In conversation with Greg Hall

August 22, 2023

My professional career has involved three employers, CSR Ltd (1968-88), Placer Dome (1988-2006) and Golden Phoenix International (2006-Present). I studied chemistry and geology at the University of New South Wales (1968-72), completing the first two years part-time while working as a junior chemist at Central Laboratory in Pyrmont. I graduated in 1973 with Bachelor of Applied Science with First Class Honors and was posted to Wittenoom in Western Australia to work on iron ore. In this period (1973-78) I was responsible for discovering the Marra Mamba iron deposits near Mt Newman (1973) and the Yandicoogina pisolite deposit (1974) in Marillana Creek. This pisolite discovery was sold to CRAE in 1981 and commenced production in 1996 as the Yandi Mine of Rio Tinto. Production rate was 50 mtpa (1996-2016) and increased to 75 mtpa in 2016. The mine has produced 1.6 bt of iron ore to date.

I worked in Queensland (1979-83) then returned to Perth in 1984. The Granny Smith project was my first gold project and the discovery of a large gold deposit in 1986 was the most satisfying. CSR Ltd sold the deposit to Placer Pacific in 1988 and I transitioned to PPL in order to see my discovery go into production. Production started in 1990 and continues to this day. I subsequently helped with the discovery of gold at Sunrise Dam and Wallaby.

I became Chief Geologist of Placer Dome in 2000 until Barrick Gold Corporation took over in 2006.

Brett Davis: Firstly, thanks for giving Coring the opportunity to interview you, Greg. Please take this as a compliment when I say it seems like you have been a geological heavyweight of the mining and exploration industry for a very long time. Very few people have a career like yours, where you’ve worked across the spheres of academia, mining, and exploration, plus gained enormous respect in the geological community while you’ve been doing it. Can you tell us what interested you in a career in geology?

Greg Hall: I am an accidental geologist.

I never intended to be a geologist rather I studied geology at Balgowlah Boys High School in Sydney in my final year to boost my aggregate Science mark in order to gain a Commonwealth Scholarship. I also applied to CSR Limited for a cadetship to study chemistry at university. I was successful in both cases, finishing 23rd in the State Science Honours list that year. CSR required cadets to complete first-year university part-time (two years) while working in CSR Ltd.’s Central Laboratory at Pyrmont in Sydney, assaying the entire annual Australian sugar production with samples representing 500 t lots. First-year cadets were analysts, and second-year cadets were supervisors. In the first year, I discovered I was not suited to chemistry as a career. At the end of that first year a UNSW, graduate Ken Maiden appeared at the laboratory and when asked what he was doing he replied he had just graduated from the University of NSW (UNSW) in geology and was going to Broken Hill to complete a PhD. Ken advised me that CSR Ltd. had taken over a junior exploration company called Mineral Engineers that year (1968) to commence exploration in their own right. Mineral Engineers became Pacminex. CSR did not have an exploration arm during their time mining blue asbestos at Wittenoom (1948-1967) and had joined the Mt Newman Mining Joint Venture and the Gove bauxite Joint Venture. I decided and CSR Ltd. agreed to transfer me to Applied Geology over three years by way of a Chemistry Geology co-major and transitioning to a Geology Applied Science Degree course. I graduated in 1973 from UNSW with Bachelor of Applied Science (First Class Honours).

BD: Coring started as a diamond drilling magazine before introducing an exploration and geology section, and we like to keep to our roots. Do you get to work much with the drilling side of the business anymore?

GH: I last sat on a drill rig in 1987 with RAB drilling the discovery holes in what subsequently became Granny Smith Gold Mine.

BD: Your company is called Golden Phoenix International Consulting. Tell us more about what you do and your client base.

GH: I spent a lot of time in China for Placer Dome commencing in 1997. In 2006 when Barrick took over Placer Dome, I decided to continue exploring in China via an unlisted public company, called Golden Phoenix Resources and consulted out of a private company called Golden Phoenix International. My association with China continued until 2018. In this period, I was made an Honorary Professor at three institutions, the Geoscience University in Wuhan, the Central South China University in Changsha and the Institute of Geology and Geophysics in Beijing. My Chinese colleague gave me the Chinese name Huo GoLin which translates as Ancient Forest implying my age (grey hair) and stature as an experienced geologist.

BD: You’ve worked in a lot of countries and on a lot of continents. Are there any skills or mindsets that have helped you in your roles in these places?

GH: You definitely need to be humble and respectful of other cultures and beliefs. To quote Walt Wittman: ‘Be Curious not Judgmental’. In the West, we do business and then become friends, in the East, we become friends and then do business. This concept is given the name ‘guangxi’ and it is taken as a sign of respect for the people you are going to rely on in the future to help with your business ventures.

BD: You’ve had the privilege of working with many of the truly influential geologists in the industry and have influenced many more. Who has been some of the positive influences in your career?

GH: This is a very long list.

Dr John Rattigan the first Chief Geologist in Pacminex, who believed in me as a new graduate and trusted me to find iron ore deposits.

Professor Bill Lacy at James Cook University in Townsville, who advised me to follow my heart (become an Exploration Manager) rather than do a PhD at JCU.

Dr Vic Wall is a major influence and was the smartest geologist I have ever met. Professors Bruce Hobbs and Christoph Heinrich helped me understand structural geology and hydrothermal geochemistry respectively.

Professor Roger Taylor and Dr Peter Pollard taught me about granites and magmatic processes at James Cook University.

Colleagues who helped me develop curiosity about hydrothermal ore deposits include Dr Scott Halley, Dr Peter Holyland, Dr Paul Kitto, Dr John Walshe and Dr Dick Tosdal.

A special mention should go to Phil Davis, who taught me about effective teamwork.

BD: Do you get much opportunity to revisit some of your old geological stomping grounds e.g. the Laverton region? And have you seen any of your ideas come to major fruition or change radically?

GH: For the last four years, I have been supporting my son Brad Hall and his not-for-profit Cycling Development Foundation with their Laverton Cycling project. One of the fund-raising events is an 8-day, 1100 km ride from Perth to Laverton. Each year, I get to see the continuing development of the Sunrise and Wallaby gold mines. I was involved in their discovery following the development of Granny Smith mine.

BD: Is there a particular mineralization style or deposit type that interests you, and why?

GH: I have a singular passion to look at the involvement of granite magmas in Orogenic Gold Deposits. I am deeply interested in far-field geochemistry by which I mean the very fringe of a hydrothermal mineral system where there is not enough energy to create new minerals rather just swap atoms in existing minerals. The mineral will look unchanged or unaltered to a petrologist, but the chemistry will tell otherwise. Once understood, this feature can allow one to optimize exploration search. Understanding the size of the system you are seeking to detect will allow you to open the grid cell size to decrease the sample density thus reducing time and cost of discovery.

BD: Leading on from the previous question – everyone has a handful of deposits that have left a mark on them, be it because of the amazing geology, the hideous conditions, the people they worked with, etc. Which deposits do you hold dear and which ones really were difficult to work on?

GH: As you have inferred, the Laverton region and the three gold deposits of Granny Smith, Sunrise and Wallaby are very special for me. Other gold deposits that are important but difficult to access are Witwatersrand (South Deep) and Carlin (Cortez). At South Deep, I found that the entrenched palaeo-placer origin belief always gets in the way of real understanding. At Cortez the reluctance to embrace real research at a mine that was spectacularly profitable was disappointing.

BD: Do you think that there are any mineral exploration strategies or technologies that are under-employed, but could make a big difference to an exploration campaign if people used them more?


It is clear that our capacity to determine the chemistry of rocks with techniques, whose detection limits are much less than crustal abundance, has the potential to revolutionize exploration effectiveness. With old techniques, we could only see the head of the anomaly, while the new techniques allow us to see the shoulders that support the head. The recognition that oxy-anions (those elements with two or more valence states) will not migrate during weathering, whereas many ore-forming elements (gold, copper, nickel, etc.) have only one valence state and become very mobile during weathering. Oxy-anions have very low abundance, but are part of a mineral system and can be used to detect the existence and location of that system.

BD: We hear all about the advances and benefits of technologies such as 3D modeling, geochemical analysis, and utilization of drones. Have you noted any negative impacts to effective exploration and mining as a result of these e.g. less people out kicking rocks?

GH: All exploration technologies cannot replace the effectiveness of better geological mapping as an aid to better exploration. Geological mapping means boots on the ground.

Greg Hall in the field
Greg Hall in the field

BD: I haven’t always agreed with your geological interpretations. However, they have always made me think. What is your opinion of the geological skillsets, experience, and knowledge of geologists today, especially those who are newly graduated?

GH: I have always considered that a university degree teaches you the language of your science, but it is the practice of geology that teaches you the science.

BD: Has there been any single satisfying moment in your career that rates above all the others?

GH: In late 1986, receiving by fax the assay results from a recently completed RAB drill program at Granny Smith to discover 25 m @ 5 gm Au from 15 m (49.2 ft) downhole in the last drill hole on that line is easily the single most satisfying moment in my career.

BD: I’ll ask a question on the flipside to the previous one. Many of us have interfaced with less than savory individuals or experienced toxic workplaces. Has there been any incident or incidents that really disappointed you?

GH: Yes, many examples of sexist behavior and disrespecting women. From 1984, I started deliberately hiring women into exploration until 1991 when the Keringal camp east of Laverton was run by a woman and the majority of employees were women. The Keringal gold deposit discovery subsequently became part of the Granny Smith Mine JV and management transitioned from exploration to mine management control. Women were quite disrespected at mine sites in those days.

BD: One of the things you are held in high regard for is your capacity for teambuilding. What makes a good geology team? And have you seen any truly dysfunctional ones?

GH: Leadership is quite important in creating a good team. The leader has to model the desired behavior and be prepared to call out undesired behavior. It is important as a leader to be able to recognize people motivated by power because these people will not subordinate their interests for the good of the team. Unfortunately, it is also true that power-motivated people are most likely to become leaders, so while you might be able to create an effective team in your area, it is very likely that the bigger organization may well be dysfunctional.

BD: I know you appreciate the value of good mentorship and have been a positive influence on many geologists, me included. What makes a good mentor?

GH: Humility and the drive for excellence as well as patience. People learn at their own speed. I am quite a believer in the ‘Learning Organization’ and failure should be recognized as a tremendous opportunity to learn. I learned more from failure than I have ever learned from success.

BD: Leading on from the previous two questions, what have you learned from field practice and your job experience that is not taught at university?

GH: Team building and how to create a good team. The principles of chemistry are also very poorly understood by many graduates.

BD: One topic we commonly talk about but rarely put into print is that of the health hazards of working in different countries and environments. Has your health ever been particularly challenged and, if so, what happened?

GH: I dodged getting malaria in Africa and Asia and have been vaccinated against a very long list of diseases. I have suffered severe gastric illness because of poor food preparation in China. I recommend everyone keep track of near misses because they are your next accident, and you should prepare as though they are likely. After years of flying, I became subject of Deep Vein Thrombosis (DVT) and I am lucky to be alive.

BD: If you had abundant financial funding, is there a fundamentally annoying geology question you’d like to solve or a topic you’d like to work on?

GH: What is the true nature of fractals in economic geology? In principle, if you understand the fractal then one drill hole will tell how big the whole system might be.

BD: Now to some personal questions. Does Greg Hall get any time away from work? If so, what does he do in his downtime?

GH: I am a big supporter of my family. My two kids have chosen careers vastly different to mine. Brad is a cycle trainer at his gym called the Exercise Institute in Subiaco and manages the racing teams in the Cycling Development Foundation. He raced in Europe while completing a Psychology Sports Science co-major. We photograph the riders in the Perth Laverton Cycle Classic each September.

Adam is a musician, plays trumpet and sings in his band The Velvet Playboys. He holds a music festival called The Underground in summer each year, as well as touring Europe during July.

My partner Maree Laffan has started a Flamenco dance troupe called Aire Flamenco and performs regularly, so I am the Chief Roadie.

BD: Is Greg Hall ever going to compile his memoirs? I imagine there is a treasure trove of stories there!

GH: There certainly is a treasure trove of experiences. I have joined the Century Club that is having visited more than 100 countries where I have slept overnight. However, I prefer to have the experiences, not to write about them.

BD: Finally, any concluding comments or words of wisdom from an industry veteran?

GH: Your task in life is to find your passion and when you do, give it ‘a red-hot go’. Exploration became my passion sometime after I graduated as a geologist and subsequently, I have never worked another day in my life.

For more information, get in touch with Greg Hall on LinkedIn