ACARP ACARP ACARP ACARP
Coal Preparation

Technical and Safety Comparison of DP Cell and Nucleonic Density Gauges

Coal Preparation » Environmental Improvement

Published: June 06Project Number: C13050

Get ReportAuthor: Andrew Vince, Ian Brake, Ben Cronin | BHP Billiton Mitsubishi Alliance

In Australian coal processing practice the measurement of slurry density is of critical to medium importance, depending on the application. A number of means are used for measuring density – traditionally nuclear and differential pressure methods. In recent times nuclear methods using Cs137 nucleonic gauges have been commonly applied by designers whatever the duty, and yet nuclear techniques are the subject of increasingly onerous statutory regulation by government that have to be managed by plant operators.

Mining industry practice and legislation relies on risk assessment prior to design and use of any technique, and nuclear techniques pose a level of compliance and health risk not seen in the alternatives. In a legal regime of making risk “as low as reasonably achievable”, it seemed incongruous that some plants use only nuclear sources, some use only differential pressure methods, and some use a combination of both. All plants appear to operate well whichever technique is used and there is often little science to the choice.

Why not just get rid of nuclear sources for density and replace with DP or other methods and save all the risk and regulatory compliance effort? The answer is that accurate density measurement is critical for dense medium circuit performance when a significant level of near gravity exists, and that there has been no technical comparison of the two methods.

This project set out to measure the accuracy of DP and Cs 137 methods on the one density “tester leg” at the Goonyella CPP. The conclusion of a detailed assessment by Dr Andrew Vince was that both methods had similar precision, the calibration methods available were much less precise than the instruments, but that both were also subject to bias. The results could not conclude that either was better than the other, but did conclude laboratory measurement at the site or the slurry sampling was problematic. This was the completion of the original ACARP Project.

4Differential Pressure cells are also inherently subject to bias due to flow rate past the cells due to dynamic rather than static pressure effects. A second study was requested and approved to use a student thesis project engineering test rig at James Cook University Townsville. This fixed price project built a test rig for pumping magnetite past DP and Cs137 measurement systems at variable speed but the rig was not sufficiently robust to deliver useful results.

BMA then privately funded two exercises. A Network query to BHP Billiton operations in many plants across many industries worldwide showed that Cs 137 methods are subject to elemental bias which can be severe – particularly for clays. One coal site in Queensland reported large changes in Cs137 measured slurry density in a tailings thickener underflow as pits changed. It is also widely known in the laterite nickel industry where the ore is principally clay. The fundamental physics for this is referenced.

Secondly a request for other methods showed some plants moving to Coriolis based measurement, or fixed DP probes useful for tank density. A test report on applying a Coriolis based sensor is included. Another ACARP project has taken this further.

The clear conclusion from the work is that all methods, nuclear, DP, Coriolis all have advantages and technical limitations. A qualitative matrix is presented showing options for various coal processing measurement points.

Only nuclear methods have their unique safety and compliance workload issues. For any new installation, a review of the technical task, the ability to design systems that suit non nuclear instruments and the accuracy required should be performed as part of a risk assessment. Without such a review there is no technical basis for simply assuming nuclear methods are the only way of accurately measuring slurry density – they are not. This type of thinking is a profound change to the “one type fits all” approach to fitting nuclear density gauges. 

Underground

Health and safety, productivity and environment initiatives.

Underground

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

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