ACARP ACARP ACARP ACARP
Open Cut

A Model of Long-Term Salt Movement in Reconstructed Soil Profiles Following Open Cut Coal Mining in Central Queensland

Open Cut » Environment

Published: May 05Project Number: C12043

Get ReportAuthor: Andrew Grigg, T Baumgartl | Centre for Mined Land Rehabilition, University of Qld

Waste rock materials exposed at the surface following open-cut coal mining in central Queensland are commonly saline, impacting on the success of revegetation efforts. The aim of this study was to develop a simple model that predicts the removal of salts from reconstructed soil profiles by leaching, thereby demonstrating an improving growth medium over time.

The study was able to draw upon salinity profile data from 49 plots established as part of routine rehabilitation monitoring programs across four mines. Plots sampled rehabilitation ranging in age from <1 to 27 years since pasture establishment and had been monitored for periods of up to eight years. The dataset was extended to include plots from a rehabilitation trial at a fifth mine where a range of spoil amendments had been applied and monitoring had been conducted for 12 years.

Results from the monitoring plot dataset revealed a general decline in average salinity in the rootzone with time, with evidence of a distinct upper boundary. Plots with initially high salinity commonly decreased rapidly, while plots with either lower initial salinity or older plots presumably subjected to leaching losses prior to measurement decreased more slowly. Using data from plots with at least four assessments over time, a simple model was able to be developed that predicts average salinity in the rootzone (EC p ) from the initial average salinity (EC 0 ), cumulative rainfall since rehabilitation establishment (P), and two terms describing the amount of rainfall required to initiate leaching (a) and the rate of leaching (). The model takes the form

The rate-of-leaching term was found to have a relatively consistent value of 2 across a number of mines and a range of situations. Variation around this figure was shown to be related to factors affecting spoil hydraulic conductivity, and with additional data, the model may be further improved by replacing the single value with a suitable function that describes this.

The model predicts downward salt migration over longer time periods, and is not intended to predict periods of capillary rise. This was shown to occur over the shorter term during years of below-average rainfall even in profiles with net long-term leaching. Net removal of salts over time requires adequate infiltration in combination with a sufficient depth of material at the surface with at least moderate permeability to combat capillary rise. The model is not applicable to saline spoils with very low permeability, which are prone to fluctuating or increasing salinity. A more complex modelling approach is needed in these cases to resolve the appropriate depth of replaced topsoil to instigate net leaching. However, from data examined in this study, a minimum depth of 30cm of replaced topsoil appears to be required for spoils with very poor permeability.

Underground

Health and safety, productivity and environment initiatives.

Recently Completed Projects

C33001Methodology Development Of Silica Analysis Of Dust On PDM Filter: Phase 1

Monitoring of personal exposure levels of respirable coal dust (RCD)...

C33009Ceramic Wall Flow Filter Commercialisation

The purpose of the project was to develop a commercially available a...

C28012Coal Micro-Fabric As A Trigger For Coal Bursts

This project was undertaken in two stages:

  • Stage 1 con...

Underground

Open Cut

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

Recently Completed Projects

C33034Evaluation Of A Novel Suspension Seat To Reduce Whole Body Vibration

Operators of earth moving equipment are known to be exposed to signi...

C35025CSR Predictions And Correlations Definition

Coke Strength after Reaction (CSR) is arguable the most price specif...

C34035Investigating Pittosporum Angustifolium For Mine Rehabilitation - Key Strain Identification, Medical And Environmental Applications And Germplasm Propagation Investigation

This project investigated the potential development of Pittosporu...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C35036Autonomous Stockpile Dozing: Quantifying Viability

The automation of bulldozer operations on stockpiles presents a sign...

C35024Froth Fotation Predicted V Actual Definition

Correct outcomes in froth flotation yield predictions for product as...

C35032Improving The Dewatering Of Fine Coal Tailings By Minimising Micro-Nano Bubbles

Dewatering of fine coal tailings remains a major operational challen...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C35038Microalgae Blending For Low Carbon Metallurgical Coke Production

The introduction of renewable biomass into coal blends is regarded a...

C35005High Efficiency Low Emission Pilot-Scale Evaluation And Pecan Nut Shell Biochar Addition To Australian Coals For Thermal Uses

Current strategies to reduce the carbon intensity of coal-fired powe...

C35043Abrasion Resistance Of Coke Under Hydrogen Reduction Blast Furnace Conditions

The hydrogen enriched blast furnace is emerging as a viable alternat...

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C34066Safe Operation Of Catalytic Reactors For The Oxidation Of VAM Operating Under Abnormal Reaction Conditions

The catalyst Pd/TS-1 has shown excellent activity in oxidising venti...

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...

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