The people, science and technology behind discovery

Subscribe to the Magazine

Get new articles sent directly to
your mailbox.

Join the network

Twitter Updates Group Forum

Earth Explorer is an online source of news, expertise and applied knowledge for resource explorers and earth scientists. Sponsored by Geosoft.

News & Views

News Archive

February 25, 2015

NexGen Drills Best Angled Hole to Date: Discovers New High Grade Zone at Arrow

NexGen Energy Ltd. announced ongoing results from their winter 2015 drilling program at their our 100% owned Rook I property, Athabasca Basin, Saskatchewan...

February 24, 2015

Phase II drilling underway on Kootenay's La Negra

Kootenay Silver Inc. announced that camp upgrades are complete and Phase II drilling has now commenced on its La Negra Silver discovery, contained within the Promontorio Mineral Belt in Sonora, Mexico...

February 23, 2015

Explorer Speaker Series at the PDAC

Geosoft's Explorer Speaker Series at the PDAC 2015 includes presentations on Peregrine's Chidliak Project and Cameco's initiatives to increase efficiency and 'harvest time' through data organization…...

February 18, 2015

Largest Dam Removal in U.S. History Scientifically Characterized

The effects of dam removal are better known as a result of several new studies released this week by government, tribal and university researchers...

February 18, 2015

Exeter outlines the significance of its Caspiche Project water discovery

Exeter Resource Corporation has announced further positive results from the expanded water exploration drilling program for its Caspiche gold-copper project in northern Chile...

February 17, 2015

Earthstar Geographics Releases Arctic Ocean 15-Meter Satellite Imagery Mosaic

In response to the rapidly increasing demand for high quality geodata of the Arctic Ocean, Earthstar Geographics LLC has compiled a detailed satellite imagery mosaic of the entire region and released it in map projections optimized for visualizing the northern polar areas...

February 11, 2015

Geophysics and Geology together for Discovery: Geosoft at ASEG-PESA

Geosoft's program for the ASEG-PESA, February 15-18 in Perth, includes a workshop on practical geophysical workflows for resolving common problems in minerals targeting...

February 9, 2015

Pilot Gold Reports Final 2014 Results from Columbaz Discovery at TV Tower

Pilot Gold announced the final 2014 results from its third gold rich porphyry discovery at TV Tower, located 6.5 kilometres north of the Valley and Hilltop porphyries...

February 5, 2015

Coastal Gold finds the high grade

Coastal Gold has defined a high grade resource at its 100%-owned Hope Brook gold deposit in Newfoundland by developing a 3D model that has tighter constraints and focuses on higher grade drill results.

February 4, 2015

Non-seismic Geophysics

Finding Petroleum is hosting a half-day event on the role of non-seismic geophysical techniques. Are they coming of age? Reserve your space for this free event, being held in London, February 19.

January 27, 2015

Factors Driving 2015 U.S. Oil Output

Rig counts are a highly imperfect guide to future oil production but they are one of the few readily available statistics on oilfield activity so it is unwise to dismiss their importance entirely...

January 23, 2015

Will 2015 Break this ‘Dry Spell’ for New Discoveries?

Steve Todoruk, a broker with Sprott Global Resource Investments, explained in Sprott’s Thoughts recently why ‘juniors’ should look for new discoveries by drilling into the unexplored depths near existing mines...

January 20, 2015

Eni Wins Two Exploration Licenses in Norway

Italian oil and gas group Eni said on Tuesday it had won two exploration licenses in the Barents sea and in the North Sea in Norway...

January 9, 2015

WVU, USGS collaboration sheds new light on coal-cleaning chemicals found in the 2014 Elk River Spill

A collaboration between the U.S. Geological Service and West Virginia University has resulted in a better understanding of the chemicals that spilled into the Elk River in 2014, affecting the drinking water of 300,000 Charleston-area residents...

January 7, 2015

Precipitate's Phase 2 IP Survey Extends Ginger Ridge Chargeability Anomaly Additional 800 metres North

Precipitate Gold Corp announced results from its recently completed Phase 2 induced polarization ("IP") geophysical survey at the Ginger Ridge Zone within the Company's Juan de Herrera project in the Dominican Republic...

December 18, 2014

IGC's completion of Eastern Seaboard regional integrated interpretation package

Integrated Geophysics Corporation (IGC) announced today the successful completion their Eastern Seaboard regional integrated interpretation package. Designed for oil and gas companies needing a First Pass Look at the regional tectonics and structural trends for this new frontier...

December 10, 2014

Advances in base of salt and sub-salt imaging, Geosoft releases VALEM HPC inversion modelling

Integrated within Geosoft’s GM-SYS 3D Modelling software program, VALEM is an improved, interactive solution for sub-salt interpretation that resolves the base of salt from gravity data bound by the constraints of seismic modelling...

December 03, 2014

Petrobras makes deepwater discovery in Colombian Caribbean

Petrobras reported the discovery of a natural gas accumulation with the Orca-1 exploratory well drilled on the Tayrona block in the deepwater Caribbean Sea, 40 km offshore La Guajira, Colombia...

It Pays to Look Deeper

Deep earth imaging is revealing previously overlooked and undiscovered
mineral bodies

By Graham Chandler

The mountains between British Columbia’s Highway 37 south of Dease Lake and the Alaska border have long been a prolific supplier of important mineral resources. Ten thousand years ago Canada’s indigenous peoples were accessing some of the world’s best obsidian - a natural volcanic glass sharper than surgical steel - from Mount Edziza and trading it all over the continent.

Fast forward to the 21st century. The bounty continues. This region can now boast two of Canada’s most significant copper, gold and silver deposits: Barrick Gold’s Eskay Creek Mine and NovaGold/Teck Resources’ Galore Creek Project. NovaGold alone has reported resources of 7.4 million ounces of gold, 117.1 million ounces of silver and 8.5 billion pounds of copper. And now thanks to a new deep imaging technique, Romios Gold Resources hopes to reveal even more in this rich paradise.

Romios Gold had begun intensively studying regional geologic maps which suggested the underlying rocks and mineralization between the two projects held serious promise and so in late 2004 began acquiring land positions there. Exploring surface mineralization supported their enthusiasm when it appeared the rocks may be closely related to the porphyry copper-gold-silver deposits at the nearby Galore Creek Project. They followed up with soil geochemistry, mapping and silt sampling programs on the Trek property in 2006.

Soon they had a diamond drilling program underway. “It was based on plain old hand drawn maps and geologic work,” says Scott Close, Principal Geologist for Romios Gold. “The very first time a drill hole was placed at the North Zone on Trek, we hit great breccia-hosted mineralization. This indicated we were within the cupola area of this porphyry so we expected the body to be nearby.”

Their hunch was right. Drilling successes in 2008, 2009 and 2010 discovered wide zones of gold-copper mineralization at the North Zone and also identified a new area of prospective copper-gold mineralization called the Tangle Zone. 2010 drilling results suggested the breccia and mineralization at the North Zone extended at least 700 by 550 metres, to a depth of 450 metres and - more importantly - it appeared that the mineralization may be traceable to a mineralized porphyry body beginning 550 to 600 metres depth.

So at this point what was really needed, before committing to further drilling, was a look deeper - beyond their drill depths, into where they expected that porphyry body to be. That’s when they brought in the Titan24 Deep Earth Imaging system. “With the Titan24 we could really get a good idea of where we sat,” recalls Close. “Predecessors to this system had imaged the Galore Creek mineralized body as we know it today, but the resolution was lower.”

The Titan24 Deep Earth Imaging is a product of Quantec Geoscience. Ron Vermey, Quantec’s President and CEO, describes what makes the system unique. “It’s a combination of array geometry,” he says. “We use a grid array on the surface that’s 2400 metres long, which gets us down to depths of 500 metres or more with IP (induced polarization, or chargeability) and resistivity, and 1500 metres with MT (magnetotelluric).” He says because of low signal strengths from such depths they also use highly sensitive electronics which can pick up very small signals. “That’s important when you’re looking at depth,” he says. The processing is important too, to recover small signals against an often noisy background.

The Titan24 system’s deep imaging capabilities were tailored for Romios Gold’s Trek property. And there was another attraction. “Quantec said they could actually couple their deep MT, their high resolution IP and resistivity - of which we hadn’t conducted in detail on any of on the Trek property - with drill results from portions of the surveys,” says Close. “So it was an excellent opportunity to do all three, allowing us to associate any anomalies, or lack thereof that appeared with data we already had and project into new territory.”

Undertaken in the summer of 2010 close on the heels of that year’s drilling program, the Titan24 Deep Imaging’s three lines revealed what Romios had suspected. The survey identified a large deep conductor 500 by 300 by 200 metres high, across all three lines in the Trek property’s North Zone; and it still remains open to the north, east and south. As Romios Gold says on its website, “this new feature, which lies east and below the previous drilling and occurs from 500 to 675 metres below surface, represents the main target for future drilling.”

The analysis and interpretation of the DC, IP and MT results also identified several chargeable anomalies above the deep conductive zone. They were reported to coincide reasonably well with the results of the existing 23 drill holes on the North Zone. Romios intends to drill test these anomalies in its upcoming program too.

Close describes the benefits that Titan24 brought. “It’s a highly sensitive system,” he says. “So it accurately reflects an interplay among the mineralization, alteration, structure and geology of the deposits; when coupled with different reference information like drilling or geochemistry, the survey provides a complete exploration picture.” 

Quantec uses Geosoft Oasis montaj to generate all of Titan24’s sections and plan maps. The Geosoft Viewer allows Romios and other customers to easily view Titan24 maps, turn layers on/off as needed, and enables them to convert them into geo-referenced images for export in a vertical plane. They can bring these directly over into GIS and various other programs.

The mapping workflow was streamlined a few years ago when Geosoft designed a custom solution for the Titan24 application. A Titan24-specific menu blended seamlessly with Geosoft’s ability to import, view, process, and share data sets and images in one integrated environment. It allowed Quantec to produce client-specific presentations such as Titan24 Custom Inversion Sections and Plan maps, Voxel presentations and 3D inverted data. Vermey adds. “We’re able to efficiently visualize drillhole databases, create Titan 2D and 3D models, integrate client data and pseudosection displays for conventional data within one environment, for consistently high quality results.”

The inversion presentations were critical. “The regular DC-based inversion on the MT did a great job for the two southern lines, which indicated a conductor consistent with the geology in the area,” says Close. “Major faults overpowered the anomaly at depth on the northern line. So, applying a static shift upon the underlying resistivities to remove the influence of the overlying faults affecting this line, Quantec was able to identify the conductive anomaly striking through all three survey lines. Knowing the geology was useful for constraining the inversion.”

The final subsurface processing that brought it all together was produced using Oasis montaj. “The contouring inherent in Geosoft can histogram-equalize (evenly spread colors over a non-linear set of values) better than any other program I’ve ever used,” says Close, “so it makes incredibly beautiful maps.” He says once they had that image, they realized their drilling had just missed the conductive body. “The image confirmed what we had suspected: we had drilled smoke near the flame.”

Now, armed with this new deep picture, they’ve picked out new drill locations. “We will have one drill hole penetrate down the middle, right at the heart of the system, and verify the target,” says Close. “Then, we’ll step out. We will drill holes further to the east through the higher IP anomalies that coincide with surface mineralization, and trace the IP anomalies back toward the deeper MT target.” It’s a whole new level of confidence.  “The Titan24 system has greatly enhanced our ability to focus our future drilling at these depths,” he says.

Vermey says Titan24 offers benefits because deposits are getting deeper. “As much as market economics say today ‘look for shallow deposits’, in many areas particularly in mature jurisdictions like North America many of the deposits are deeper, harder to find, or under cover,” he says. “So for ten years Quantec’s Titan24 method enables you to look almost as deep as you want to detect these ore bodies. In some places like Arizona you are looking down 1300 metres for porphyry copper.” And, he adds, with recent rises in commodity prices that certainly makes it economic to go back and re-explore old mines and camps. “Titan24 is a proven system in a mine site environment so you can come up with some good data out of what is normally a noisy environment.”

Romios used the Titan24 survey even in the absence of any existing drilling information - in the Tangle zone of their Trek property. They had nothing but a large soil anomaly, on which Close says “it’s hard to find funding to drill anomalous soils.” So they ran a single Titan24 line across the zone. It revealed a one-to-one correlation among all three DC, IP and MT surveys, exposing a deeper anomaly connected with the anomalous soils at surface. “That single line added enough confidence for us to attract investors to the potential of this new area,” says Close. “It brought us a wealth of possibilities. Really, to me, Titan24 is the new wave of ground geophysics.”