Posts Tagged gravity

Gravity survey for uranium in Athabasca

Posted by on Thursday, 20 February, 2014
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Athabasca Nuclear Corporation  announces the completion of gravity surveys which have resulted in the identification of twenty-three (23) gravity low anomalies on the Western Athabasca Syndicate’s (the “Syndicate”) flagship Preston Lake Uranium Property (the “Property”). The identification process covers a portion of its’ Property and included a RadonEx survey (ground and water) to further refine targets in advance of a drill program scheduled to commence in March.

“As the largest tenure holder in the Western Athabasca Basin and having carried out the most significant regional target delineation program in the area, we are keen to commence further exploration through drilling on some of the gravity low anomalies identified to-date,” stated Ryan Kalt, Chief Executive Officer (Interim) of the Corporation.

Preston Lake Property Map and Regional Exploration Corridors:

http://www.athabascanuclear.com/wp-content/uploads/2014/02/Patterson_Lake_Regional_Map.pdf

Interpretation of the gravity data by Phil Robertshaw, P.Geo., has successfully delineated gravity low anomalies associated with previously identified high-potential exploration corridors defined by structure, magnetic lows, conductors, favorable geology and geochemistry. Gravity is a defining tool for exploration for uranium in the Athabasca Basin and was a key mechanism for vectoring in on the recent discovery made by NexGen at the Rook 1 Project.

 

Hydrothermal fluids associated with high grade uranium deposits will cause extensive alteration of the host rock, resulting in displacement and removal of minerals/elements, creating porosity and subsequent density contrast. This density contrast will be expressed as a gravity low anomaly and is a prime drill target when qualified by other coincident indicators of uranium mineralization such as geochemistry and radon.

Preston Lake Property - Gravity Survey Coverage:

http://www.athabascanuclear.com/wp-content/uploads/2014/02/Preston_Lake_Exploration_Update.jpg

In addition, several of the Syndicate’s gravity low targets have been further refined using a proprietary RadonEx survey which has been instrumental in assisting with numerous discoveries in the Athabasca Basin region. The Syndicate is carrying out a ground EM survey to further refine conductor trends and pinpoint drill pad locations. Details concerning the upcoming drill program shall be provided in the near-future.

The 246,643 hectare Preston Property is the largest individual property proximal to Fission Uranium Corp.’s Patterson Lake South (“PLS”) high-grade uranium discovery and the recent discovery made by NexGen Energy (“NexGen”) on the Rook 1 Project . The Syndicate is the largest land tenure holder in the southwest Athabasca Basin region including properties strategically situated to the southwest and to the northeast of the PLS and NexGen discoveries.

About the Preston Lake Property:

The 246,643 hectare Preston Lake Property is the largest land package proximal to the Patterson Lake South (PLS) high-grade uranium discovery, owned by Fission Uranium Corp. The Syndicate continues to employ a systematic, proven exploration methodology that has led to numerous uranium discoveries in the region and throughout the Athabasca Basin. This has been very effective in identifying numerous high-quality targets with similar geological features and exploratory indicators also present at the nearby PLS discovery and in other deposits in the Athabasca Basin. Management cautions, mineralization present on proximal properties is not necessarily indicative of mineralization on the Syndicate’s Property.


Gravity Anomalies at Depth in Ptarmigan Basin in BC

Posted by on Wednesday, 22 January, 2014

Silver Mountain Mines Inc. announces new results from further modeling of data acquired from the 2013 gravity survey completed on its wholly-owned Ptarmigan Property (the “Property”), located near Radium, British Columbia (see News Release dated October 17, 2013).

Detailed gravity survey data collected by Excel Geophysics previously identified a number of exciting gravity anomalies in the Ptarmigan Basin that merit subsequent evaluation. Continued modeling and interpretation of the gravity data indicates these significant anomalies are located at greater depth than known high grade mineralization identified through surface sampling, trenching and/or diamond drilling completed between 2009 and 2012 (“2009-2012 Geological Exploration Results”). Diamond drilling proposed for 2014 will require deeper holes to evaluate these recently discovered gravity anomalies.

The detailed gravity survey completed within the Ptarmigan Basin comprised a total of 329 gravity stations, with 56 stations along the upper ridge and 273 stations within the basin. Stations within the basin were collected along 25 survey lines oriented east – west, with a station spacing of 50 meters. Survey lines were spaced 50 meters apart within the basin and 25 meters apart in the area over the former Ptarmigan mine workings and the Upper-East Ptarmigan Basin.

Modeling and interpretation of the gravity data has resulted in identification of 3 well defined anomalies in the Ptarmigan Basin (Anomalies D, E, F) (www.silvermountainmines.com/maps.asp), which are interpreted to be located below 240m depth, extending to at least 540 m below surface, based on a minimum density contrast of 1.4 g/cm3. All three anomalies are strong and modeling. Interpretation of the data, as well as correlation to results reported in the “2009-2012 Geological Exploration Results” suggests that these new anomalies are sources and/or deeper extensions of the previously identified shallow mineralization. All three anomalies present very attractive targets and will be drilled in 2014.

Ptarmigan

The northern anomaly (D) is located northwest of the former Ptarmigan Mine, underlying the valley floor and has been interpreted from prior geophysical surveys. The middle anomaly (E) is located east of the surface trace of the former Ptarmigan Mine, with approximate surface dimensions of 172 m x 50 m. The southern anomaly (F) has estimated surface dimensions of 100 m x 26 m. The Upper Ptarmigan massive sulphide occurrence, spatially associated with the west margin of gravity anomaly (F), extends east toward the East Ptarmigan area, where additional drill holes were completed to further evaluate and develop semi-massive to massive sulphide intercepts, identified by surface trenching and drilling in 2009-2012.

These anomalies are the objective of the Company’s proposed 2014 drill program. Analysis and modeling continues on the gravity results from the 2013 program to better define and develop the anomalies.


High Resolution Airborne Geophysical Survey in Tanzania

Posted by on Sunday, 19 January, 2014

Geological Survey of Tanzania (GST) and Ministry of Energy and Minerals of Tanzania have organized the Workshop “Launching High Resolution Airborne Geophysical Data at Julius Nyerera Convention Center (17 January, 2014, Dar es Salaam, Tanzania). Around 150 delegates have attended the workshop from government and private sectors.

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Geotech Ltd. and Sander Geophysics have finished the airborne magnetic, gravity, electromagnetic (VTEM), radiometric surveys in 31 districts and presented some results of the surveys.

Permanent Secretary (PS) of Ministry of Energy and Minerals Mr.Eliakim Maswi said – the surveys were carried out under the Sustainable Management of Mineral Resources Project, saying the purpose of the survey was to identify potential zones of mineralization. “The main objective of the project is to improve the socioeconomic impacts of mining for Tanzania and Tanzanians and therefore enhance local and foreign investments”, said PS.

GST Chief Executive Officer , Prof. Abdulkarim Mruma said: “geophysical data acquired through the high resolution airborne geophysical surveys allow fast and accurate delineation of mineralised targets and when augmented with geological and geochemical datasets are highly effective in attracting new exploration ventures.” Prof. Mruma noted that the availability of the modern geo-scientific  data will stimulate investments into mineral and other sectors and will improve the effectiveness of exploration programs.

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Photo: A.Prikhodko


Gravity, EM, radiometry and magnetic features for uranium exploration in Athabasca

Posted by on Wednesday, 4 December, 2013

 Aldrin Resource Corp. (“Aldrin”) announces completion of the ground gravity survey on the Triple M Property in northern Saskatchewan. Preliminary analysis has identified gravity anomalies coincident with our already identified priority drill targets that are consistent with bedrock uranium mineralization. Aldrin’s Triple M Uranium Property is located adjacent to and southwest of Fission-Alpha’s Patterson Lake discovery property, in the newly prospective southwestern region of the Athabasca Basin.

The gravity survey was completed by MWH Geo-Surveys Ltd. (“MWH”), based in Kelowna, British Columbia, who collected data at 871 unique stations. The survey covered two parallel strong bedrock conductors previously identified from the Geotech VTEM airborne geophysical survey, and associated surface radon anomalies. Gravity anomalies were identified over the same portions of the bedrock conductors previously highlighted by radon anomalies. The gravity anomalies are relative lows reflecting the dissolution and removal of rock mass by the same basinal fluids that may also precipitate uranium. Such extensively altered gravity lows are associated with high-grade uranium mineralization in other parts of the Athabasca Basin, and are a strong addition to our already prioritized drill targets.

Aldrin drill targets

Aldrin has developed high-priority drill tar gets on the Triple M Property. The targets are now characterized by coincident gravity lows, basement structures, conductive anomalies, radon highs, and relative magnetic lows. The return of positive results from multiple independent geophysical, geochemical and geological data sets strengthens Aldrin’s belief in the importance of the Triple M Property drill targets.

Aldrin’s CEO Johnathan More states, “We are becoming more confident in our drill targets of the Triple M Property, because each survey method we employ yields coincident anomalies consistent with uranium mineralization below. Now we have drill targets supported by coincident gravity lows, radon highs, linear bedrock conductors and geological mapping.”

 


Training Course: Gravity and Magnetic Geophysical Methods in Oil Exploration

Posted by on Wednesday, 23 October, 2013
Location:
Calgary, Alberta
Date:
Wednesday, April 9, 2014

8:30 AM – 4:30 PM

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Course Description
This basic one-day course reviews the fundamental geological and physical concepts behind oil exploration using gravity and magnetic methods. It is presented in plain English with minimal math or technical jargon, and it includes hands-on exploration examples and case studies.

Delineation of regional and local fault networks, which gravity and magnetic data enable, is crucial in both conventional and unconventional exploration and production. In frontier regions, these data help to delineate the raised and subsided crustal blocks and depocenters, as well as the distribution of igneous rocks.

The course reviews all stages of gravity and magnetic survey design, as well as data acquisition and geological interpretation. These steps are put in the context of designing and executing overall exploration programs for both conventional and unconventional targets.

A complete set of course materials and lunch is included in this course.

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Who Should Attend
This course is designed for professional and technical personnel who need to understand the basics of gravity and magnetic methods in order to assess their effectiveness in various exploration circumstances. The course is intended for all staff levels including geological, geophysical, administrative and management personnel.
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Course Outline
  • Geological Meaning of Geophysical Anomalies: Anomaly-Lithology Relationships and Relevant Rock Properties
  • Forms of Rock Bodies Encountered in Oil and Mineral Exploration
  • Gravity Exploration Methods
  • Magnetic Exploration Methods
  • Design of Gravity and Magnetic Surveys for Geologic Targets
  • Processing Methods for Gravity and Magnetic Data to Separate and Enhance Desirable Anomalies
  • Data Display and Anomaly Enhancement
  • Exploration Example: Gravity and Magnetic Studies of Alberta Basement Structure
  • Exploration Example: Gravity and Magnetic Studies in a Frontier Basin Offshore British Columbia
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Instructor
Dr. Henry Lyatsky

Henry Lyatsky is a Calgary-based geophysical and geological consultant who has worked across Canada, northern and western U.S., and internationally in oil and mineral exploration.

He was born in St. Petersburg, Russia and moved to Calgary as a teenager. He holds a B.Sc. in geology and geophysics (1985, University of Calgary), an M.Sc. in geophysics (1988, University of Calgary) and a Ph.D. in geology (1992, University of British Columbia). He is the first or sole author of three books (Springer-Verlag) on the regional geology and geophysics of western Canada, two gravity and magnetic atlases of the Alberta Basin (Alberta Geological Survey) and many papers. He is a member of CSEG, MEG and APEGA.

Henry is a past president of the Mineral Exploration Group, a province-wide mining-industry association in Alberta. To avoid the downtown rat-race and congestion, he works from home, enjoys the free space of the Alberta outdoors, and loves nothing better than in-depth history books and good hikes in the mountains.


Geoscience Program in Colorado

Posted by on Wednesday, 18 September, 2013
NEOS GeoSolutions, Inc. announced that it has secured underwriting for a multi-client, integrated geological and geophysical program in Colorado, the second project NEOS has undertaken in the state this year. This newly announced neoBASIN™ project covers 3,000 square miles over the Denver-Julesburg (D-J) Basin, a sedimentary basin that reaches its deepest point near Denver and then extends northward into southeastern Wyoming and the western parts of Kansas and Nebraska. NEOS’s Denver-Julesburg geoscience program has been designed to provide a regional view into the subsurface from the basement through the target reservoir intervals, including the liquids-rich Niobrara shale. By applying an advanced geostatistical technique known as predictive analytics, NEOS will be working on behalf of the project’s underwriters to identify the geological and geophysical measurements and attributes that correspond to the best producing wells in the area of investigation and to determine where similar areas occur in less developed parts of the survey area.
Lance Moreland, Director of Rockies Programs for NEOS, commented, “We’ll be acquiring new airborne geophysical datasets – magnetic, electromagnetic, radiometric, and gravity –and integrating these with existing seismic and well information. We’ll analyze all of the acquired datasets individually, but also interpret them simultaneously to determine the measurements, attributes, and derivatives that correspond with the best wells in the basin. Our predictive analytics methodology will then ‘pattern search’ for these same measurements in less developed parts of the area being studied. This is our standard neoBASIN workflow, though we’ll tailor it slightly to test some of the specific hypotheses operators have about the drivers of Niobrara productivity, including basement topography, basement faulting, and regional intrusive activity.”
The neoBASIN survey is being exec ted under a multi-client commercial model. The window for late underwriters will close on January 15, 2014. Final results should be available to the project underwriters in the first half of 2014. To learn more about NEOS’s multi-measurement methodology for oil & gas exploration and development, read the white paper at: tinyurl.com/MMI-WhitePaper. To learn more about NEOS’s regional imaging programs in the D-J, Piceance, and Sand Wash basins of Colorado, visit: tinyurl.com/neos-Colorado.


Continuing of geophysical investigations at Patterson Lake for uranium

Posted by on Tuesday, 17 September, 2013

Forum Uranium Corp. announces further exploration of its 100% owned Clearwater Project on trend and immediately adjacent to the southwest of the Alpha Minerals/Fission Uranium Patterson Lake South discovery. Forum conducted ground radiometric prospecting, lake sediment geochemical surveys and soil gas radon surveys in late August/early September.

As a result of this program, further prospecting of airborne radiometric anomalies and expansion of the radon survey will take place. The radon survey has outlined a number of anomalous zones on two grids immediately southwest of the Alpha/Fission claim boundary. These results are very encouraging so the grids will be expanded to cover areas with airborne electromagnetic conductors on strike with the Patterson Lake South conductive trend. Upon completion of this follow-up program, Forum will conduct ground electromagnetic surveys this fall and ground gravity in early winter to outline targets for drilling in late January 2014.


Geophysics for kimberlites on Baffin Island

Posted by on Monday, 9 September, 2013

Peregrine Diamonds Ltd.  provides an update on activities at its 100 percent-owned Chidliak project , located on Baffin Island, 120 kilometres from Iqaluit, the capital of Nunavut, Canada. The Chidliak summer exploration program operated by De Beers Canada Inc. (“De Beers”) was completed on August 19. Highlights from this program include the discovery by De Beers of two new kimberlites and the discovery of a kimberlite dyke by government geologists. In addition, possible kimberlite float, which is undergoing final petrographic confirmation by De Beers, was found in numerous other locations.
The De Beers summer exploration program at Chidliak included the evaluation of priority geophysical anomalies by prospecting, orientation geophysical surveys, and bedrock and surficial mapping. During the course of the program, De Beers field teams discovered two new kimberlite occurrences and numerous occurrences of possible kimberlite float requiring additional work before being confirmed. The first confirmed discovery is a kimberlite dyke approximately one metre wide associated with a circular magnetic anomaly with an estimated surface expression from ground magnetics of approximately 0.5 hectares. At the second site, kimberlite float was found associated with a circular geophysical anomaly that has an estimated surface expression from airborne magnetics of approximately 0.5 hectares. Concurrent with the De Beers Chidliak exploration program, the Canada Nunavut Geoscience Office (“CNGO”) conducted a bedrock and surficial mapping program over a portion of the Hall Peninsula of Baffin Island. During the course of their fieldwork, the CNGO reported the discovery of a new kimberlite dyke on the Project. In total three new confirmed kimberlites have been discovered in 2013 bringing the total number of kimberlites at Chidliak to 64.

De Beers completed ground geophysical orientation surveys over twelve known kimberlites using the following methods: gravity, electromagnetics, ground penetrating radar and magnetics. The results from these surveys will be used to determine the most effective geophysical technique for discovering additional kimberlites in future exploration programs. To date initial results from the gravity surveys have been reviewed by Peregrine and indicate that most of the known kimberlites that were surveyed have a strong gravity response. Prior to this year, no gravity surveys had been executed on the Project. Peregrine believes that gravity could play a key role in future kimberlite discoveries at Chidliak. A complete summary of the summer exploration program, including confirmation of additional kimberlite discoveries, and results from the other geophysical surveys will be provided after all information from the program has been evaluated by Peregrine.


Does “geophysics” mean only “seismic” in oil exploration?

Posted by on Friday, 23 August, 2013

Magnetic and Gravity Methods in Mineral Exploration: the Value of Well-Rounded Geophysical Skills.

Henry Lyatsky

Geoscience Research & Consulting Ltd., Calgary, Alberta, Canada

The word “geophysics” in oil exploration is often used synonymously with “seismic”, overlooking many other fruitful techniques. In mineral exploration and engineering projects, applicability of seismic imaging is often limited and other geophysical methods take the front seat.

Gravity and magnetic methods, which are discussed in this article, are extremely useful in both mineral and oil exploration. Unfortunately, among oil-industry geophysicists and managers the knowledge and appreciation of these techniques tend to be comparatively thin. Rooted in over-specialized college training, a too-narrow focus on only some geophysical methods impoverishes oil exploration if potential- field surveys are underutilized. By limiting geophysicists’ ability to switch between oil and mining industries, it restricts their employment flexibility and career choices.

The multi-faceted exploration market calls for many different types of geophysical work. Professional associations and alumni groups need to put pressure on academic institutions to diversify and round out their curricula. Fluctuating economic conditions, and future well-being of new graduates, demand nothing less.

Continuing and Details..


Results from Spring Exploration on Ring of Fire

Posted by on Friday, 9 August, 2013

MacDonald Mines Exploration has received the results from its Spring 2013 drill program targeting volcanogenic massive sulfides (“VMS”) in the Ring of Fire (“ROF”).

The history of geophysical investigation of the property can be found here.

Two drill targets were tested during the program over the Butler 3 and Butler 4 targets respectively. The Butler 3 drilling did not hit appreciable copper or zinc mineralization, but did intersect hydrothermally altered felsic and intermediate volcanic rocks that are indicative that the drill holes are proximal to a large VMS body. The Butler 4 drilling intersected copper and zinc mineralization that Company geoscientists believe to be associated with stratabound mineralization that extends to depth.

“MacDonald is keenly aware that the market, especially today, is only motivated by huge success. James Bay exploration is tough, it is a wetland with little outcrop. Consequently we must utilize drill results for ongoing quantification that further exploration is warranted. The Butler 3 and Butler 4 targets have all the necessary components for discovery:

  • A large heat source (ultramafics, proven komatiates)
  • Laterally extensive alteration (a large system)
  • Known mineralization; zinc, copper, silver and lead
  • Secondary mineralization typically associated with larger VMS systems – tin, enrichment of P2O5 “icelandite”
  • Geophysical signatures (EM, IP, magnetics, and gravity)

We believe we are now moving to the final stages of our exploration efforts. We have quantified geochemical, geophysical and geological (structural) targets and are working on prioritizing these for the next stage of exploration. We expect to be drilling in the fall of 2013 after a full compilation of the data.” – Kirk McKinnon, President & CEO

Two drill holes (BP13-CU19 and CU20), were drilled on the Butler 3 geochemical/geophysical anomaly. No appreciable copper or zinc mineralization was intersected within these drill holes, however the lithologies intersected sodium depleted intermediate and felsic volcanic rocks. This geochemical signature represents a classic alteration vector for VMS mineralization, and leads Company geoscientists to the conclusion that VMS mineralization is to the south-west.

The targeting of the south-west likely represents the extension of the mineralized zone intersecting in drill hole BP12-Cu14. It appears that BP12-Cu19 and BP12-Cu20 are lateral to the mineralized zone.

  • Hole BP12-Cu14 intersected 41.5m of 0.4% Cu, 3.26% Zn and 6g/t Ag
    • Including:
    • 12.5m of 8.54% Zn and 6.24 g/t Ag
    • 5.0m of 1.18% Cu, 3.86% Zn and 14.48 g/t Ag

The target area to the south-west is corroborated by a coincident EM and IP anomaly. Before drilling this target however, the Company intends to conduct a robust structural analysis of the existing drill holes under the direction of Rogerio Noal Monteiro, Ph. D. (Vektore Exploration and Consulting). This data will be used in conjunction with the geochemical and geophysical vector analysis to guide drill targeting.

Drill holes BP13-CU21 and CU22 were drilled on the Butler 4 geophysical anomaly (with coincident IP and EM geophysical anomalies). BP13-CU22 intersected 7.50% zinc over a 3 metre interval, and 0.23% copper over 2 metres. Drill hole BP13-CU21 intersected 0.15% copper over a 12 metre interval. These drill intersections are significant in that they pierced the upper edge of a large sub-vertical electromagnetic plate that was postulated to be associated with VMS mineralization. Now that the Company has verified that this geophysical target is associated with copper and zinc mineralization, a detailed analysis of the structural geology will be undertaken on the target. This information, in conjunction with geochemical and geophysical analysis will be used to develop discrete drill targets.


Airborne EM-Magnetic, ground DC and gravity initiated expanding of the drilling program in Athabasca

Posted by on Wednesday, 24 July, 2013

NexGen Energy Ltd announces it has entered into a contract with GDC Drilling for diamond core drilling at its 100% owned Rook I project to commence mid-August 2013.

Highlights

  • 3,000m planned program doubles the size of previous planned program of 1,500m (see news release 15 May 2013),
  • Two rigs to test several land-based targets identified by VTEM and Gravity Surveys in the southwestern section of Rook I,
  • Rook 1 is immediately adjacent to the high grade Patterson Lake South discovery owned 50/50 by Fission Uranium Corporation and Alpha Minerals Inc.

The 3,000m program (approximately 20 holes) will incorporate two rigs and focus upon target areas in the southwestern section of Rook I identified by VTEM airborne and ground gravity surveys. The targets are all land based, at shallow depth and immediately northeast to the high-grade uranium mineralization discovered on Patterson Lake South. The northeast trending mineralized conductor corridor is interpreted to extend into the southwestern zone of Rook I.

The recently completed ground DC resistivity survey covering the southwestern area of Rook I will further assist in refining previously identified drilling targets.

Leigh Curyer, NexGen’s CEO commented “The 100% owned Rook I is an exciting project for NexGen and our investors. NexGen has doubled the size of the drill campaign; the land-based targets are shallow and are only some of a number of highly prospective identified target areas on the property. We look forward to commencing this campaign in mid-August.”

http://media3.marketwire.com/docs/NXE_Figure1-Figure2.pdf.

Rook I is located directly to the northeast of the Patterson Lake South property being explored by Fission Energy Corp. and its joint venture partner Alpha Minerals Inc. who recently reported results including a reported intersection of 12.5M @ 2.49% U3O8 with assays to 11.1% U3O8 at PLS (holes PLS12-024, from 65.5m downhole; 05 Dec12 FIS press release).

Untested conductors on the Rook I property lie directly on strike and 3km to the northeast of the mineralised intercepts reported by Fission Energy Corp.


Initial Drill Program Successfully Extends Blackbird and Black Horse Chromite Zones in Ring of Fire

Posted by on Tuesday, 23 July, 2013

Bold Ventures Inc. and KWG Resources Inc. announce jointly the following drilling results from the initial diamond drill program on their Koper Lake Joint Venture in the Ring of Fire (ROF) Northeastern Ontario, which is under option from Fancamp Exploration Ltd. (FNC) (see Bold’s press release dated January 7 2013). In turn KWG has optioned the property from Bold on terms that are described in a Bold press release dated March 4, 2013.

Drilling with three drills commenced early in March 2013. The drilling was briefly halted in early April 2013 pending the issuance of an Exploration Permit by the Ontario Ministry of Northern Development and Mines pursuant to the revised Ontario Mining Act.

In late May while drilling the last two holes of the program a forest fire, in close proximity, threatened the drill camp which housed the project personnel. All personnel were evacuated from the area until the fire was brought under control. As a result, the program budget was exhausted and the last two holes were stopped short of the target depth. Casing for holes FNCB-13-35 and FNCB-13-37 was left in place and capped for access at a later date.

During the program a total of ten holes (FNCA-13-29 and 29W1, and FNCB-13-30 to 37) totaling 6040.8 metres were drilled.

Drill Results Nickel/Copper Massive Sulphide Potential

Hole FNCA1329 was collared in the northwest corner of the Fancamp property to provide a platform for down hole geophysical surveying in a northerly oriented ultramafic conduit feeding the northeast-southwest striking Ring of Fire (ROF) ultramafic complex. A similar north-south striking conduit further west hosts the Eagle’s Nest copper-nickel base metal deposit previously discovered by Noront Resources Ltd. in 2007. The hole encountered poor ground conditions and had to be halted before reaching its target depth and was wedged off at 1015 metres. This wedge hole, FNCA-13-29W1, was advanced as far as 1051 metres when the hole was stopped and surveyed with a down-hole electro-magnetic system. Results did not warrant any further drilling from this platform.

Drill Results Chromite

Holes FNCB-13-30 to 37 were drilled to further explore the Black Horse chromite mineralization previously discovered by FNC (see Fancamp’s press release dated May 24th, 2011) as well as to test for the eastern extension of the Blackbird chromite mineralization located on the adjoining Noront Resources Ltd. claims (see Noront’s press release dated March 20th, 2012). The holes were drilled to test an approximate 800 metre strike length of the Blackbird – Black Horse horizon on the western most claim of the four-claim Koper Lake Property. The program was successful in confirming that chromite mineralization does exist within the Koper Lake property directly to the east of the adjoining Blackbird deposit owned by Noront Resources and also in extending the Black Horse mineralization outwards from previously drilled (2010) holes FN1025 and FN1026. Further drilling is required in order to understand the spatial relationship of the Blackbird and Black Horse horizons and the continuity and orientation of those mineralized zones.

Highlights

Holes FNCB1330, 32 and 33 were drilled to test the downplunge continuity of chromite mineralization delineated on the adjacent Noront Resources property.

Hole FNCB1330 intersected 45.76 metres of chromite mineralization from 655.5 to 701.26 metres consisting of disseminated, heavily disseminated, semi-massive and massive chromite. This intercept contains two intervals dominated by massive chromite: from 664.67 to 677.65 metres (12.98 metres) and from 685.67 to 696.32 metres (10.65 metres). The weighted average percentage of Cr2O3 of these two intervals is 26.44% and 31.89% respectively.

Hole FNCB1332 encountered a thin band of massive chromite between 656.13 and 659.0 metres. The intercept assayed 34.48% Cr2O3 over 2.87 metres.

Hole FNCB1333 intercepted two intervals dominated by massive chromite, from 695.48 to 721.07 metres (25.59 metres) and from 753.0 to 813.26 metres (60.26 metres). The weighted average percentage of Cr2O3 of these two intervals was 27.98% and 28.31% respectively. These zones were encountered within a broader low-grade horizon of chromite mineralization.

Diamond drill holes FNCB1334 and 36 from the same collar location were drilled to test a shallow gravity anomaly which was interpreted to possibly represent the updip extension of the Black Horse mineralization.

Hole FNCB1334 drilled at -68 degrees encountered disseminated to layered chromite between 127.44 and 144.14. Assay results included 5.66 metres grading 18.51% Cr2O3 (from 137.58 metres to 143.24 metres).

Hole FNCB1336 drilled at -45 degrees intersected massive to heavily disseminated chromite between 126.44 and 132.84 metres. Assay results included 4.01 metres grading 18.56% Cr2O3 (from 126.44 metres to 1304.5 metres)

Holes FNC1335 and 37 were stopped short of target depth. Future plans will include continuing those holes to their completion.


“the promise of airborne gravity gradiometry”

Posted by on Wednesday, 10 July, 2013

by DAN ZLOTNIKOV on JUNE 21, 2013 EXPERTISE

A versatile tool, airborne gravity gradiometry is changing the face of mineral exploration.

A relative newcomer to the resource exploration world, gravity gradiometry is already having a major impact. Its potential for producing high-quality data has caused many explorers to take notice and wonder how they might best make use of the technology.

- See more at:


Airborne Gravity and Magnetic Data Acquisition in Kenya

Posted by on Friday, 26 April, 2013

CAMAC Energy Inc.  has announced that Sander Geophysics Limited (“SGL”) has completed shooting  airborne gravity and magnetic geophysical surveys on the Company’s Kenya onshore Lamu Basin Blocks L1B and L16 (“Blocks”). The data acquisition covers essentially the entire 12,129 square kilometers in Block L1B and the entire 3,613 square kilometers in Block L16 and satisfies the gravity and magnetic survey requirements for each Block under the relevant Production Sharing Agreements.

The Company expects to receive initial results of the shoot in the third quarter of 2013. Results will be used to optimize the placement of 2-D seismic lines by identifying faults, basement structures and intra-sedimentary volcanic layers and/or intrusions.

“I am pleased that we completed the acquisition of the airborne gravity and magnetic geophysical surveys in Kenya safely, on time, and under budget,” said Senior Vice President of Exploration and Production Segun Omidele. “Our geophysical team will now work with SGL to interpret the data and delineate optimal areas for 2-D seismic acquisition.”


Practical Inversion for Geoscientists

Posted by on Wednesday, 10 April, 2013

A short course on the why, how, and what of geophysical inversion

Presented by the B.C. Geophysical Society

This is a 2-day workshop consisting of 1 day of lectures (April 24th) followed by a 1 day hands-on workshop (either April 25th or 26th). Delegates can register for just the lectures or both the lectures and workshop.

Registration available until April 15th at: www.bcgsonline.org

Date: April 24th – 26th 2013

Address: SFU Downtown Campus; Vancouver BC

Registration: Registration is now open!  Please fill out attached pdf form (link below) and click submit.  Registration will be complete once payment is made via Paypal link.  Delegates are asked to choose one workshop day among April 25th or 26th.

Day 1 – Introduction to inversion
– Introduction to inversion in exploration

Reasons for doing inversion
Range of inversion options: magnetics, gravity, EM, IP-resistivity, seismic
Fitting geology and data

– Background on inversion

Unconstrained/constrained
Joint and collaborative
The future of inversion

– Before inversion – forward modeling

forward modeling
petrophysics drives the story
complexity vs. adequacy

– Case studies

Potential fields
EM
IP-resistivity

Day 2 – Workshop with Case studies
Multi-disciplinary teams will use geological, geophysical and geochemical data from two deposits (Babine Lake porphyry Cu-Mo, BC and Minto Cu, YK) to develop exploration targets. Teams will present their evaluations of the data to stimulate group discussion.

Inversion results for the available geophysical surveys will be presented to demonstrate state-of-the-art technology and best practices.
Sponsors for the short course are currently being solicited. Please contact Victoria Sterritt at Victoria.Sterritt@teck.com for details. Proceeds go to the KEGS Foundation.
For those interested in more information about the short course, please email info@bcgsonline.org


USGS: Iowa Meteorite Crater Confirmed

Posted by on Wednesday, 13 March, 2013

Recent airborne geophysical surveys near Decorah, Iowa are providing an unprecedented look at a 470- million-year-old meteorite crater concealed beneath bedrock and sediments.

The aerial surveys, a collaboration of the U.S. Geological Survey with the Iowa and Minnesota Geological Surveys, were conducted in the last 60 days to map geologic structures and assess the mineral and water resources of the region.

“Capturing images of an ancient meteorite impact was a huge bonus,” said Dr. Paul Bedrosian, a USGS geophysicist in Denver who is leading the effort to model the recently acquired geophysical data. “These findings highlight the range of applications that these geophysical methods can address.”

In 2008-09, geologists from the Iowa Department of Natural Resources’ (Iowa DNR) Iowa Geological and Water Survey hypothesized what has become known as the Decorah Impact Structure. The scientists examined water well drill-cuttings and recognized a unique shale unit preserved only beneath and near the city of Decorah. The extent of the shale, which was deposited after the impact by an ancient seaway, defines a “nice circular basin” of 5.5 km width, according to Robert McKay, a geologist at the Iowa Geological Survey.

Bevan French, a scientist the Smithsonian’s National Museum of Natural History, subsequently identified shocked quartz – considered strong evidence of an extra-terrestrial impact – in samples of sub-shale breccia from within the crater.

“The recognition of this buried geological structure was possible because of the collaboration of a local geologist, water well drillers, the USGS STATEMAP program, and the support of the Iowa DNR concerning research on fundamental aspects of Iowa geology,” said McKay.

The recent geophysical surveys include an airborne electromagnetic system, which is sensitive to how well rocks conduct electricity, and airborne gravity gradiometry, which measures subtle changes in rock density. The surveys both confirm the earlier work and provide a new view of the Decorah Impact Structure. Models of the electromagnetic data show a crater filled with electrically conductive shale and the underlying breccia, which is rock composed of broken fragments of rock cemented together by a fine-grained matrix.

“The shale is an ideal target and provides the electrical contrast that allows us to clearly image the geometry and internal structure of the crater,” Bedrosian said.

More analysis of the data will provide additional detail. These data show the impact as a nearly circular region distinct from the surrounding area to a depth of several hundred meters.

“These data, when coupled with physical property measurements on drill core samples, will form the basis for modeling efforts to constrain the impact geometry and energy of the meteorite,” said Dr. Andy Kass, a USGS geophysicist working on the effort.

The Iowa and Minnesota airborne geophysical surveys are targeting an igneous intrusion, known as the Northeast Iowa Igneous Intrusive complex, that may be similar to the Duluth layered igneous complex exposed in the Lake Superior region of northern Minnesota. Known copper, nickel, and platinum group metal resources were deposited during the formation of the Duluth complex. Both of these complexes are associated with a large structural feature known as the Midcontinent Rift, which is exposed in the Lake Superior Region but is covered by younger rocks as it extends to the south through Iowa, Nebraska, Kansas, and Missouri.

This geophysical survey is part of a larger USGS effort to evaluate the concealed mineral resource potential of the greater Midcontinent Rift region that formed about 1.1 billion years ago.

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The new gravity books

Posted by on Sunday, 3 March, 2013

Acquisition and Analysis of Terrestrial Gravity Data

  • Leland Timothy Long, Georgia Institute of Technology
  • Ronald Douglas Kaufmann, Spotlight Geophysical Services

Gravity surveys have a huge range of applications, indicating density variations in the subsurface and identifying man-made structures, local changes of rock type or even deep-seated structures at the crust/mantle boundary. This important one-stop book combines an introductory manual of practical procedures with a full explanation of analysis techniques, enabling students, geophysicists, geologists and engineers to understand the methodology, applications and limitations of a gravity survey. Filled with examples from a wide variety of acquisition problems, the book instructs students in avoiding common mistakes and misconceptions. It explores the increasing near-surface geophysical applications being opened up by improvements in instrumentation and provides more advance-level material as a useful introduction to potential theory. This is a key text for graduate students of geophysics and for professionals using gravity surveys, from civil engineers and archaeologists to oil and mineral prospectors and geophysicists seeking to learn more about the Earth’s deep interior.

Author(s)/Editor(s):Thomas R. LaFehr and Misac N. Nabighian

Fundamentals of Gravity Exploration (Geophysical Monograph Series No. 17) covers a full range of gravity-exploration topics, including first principles, field instrumentation and operations, rock densities and density contrasts, data reduction, methods of interpretation, and geologic examples.  The subject matter includes inversion and an appendix on the Fourier transform.  This book will help students to efficiently gain knowledge and appreciation for the method, and it will provide experienced earth scientists with a valuable addition to their exploration libraries, both for reference and understanding of this important method.