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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...

Inversion modelling helps define kimberlite targets in the Northwest Territories

by Virginia Heffernan on June 4, 2015 applied

[Click to enlarge]

Area map for Margaret Lake Diamonds’ 50,000 acre diamond property in the Northwest Territories.


[Click to enlarge]

Anomaly ML006 with AGG results.

A filtering process refined by inversion modelling has given Margaret Lake Diamonds (MLD) the confidence to select 12 drill targets from more than 60 geophysical anomalies on its 50,000 acre diamond property in the Northwest Territories.

MLD is a relative newcomer to the diamond camp in the southeastern Slave geological province that hosts the Snap Lake mine, the Gahcho Kué project currently under construction and Kennady Diamonds’ bulk sampling and advanced exploration projects. President and CEO Paul Brockington, a Kennady shareholder, first heard of the Margaret Lake property in 2013 while in London chatting with a former classmate from the Camborne School of Mines. The mining engineer recognized the potential of the underexplored claims immediately.

“The claims were staked by a private British group in 2011, but their primary interest was tin and they devoted no time to the diamond property,” says Brockington, who used $100,000 from privately owned Harsbo Minerals to keep the claims in good standing and then vended the property to MLD. “I met with my lawyer in Vancouver on the Friday night, flew to London on Saturday and closed the deal in a hotel room on Sunday night.”

In order to earn a 60% interest, MLD had to spend $1 million on the property by October of this year. The company flew a HeliFALCON® survey incorporating gravity (AGG) and magnetics over 2,800 line kilometres at 75 metre line spacings. To correct the gravity data for water depth, the company ran a property-wide bathymetry survey using Worldview2 high-resolution satellite imagery.

Though bathymetry is commonly used to correct gravity data from the lakes dotting the Northwest Territories, the measurements are usually taken at lake level from zodiacs. By acquiring satellite data, MLD was able to process the gravity data immediately, instead of waiting several months for data collection from the lakes.

(Because most of the lakes on the Margaret Lake property are shallow, MLD believes the satellite imagery is an accurate rendering of the bathymetry, but measurements in the deeper lakes may warrant ground confirmation.)

Unlike the pipes in the Lac de Gras camp to the north, the area’s kimberlites tend to be highly eroded by glaciation leaving irregular dykes and sheet-like structures that represent the root and diatreme zones of the pipe. Their emplacement is believed to date back to the Cambrian Period about 540 million years ago.

To narrow down the 67 geophysical anomalies resulting from the HeliFALCON® survey, consultants Campbell & Walker Geophysics used all the information they could gather to rank targets, including historic geophysical and geochemical results from ground surveys. Of the 67, eight were based solely on their magnetic response and eleven on previous geophysical data in the assessment files that was confirmed by the 2014 AGG survey. The remaining 48 were based on a combination of their AGG and magnetic responses.

[Click to enlarge]

ML006 inversion results

The consultants assigned a rank of one (highest) to four (lowest) to each of the 67 anomalies based on its geophysical and geological (e.g. proximity to indicator minerals) character. None of the anomalies received the highest ranking, but there were 37 in rank 3 and one in rank 2.

After further review, the team selected five Priority A and 17 Priority B targets for inversion modeling using Geosoft VOXI. The model included the Fourier-processed tensor GED, GND and GDD components of the gravity gradiometry data and incorporated magnetics where applicable.

“We made an initial decision to model - or attempt to model - all the geophysical targets we deemed as priority A and B on the premise that if we couldn’t derive a geophysically and geologically coherent model from our data, then we probably shouldn’t be drilling it, at least not without further ground-based evidence that the feature may indeed be kimberlite prospective” says geophysicist Kit Campbell.

[Click to enlarge]

ML006 inversion results – recovered density model

They viewed and imaged the results in 3D along with the high-resolution satellite imagery and physiographic vector data, allowing them to optimize the drilling program both for ice-based vertical holes designed to test the root of the kimberlite and for angled holes from land.

“In both cases, we were targeting the maximum physical contrast mass of the selected anomaly.”

The next step for MLD is to correlate the results of a till sampling program from areas where there is a combination of historic geophysics and indicator minerals with the recent geophysics to derive the final target selection.

MLD has applied for a drilling permit and Brockington hopes to begin drilling the lake-covered targets next winter. The goal is to collect a large enough sample of any kimberlite the company might intersect (a couple of hundred kilograms) in order to complete microdiamond analysis.


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