Posts Tagged GEOTEM

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:

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.

Geophysical prospecting in Southwest Greenland

Posted by on Tuesday, 30 August, 2011

North American Nickel Inc. (“NAN”) announces that it has commenced a field campaign to evaluate prospective areas within its 4,841 km2 exclusive mineral exploration licence. Electromagnetic anomalies, identified from a recent re-interpretation of a 1995 GeoTEM fixed wing survey, along with other areas of interest derived from compilation of previous work and satellite imagery will be ground checked in order to prioritize areas for helicopter borne time domain electromagnetic (TEM) surveying planned for September and October.

NAN plans to integrate the results from the field program with its existing database of historical work to optimize the upcoming helicopter borne TEM survey. The helicopter TEM system has much higher signal to noise ratios than the 1995 fixed wing survey and the helicopter can better maintain the required altitude above the ground to maximize the detection of geophysical signals from nickel-copper sulphide mineralization.

North American Nickel also controls a 4,841 square km Mineral Exploration Licence in southwest Greenland with exclusive mineral exploration rights. The principal target is high-grade nickel-copper occurrences associated with norite and other mafic and ultramafic intrusions.