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

August 17, 2016

New IGS Xplore prospectivity maps for Botswana

International Geoscience Services have released a series of base metal prospectivity maps for the Ngamiland District of northwestern Botswana using free geodata available on the recently-launched Botswana Geoscience Portal, hosted by Geosoft. The maps identify favorable areas for copper, zinc and lead mineralization using geological, geochemical and geophysical datasets downloaded directly from the portal.

August 11, 2016

NexGen Makes New High Grade Discovery

NexGen Energy reported the discovery of a new high grade zone of mineralization 4.7 km northeast of the Arrow Deposit as part of an on-going summer drilling program on its 100% owned, Rook I property, Athabasca Basin, Saskatchewan...

August 10, 2016

Rampion UXO Disposal to Take Place This Week

E.ON has confirmed that the two unexploded devices, detected along the Rampion offshore cable route will be safely disposed this week following the consultation with the Marine Management Organisation...

August 9, 2016

Diamonds In The Rough: E&Ps Find New Reserves In Mature Basins

The oil industry’s history demonstrates clearly that new plays and prospects have long been found in mature basins that were thought to be well on the way to being squeezed dry. Through the acquisition of new data, developing new concepts and coming up with fresh interpretations, long-producing basins around the world from the North Sea to Malaysia have continued to reveal new riches...

August 8, 2016

Northern Shield Identifies High Quality VTEM Targets at Séquoi

Northern Shield Resources announced the results of the interpretation and modelling of the VTEM survey from the Séquoi Property in the Labrador Trough of Quebec . Séquoi is owned 100% by Northern Shield and is being explored for Noril'sk style Ni-Cu-PGE massive sulphides. After geophysical modelling and interpretation of the VTEM data from Séquoi, six VTEM anomalies of significant interest have been identified...

August 3, 2016

Rio Tinto tailors big data drive to copper

Rio Tinto will put the weight of an exploration big data push and its newly-formed Growth and Innovation group behind its desire to identify a "tier 1" copper asset. Speaking at the annual Diggers & Dealers conference in Kalgoorlie, Growth and Innovation group executive Stephen McIntosh said Australia was "overdue for a tier 1" mineral discovery of any type...

August 1, 2016

Tetra Tech Awarded $200 Million Navy CLEAN Contract

Tetra Tech announced that it has been awarded a $200 million, single-award contract by Naval Facilities Engineering Command (NAVFAC) Atlantic. Through the Comprehensive Long-term Environmental Action Navy (CLEAN) contract, Tetra Tech will provide environmental engineering support services to installations within the NAVFAC Atlantic Area of Responsibility...

May 3, 2016

NATO Science for Peace and Security (SPS), MODUM Partners announce "Young Scientist Summer School on Sea Dumped Chemical Weapons"

This international project cooperates closely with CHEMSEA (Search and Assessment of Chemical Weapons) Project for and sharing and knowledge transfer...

April 12, 2016

Monday mad rush for gold stocks

Renewed optimism about the outlook for gold saw investors pile back into gold stocks, pushing many stock to 52-week highs in heavy volumes...

April 11, 2016

Medgold Resources: Continues to Expand the Boticas Gold Project, Portugal; Proposes $200,000 Private Placement

Medgold Resources is pleased to announce new assay results from contiguous rock-chip sampling from the Limarinho South zone at its Boticas gold project in Portugal, which include a highlight of 6.0m @ 5.7 g/t Au...

April 8, 2016

De-carbonizing our energy sector

Nuclear energy currently provides around 11 percent of the world's electricity. China, the European Union, the United States, India, Russia, South Korea, and other nations’ have major existing fleets...

April 1, 2016

Follow-Up Drilling Results Indicate Wide Gold Zones at Hendricks Gold Discovery

Gascoyne Resources Limited announced that it has received the final assay results from the 10,000 metre aircore exploration drilling programme...

March 26, 2016

The Oil Market Is Finally Hitting Its Breaking Point

After a significant reduction in investments over the past two years, oil companies can no longer overcome the production declines from legacy wells...

March 15, 2016

N-Sea Expands into the French Offshore Wind Industry

Subsea IMR provider, N-Sea, has signed a letter of intent with CERES Recherches & Expertise Sous-Marine and TechSub Industrie Environement, to provide subsea survey, installation and remediation services to the French offshore wind industry...

March 9, 2016

PDAC 2016 Convention Exceeds 22,000 Attendees

Optimism and opportunity abounded at the PDAC 2016 Convention of The Prospectors & Developers Association of Canada in spite of recent industry challenges...

March 3, 2016

6 Alpha Launches EOD Contracting Division

6 Alpha Associates, a specialist risk consultancy practice, with expertise in the assessment and management of unexploded ordnance, has launched a dedicated explosive ordnance disposal division...

February 10, 2016

Cameco's new uranium discovery revealed

Canada's top uranium producer has a significant new discovery nearby to one of its largest existing mines...

February 9, 2016

NexGen Drills Most Intense Mineralization to Date at Arrow

NexGen announces further results from its on-going six rig 30,000 m winter 2016 drill program on its 100% owned Rook I Property in the Athabasca Basin, Saskatchewan...

February 9, 2016

Rio Tinto scales up its big data ambitions

Rio Tinto is opening its "vast troves" of exploration data to junior explorers in the hopes they will help sift for opportunities and supply ideas and labour...

February 8, 2016

Online portal improves access to geoscience data from Africa

The Botswana Geoscience Institute is launching a Geoscience Portal...

February 8, 2016

5 Best Minerals & Fossils To Buy With Your IRS Tax Refund

You just got your IRS tax refund and now you're presented with some cash to go out and buy one of a kind minerals and fossils from your local...

February 5, 2016

World's largest offshore windfarm to be built off Yorkshire coast

Dong Energy makes final investment decision on 1.2-gigawatt project that will power more than a million UK homes...

February 2, 2016

World's top 10 rookie gold mines

These high-grade mines will soon start competing with gold mining's industry leaders ...

January 25, 2016

Exxon Mobil Corp's defiant outlook predicts Canadian and Venezuelan oilsands output will 'quadruple' over next 24 years

In sharp contrast to the grim medium-term prognosis for the Canadian oilsands, Exxon Mobil Corp. is predicting sunnier times for bitumen in the decades ahead...

January 23, 2016

Magnetic Survey Keeps Cost Down

At a contaminated furniture factory site in North Carolina, a reconnaissance magnetic survey was conducted toward the end of a Phase 2 investigation ...

Magnetization Vector Inversion lends confidence to 3D modelling of mineral projects in South America

by Virginia Heffernan on July 28, 2014 technology

Magnetization Vector Inversion (MVI) is proving to be an effective exploration guide for two promising projects in South America.

At the Mercedes project in west-central Colombia, 3D inversion of airborne magnetic data produced an MVI susceptibility model that clearly outlined a major geophysical lineament (the DWI trend) and helped identify 20 highly prospective anomalies within the trend. The project, owned by Vancouver-based Colombian Mines Corporation, covers a large volcano-sedimentary hosted epithermal vein system with outcropping mineralization grading up to 50g/t gold, 1,120g/t silver and 26.5% copper. Consulting geophysicist, Robert Ellis, with EGC Inc. of Reno, Nevada developed the models from the high resolution airborne magnetic and radiometric data collected by MPX Geophysics, the acquisition contractor.

Colombian Mines’ Mercedes Project: MVI Susceptibility Amplitude Section A-A'

“I have used a lot of magnetic data all over the world, from far northern Canada to the Equator and south, but the use of 3D voxel inversion modelling was an eye opener,” said Robert Carrington, President and CEO of Colombian Mines. “I felt like I had been taken from the Stone Age to the Space Age over a cup of coffee. With these advances, magnetics is no longer the ‘poor country cousin’, but ranks in the same realm as 3D seismics and other high end geophysical exploration tools. Of course the proof will be in the drilling.”

At the Alumbre project in northern Peru, MVI is validating the exploration methodologies chosen by Australian Securities Exchange (ASX) listed explorer Promesa Ltd , which recently pulled a significant copper intercept during its first phase of drilling. The intersection (7 metres @ 0.72% copper) is associated with magnetite highs in the core. The 3D MVI model suggests there is a relationship between a large subsurface volume of rock with a strong magnetic signature and anomalous copper-molybdenum-gold surface and down hole geochemistry, providing further targets for follow up.

Promesa's Alumbre Project: The image on the left shows the historical ground based magnetic data (i.e. Total Magnetic Intensity) and the image on the right illustrates 3D MVI Inversion in grey underneath historical ground based magnetics in the background and drillhole traces Stage 1 program.

Alumbre covers a Cu-Au-Mo porphyry system that has never been systematically explored for porphyry style deposits. Geophysicist Barry Bourne, with Terra Resources Pty Ltd, re-interpreted the company’s historical ground based magnetic data with the MVI methodology to estimate the magnetic susceptibility.

In a recent announcement, Promesa Director, Ananda Kathiravelu said: “This appears to be an entirely new low altitude district with excellent infrastructure and logistical amenities.” The exploration model includes extensive alteration mapping geochemistry, sampling, geophysics and an interpretation of a new magnetic susceptibility 3D model of the project area.

Both companies are planning to follow up their promising MVI interpretations with further drilling. At Mercedes, plans and sections generated through the susceptibility model can be compared with known geology to outline drill targets with greater accuracy. At Alumbre, Promesa will use the model to zero in on higher grade mineralization within the larger Cu-Mo-Au porphyry system. The magnetic susceptibility and geochemistry of the discovery hole indicates that mineralization continues to the north, west and down dip.

Both projects lie at low latitudes, where the low inclination of the Earth’s magnetic field can make magnetic interpretation challenging. Useful in all geological environments, Magnetization Vector Inversion is most effective in situations where geological processes or geophysical effects, such as deformation, anisotropy, remanent magnetization and high susceptibilities, alter magnetization direction. 

MVI, part of Geosoft VOXI Earth Modelling, is an effective tool for visualizing the subsurface quickly and accurately because it solves for both the magnitude and direction of rock magnetization, making it more generally applicable than traditional susceptibility modelling.

Sources: Colombian Mines Corporation and Promesa Ltd

Related Articles

Best targets yet to be drilled at Promesa’s Alumbre project in Peru

View all articles »