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

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...

Sea Floor Exploration: Nautilus Masters the Sea

Toronto-based Nautilus Minerals leads the charge in exploring the Pacific Rim of Fire for sea floor massive sulphide deposits

By Virginia Heffernan

On an autumn day in 1995, Roger Moss slipped his passport into his breast pocket, kissed his wife and baby son goodbye and embarked on a six week journey from Toronto to Lau, Papua New Guinea, where he would join other scientists aboard the RV Yokosuka, a Japanese research vessel.
The mission? To plumb the depths of the Bismarck Sea for "black smokers" that might serve as modern analogues to - and provide an exploration guide for - land-based volcanogenic massive sulphide (VMS) deposits.

Several days into the voyage, Moss found himself bent double in a tiny submersible, his calves stinging with pins and needles, as he scanned the ocean floor for vent sites. But the discomfort would be worth it. While traversing the side of a rocky ridge at depths of almost two kilometres below surface, Moss came across a tell-tale plume.

A Remote Operated Vehicle (ROV) and drilling equipment is used
for sea floor exploration.

The eponymous "Rogers Ruins" now form the most northerly site of the Solwara 4 prospect, one of several high-grade massive sulphide systems being evaluated by Toronto-based Nautilus Minerals as potential mining opportunities.

"This was purely a research mission to see if we could observe VMS deposits as they were forming and apply that knowledge to land-based exploration." recalls Moss, a graduate student at the University of Toronto at the time. "I was skeptical about the possibility of them ever being mined."

But as land-based deposits become increasingly scarce, explorers are turning to the ocean bed as a source of metals to meet growing demand from developing economies such as China and India. Leading the charge is Nautilus, which has been exploring the Pacific Rim of Fire for sea floor massive sulphide (SMS) deposits since Papua New Guinea (PNG) became the first country in the world to grant commercial exploration licenses for such deposits in 1997.

Though Nautilus was a hard sell in the early days, when low metal prices were driving investors away from even the most conventional mineral exploration, the junior eventually convinced Placer Dome (now Barrick Gold) to invest in the sea floor venture through a farm-in agreement that allowed commercial exploration to begin in earnest in 2005.

Today Nautilus is preparing to start up the world's first sea floor copper gold mine in 2010, just off the coast of PNG. The company will use a sea floor mining tool to break up and suck the ore from the ocean floor and pump it though a steel pipe to a ship at surface, where the ore will be dewatered and loaded onto barges.

The first deposit slated for mining, Solwara 1, has inferred and indicated resources of 2.17 million tonnes averaging (at 4% copper cut-off grade) 7.2% copper, 0.6% zinc, 31 g/t silver and 6.2 g/t gold: small by land-based standards, but one of several high-grade deposits the company is continuously discovering.

Underwater sampling of a snail.

This is not the first time explorers have looked to the ocean as a source of metal. In the 1970s, a consortia of private and government companies spent about $US1 billion to mine polymetallic nodules scattered around the ocean floor in international waters. But the venture failed for a variety of reasons – low metal prices, metallurgical challenges and the lack of a title system chief among them.

Research on SMS deposits began in the 1980s when geoscientists realized that the massive sulphides forming on the ocean floor were modern analogues of the VMS deposits currently being mined on land and, as such, may hold the secret to finding more land-based ore.

To test this theory, a team led by Ray Binns from CSIRO, Australia's national research organization, in collaboration with geologist Steve Scott from the University of Toronto began to study the seafloor vents. The Yokosuka cruise that Moss participated in was one of several expeditions they helped to organize.

The focus of most of the research to date has been on hydrothermally active vent fields that produce signatures that can be detected up to 10 kilometres away. This has led to the discovery of about 150 fossil and active sites mostly lying at depths of 1500-3500 m.

The challenge for commercial explorers is to find the inactive SMS deposits that have cooled enough to be mined.

With that in mind, Nautilus has developed a deep-ocean electromagnetic (EM) technique along with its new joint venture partner, Teck Cominco Ltd., and Vancouver-based Ocean Floor Geophysics. The new technology allows the partners to better target their drilling for faster, more cost-effective exploration.

Nautilus is currently conducting detailed environmental monitoring of the project site.

"The system is spectacularly successful in finding copper-rich systems because copper is highly conductive," says Michael Johnston, vice-president of corporate development for Nautilus.

The exploration sequence at sea mirrors that of land-based projects: outline a large area of interest, and then progressively narrow down the target. The difference is that sea floor explorers know exactly where the deposits lie in the stratigraphic sequence, an advantage that saves both time and money.

"Our systems are generally outcropping," says Johnston. We know where that sea floor boundary is, and we drill it only when we think the system warrants drilling and want to know what the average grade of it is, not whether it is there or not."

When looking for SMS deposits, explorers first conduct a study of seafloor topography using bathymetric maps and other nautical information to find target structures. Then they run echosounder traverses to gather further detail on prospective topographic features. The next step is to go plume hunting, looking for increases in particulate material reflected by decreases in transmissivity and/or slight changes in temperature or pH.

At 1500 m below surface, ocean conditions are fairly uniform in terms of water temperature (2.5-2.6° C), acidity, turbidity and sediment concentrations. "It has the same general properties all around the planet, so what you are looking for are any slight changes in those normal conditions," says Johnston.

(Click to enlarge)

(Click to enlarge)

Geophysical surveys, both magnetic and electromagnetic,
are helping to pinpoint the best targets.

Geophysical surveys, both magnetic and electromagnetic, can help pinpoint the best targets. Finally, the vents are sampled by dredging, grab sampling and sediment coring. If the results are promising, core drilling follows.

"Improvements in seafloor exploration technology are continuously occurring," says Joanna Parr, project leader for the seabed minerals division of CSIRO Exploration and Mining. "This is a relatively new field of commercial endeavour so advancements are happening rapidly. Some of the techniques are unique to seafloor systems -  looking for active plume signatures in the water column, for example - but others are adaptations of well-tested land-based technology."

Considering that only about 3% of the ocean floor has been explored for SMS deposits, the potential for further discovery is enormous. But there remain barriers to exploration that may prevent the activity from becoming commonplace just yet.

Though Nautilus holds tenements and exploration licences off the shores of Papua New Guinea Fiji, Tonga, the Solomon Islands and New Zealand, many maritime states do not have legislation that would allow commercial exploration in their Exclusive Economic Zones (the area in which a coastal state has sovereign rights over all the economic resources of the sea, seabed and subsoil.)

Another barrier is the environmental impact. Environmentalists worry about the potential for disturbing unique ecosystems that surround the active vent sites, which sometimes lie in close proximity to the inactive sites that will be mined. There is also concern that the particulate matter stirred up by mining could clog the gills of fish, and the noise could disturb passing fish and whales.

These impacts, and how to mitigate them, will be addressed in the Environmental Impact Statement for Solwara 1 that will be submitted to PNG’s Department of Environment and Conservation by the end of the year. Nautilus is currently conducting detailed environmental monitoring of the project site.

Johnston believes that while sea floor exploration will never match what takes place on land, parts of the world that have a combination of hydrothermal activity and legislation to allow commercial exploration may become hotspots in the not-so-distant future.