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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

December 7, 2016

Geosoft introduces IP and resistivity inversion in VOXI Earth Modelling

Geosoft has added induced polarization and resistivity data inversion to its VOXI Earth Modelling 3D inversion software service. Geoscientists are now able to create detailed 3D models of conductivity and chargeability from IP and resistivity survey data with VOXI. The resulting models can assist in interpreting and targeting regions for mineral and environmental applications...

December 5, 2016

Mexico's Deepwater Round Exceeds Expectations

Some of the world's biggest oil companies showed up Dec. 5 and agreed to invest on the Mexican side of the Gulf of Mexico, proving that deepwater exploration still has a pulse despite challenging market conditions...

November 30, 2016

Magnetic inversion results for Ngamiland available for download

A regional-scale geophysical inversion of magnetic field data in the Ngamiland region of northwestern Botswana is now available for download from the Botswana Geoscience Portal, a partnership initiative of the Botswana Geoscience Institute, industry sponsors and Geosoft...

November 30, 2016

LIGO Resumes Search for Gravitational Waves

After a series of upgrades, the twin detectors of LIGO, the Laser Interferometer Gravitational-wave Observatory, have turned back on and resumed their search for ripples in the fabric of space and time known as gravitational waves. LIGO transitioned from their engineering test runs to full science observations at 8 a.m. Pacific Standard Time on November 30...

November 9, 2016

International Volcano Scientists Unite

For the first time, the United States will host the international Volcano Observatory Best Practices workshop, previously held only in Italy. The workshop will take place this month in Vancouver, Washington. It is designed specifically for volcano observatories around the world and their staff to exchange ideas and best practices with each other...

October 4, 2016

USGS Assesses Mineral Potential for Sagebrush Habitats in Six Western States

USGS has completed a comprehensive assessment and inventory of potential mineral resources covering approximately 10 million acres of Federal and adjacent lands in Idaho, Montana, Nevada, Oregon, Utah and Wyoming...

October 3, 2016

Uganda Targets Up to U.S.$100 Million for Mineral Exploration

Uganda is well endowed with mineral resources and, like many naturally-gifted African countries, is becoming keen on ensuring that these resources play a transformative role in its long-term structural transformation dream - the Vision 2040...

September 9, 2016

Small-Scale Fishers Get A Big Boost With First-Of-Its Kind Impact Investment Fund

Conservation organization Rare announces the Meloy Fund for Small-Scale Fisheries at Our Ocean Conference. The Global Environment Facility, one of the largest funders of conservation worldwide, will be investing $6 million into the fund...

September 1, 2016

Scientists take to the skies to track West African pollution

Scientists operating research aircraft over West Africa have detected organic materials in the atmosphere over a number of urban areas, contributing to concerns of the rise in pollution across the region...

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...

VMS exploration: New life for old camps

Virginia Heffernan

Alan Vowles and Dave Koop

Alan Vowles, Project Geophysicist for Hudson Bay Exploration,and Dave Koop, President of Koop Geotechnical Services Inc., at the discovery hole

With a tendency to be small, zinc-rich and sometimes difficult to process, Volcanogenic Massive Sulphide (VMS) deposits fell out of favour in the low metal price environment that characterized the late 1990s and early 2000s.

But with increasing demand for base metals - including zinc, an early laggard in the metals revival - explorers are returning to some of the old Canadian mining camps known for their VMS production to see if they can find ore deposits missed by their predecessors.

This time, they come armed with powerful exploration tools that can see deep into the subsurface, can detect subtle geochemical signatures and/or are capable of integrating multiple historical datasets with more recent information to generate new targets.

From Matagami, Quebec to Flin Flon, Manitoba, they are succeeding. This year alone, several new VMS deposits have been found in mining camps that were thought to have had their day. And in most cases, explorers are crediting improved technology with their success.

VMS deposits are significant sources of copper, zinc and, sometimes, precious metals (e.g. Eskay Creek in British Columbia). The model for VMS deposits, which form on the ocean floor and are one of the few deposit types to have active, modern analogues, is constantly evolving as are the exploration methods to find them.

Surface crew conducts deep-penterating TDEM survey

Surface crew conducts deep-penetrating TDEM survey over the Lalor Lake discovery

Take Lalor Lake, a discovery in the Flin Flon - Snow Lake greenstone belt of northwestern Manitoba. The new discovery is showing potential to be a relatively large VMS deposit that could reach production as early as 2010 if ongoing drilling continues to intersect ore-grade mineralization.

Winnipeg-based HudBay Minerals had identified the Chisel Lake Basin where Lalor Lake occurs as prospective, but it was an experimental deep penetrating TDEM (time domain electromagnetic) survey incorporating proprietary "innovative techniques" that identified a large bull's eye anomaly, according to project geophysicist Alan Vowles.

Using 3-D computer modeling software, HudBay geophysicists defined the conductor as a flat-lying, tabular body within favourable stratigraphy at a depth of 800 m. They plotted it using Geosoft software, and this year, won approval from management to test it with drilling. The company hit 45 m of high-grade zinc and copper in the first hole and sees the potential to develop an 18-20 million tonne deposit grading about 8% zinc and 0.8% copper.

"We believe we have in hand one of the most significant zinc discoveries in Canada in recent years and, of course, we are now fast-tracking that opportunity," Peter Jones, president and CEO of HudBay told mining analysts in a conference call.

Though relatively deep, Lalor Lake has the advantage of occurring within an established mining belt. The deposit lies within 15 km of the company's Snow Lake concentrator and just 3 km from a haulage road and power line, so the cost of developing the project would be considerably less than if it were a greenfields discovery.

Inspired by HudBay's success, other companies in the area are using a combination of geophysics and geochemistry to find similar pockets of mineralization within the Flin Flon- Snow Lake belt, which contains 20 known VMS deposits with an average size of five million tonnes. The belt is covered by Paleozoic limestone sediments, making airborne and ground geophysical tools that can see through the cover particularly useful.

Igneous geochemistry of the mafic and felsic rocks associated with VMS deposits has also been refined to better delineate prospective ground for VMS mineralization. The two rock types can be used in tandem to identify key ingredients required to form VMS deposits - rifting and high-temperature magnetism - according to S.J. Piercey of Laurentian University in a paper presented at Exploration '07, a once-a-decade event that covers recent advances in exploration technology.

It was geochemistry that lead VMS Ventures Inc., the second largest landholder in the Flin Flon-Snow Lake belt, to the Reed Lake project southwest of Snow Lake, though geophysics that confirmed its potential.

Lynda Bloom, President and CEO of Halo Resources Ltd

Lynda Bloom, President and CEO of Halo Resources Ltd., oversees 28,000 m drilling program at the Sherridon VMS Property in Manitoba.

Past drilling campaigns had identified altered rhyolites with geochemical signatures typical of the alteration halo around VMS deposits in the belt, prompting the junior to acquire Reed Lake. A subsequent airborne VTEM (Versatile Time-Domain Electromagnetic) survey identified an 800-metre-long southwest-trending anomaly and follow-up drilling hit the jackpot - 10.5 m grading 11.2% copper at a depth of 270 m.

VTEM is a leading airborne geophysical survey system capable of providing high definition, deep penetrating magnetic and electro-magnetic measurements of the underlying rock. The system, produced by Geotech Ltd., is particularly good at detecting copper-zinc massive sulphide deposits.

"We've primarily relied on geophysics to guide our drilling," concurs Lynda Bloom, president of Halo Resources, which is also using VTEM technology to identify mineralization within favourable stratigraphy at the contact between felsic and mafic volcanics in the Sherridon camp in northwest Manitoba, about 70 km northeast of HudBay's mining and metallurgical complex in Flin Flon and just north of Reed Lake.

The Sherridon property , which contains the past-producing Sherritt Gordon mine, has only recently been considered a VMS target. New thinking is that the felsic gneisses on the property may be equivalent to the suite of rocks that hosts the VMS mineralization in the Flin Flon and Snow Lake camps.

Last year, Halo identified 122 new targets with an airborne survey and, in combination with alteration mapping, prioritized new areas of VMS mineralization for drilling.

An ongoing 30,000 m drill program has intersected moderate widths of copper-zinc mineralization including 1.2% copper and 6.3% zinc over 6.5 m and 1.6% copper and 4.9% zinc over 5.1 m.

Because VMS deposits often occur as a series of lenses, down-hole magnetic and EM surveys to detect conductive sulphide bodies near the borehole are also becoming an increasingly powerful tool for VMS exploration as modeling software improves, says Marc Boivin of MB Geosolutions in a paper presented at Exploration '07.

Partners Alexis Minerals Corporation and Xstrata Zinc Canada, for instance, used a combination of magnetic and EM borehole surveys to detect buried VMS occurrences on the Ansil West property in the Rouyn-Noranda camp of northern Quebec. He team used the magnetic data from a borehole orientation probe to optimise EM interpretation and drilling locations.

Xstrata inherited West Anvil and other properties from its predecessor Noranda, which revived exploration in the Noranda camp five years ago with the objective of finding more ore in the vicinity of its Horne smelter by using new exploration technologies.

The prolific camp is one of the most studied VMS camps in the world and literally hundreds of companies have scoured its ground over the years since the Horne deposit was discovered in 1923, leaving behind not only truckloads of data but the impression that there was nothing left to find.

Alan Vowles and Dave Koop

Geotech's airborne VTEM technology provides high definition, deep penetrating magnetic and electro-magnetic measurements of the underlying rock.

Xstrata's toolbox included MegaTEM and VTEM, both airborne EM systems, as well as Titan24 for deep penetration from the surface and advanced borehole survey systems. An integral part of the program was the use of 3-D earth modelling technology, particularly 3-D GIS systems, to integrate and interpret the vast amounts of multidisciplinary historical data with new data.

By developing a series of quantitative queries from conceptual geological models (e.g. proximity queries to select cells within 150 m of typical VMS associations, including hydrothermal alteration and exhalites), the partners were able to use a process of elimination to highlight prospective areas.

The resulting West Anvil discovery hole assayed 3.6 % copper over a core length of 53 m, representing the first major base metal discovery in the 17 km2 central area of the camp in 25 years, according to a paper given to Exploration '07 by the Xstrata team.

Xstrata, along with partner Donner Metals Ltd., is also using a combination of 3D data integration, advanced technologies, new concepts and diamond drilling to find ore in the Matagami camp about 300 km north of Noranda. Matagami contains 18 known VMS deposits.

The use of advanced technology to find hidden orebodies in the camp has been ongoing since 1999, when a new EM system survey led to the discovery of the Perseverance deposits containing a resource of 5.1 million tonnes grading 15.8% zinc, 1.24% copper, 29 gpt silver and 0.38 gpt gold.

The main productive horizon in the Matagami camp is a "Key Tuffite" at the top of the felsic volcanics, but earlier this year, Donner made a significant discovery in mafic volcanics about 220 m statigraphically above the Key Tuffite zone. This initial discovery, and subsequent others, demonstrates the potential for stacked mineralization in the Matagami camp.

The drilling success also validates the multidisciplinary approach the partners have used on the project. In recognition, the Québec Mineral Exploration Association (l'Association de l'Exploration Minière du Québec) awarded the 2007 Prospector of the Year Award to the Xstrata/Donner exploration team.

What lies ahead for VMS exploration in Canada after the significant successes of the past couple of years?

Laurentian's Piercey says future geochemical research will focus on distinguishing productive from non-productive volcanoes within rifts. This will require a combination of field methods, new analytical techniques and thermodynamic modeling to better understand the way tectonic, igneous and hydrothermal processes interact.

In the geophysics field, Boivin says further improvements in depth penetration of geophysical tools will be the key to discovering more deep orebodies that can contribute to the next generation of base metal production in Canada.

And finally, 3-D mapping and modeling software and GIS systems continue to evolve. Exploration software companies, like Geosoft, are giving companies more powerful tools to visualize, integrate and interpret both historical and new data. The end result is new techniques and better tools for accessing and working with their data - whether geophysics, geochemistry, drilling or 3D models.

Bring on the old mining camps.