ACARP ACARP ACARP ACARP
Open Cut

Monitoring of Temperature and Oxygen Profiles in Self Heating Spoil Piles

Open Cut » Environment

Published: December 99Project Number: C6003

Get ReportAuthor: John Carras, J Bus, O Roberts, F Fzemes | CSIRO Energy Technology

The long-term behaviour of spoil piles subject to spontaneous combustion has been evaluated at three hunter valley mines over an 18 month period. Spontaneous combustion has emerged in recent years as a significant issue in the Muswellbrook region of the Hunter Valley.  Spontaneous combustion can cause open and smouldering fires, which can emit carbon dioxide, carbon monoxide, nitrogen dioxide, sulphur dioxide and the "tarry" emission products associated with incomplete coal combustion. There is also the danger of fire spreading to surrounding land, destabilisation of the landform and vegetation dying near the hot spoil.  Monitoring the long-term behaviour of spoil piles subject to self heating can more accurately define the processes important for heating, predict spoil behaviour and assess the effectiveness of control methods.

 Project Objectives

The overall objective of the project is to continue to measure the temperature and oxygen profiles from probes already installed in spoil piles at Drayton, Muswellbrook and Ravensworth at three monthly intervals over 18 months. The project will help to maintain a data set on the long-term behaviour of self heating spoil piles.

Researchers also monitored the behaviour of an area at Drayton grouted with flyash.

 Findings

Ravensworth
The data from Ravensworth probes highlights the heterogeneous nature of spoil pile heating with large fluctuations in the temperature profiles measured. The data was derived from probes near the edge of a spoil pile batter undergoing active spontaneous combustion. The data was obtained after an inert cover layer was applied to the surface with the batters left exposed.

The data shows that:

  • Covering the surface of a burning spoil pile with a thick layer of inert material without covering the batters will not control fires in spoil.
  • Active combustion can occur ~90m in from the batter edge.

The intermittent and heterogeneous nature of the heating at Ravensworth Site 2 shows that individual circumstances (location of reactive materials, presence of cracks, access of oxygen through the batter and transport of water through channels and cracks) are important in determining the nature and extent of spontaneous combustion fires.

Drayton
The hot Drayton spoil, which has been capped by clay, continues to show a temperature decline at the 19.5m level, consistent with the cessation of combustion and the loss of heat by conduction and water flow through the spoil. The temperature at the hottest location decreased from ~260oC when the probe was installed to ~55oC in June 1999, a loss of more than 200oC over seven years, averaging 32oC per year. While control has been successful to date, careful monitoring is required to ensure it continues.

Muswellbrook
The Muswellbrook data shows that the small heating induced in the marine conglomerate remains low and does not proceed to combustion in the absence of carbonaceous material.

Flyash
Data from Drayton shows that the role of grouting is limited to specific applications rather than for use as a general method of controlling spontaneous combustion. Such application might include grouting into highwalls to control in-seam fires or grouting to control fires in well defined volumes of carbonaceous material so that a complete grout curtain can be produced to limit oxygen ingress.

Where To From Here

Further work on spontaneous combustion is being carried out under the ACARP project (C8059 Greenhouse Gas Emissions from Spontaneous Combustion in Coal Mining). This project is due for completion in early 2002.

Underground

Health and safety, productivity and environment initiatives.

Recently Completed Projects

C27039True Triaxial Strength Of Coal Measure Rocks And Its Impact On Roadway Stability And Coal Burst Assessment

Rocks in the ground are subject to a range of stresses. The stresses...

C3063Underground Vehicle Design Standards And Statutory Implications

The Australian underground diesel vehicle fleet has evolved since di...

C3064Conveyor Belting And Lagging Shear Characteristics - Drive Drum Slip

The primary aim of this project was to investigate the relationsh...

Underground

Open Cut

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

Recently Completed Projects

C29021Assessing The Impact Of Consecutive Night Shifts On Night-Time Alertness, Daytime Sleep And Timing Of The Circadian System

In the Australian coal mining industry, most guidelines for managing...

C33037Quantifying Recharge To Groundwater Systems In The NSW Coalfields (Sydney, Gunnedah And Gloucester Basins)

The purpose of this project was to estimate the rate of diffuse rec...

C26029Geological Controls On Fluorine And Phosphorus In Bowen Basin Coals

Increasing global restrictions on fluorine in product coal prompted ...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C27064Dry Beneficiation Using FGX And X-Ray Sorters

Conventional dry processing methods engage a single beneficiation de...

C26010Multi-Sloped Screening Efficiency With Changing Strokes, Frequencies, Feed Solids And Feed Rates-Pilot Plant Study

Optimising multi-sloped screens is often described as an art and the...

C28059Impact Of Water Quality In Coal Handling And Preparations Plants

The objective of this project was to deliver a concise reference do...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C23052Novel Stone Dust Looping Process For Ventilation Air Methane Abatement

This multi‐phase project is concerned with the mitigation of m...

C27054Optimisation Of A Thermal Flow Reversal Reactor For Ventilation Air Methane Mitigation

Ventilation air methane (VAM) generally accounts for 50-85% of the t...

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...

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