Segue Resources (ASX:SEG) has completed a large scale multi-phase gravity survey that identified 15 high priority nickel targets at the Plumridge Nickel Project in Western Australia’s Fraser Range.
This comes amidst heightened interest in the Fraser Range following Independence Group’s (ASX:IGO) move to acquire Fraser Range pioneer Sirius Resources (ASX:SIR) for $1.8 billion.
As one of the largest tenement holders with 4,770 square kilometres of exploration licences in the Fraser Range, the company’s planned exploration in the third quarter is likely to be closely watched.
This will focus on confirming the presence for mafic/ultramafic intrusions with fertile geochemistry before direct targeting of massive Ni-Cu mineralisation.
“Over the past six months Segue and its exploration team has collected a project-wide gravity dataset which has provided an enormous insight into the tectonic architecture of the Fraser Range Province and, more importantly, the key structures which are essential for mineral emplacement at the Plumridge Nickel Project,” managing director Steven Michael said.
“The gravity survey generated over 130 anomalies, which Segue has reduced to 15 high priority exploration targets by applying several criteria relating to pervasiveness of the gravity anomaly, regional geology, proximity to cross-cutting structures and physical properties.
“The next stage of exploration, focussing on two key target areas, will commence in 3Q 2015 and will include drill testing of 5-6 prioritised targets.”
Over the past five months, Segue has undertaken one of the largest gravity surveys in the Fraser Range Province, comprising over 19,000 gravity stations and 2,345 line kilometres.
The gravity survey covered the entire 3,150 square kilometre Plumridge Nickel Project area on a spacing of 1,600 metre by 100 metre, with a more detailed survey over the E21 Target area on spacing of 800 metre by 100 metre.
Project-wide gravity and magnetic data has been imaged by the company’s geophysical consultants through 3D inversion modelling methods to:
- Provide insight into the tectonic architecture of the Project area to better understand mechanisms and pathways for large scale intrusion of fertile mafic-ultramafic magmas;
- Identify gravity anomalies (dense bodies) in near surface positions that may represent mafic intrusions capable of hosting nickel sulphides;
- Focus on dense bodies associated with near-surface disruptive (ovoid) magnetic features and major structural intersections that provide magma pathways to deeper bodies; and
- Remove the large number of false positive EM conductors associated with graphitic schists that are pervasive throughout the region.
As previously reported, 3D inversion modelling of the preliminary gravity data highlighted a major zone of disruption in the basement architecture (Transform Graben Zone (TGZ)), which is of primary importance in providing a potential magma pathway from the mantle to the upper crust.
The most recent 3D inversion modelling has continued to support the presence of this major crustal scale feature, and has refined it into a major corridor of deep-seated NW-SE structures which cross-cut the general SW-NE linear stratigraphy seen in the Fraser Range Complex.
High Priority Exploration Targets
Following a thorough review of all available datasets, Segue has prioritised 15 exploration targets from an initial suite of over 130 anomalies.
These priority targets form two clusters each covering an areal extent consistent with a mineralised district.
The targets all lie within the TGZ and are consistent with the company’s geological and mineral emplacement models.
A subset of these targets will be assessed in the first phase of systematic follow-up which will commence in 3Q 2015 and will include:
- Desk-top modelling of detailed geophysical line data to confirm the size and depth of the target;
- Low-cost, shallow drilling to confirm the presence of mafic-ultramafic intrusions in the target areas;
- Geochemical fingerprinting of the intrusive rocks to identify those with fertile chemistry for nickel sulphides; and
- Ground EM surveying and drill testing of the fertile targets to directly intersect nickel sulphide mineralisation.
Plumridge Nickel Project
Segue recently completed the acquisition of its minority partner in the Plumridge East Joint Venture, giving it a 100% interest in the Plumridge Nickel Project.
It is prospective for massive nickel sulphide deposits and has previously been explored for gold with several prospects.
Plumridge covers over 10% of the Gravity High which represents the area of greatest nickel prospectivity.
In November 2014, drilling at the E21 Target identified the presence of mafic-ultramafic rocks that host magmatic iron-rich sulphides.
These are interpreted to potentially be part of a larger intrusive system.
All assay data has now been returned, confirming the magmatic sulphides are predominantly pyrrhotite and pyrite, with minor chalcopyrite.
Moving Loop Electromagnetic (MLEM) and Fixed Loop Electromagnetic (FLEM) surveys were undertaken and successfully defined five bedrock conductors. The drill program was designed to test the three highest priority conductors.
In addition, the detailed aeromagnetic survey acquired in the December quarter 2014 show the presence of a distinct “bullseye” magnetic feature approximately 1 kilometre to the west of the drilling.
This magnetic target is inferred to represent a larger mafic-ultramafic intrusion with the potential to host nickel-copper sulphides.
Interest in the Fraser Range has been renewed following Independence Group’s $1.8 billion acquisition bid for Sirius Resources (ASX:SIR).
This could not have come at a better time for Segue Resources as its complete gravity survey, one of the largest of its kind in the region generated over 130 anomalies.
It has narrowed this down to 15 priority targets and will soon carry out exploration including drilling of up to 6 targets in the third quarter of 2015.
Success will bring with it significant upside potential given that the company has one of the largest tenement packages in the Fraser Range with 4,770 square kilometres of exploration licences.
Share Price Catalysts
- Results of desktop modelling;
- Results from shallow drilling to confirm the presence of mafic-ultramafic intrusions; and
- Drilling of fertile nickel sulphide targets.
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