Posts Tagged SkyTEM

Airborne and borehole geophysics in Greenland

Posted by on Friday, 21 September, 2012
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North American Nickel Inc. reports that it has completed its first drill campaign at its 100% owned Maniitsoq project. Drilling commenced on August 26 and was completed on September 16. Nine diamond drill holes totalling 1,550 metres were drilled.

All nine holes have been logged and all mineralized intersections have been sampled. A total of 531 samples have been collected for assay. The samples are now on their way to Activation Laboratories for analysis and results are expected in four to eight weeks.

The holes tested electromagnetic (EM) anomalies associated with noritic rocks and nickel sulphide showings. The anomalies were outlined by SkyTEM and VTEM helicopter-borne, time domain, EM surveys flown by the company in 2011 and 2012. Crone Geophysics Ltd of Mississauga, Ontario surveyed eight of the holes with their 3-component borehole pulse EM (BHEM) system. Preliminary analysis has been completed and final analysis will be done before assay results are received.

Results from the drilling and BHEM surveys will be merged with the Company’s existing exploration database which will allow the NAN geological team to finalize its plans for the 2013 drill season at Maniitsoq.

The Maniitsoq property in Greenland is a district scale project. It comprises a 4,983 square km mineral exploration licence covering numerous high-grade nickel-copper sulphide occurrences associated with norite and other mafic-ultramafic intrusions. The 70km plus long belt is situated along, and near, the southwest coast of Greenland, which is ice free year round. The Maniitsoq area is underlain predominantly by highly deformed and metamorphosed Archean gneisses. Supracrustal rocks comprise about 10% of the area and consist mainly of amphibolite (metamorphosed and deformed volcano-sedimentary sequences). Most of the nickel discovered to date is associated with younger, undeformed norite intrusions that are concentrated in (but not restricted to) a 15 km wide by 75 km long “J”-shaped belt, referred to as the Greenland Norite Belt (GNB), that rims a large, complex known as the Finnefjeld gneiss complex.


Airborne EM Survey over the Oldest Meteor Impact Site

Posted by on Tuesday, 24 July, 2012

North American Nickel Inc. reports that fifty zones of conductivity, many with significant strike lengths, have been identified in preliminary data from its recently completed VTEM Plus helicopter time domain electromagnetic survey over its 100% owned Maniitsoq project in Southwest Greenland.

The Geological Survey of Denmark and Greenland (GEUS) had recently announced the discovery of the oldest-known meteorite impact site in the world, rousing the company’s interest in its Maniitsoq project.

More than twelve of the fifty have already been identified as higher priority zones which have the potential to become targets for the company’s upcoming drill program in August. A more detailed analysis of all the VTEM Plus data is underway.

NAN CEO, Rick Mark, states: “We are very pleased that the VTEM Plus system has been successful in delineating fifty new conductors. With this data, we already have a dozen new targets similar in priority to the three drill targets previously identified in last fall’s smaller SkyTEM survey, some with apparent strike lengths in excess of 1 km. Now that we can point conclusively to conductors occurring throughout the 75 km long belt, we are more comfortable than ever in describing this as a camp-scale exploration play.”

The Greenland Norite Belt (GNB) is a 75 km long by 15 km wide belt of crustally contaminated noritic intrusions with numerous historical, high-grade nickel sulphide showings (e.g. 9.85 m averaging 2.67% Ni and 0.60% Cu at the Imiak Hill showing). Mineralization within the belt has consistently high nickel tenor (6-8% Ni in 100% sulphide according to work done by Falconbridge in 2000).

Despite its obvious high prospectivity, the GNB has seen little drilling. A total of 119 holes totalling only 6,300 m, for an average hole length of less than 53 m, were drilled in the 1960′s and 70′s. More recent exploration programs stopped short of drilling due to a lack of EM anomalies to guide drilling. NAN’s strategy at Maniitsoq has been to use modern helicopter borne TEM systems to develop drill targets and it has proven successful. This technology was not available to previous explorers.

The VTEM Plus survey, combined with a SkyTEM survey flown by NAN last year, provides the company with high resolution TEM coverage over a total area of 860 square kilometers centred on the Greenland Norite Belt).

Data from the VTEM Plus survey is currently being processed and interpreted. All significant electromagnetic anomalies will be checked in the field and ranked. The highest priority targets will be tested during a drill program that is planned to commence in August.

The survey, which ran from June 20 to July 17 and comprised 3,532 line-km of surveying, was performed by Geotech Ltd. of Toronto, OntarioCondor Consulting Inc. of Lakewood, Colorado provided daily QA/QC analysis of the data.

http://media3.marketwire.com/docs/nan-0724-image1.pdf


Three High Priority EM Targets on Greenland project

Posted by on Tuesday, 31 January, 2012

North American Nickel Inc. announce that the three-dimensional modelling of SkyTEM helicopter time domain electromagnetic (EM) data collected last fall over parts of its Maniitsoq project in southwest Greenland is complete and has identified three high priority targets for follow-up this summer. Details on each are discussed in the sections below.

Highlights:

  • Target B1-L – modeled as a 330 x 100 m flat-lying conductor located 160 m below surface within a norite intrusion. The conductor is untested but past shallow drilling 100 to 150 m above the conductor intersected weakly disseminated, nickeliferous sulphides grading up to 0.52% Ni and 0.26% Cu over 12.94 m, demonstrating that mineralizing processes were at work in the intrusion.
  • Target B1-B – 700 m long, untested, near surface conductive zone. The characteristics and orientation of the conductor vary considerably along strike suggesting it is not formational. Magnetic data suggests that it is hosted in a large (2.5 x 1.0 km) norite body.
  • Target B1-J – 170 m long by 16 m wide conductor that comes to surface and is directly coincident with the Imiak Hill showing, the most significant nickel occurrence discovered to date in our Maniitsoq licence area. The model shows that the Imiak Hill mineralization strikes parallel to most of the historical drilling and therefore has not been properly tested. The model has very limited dip extent (21 m), but the best intersection on the showing (9.85 m averaging 2.67% Ni and 0.60% Cu) occurs 130 m below surface indicating that strong mineralization at surface is masking mineralization at depth.

North American Nickel CEO Rick Mark states: “The Maniitsoq project is progressing remarkably well. Our primary objective in 2011 was to employ today’s airborne EM survey technology in this highly prospective nickel belt. Fifteen years ago Falconbridge and Cominco used fixed wing aircraft and the technology of the day searching for conductive bodies to indicate drill targets. It simply didn’t work. After flying only 8% of our Maniitsoq license, we have proven that modern helicopter EM is much more effective than previous techniques used in this 75 km long belt of nickeliferous norites. Today’s release describes, in detail, the first three targets we have identified in this potential nickel camp.”

Background

As described in NAN news releases dated December 6 and 8, 2011, SkyTEM helicopter EM and magnetic surveys flown over two flight blocks covering approximately 8% of the 4,841 km2 Maniitsoq project, detected twenty five anomalous target zones. The location of the project and the flight blocks are shown in figures 1 and 2.

The purpose of the EM modeling discussed in this news release was to determine the characteristics of the anomalies in three dimensions in preparation for follow-up prospecting and drilling. All three high priority targets are located within flight block 1.

Target B1-L

The target corresponds to the Spotty Hill showing, which consists of weak (<1 to 2%) disseminated sulphide mineralization in a lenticular exposure of norite roughly 400 m long and 150 m wide. It was discovered in the early 1960′s by Kyrolitselskabet Øresund A/S who tested it with five very shallow (<60 m long) holes. All five intersected norite with weak, disseminated, nickeliferous sulphide mineralization. The best intersection was 12.94 m averaging 0.52% Ni and 0.26% Cu in norite containing about 5% sulphide.

The SkyTEM survey detected a moderate strength EM anomaly directly over the showing. Modeling indicates that the anomaly is produced by a flat-lying conductor, approximately 330 m long by 100 m wide, located at a depth of 160 m below surface, which is over 100 m below the deepest hole on the showing (figures 4 and 5).

Target B1-B

This target was modeled as a series of six conductive plates ranging in thickness from 9 to 43 m that occur over a distance of about 700 m. In Figure 6 it can be seen that the strike and dip of the plates vary considerably along the length of the target suggesting that it is not a simple stratigraphic conductor. It should be noted that the plates in Figure 6 have been truncated along their strike length in order to show their orientations more clearly. In most cases the plates actually overlap along strike; although the large gap in the middle of the target does appear to be real.

The target is situated within a 2.5 km by 1.0 km magnetic feature interpreted to be a norite intrusion. Some of the model plates come very close to surface and it may be possible to determine the source of the anomaly through surface prospecting which will be carried out this season.

Target B1-J

This target corresponds to the Imiak Hill showing and models as a 172 m long by 16 m thick plate that comes to surface and has a depth extent of just 21 m (figures 7 and 8). Clearly, the mineralization continues well below 21 m as evidenced by hole Im-9, which intersected 9.85 m of massive to semi-massive sulphide averaging 2.67% Ni and 0.60% Cu at a depth of 130 m vertically below surface. It therefore appears that highly conductive material at surface is masking responses from deeper mineralization, which is to be expected. The modeling results are significant, however, in that they show that most of previous drilling at Imiak was oriented parallel to strike and that, despite the numerous shallow drill holes, many of which intersected significant mineralization (see table in Figure 8), the zone has not been properly tested. Two or three holes oriented perpendicular to strike followed by down-hole 3-component EM surveying is required to get a better interpretation of the potential of this zone.

http://media3.marketwire.com/docs/NAN_figures.pdf


Comparison Between 2011 SkyTEM and 1995 GeoTEM Geophysical Surveys, Greenland

Posted by on Saturday, 10 December, 2011

North American Nickel Inc. provides details comparing the electromagnetic (EM) results from its recently completed SkyTEM helicopter-borne survey and those from a 1995 vintage GeoTEM fixed-wing survey.

SkyTEM geophysical system is detecting conductors not seen before and is also resolving previously known EM anomalies in much greater detail. These results have met or exceeded NAN’s expectations and firmly establish that the new exploration technology available today is able to identify new, previously unrecognized targets.

The area surveyed in 2011 comprises only 8% of the total Maniitsoq project. Based on the success of this program, additional areas are now being evaluated for helicopter-borne surveying in 2012.

NAN Chief Geologist John Pattison states: “The 1995 GeoTEM fixed-wing survey was the only large scale, airborne Time Domain EM survey ever performed in the Maniitsoq nickel belt prior to our SkyTEM survey. The SkyTEM system has identified new EM targets. It is clear to us that we now have a powerful exploration tool that provides us new opportunities for the discovery of nickel-copper PGM deposits in an underexplored area of the world, adjacent to year round, ice free tide water.”

As reported in the December 6th 2011 news release, NAN completed 2,217 line-kilometers of SkyTEM helicopter time domain EM (TEM) surveying this past summer covering two blocks of ground totalling 373 km2 within its 4,841 km2, 100% controlled, mineral exploration licence.

Block 1 is situated at the northern end of the 80 plus kilometre long norite belt and hosts the largest of the known nickel bearing norite bodies and strongest nickel occurrences discovered to date in the belt. Block 2 covers a four kilometre long rusty norite body northwest of the main norite belt trend.

In 1995, there were only three significant (>2 channel) responses and they were all single line anomalies associated with exposed mineralization at the Imiak Hill, Fossilik II and Spotty Hill showings. The cluster of 1 and 2 1995 channel anomalies on the west side of the block corresponds with a lake and is probably caused by conductive sediments.

In Block 2, the 1995 GeoTEM system only detected one weak (2 channel) anomaly near the northern boundary of the block, while the 2011 SkyTEM survey outlined 8 target zones one of which (B2-B) corresponded to the lone GeoTEM anomaly.

To view the images associated with this news release, please click the following link:http://media3.marketwire.com/docs/nan_images.pdf.


Helicopter EM and Magnetic Surveys on Southwest Greenland

Posted by on Monday, 12 September, 2011

North American Nickel Inc. announces that, based on the results of compilation work, including a re-interpretation of historical airborne geophysical data and a recently completed field program, it has selected two areas for helicopter, time domain electromagnetic (TEM) and magnetic surveys.

Locations of the two areas, referred to as blocks 1 and 2, are shown in Figure 1 (Download this Press Release (PDF 528 KB). They cover a total area of approximately 360 km2 and will involve approximately 2,000 line-kilometres of surveying. Flight line spacing will range from 100 to 200 metres.

NAN has signed a contract with SkyTEM Surveys ApS to do the helicopter TEM surveying, which is scheduled to begin in mid September. SkyTEM is a Danish company with experience in Greenland and expertise in the execution and interpretation of helicopter TEM and magnetic surveys.

Purpose of the Survey

The purpose of this work is to locate targets for drilling. As described in a NAN news release dated August 15, 2011, the Maniitsoq property hosts numerous high-grade nickel-copper sulphide occurrences associated with noritic intrusions. A large portion of the project area was covered by a fixed wing GeoTEM survey in 1995, but very few EM anomalies were detected and no follow-up drilling was done. NAN believes that a modern helicopter TEM system is much better suited to locating anomalies associated with irregularly shaped nickel-copper sulphide bodies in the rugged terrain that characterizes the Maniitsoq project. The 1995 fixed wing GeoTEM system was often forced to fly at a low angle to strike and well above mandated ground clearance whereas a helicopter system will be able to hug the terrain and survey perpendicular to strike. Also, the signal to noise ratio of the helicopter system will be significantly lower, which will aid in the detection of irregularly shaped sulphide bodies.

Block 1 and 2 Survey Areas

Block 1 covers 346 km2. It includes the largest noritic intrusions and most significant nickel occurrences in the project area (Figure 2). A re-interpretation of historical aeromagnetic data has shown that in this part of the project area the noritic intrusions have a significant component of remnant magnetism giving them a very distinctive magnetic signature. Mapping out this signature suggests that there may be significantly more noritic rock and associated nickel-copper mineralization than is exposed on surface.

Block 2 is centred on a northeast-striking, noritic intrusion known as Pingo that is exposed over a strike length of more than 4 km (Figure 3). Rusty zones ranging from <1 m2 to over 100 m2 occur throughout the exposed norite and typically contain trace to several percent pyrrhotite and trace chalcopyrite. A short (61.88 m) hole was drilled near the centre of the exposure in 1970 and intersected a 4.16 m interval of weak sulphide mineralization averaging 0.58% Ni and 0.24% Cu. This is the only recorded drilling on the intrusion.

Survey Terrain

The terrain in the Pingo area is extremely rugged and the 1995 GeoTEM survey was forced to fly with a ground clearance over 100 m above the mandated 125 m clearance, severely hindering the ability of the system to see prospective EM anomalies. No EM anomalies were picked in the original interpretation of the data, but NAN’s re-interpretation has revealed three high priority EM anomalies forming a line that intersects the south edge of the Pingo norite. These anomalies are at the noise threshold and, accordingly, it becomes difficult to differentiate anomalous from background responses. A helicopter survey is required to properly evaluate them and determine if there are other conductors associated with the Pingo norite.

It has retained the services of Condor Consulting Inc., recognized experts in the field of airborne electromagnetics, to provide QA/QC and advanced interpretation services for the company’s SkyTEM helicopter EM and magnetic survey at its 100% owned Maniitsoq project in southwestern Greenland. The survey is scheduled to commence at the end of this week and is being performed by SkyTEM Surveys ApS.  SkyTEM is a Danish company with experience in Greenland and expertise in the execution and interpretation of helicopter TEM and magnetic surveys.


SkyTEM’s groundwater case study in Italy

Posted by on Saturday, 19 December, 2009

Aarhus Geophysics ApS at Department of Earth Sciences of University of Aarhus (Denmark) which provides software and know-how for large scale surveys, presents some news about their activity.

At software level, the Aarhus Workbench has undergone a robust developing phase on the GIS components, and on the QC of inversion results: completely revolutionized the colour scale interface, created a shading option for horizontal maps, and the possibility to create comprehensive print ready pdf maps is activated. Regarding the second issue, the user can now visualize, with just few clicks, different maps on the GIS component of the parameters that allow to QC inversion results. These include, for example, data residual, difference between frame altitude input and output, model parameter sensitivity analysis, etc.

In terms of AEM data processing, inversion and survey planning it is also continuing with a number of new projects both for private and public clients worldwide. As an example,  the first ever AEM survey dataset from the Venice lagoon, in Italy has processed. The results of this project are very promising in terms of applicability of AEM data to hydrogeological modeling within and underneath wetlands, lagoons, and surface waters in general. The description of the project: “Surface water–groundwater exchange in transitional coastal environments by airborne electromagnetics : The Venice Lagoon example” (pdf). The low 12.5 Hz base frequency was used on the project.