Speaker:  Professor Dave Craw, Emeritus Professor, University of Otago, New Zealand

Abstract:  Accurate prediction of environmental issues from pre-emptive rock studies is the aim. Successes are heart-warming, but the lessons (best not to call them failures) can be most instructive, and this webinar will cover both. Southern NZ has 150 year history of gold mining, both placer and hard-rock. The biggest issue for placer mining has always been downstream suspended sediments. This issue is affected by geology and is partly predictable and manageable, but subtle features can lead to large negative effects. Revegetation after mining raises some philosophical questions: is the target a uniform restored landscape or enhanced biodiversity? Hard-rock gold mining involves predictable arsenic issues that can be controlled. However, antimony has some negative and positive surprises. Acid-base accounting is useful and accurate, but associated elevated sulphate discharges are an emerging issue that requires attention. The main conclusion is that we need to understand the whole rock mass before mining commences. This point is already well known in theory, but some of the small things that we gloss over in practice, can have significant negative consequences.

Bio:  Dave Craw is a lecturer and researcher in economic geology and environmental geology for 35 years at University of Otago,  New Zealand. His principal research topics relate to orogenic and placer gold: exploration, mining, processing and downstream environmental issues. Dave has worked closely with active mine projects to enable prediction of key environmental parameters.

About JKMRC Friday Seminars 2020

Welcome to the 2020 Series of the JKMRC Friday Seminars.  The list of presentations will aim to cover a range of topics related to the minerals sector from decision making in exploration, new mineral processing technologies, social licence to operate and mine closure.

Due to COVID-19 social distancing restrictions, all JKMRC Friday Seminars will be presented as webinars only.

If you wish to watch past webinars you can access the videos on the SMI website https://smi.uq.edu.au/webinars

Previous seminars have been uploaded to YouTube via the following link: https://www.youtube.com/user/smiuq