August 2019

Ask the author: Alan Sherwood

  • By AusIMM

The Geology and Resources of New Zealand Coalfields (Monograph 33) is AusIMM’s latest monograph. We caught up with author Alan Sherwood to discuss the project and its background.

What is the focus of Monograph 33, and the scope of topics covered?

The monograph is quite broad in scope. While it is primarily a general reference on New Zealand coalfields, it has a geological story, and a story of the coal industry in New Zealand. It has an updated coal resource and reserve inventory, and has some commentary on coal use and future mining prospects. There is also a bit of textbook about it, with discussion on coal resource classification; it also has an extensive glossary, and appendices on coal rank and other topics. The content does not discuss the politics of coal, or its role in climate change. It neither advocates for coal use, nor discourages it, but endeavours to provide factual information on a commodity and an industry.

Can you tell us a bit about the existing work that you drew upon to create the monograph, and any gaps in the record that the book fills?

There has never been a summary of New Zealand coalfield geology of this scope, and the last general account is 25 years old. While there is nothing very new about the content – the book is predominantly a packaging of work by others – what is new is that the book synthesises a lot of existing information from which it is difficult to get an overview. In particular, with over 500 references, it is something of a window on a large number of unpublished exploration reports. 

Can you describe the part coal plays in New Zealand’s current economy?

New Zealand consumes a mere 2.4 million tonnes of coal a year, which accounts for only six per cent of consumer energy, but that belies coal’s importance to the economy. About 80 per cent of consumption is for steel making, food processing and electricity generation. Dairy factories account for a large part of the consumption (for food processing). Coal-fired electricity provides back-up to a generation system dominated by renewables. Gas supplies are becoming constrained, and the immediate alternative is coal. There is also a modest coking coal export industry. 

Could you talk us through your own career experience and interests that led you to producing this work?

Although the first part of my career was as a coal exploration geologist, I was working for what was then called the New Zealand Geological Survey. It was a knowledge-focused organisation, and that imparted in me the value of collating and documenting information to provide a platform for ongoing work. The concept of the knowledge value chain has stayed with me ever since. As I got closer to retirement, I thought it would be useful to document some of what I had learned for others to use. 

Which readers will benefit most from reading Monograph 33?

I hope that the content will be useful to a broad readership. The monograph is primarily a reference, and is not meant to be read from beginning to end. It would be a good introduction to New Zealand coal for young geologists, and should be a useful general reference to those more experienced. The resource and reserve inventory, looking at coal as a commodity, has application for users, investors and the consulting community. The content is by no means restricted to a technical audience, and commentators, policy makers and regulators should find some benefit.

What other groups were involved to make the final publication possible?

New Zealand Petroleum and Minerals (NZPM), the government regulatory agency for Crown-owned earth resources, was my last employer. The organisation generously allowed me to finish my career by writing Monograph 33. Key to my work was NZPM’s online exploration database, and the support I received from other staff, particularly the Geographic Information System compilations that were used in many of the maps. I also collaborated with GNS Science to use their digital map data. Coal companies provided detail to improve the content of the monograph, but it was the contact I had with many of their geologists, as a consultant and later as a regulator, that helped my understanding of many of New Zealand’s coalfields. Philip Carthew drafted the figures, a contribution that can hardly be overstated. The publication team at AusIMM in Melbourne were brilliant. 

The Geology and Resources of New Zealand Coalfields is available now from the online AusIMM library in hard copy and PDF formats.

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