Fiery Mt Kilauea in Hawaii is helping to reveal major new nickel discoveries worth billions of dollars in Western Australia, from fossil volcanoes that became extinct there nearly three billion years ago.
The Magmatic Ore Deposits Research Group of CSIRO Exploration and Mining have found close links between the rich nickel sulphide deposits and ancient volcanic rocks called komatiites.
Understand how komatiite lavas erupted and were emplaced and you have vital clues to help pinpoint new nickel discoveries, says head of the research team, Dr Robin Hill.
The problem is that Australia has no active volcanoes in which to study lava emplacement processes - so the Group headed to Hawaii where they established strong research links with staff from the United States Geological Survey (USGS) Hawaiian Volcano Observatory.
Dr Hill says results so far show that nickel deposits were formed in ancient lava rivers or tubes that were the arteries feeding the komatiite flow fields which covered vast areas of the earth's surface around three billion years ago. Some of these pathways resemble the extraterrestrial “rills” seen on the moon, Mars and Venus.
Along these pathways the lava poured at temperatures above 1400 degrees celsius for tens or even hundreds of kilometres. These tubes insulated the lava from rapid cooling, but eventually the intense heat melted the floor of the tubes, causing nickel sulphide deposits to form.
"We've developed techniques for identifying and locating these tubes, thereby providing exploration companies with better tools for selecting the right area and the most promising targets in the hunt for quality nickel-sulphide deposits," Dr Hill says.
As well as the clues from their live Hawaiian 'laboratory' the team has also gleaned data from known mineral deposits and by studying the volcanology and petrology of their komatiite host rocks, slowly but surely completing the nickel exploration jigsaw.
The Group’s work has received international acclaim, and its results and exploration models are now being applied world-wide. Estimates by industry place a value of about US$6 billion on the deposits found in WA with the help of the CSIRO models.
Mr Steve Vallance, senior nickel geologist with Maggie Hays Nickel says his company used the models for discovering the Maggie Hays find at Lake Johnston. Similarly, when Vallance was working with ACM, a collaborative effort with the CSIRO project led to the earlier Sarah's Find nickel discovery at Mount Keith.
"The CSIRO models were instrumental with both finds. The team has contributed enormously to the discovery of nickel in WA over the past decade," Mr Vallance says.
Mr David Burt, exploration director with Mining Project Investors PL, says full use is made of the CSIRO model when it comes to selecting targets for exploration. The high grade Silver Swan nickel find is one notable outcome.
“The CSIRO technique has certainly helped us to find new nickel resources,” says Mr Ian Neuss, managing director of Outokumpu Pty Ltd. “It provides new insights into the rocks, new ideas that lead to a reinterpretation of the whole geology. And this has led to a lot more investment in nickel exploration in WA.”
To hone the skills of the explorers, and to develop new paradigms which will underpin success in exploration, Dr. Hill holds an annual workshop on the flanks of the Kilauea Volcano, Hawaii, which deals with komatiite volcanism, nickel deposits, and exploration. The workshops comprise two days of lectures followed by four days field excursion across the erupting volcano.
"Understanding volcanology is the basis for successful exploration. After these workshops participants never approach their work with the old paradigms again," Dr. Hill says.
Dr Robin Hill, CSIRO Exploration and Mining
08 9333 6373
The above post is reprinted from materials provided by CSIRO Australia. Note: Content may be edited for style and length.
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