School of Mechanical & Mining Engineering

The evolution of the coal industry to incorporate gas production and deeper mining has given rise to a suite of research projects. In addition, many of these focus areas are relevant to aspects of geothermal energy and shale gas which form a part of an evolving energy landscape. Deep coal mines generate additional heat and ventilation loads, and this combines with the need to prevent spontaneous combustion at depth and to control ventilation air methane (VAM) emissions. Effective hydraulic fracturing is essential for the economical extraction of unconventional hydrocarbons such as coal seam gas however this can only proceed in an environmentally sustainable fashion.

The Energy, Safety and Environment Group conducts research in:

  • Fibre-optic based sensors for mining applications
  • Computational Fluid Dynamics for simulation of underground mine environment
  • Energy saving opportunities in the mining industry
  • Mine subsidence prediction
  • Portable analyser for rapid measurement of coal seam gas
  • Characterising the behaviour of hydraulic fracturing fluids
  • Modelling of multi-phase fluid flow in reservoirs

Staff

Dr Saiied Aminossadati

Dr Zhongwei Chen

Associate Professor Mehmet Kizil

Dr Christopher Leonardi

Associated Research Centre

CRCMining


Current Research

Fibre-Optic based Sensors (Dr Saiied Aminossadati) With the support of UQ, CRCMining Australia and ACARP, the research aims to identify the true value-adding fibre-optic based sensing (FOS) applications, and create a roadmap for the core technology development requirements in mining. The current projects include: 1-Environmental monitoring of underground mines using a Distributed Temperature Sensing (DTS) system; 2-Application of DTS to monitor pre-drainage boreholes (C17056; C19057); 3-Development of microstructure fibre optic gas sensors that measure the methane concentration in underground coal mines (C20014); and 4-Development of a real-time fibre-optic based temperature monitoring system that predicts costly failure of conveyor idlers (C21012).

Computational Fluid Dynamics (Dr Saiied Aminossadati)  With the support of UQ and CRCMining, the research aims to simulate the flow behaviour in underground mine environment and gas drainage boreholes using Computational Fluid Dynamics (CFD). The designers of mine ventilation systems and gas drainage techniques obtain a better understanding of the flow behaviour (air, humidity, gas, dust and diesel particulate matter) in underground ventilation networks and drainage boreholes without a need to expensive and risky experimental development. The current projects include: 1-Investigation of brattice geometry effects on the ventilation effectiveness in underground dead-end regions; 2-Simulation of auxiliary ventilation to maximise gas, dust and humidity removal in coal face development workings; 3-Numerical analysis of goaf gas migration in underground longwall coal mines; 4‑Computational analysis of gas flow behaviour in pre-drainage boreholes; and 5-Spontanous combustion simulation in coal stockpiles. In addition to the above-mentioned projects, Computational Fluid Dynamics has also been employed to simulate the gas flow behaviour in sintering process of Aluminium alloys.

Energy saving opportunities (Dr Saiied Aminossadati) With the support of UQ and CRCMining, the research aims to identify opportunities to improve the energy efficiency in mining industry. The current project focuses on the energy saving opportunities in haul truck operations in surface mining by using multi-function optimisation based on Genetic Algorithm. It is expected that the optimum values of multiple key factors that results in the minimum fuel consumption in haul trucks can be determined.

Mine subsidence prediction (Dr Zhongwei Chen)  Subsidence occurs as the roof of the mined area behind the roof supports progressively collapses under the weight of the layers above the coal seams, and exposes significantly impact on our ecological environment. The research is to investigate the impacts of different mining designs, topography, overburden strata properties, and geological conditions of mining on the surface infrastructure, water bodies and roads, particularly its effect on the ground water flow pattern.

Portable analyser for rapid measurement of coal seam gas (A/Prof Mehmet Kizil)  There are currently two methods used to determine the gas content of coal samples. The slow desorption method has been supplemented with the development of the quick crush test to speed up the process of determining a gas content value. The latter was a step change introduced in the early 1990’s by GeoGAS, with the addition of the desorption rate index data for outburst-proneness assessment. Since then, there has been no major advance on this technique, particularly in terms of obtaining values underground (either at the mining face or along mine roadways). The opportunity now exists for a step change to be demonstrated and evaluated for reliably and accurately measuring gas contents and desorption rate data on site using a Portable Gas Content Analyser (PGCA).

The main objectives of this project are to:

  • Demonstrate and evaluate the capability of a portable instrument to rapidly measure coal gas contents and desorption rate data both accurately and cost effectively in the underground mine environment;
  • Validate the results obtained by comparing them against the current industry standard methods; and
  • Develop a standard procedure that can be applied at all underground coal mines.

Characterising the behaviour of hydraulic fracturing fluids (Dr Christopher Leonardi) The effectiveness of a hydraulic fracturing job depends largely on how well the fracture is propped open after the injected fluid is removed. This has led to the research and development of novel fracturing fluid (e.g. slickwater, gels) and proppant (e.g. sand, ceramics) combinations which maximise the propped area of a fracture and minimize the use of resources such as water. To aid the development of these fracturing fluids this project is developing and applying a new computational tool that is capable of both characterising their rheology and simulating their injection in fractures. This tool will facilitate a better understanding of the placement and settling of proppants in fractures, thereby assisting the design of fluid-proppant combinations and injection sequences. The direct numerical simulation approach employed represents a paradigm shift in the way that proppant transport is characterised, and has the potential to complement and or improve the semi-empirical models that are currently used in hydraulic fracture design software.

Modelling of multiphase flow in reservoirs (Dr Christopher Leonardi) The modelling of multi-phase flow in reservoir rocks at the pore-scale can serve as an important input for field-scale simulation. As the resolution of reservoir simulators increases the need for more detailed input parameters, such as the spatial distribution of transport properties, becomes increasingly apparent. Via collaboration with some of the world’s largest oil and gas producers and service companies, this research has developed the capability to robustly predict the absolute permeability of reservoir core samples. The numerical procedure takes as input a segmented mCT image of the rock sample. A computational fluid dynamics solver such as the lattice Boltzmann method is then applied to the image geometry resulting in a permeability-porosity relationship with data points from a number of analysed subsamples. This digital workflow offers significant cost and time savings over traditional experimental techniques. It also has the potential to be applied to modelling in unconventional reservoirs where the porosity is low and the exact limits of Darcy flow are unclear.

Permeability modeling in porous media and coal gas production forecasting and optimization The research mainly aims to develop rock permeability model applicable to the unconventional gas reservoirs, and the model is expected to couple the impacts from geomechanical deformation, hydraulic flow, geochemical process, and rock creep behaviour. The expected new permeability model will be implemented into a fully coupled numerical model to investigate the dynamic rock-gas interactions and their impact on gas production performance. The fully coupled simulation model will also be used to predict gas production, and to optimize reservoir performance.