PETRA brings together a transdisciplinary team of PhD qualified engineers, mathematicians and programmers whose sole purpose is to engineer data science solutions for the resources industry.

PETRA’s proven proprietary data science services help our clients get the most out of their data. Our solutions focus on three key principles:

  • Big data value chain optimisation (e.g. mine to mill)
  • Downtime prediction algorithms and
  • Machine learning and AI

The value of data is becoming increasingly understood and valued but remains largely an untapped by resource companies. We work with you and your team to develop a scope of work to reduce downtime and improve operational efficiency.

Our Team


Penny Stewart – Managing Director & Principal

In June 2015, Penny founded PETRA Data Science Pty Ltd to extract value from resource industry data using an engineered approach to data science. In response to industry demand, Penny has developed a number of data science solutions for the resources industry e.g FORESTALL algorithms to predict equipment downtime and loss events, PRODFINDER big data integration for mine-to-mill studies, and a new method to quantify intact rock damage from microCT data – LABYRINTH®. Penny worked on mine sites for five years before obtaining her Queensland 1st Class Mine Managers’ Certificate of Competency in 2000.  Her open and collaborative interpersonal style, has enabled her to implement technology and innovation projects across diverse cultural, operational and organisational settings. 

Aust. Mining Review Interview with MD, Penny Stewart



Dr. Zeljka Pokrajcic – Principal
PhD BE(Met)

Dr Zeljka Pokrajcic joined PETRA as a Principal in August 2016. Zeljka is a mineral processing professional with 20 years experience in the mineral industry globally. She has experience in the commissioning, operation and optimisation of comminution and separation circuit. She holds a PhD in the design of energy efficient comminution circuits and was awarded the international TMS prize for her work.

Zeljka is also a founding Director of CEEC International, a global not-for-profit group aimed at increasing awareness around energy efficiency in comminution. With such a stellar track record in comminution efficiency, Zeljka is the perfect fit to run our LABYRINTH’s® blast preconditioning and big-data mine-to-mill projects. With Zeljka’s expertise, we are now able to very efficiently understand any type of plant data, and very quickly get stuck into extracting value from our clients data assets.

Alan Offer – Principal Mathematician

Alan has joined PETRA as Principal Mathematician in August 2016. Alan has a great passion for all aspects of mathematics and its application across a wide range of fields and industries. His previous data analytics roles include mining, meteorology, transport, ecology, programming and biology. As a highly proficient R and Python programmer he is working with us to develop innovative and creative workflows.

Since joining PETRA only a few weeks ago Alan has single-handedly increased our FORESTALL workflow productivity by 30%, reducing our project turnaround time from about 6 weeks to about 4 weeks. Alan is the AMOC State Director (Queensland) and member of the Senior Problems committee for the Australian Mathematics Trust.


Dr. Evan Jones
PhD MASt BSc(Mathematics)

Evan joined PETRA as Principal Mathematical Solutions in February 2017. He has a great passion for wrestling solutions from complex problems through mathematical and computational techniques.

Evan holds a PhD in mathematical optimisation from the University of Cambridge; and over his career he has applied his talents to a wide range of industries including finance, transport, computer hardware and software and the visual arts.

Evan is also a highly skilled and experienced software engineer. He survived the dot-com bust and is currently also engaged in development at another software start-up (this one is sure to make it). Some more high profile projects he has worked on include the Virgin Australia website and Online Check-in. More interesting projects have involved deriving financial information from email text and VOIP network discovery and management.


Dr. Jim Gunson
PhD BSc (Physics)

Jim joined PETRA as Principal in May 2017. Jim has a PhD in physical oceanography from MIT, that explored the mathematics of combining ocean model predictions with data. He has over twenty years experience in the numerical modelling of ocean dynamics, marine ecosystems, and coastal processes.

Jim has specialist expertise in implement computer models, and improving model simulations using data from diverse sources. He has worked in research and consulting positions at the Met Office (UK), the CSIRO, and most recently the University of Western Australia, where he explored the range of beach response to changing oceanic conditions, affecting turtle nesting.

Jim enjoys taking on new methodologies, and ways of solving complex problems, such as machine learning. He is passionate about the sea and enjoys sailing and diving.


Micah Nehring
PhD BE (Mining)

Micah joined PETRA in October 2016. Micah is an academic in Mining Engineering within the School of Mechanical and Mining at The University of Queensland. He holds a PhD in Mining Engineering which he also obtained from the University of Queensland.

Micah was previously a Mining Engineer at the Mount Isa underground copper operations. Based on his scheduling experience at Mount Isa he developed a Mixed Integer Programming model to optimally schedule long term production from Sublevel Stoping operations while also integrating some the short term elements with the objective of minimising deviation to a target production rate as part of his postgraduate study. This model included new constraints to reflect the ongoing fillmass interactions inherent to the mining method.

Micah specialises in long term strategic optimisation of mine plans with the objective of maximising Net Present Value with a focus on initial pit limit / stope envelope definition and the production sequencing and scheduling aspects of the mining value chain.


Dr. Gideon Steyl
Hydrogeol PhD Chem MSc (Appl. Mathematics) MIEAust CCHEM MSPE PrSciNat

Gideon joined PETRA in April 2017. He has a diverse field of experience which includes mathematical modelling, numerical time series analysis and environmental data analytics to solve problems in the mining and petroleum sectors.

Gideon is a subject expert in hydrogeology and applied chemistry fields where he supplies advice for the development of engineering projects. Notable projects include hydrograph time series analysis for Coal Seam Gas Operators and Mining operations, development of deep sea nodule identification software for Nautilus Minerals, design review with application of data analytics to assess seepage structures in waste facilities at mine sites and aerial processing systems. Gideon has also performed risk based analytics for environmental impact assessments in coal, copper, zinc and gold mining operations.


Arun Pillal
BTech (IT)

Arun joined PETRA as a Data Scientist in May 2017 and comes with a lot of energy, devotion and a solid record of accomplishment and involvement in his field of skill. He believes in utilizing his impeccable skills to combine machine and statistical learning to analyze and interpret complex data for the company.

Arun is currently pursuing his master’s degree in computer science and majoring in artificial intelligence (AI) and machine learning. He has worked as a Software developer and also as a Full-Stack Web Developer in travel and education industries. He has a great passion for building end-end machine learning web applications.

Arun enjoys participating in machine learning hackathons (which is how he came to the attention of PETRA!) and shares his experiences and learning on his blog. He also enjoys playing tennis in his free time.


Alexandra Atkins
BE (Mineral Expln & Mining Geology)Hon BE (Mining) MBA (Fin) FAusIMM(CP) GAICD

Alex joined PETRA as COO in May 2017 to enhance PETRA’s corporate governance and risk capabilities. Her multi-disciplinary mining career – which started in 1986 in Kalgoorlie, WA – spans 25+ years all over Australia & PNG. Her experience is mostly in underground base and precious metals (minor open cut experience) as a mining engineer, geologist & geotechnical engineer.

Her career started with 15 years of on-site operational mine design & management mostly working for Placer Dome APAC (earning her 1st Class Mine Manager’s Tickets in 1998 in WA & 2000 in Qld). This was followed by over a decade of consulting at various boutique mining consultancies and Deloitte and a stint in mine safety regulation (WA District Inspector of Mines 2009-2012).

Alex’s multi-disciplinary industry experience and her large network in industry, government and academia makes her a natural at collaboration and innovation. Alex is also a Director of The AusIMM – The Minerals Institute.

Alex’s Curtin University alumni story captures the can do attitude that served her so well during her early career.

Alumni Story

Leadership Team

Dr Penny Stewart
Principal & Managing Director    

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 Lyle Bruce
Business Advisor 

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Professor Tim Napier-Munn
Associate Director

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