Rethinking approach to greenfields

TIGHTER budgets are making greenfields exploration work more complicated.
Rethinking approach to greenfields Rethinking approach to greenfields Rethinking approach to greenfields Rethinking approach to greenfields Rethinking approach to greenfields


Justin Niessner

Gone are the days when a typical explorer scoops up 50 square kilometres in greenfields tenements and follows a drill program based on a couple of rudimentary survey leads until the good stuff starts coming up in core.

The high failure rate for hard rock drill targets and the bureaucratic obstacles of large land holdings have put a financial burden on greenfields exploration that the current investment climate cannot support.

The knock-on effect of this has been a pullback in greenfields activity.

However, the funding pinch has also inspired a wave of trends aimed at making greenfields exploration more statistically successful, diligent and well-researched.

In recent years, state governments competing for company investment dollars have added specialised information to their usual mapping services, offering more in the way of seismic, resistivity and depth-to-basement studies.

A renewed quest to pursue diversified datasets has also led to some pretty striking science journal headlines, with CSIRO notably sizing up the discovery of gold in eucalyptus leaves as well as the exploration potential of ants and termites.

More prosaically, historical surveys are getting a closer look, and companies feeling pressure on their greenfields budgets have begun embracing an all-of-the-above approach to exploration techniques before committing to spending money on fresh acquisitions.

“The one thing that’s been very noticeable in the last 12 months is that companies still doing greenfields are concentrating more on rehashing existing data,” GeoDiscovery Group principal geophysicist Graeme Mackee told MiningNewsPremium.

“They’re trying to squeeze every last little bit of information they can out of existing survey data, rather than going out and doing large surveys themselves.”

Mackee’s company offers exploration consulting services with an emphasis on greenfields operations.

He says the greenfields exploration playbook is expanding, with commonly overlooked radiometrics, satellite remote sensing data and even pedestrian tools like Google Earth images, which can now be merged with survey data for landform interpretation.

But whether a company is using airborne magnetics or stream sediment geochemistry, creative data collection runs the risk of becoming an expensive redundancy.

“The first job that has to be done is looking at the historical data and making sure you’re not overlooking something that’s already been done,” Mackee explained.

“There have been numerous cases of companies going in and essentially reinventing the wheel. Someone’s been there and done that before, and they haven’t realised it.”

On average, a half a dozen companies are likely to have been the custodians of any particular deposit before it ever began to bear fruit.

The good thing about existing data is that companies can use it without having to jump through all the hoops and funding all the expenses related to government land use regulations.

Unfortunately, a company can look at data, reprocess it and model it as much as it likes, but until it actually drills a hole, there’s really no telling what’s down there.

This means that, generally speaking, the first hole into a greenfields target is what will determine whether a company persists or walks away.

It’s a compelling argument for cash-strapped explorers to exploit all the pre-drilling tricks of the trade before pulling up their first intersection.

As a case in point last Tuesday, MMG Exploration nixed plans for a wildcat-style drilling campaign at its Treasure project in the Northern Territory after a technical review revealed that a more targeted electromagnetics program would be more prudent.

“It’s been a philosophical viewpoint from quite a few explorers – that targets should be tested by more than just one hole,” Mackee said.

“But practically, if that first hole doesn’t necessarily come up with some encouragement, mineralisation, the correct alteration or at least the correct geology, then generally more holes are not drilled.”