EAST PILBARA


The Company’s East Pilbara tenements are located south of Marble Bar and contain exploration ground prospective for Iron, Base Metals, Gold and Nickel covering an area of 1,350 km².  The tenements include 100km of the Coongan Greenstone Belt, extending south from Marble Bar.  Currently only 3 tenements are granted, with the remainder expected to be granted in 2010 once Alternative Heritage Agreements have been finalised.

A large 7,500 line km aeromagnetic and radiometric survey has recently been flown over the central tenements and the eastern most tenement north of Nullagine.

The principal focus of 2009 exploration activity was on the Corunna Downs Iron Project, the Gobbo’s molybdenum prospect and the Cyclops nickel prospect to the eastern end of the tenement package.

C:\1.Gondwana\Pilbara\Images\pilbara_tenements_Nov09.jpg

East Pilbara tenements over 500K scale geology identifying live tenements as pink


Corunna Downs Iron Project
(Gondwana 100%)


The Corunna Downs Iron Project is located within the south western portion of the Marble Bar 1:250,000 map sheet, centred approximately 30km south of Marble Bar and 180km south of Port Hedland, WA.  The project lies within E45/2585 and contains a Jaspilitic BIF ridge trending north to south approximately 5km.  The Company also holds a 90% interest in two exploration licence applications (E45/3320 & E45/332) that contain ~8km untested extensions along the BIF ridge.

Historic drilling

Historic drilling was undertaken on the Corunna Downs prospect in 1972 and intersected various thicknesses of iron.  The best historic result was from drill hole PDH1 which intersected 47.7% Fe representing approximately 14m thickness.  Current interpretation is that the vertical drill holes were drilled along the edge of the coincident magnetic/gravity anomaly, therefore failing to test the magnetite target zone and potentially missing any steeply dipping mineralised BIF stratigraphy.

Preliminary surface sampling

In early 2008, surface rock chip sampling produced results up to 62.5% Fe at Corunna Downs with an average of 60.6% Fe with low alumina and phosphorus characteristics across four samples collected along the eastern edge of the jaspilite sequence.

Gravity survey

A helicopter-assisted gravity survey was conducted over the BIF and Jaspilite outcrop in October 2008 to locate the densest section of the Jaspilite.  Southern Geoscience was engaged to apply terrane corrections to the dataset based upon a detailed Digital Elevation Model.  Importantly, the gravity anomaly is coincident with the anomaly shown in the regional aeromagnetic data. 

Close-spaced aeromagnetic survey

In 2009, a fixed wing close-spaced aeromagnetic and radiometric survey was conducted for the Company by Fugro in the third quarter 2009.  This survey showed magnetic zones +800m in width, with a combined strike length of +13km.

C:\1.Gondwana\Pilbara\Photos\October_2009\P1010227.JPG

Corunna Downs iron outcrop over 800m wide (photo towards north)

Rock chip geochemical survey

In October 2009 a detailed helicopter assisted rock chip program extracted 466 samples from the Corunna Downs ridge. The survey was conducted on 200m line spacing with sampling 50m along line. 

n               Samples were split and half submitted for assay: averaging 35.26% Fe with a maximum of 62.08% Fe.

n               Assessment of the assay distribution identified 310 samples over 30% Fe in a continuous 3 km² area along 5km of magnetic strike. 

n               Iron assays within the 3 km² mineralised area averaged 43.00% Fe.

The other half of the samples was submitted for preliminary metallurgical test work and Satmagan magnetite strength measurement.  This test work indicated that the surface rock chip samples were heavily oxidised and consequently contained lower levels of magnetite than expected.  Further metallurgical test work will be conducted on fresh RC chips from the planned Phase 1 drill program (see below).

C:\1.Gondwana\Pilbara\Photos\October_2009\P1010216.JPG

Rock chip sampling of BIF outcrop using a helicopter to transport samples

Interpretation of the results summarised above indicates that the linear aeromagnetic anomalies measured in the September 2009 close-spaced survey are coincident with both –

n               the geochemical anomaly outlined in the October 2009 rock-chip sampling program covering the outcropping BIF; and

n               the linear aeromagnetic anomaly is coincident with the ground gravity anomaly measured in the October 2008 survey.

This is illustrated in the two Figures below.

Corunna Downs Iron Project Rock Chip Fe Assay Results Gridded

 

Corunna Downs rock -chip Fe assay results plotted on Aeromagnetic RTP 2VD

Proposed Drilling Program

Based on potential for a large tonnage magnetite deposit, the phase 1 drill program has been designed to test grade and tonnage potential across the central target zone where the densest gravity and highest aeromagnetic responses are located.  This will be preceded by a detailed geological mapping program.

A further three-phase exploration program has been designed to be undertaken if the phase 1 drilling program is successful.  The phase 2 drill program is planned test the northern and southern target zones contained within the areas under application. The phase 3 drilling program is planned to infill the entire project area on 200m-spaced drill lines and the phase 4 program will focus on the north eastern target under basalt cover.

The phase 1 RC drilling program has been planned on 600m line spacing, and aims to test across 2.4km of strike, covering the strongest coincident magnetic and gravity anomalies.  The drilling is designed at 50m along line with 100m deep angled holes to provide drill coverage across the ore zone to 86m vertical depth.  By drilling sections across the sub-vertical stratigraphy using angled RC holes, an estimate of the mineralisation width and grade can be produced.

Fusion of the aeromagnetic and gravity data in the Figure below shows coincident geophysical responses.

The Figures below both show the proposed Phase 1 drill program collars together with the location of the historic drill collars that generally missed the magnetite target zone.  The image colour is from the terrain corrected Bouger gravity data (with a residual filter applied).  The intensity or greyscale background is from the aeromagnetic data (reduced to the pole with second vertical derivative filter applied) showing correlation of the two geophysical datasets.

Phase1_drilling_on_mag_grav_compositePOW_map_phase1

Proposed Phase 1 collars on aeromagnetic / gravity fusion and satellite imagery

Infrastructure

Access road

The access track to site and the 6 drill lines proposed in the Phase 1 drilling program require a heritage clearance survey scheduled for first half 2010.  The drill rig access track has been assessed by ground inspection for engineering feasibility and preliminary cost estimation.  Environmental assessment for beds and banks clearances on the pending tenements approaching the drilling area has also been completed by Golder Associates to expedite the permitting process.  The clearing and drilling permit applications will be submitted to the government after the Traditional Owners approve the new access track location, which avoids the native title sites of significance which were identified in the 2008 heritage survey.

Transport to Port Hedland

Should a large tonnage magnetite deposit with +30% Fe grade be confirmed by the Phase 1 drilling program, two transport options will be assessed from Marble Bar to Port Hedland – one being the construction of an independent 190km railway and the other being utilization of the existing Marble Bar–Port Hedland Road. The map below shows both transport options and location of outcropping BIF extracted from 100K geology maps.

Railway

The Marble Bar to Port Hedland railway line, which was used up to 1951 could be refurbished and would be up to 190km of line.  A 30km rail extension to the south of Marble Bar to the Corunna Downs area would be required.  This option is currently preferred to a possible 80km connection with the FMG rail line to Port Hedland.

Road

The road infrastructure is excellent from Marble Bar to Port Hedland with 90t road trains using the road from the Woodie Woodie manganese mine to Port Hedland daily.  This represents a low capex/high opex option.

rail_line_road_to_Port_Hedland_blue_water

Proposed transport options from Corunna Downs to Port Hedland


Cyclops Nickel Prospect

(Gondwana 90%)


A significant nickel prospect within ELA 45/3326 was identified in late 2009.  This prospect is an outcropping serpentinised metaperidotite mapped on the 100K geology map and plunges to the north under Mt Roe Basalt.  The ultramafic intrusive has now been named Cyclops Nickel Prospect after the mythical one eyed giant due to its magnetic signature.

An aeromagnetic survey was originally flown to map the northern magnetic ultramafic zone under cover and was successful in delineating plunging magnetic targets.  What has been discovered in the centre of the mapped serpentinized ultramafics is a 1.1km long x 500m wide oval shaped magnetic anomaly which was only partially drill-tested in 1972 (Wamex report 3989).

The elongate aeromagnetic anomaly shape could be produced from a doubly plunging syncline (basin) however other possible scenarios exist, such as a volcanic feeder zone.  Ultramafic complexes rarely have perfectly shaped elongated aeromagnetic anomalies associated with them.  Nickel mineralisation in this style of geological environment is usually at the base of the intrusive pile and may contain disseminated or massive sulphide lenses. 

C:\1.Gondwana\Pilbara\Projects\Cyclops\Images\cyclops_contours.jpg

Cyclops Nickel Prospect

100nT TMI contours over RTP 2VD image showing elongated anomaly

A V-TEM airborne electromagnetic survey has been contracted to commence in April or early May 2010. The 100m line spaced AEM survey will locate any highly conductive sulphides at the base of this intrusive system if they exist, and like the Marvel Loch survey, this area has never had an AEM survey performed.


Go back to the Projects page...