In profile: Timothy McMillan, PhD student

The area known as the Southern Sydney Coalfields is home to seven underground mines, producing millions of tons of coal which is primarily exported as coking coal. The oldest mine in operation has been functioning for over 130 years.

Currently, mining operations in the Southern Sydney Coalfields are seen as a risk to the overlying drinking water reservoirs due to the potential for the cracking of streams beds and subsequent loss of surface water.

Through his PhD research, UNSW’s Timothy McMillan is helping to reduce the uncertainties around groundwater and potential for surface to seam connections in the Southern Sydney Coalfields by identifying and understanding the unique hydrogeology and hydromechanics of geological structures in the region.

It is well known that with mining comes a certain level of risk, particularly to surrounding ecosystems and water resources. While there are certain precautions that are must be taken across any mine site in Australia, other risks are unique to the characteristics of a specific site or catchment and should be mitigated through tailored solutions.

“It is unlikely that we can avoid all mining in catchment areas, so we need to be realistic, while identifying the greatest risks that can be addressed. Dedicated research into groundwater and geological structures in the Southern Coalfields can help us to create a fundamental basis of understanding from which safe, efficient and sustainable decisions can be made,” says Timothy.

Timothy says that modelling and other predictions of surface water impacts in the region have often resulted in surprises and it is clear that we do not fully understand the rock mechanics and groundwater flows in the region.

He is using terrain analysis, field mapping and earth and atmospheric tides analysisto gain a clear understanding of these elements.

“By understanding the hydrogeology of the most high-risk features, such as geological faults within the region, we may be able to prevent further damage from occurring by enabling more robust modelling and mine designs,” says Timothy.

Timothy’s PhD begun after completing an Advance Bachelor of Science (Honours) in Geology at the University of Wollongong. The PhD project advertised by UNSW’s Dr Wendy Timms, Director of Postgraduate Studies (Coursework) at the UNSW School of Mining Engineering, sparked his interest along with a realisation that so much more could be done to reduce mining impacts.

It is unlikely that we can avoid all mining in catchment areas, so we need to be realistic, while identifying the greatest risks that can be addressed

Timothy McMillan, PhD Student

“I realised that the mining induced damage to the Woronora reservoir, which had supplied drinking water to me for the majority of my life, occurred because we don’t yet really know what we are doing – instead we are just hoping for the best,” says Timothy.

While undertaking his research, Timothy is also working collaboratively with the New South Wales Office of Environment and Heritage as part of the geology team for the Thirlmere Lakes Research Program, investigating fluctuating water levels in the 15 million year old lakes.

Timothy says that the greatest joy of studying at UNSW has been making new friends from around the world with other PhD students, and he has enjoyed the kind mentoring and support provided by his extensive supervisory team—comprised of Professor Paul Hagan, Dr Martin Andersen, Dr Wendy Timms, Dr Gabriel Rau and Titus Murray.