Operating Data

This report represents a follow-on project from the first stage large diameter dense medium cyclone (LD DMC) project (ACARP C10048).

The use of LD DMCs has become widespread in the Australian coal industry and, in the future, they are likely to be the dominant processing ....  read more

Larger Scale Evaluation Of The Gekko IPJ Coal Separator

This report concerns testing of the Gekko IPJ Coal Separator 1000 unit at a coal preparation plant in the Hunter Valley. The unit was tested with feed in the 6 x 0 mm size range with three different coals and feed solids concentrations varying between 16.0% and 26.3%, volumetric feed rates ....  read more

Linkage of Dynamic Changes in DMC Circuits to Plant Conditions

This project was an extension project to ACARP Project C20050 Linkage of Dynamic Changes in DMC Circuits to Plant Conditions. The project also provided necessary data for the ACARP PhD student, Nerrida Scott, for her thesis, Dynamic Analysis of Dense Medium Circuits.

The ....  read more

Long Cylinder Dense Medium Cyclones for High Near-Gravity Separations

This project was conducted by ACIRL. In late 1999, Partition Enterprises was invited to assist with data assessment and preparation of the final report.

 ....  read more

Low Toxicity Liquids for Coal Float / Sink Separations

Low toxicity aqueous solutions were evaluated as potential replacements for white spirit, perchloroethylene, bromoform and tetrabromoethane in laboratory coal float/sink testing. It was confirmed that aqueous caesium formate solutions spanned the required density range for coal float  ....  read more

Mathematical Methods for Estimating Washability Curves

The main purpose of the project was to assess the feasibility of developing a fast and cheap procedure for estimating coal density distribution curves without using float-sink testing. The new envisaged procedure was most suited to plants with primary and secondary density separation,  ....  read more

Maximisation of Yield from Gravity Separators

Although coal-washing dense medium cyclones can be extremely efficient, they continue to lose yield due to inadequate attention to simple issues such as spigot size and control of medium density, particularly in plants with parallel separators.

Dense medium cyclones (DMC) circuits in ....  read more

Modelling and Control of Classifying Cyclones

Hydrocyclones are one of the key technologies for the classification of fine coal. However, there have been limited advancements in modelling and simulation of hydrocyclones in the last 20 years. This project was concerned with the potential of using Coal Grain Analysis (CGA) and vibration ....  read more

Modern Coal Spiral In-plant Evaluation & Coal Spirals Handbook

This project provides the industry with comprehensive and accurate audit data on the Mineral Technologies LC3, LD7RC and LD7, and Multotec SX4 spirals for semi-soft coking coal (SSCC) and thermal coal applications.

Over sixty cuts that were taken over a >2 hrs for each test with ....  read more

Monitoring and Prediction of Catastrophic Multi-Sloped Screen Failures

Multislope Screen failure has been an ongoing issue since the introduction of these screens into the coal industry in the 1980s. Failures can be minor resulting in a minimum loss of production however some have been major requiring major repairs not only to the screen itself but to surrounding ....  read more

New Dense Medium Cyclone Design

The novel dense medium cyclone (DMC) developed at the JKMRC was scaled up to 200mm in diameter and tested in the JKMRC pilot plant while its geometry was optimised. A 200mm DSM type cyclone was also tested for comparison.

Colour-coded narrow increment density tracers, 8-0.3mm in size, ....  read more

New Dense Medium Cyclonic Separators

Dense medium cyclone plant performance could be improved by ensuring that all particles are separated at an equivalent incremental ash. In practice, this means at an equal separation density.

The yield gain from such practice is estimated to be between 1 ....  read more

On-Line Dynamic Modelling of Dense Medium Cyclones

This project has shown that it is possible to make useful predictions of dense medium cyclone performance with a dynamic model of the DMC running side-by-side with the real plant. Two different DMC models were evaluated, the Wood coal washing model, and the Dunglison general purpose ....  read more

Optimisation of the New Classification Cyclone Design

A feasibility study of a new cyclone design concept for fine coal was completed at the JKMRC pilot plant as ACARP project C7043. This study covered two types of cyclones - dense medium cyclones and classification cyclones. Numerous comparison tests were conducted under similar  ....  read more

Options For Sink / Float Analysis - Economic & Technical Review

Float and sink testing is the standard laboratory method for determining, with respect to relative density, the washability characteristics of a wide range of coal samples, from bore core to mine production and coal preparation plant products.

The medium used to separate particles into ....  read more

Options For the Addition and Control of Non-Magnetic Material in the Correct Medium

The non-magnetic concentration in the correct medium is important, particularly at correct medium densities below RD 1.4 where the Dense Medium Cyclone (DMC) differential - which is the difference between the density of the underflow medium and the overflow medium - may be too high. This can ....  read more

Options for Washability Analysis of Coal - A Literature Review

The Australian Coal industry needs to find an alternative to the heavy organic liquids used to produce its coal washability analyses. Indeed, the existing Australian Standard for the Float and Sink analysis of coal is likely to be phased out over the next five years, and thus the matter ....  read more

Pilot Scale Testing of Modified Downcomer in Jameson Cell

The plunging flow at the base of the downcomer in Jameson cell generates high shear stress, leading to the detachment of some particles from particle‐bubble aggregates, particularly for coarse and/or less hydrophobic particles. Laboratory tests of a downcomer modified with a cone type ....  read more

Quality Of Dense Medium

The objective of this project was to quantitatively detail the impact the particle characteristics constituting the dense medium in a coal preparation plant have on the properties which are key in defining the performance of a dense medium circuit; that is the viscosity and medium stability. ....  read more

Remote Inspection of Dense Medium Cyclones

A project was undertaken to develop of a unit capable of remote inspections of Dense Medium Cyclones (DMC's) in coal preparation plants. The prototype unit that was produced consisted of a computer controlled camera and laser inspection head mounted on an aluminium, one way chain capable of ....  read more

RFID Residence Time Modelling

The project had two main objectives, the first to provide residence times for density tracers in the different flow streams of the correct medium circuit. From these residence times, the lags associated with the coal and correct medium movements will be determined for use in a dynamic model. ....  read more

Safe Rapid Washability Assessment - The JKPycnometer

The objective of this project was to develop a machine to sort +4mm coal particles by density in the laboratory, to replace conventional heavy liquids fractionation (sink float analysis). The benefits were expected to include improved safety through the elimination of heavy liquids, reduced ....  read more

Sensor Development for On-Line Dynamic Simulation of Dense Medium Cyclones

The objective of this project was to develop and test instrumentation to monitor dense medium cyclone (DMC) underflow or overflow medium density, as well as feed flow rate, as a check on predictions made by an on-line DMC model.  The project was a continuation of C12001, which ....  read more

Sensor Development for On-Line Dynamic Simulation of Dense Medium Cyclones

C12001On-Line Simulation of a DMC Circuit
This project has shown that it is possible to make useful predictions of dense medium cyclone performance with a dynamic model of the DMC running side-by-side with the real plant. Two different DMC models were evaluated, the ....  read more

Teetered Bed Separator (TBS) Handbook

Hydraulic classifiers have been in use since 1934, typically employed to sort out and group particles of different specific gravities and different size distributions. Advances in electronic sensing instrumentation and pneumatic and electrical process actuation have seen the development ....  read more

Teetered Bed Separator with Jigging Action

The phenomenon of "bed inversion" was observed for fluidised beds of plastic particles. At low fluidisation rates, small sized but high density particles form a suspended bed below larger but less dense particles of similar settling velocities. At higher fluidisation rates, the order ....  read more

The Affect of Dynamic Changes in Medium Quality in Coal Processing

Research has shown that the amount of non‐magnetic material in the correct medium solids will have an effect on the operation of a dense medium cyclone (DMC) particularly when operating at correct medium densities less than a relative density (RD) of 1.4. ACARP projects C15053 and C18040 ....  read more

Unreliability of Performance Comparisons for Density Separators

Partition curve determinations based on coal sampling and float/sink analyses are subject to a wide range of errors arising from sampling, particle breakage and problems inherent in float/sink analyses. This study focussed on errors which arise from considerations of particle statistics. It ....  read more

Vol 1. Experimental Validation of a Fundamental Model of Coal Spirals Vol 2. Handbook and Reference Source for Plant Metallurgists & Designers

Volume 1

A Computational fluid dynamics (CFD) model of the spiral has been under development by the Centre for Advanced Numerical Computation in Engineering and  ....  read more

Washability Analysis by Water Fluidisation and Jigging

Washability data has traditionally been generated for the coal industry using the float-sink method AS4156.1-1994. This technique relies on heavy organic liquids to fractionate coal and mineral particles based on particle density. These organic liquids are considered problematic for ....  read more