The Hawks Nest exploration license contains a number of significant magnetite deposits originally identified in 1977 by Newmont-Dampier with the majority of the historical exploration work conducted as part of the South Australian Steel and Energy Project in the late 1990's and more recently by Arrium Ltd up to 2016. The magnetite mineralisation identified include large tonnage/medium grade (including Kestrel, Harrier) deposits as well as lower tonnage/high grade deposits (including Kite, Raptor, Whistling Kite).
Hawks Nest magneite represents a significant advantage to other magnetite deposits in South Australia as it is well serviced by public infrastructure including major highways and rail lines and is the contains the highest grade magnetite in the state.
The project has benefited from a significant amount of historical exploration and metallurgical testwork, indicating that a feasible project can be developed to produce high grade magnetite concentrate (>66% Fe) with mass yields of~50%. As part of the ongoing investigations into development of the Hawks Nest magnetite project, Peak has conducted several metallurgical testwork programs targeting the production of an intermediate (~53-57% Fe) grade product at course particle sizes which would require significantly lower operational and capital costs to develop
Regional Geology
EL 6395 is located in the northern Gawler Craton, with basement in the Hawks Nest area comprising a varied Archaean to Middle Proterozoic sequence, probably belonging to the Wilgena Subdomain. Throughout much of the Tarcoola to Bulgunnia region, Tarcoola Formation and Gawler Range Volcanics overlie BIF.
Historically the BIFs in the Wilgena Subdomain portion of the Gawler Craton were identified as equivalent to the Middleback Super Group of the Eyre Peninsula. Department of Mines and Energy South Australia (1997) suggest the Hawks Nest area is part of an uplifted fault block. Regional aeromagnetic maps show BIF as a strong north-northeast trending linear anomaly. In the Hawks Nest area, BIF is largely concealed beneath Cretaceous sediments and recent colluvium; several small areas of BIF outcrop occur within the tenement area. These outcrops tend to form low rocky ridges with steep dips on exposed bedding.
Historical geophysical surveys suggested that major magnetic anomalies indicate areas underlain by BIF. Ground geophysical surveys identified significant Bouguer anomalies; the resulting gravity anomalies are virtually coincident with the magnetic anomalies, however some anomalies exist in areas of poor gravity response.
Hawks Nest has numerous southeast-trending linear magnetic anomalies traversing across the main magnetic anomaly. These are interpreted to represent the Gairdner Dyke Swarm or could be brittle faults.
The Bulgunnia Shear Zone runs through EL 6395 from southwest to northeast and delineates the tectonic boundary between the Wilgena and Christie Domains to the northwest, and the Olympic Domain to the southeast. The main magnetic anomaly sits along the shear zone and appears to lie largely within the Wilgena Domain.
The hematite occurs in stacked lenses and is highly contorted at hand specimen scale. At Buzzard, a thin discontinuous limonitic goethite mineralisation of variable thickness is also present.
Local Geology
Scattered outcrops of BIF and isolated granite occur in the southwestern 6km of the main magnetic anomaly along the Bulgunnia Shear Zone. Sedimentary cover deepens towards the northeast (>100m). Rare granite outcrops may represent younger intrusives associated with the Hiltaba Granite suite.
Geophysical modelling verifies that dips are gentle to vertical and implies that the depth of the BIF extends 500 to 1000m or deeper.
Recent drill holes also confirm that the dips vary from gentle to near vertical with the number of mineralised vertically stacked lenses increasing towards the North East of Buzzard.
Drilling intersected mainly soil and clay at surface, underlain by BIF, interspersed with hematite enrichment and occasional goethite. Further to the southeast, holes usually begin in clay followed by shale. Depth of cover ranges from 20 to 60 metres, deeper towards the northeast. Drilling intersected abundant groundwater throughout the Buzzard deposit.
Tui is relatively similar in lithology, with soil and clay cover ranging from 40m to 60m, underlain by BIF with zones of hematite-enriched lenses steeply dipping to the southeast. In drillhole TU002RC, the cover overlies shale, similar to holes in Buzzard drilled further southeast.
Throughout the remainder of the tenements, BIF packages with hematite and magnetite enriched zones display variable dip and strike. Enrichment is observed in multiple zones and is almost always associated with the BIF packages. The control of mineralisation is not well understood but is believed to include primary and/or supergene enrichment.
South Australia Department of Mines and Energy
1995 to 1996:
- 367 percussion drillholes for a total of 20,418 m completed.
- Significant gold drill intercepts were returned in drillhole HKN99 4 m @ 4.3 g/t Au (900 m west of Raptor) and drillhole HKN53 4 m @ 0.59g/t Au (Kestrel).
SASE Pty Ltd / AuIron Energy Ltd
2000:
- 108 reverse circulation percussion (RCP) drillholes for 12,284 m completed over Kestrel and Buzzard deposits.
- 2,630 m of diamond drilling.
- Hellman and Schofield (H&S), on behalf of AuIron Energy Pty Ltd, estimated a Mineral Resource of 220 Mt @ 36% Fe (30% Fe cut-off), 38% SiO2, 0.94%, Al2O3, 0.13% P2O5 (Measured, Indicated and Inferred) over Kestrel.
- H&S completed a Mineral Resource estimate (MRE) (Measured, Indicated and Inferred) over Buzzard of 6.7 Mt grading 60% Fe (55% Fe cut-off), 0.10% P2O5, 9.9% SiO2, 1.9% Al2O3 and 1.5% LOI.
- Inferred Resources based on limited drilling and ground geophysics were estimated for Goshawk (148 Mt @ 35% Fe), Harrier (54 Mt @ 35% Fe), Eagle (92 Mt @ 31% Fe), Kite (30 Mt @ 51% Fe) and Falcon (25 Mt @ 32% Fe).
2003:
- Minotaur Resources completed exploration on Hawks Nest tenement EL2587 under an Access-Option Agreement with SASE Pty Ltd.
- Three semi-coincident gravity/magnetic anomalies were reverse circulation (RC) drill tested in April 2003, totalling 777 m. One hole failed to intersect the cause of the anomaly, whilst the other two failed to intersect any alteration system, although did explain the causative body.
- Two calcrete surveys were conducted across the tenement (299 samples), which upgraded some earlier anomalies and warranted an air-core drilling program.
- A 40-hole air-core program over gold-in-calcrete anomalies failed to locate significant gold in bedrock.
- Drilling results did not meet the requirements of Minotaur Resources, and consequently Minotaur Resources withdrew from the Access-Option Agreement on 2 February 2004.
Western Plains Resources
2003:
- Pells Sullivan Meynink Pty Ltd completed a geotechnical design for feasibility-level open cut mining of Buzzard for Western Plains Resources (WPR).
2007:
- WPR drilled six RCP holes over Kite targeting shallow high-grade banded iron formation (BIF). Significant intercepts included:
- HHWPR3 – 70–124 m @ 40.9% Fe
- HNWPR6 – 5–87 m @ 41.3% Fe including 5–49 m @49% Fe
2008:
- WPR completed eight RCP drillholes (HNPR26–HNPR33) to the northeast of the Kite magnetite deposit.
- Four RCP drillholes with diamond tails were completed over Buzzard for a total of 445 m core drilled – predominantly PQ3 with minor HQ3.
- WPR completed a Mineral Resource estimate over the Buzzard and Tui deposits. In addition, a reserve statement based on the WPG resource was prepared by AMDAD (Australian Mine Design and Development).
- WPR complete a Kestrel Pit optimisation – unconstrained at 0% Fe cut and at 25% Fe cut. At a 25% Fe cut, the optimised pit at Kestrel resulted in 216 Mt grading 35.7% Fe.
One Steel Ltd / Arrium Ltd
2010:
- Central Iron Pty Ltd incorporated in 2010 and operating as a subsidiary of Arrium Limited.
2011:
- WPR sells all South Australian iron ore assts for $320 million to One Steel Limited.
- One Steel Limited changes its name to Arrium Limited in July 2012.
- Arrium operate multiple subsidiary companies including Southern Iron Pty Ltd and Central Iron Pty Ltd. The Hawks Nest Project is operated by Central Iron Pty Ltd.
2012:
- Coffey Mining Ltd, on behalf of OneSteel Manufacturing Pty Ltd, completed an examination of the resource and reserve estimates complied for the Buzzard and Tui deposits of the Hawks Nest Project.
2013:
- Exploration work completed included:
- Central Iron Pty Ltd drilled 29 RC and one diamond drillhole (DDH) to infill and improve the Buzzard and Tui resources. Drilling generally targeted specific zones of the deposit, and was not on any specific grid, although some were spaced at 50 m x 50 m, notably at Tui.
- Ongoing groundwater monitoring (as required by various licences and the access agreement with McDouall Peak Station stakeholders).
- Parsons Brinckerhoff complete a Hawks Nest Development – Valued User Requirement Specification.
- An airborne magnetic survey at 50 m line spacing over the entire tenement and initial ground gravity survey.
- A resource estimation of Buzzard and Tui deposits:
- Buzzard: 19.0 Mt grading 60.5% Fe (50% Fe cut-off), 9.70% SiO2, 1.62% Al2O3, 0.07% P and 1.06% LOI.
- Tui: 3.49 Mt grading 59.9% Fe (50% Fe cut-off), 11.67% SiO2, 0.87% Al2O3, 0.08% P and 0.94% LOI
2014:
Exploration work completed included:
- Drilling of 47 RC holes (8,018 m) and one diamond tail (24.9 m). Drilling focused on the Buzzard hematite resource with a series of holes being drilled on 25 m x 25 m spacing to better understand the complexity of mineralisation. Little drilling was done outside of the Buzzard resource.
- Other fieldwork on the tenement included: installation of four groundwater monitoring bores, ongoing groundwater monitoring (as required by various licences and the access agreement with McDouall Peak Station stakeholders), downhole geophysical surveys and rehabilitation.
- A detailed gravity survey completed by Daishsat Geodetic Surveyors (Daishsat) over the western parts of Hawks Nest Project. This survey infilled and extended the coverage of the gravity surveying completed over the Buzzard area in November 2013. In total, over Hawks Nest East, 5,278 stations were surveyed at 25 m spacings along north-south orientated lines 50 m apart, covering an area of approximately 6.95 km2. Over Hawks Nest West, 3,372 gravity stations on a 50 m x 5 0m square grid covering an area of 8.45 km2 were collected.
- Southern Geoscience Consultants (SGC) was engaged to design, oversee, process, and interpret the Daishsat collected gravity survey blocks over Hawks Nest East (colloquially named Area 1 by SGC) and Hawks Nest West (Area 2 which covers the Eagle, Falcon and Kite prospects). There was a focus on identifying additional areas of interest for potential hematite mineralisation.
- Quality assurance/quality control report on Buzzard completed.
- Update of the 2013 Buzzard and Tui resource models to include drilling not captured in the 2013 model.
2015:
- Exploration work completed included:
- The regional drilling program consisted of 35 RC holes (3,744 m) drilled at Hawks Nest East and 36 RC holes (2,812 m) drilled at Hawks Nest West, following up historical drilling around the Kite prospect and new geophysical anomalies throughout the western portion of EL6395 (then EL5399). The mineralisation observed at Hawks Nest East consisted of hematite or magnetite and the dip of mineralisation varied from sub vertical to flat lying. Drilling at Hawks Nest East intersected hematite and magnetite mineralisation at multiple targets.
- Four new prospects were identified – Hobby, Sparrow Hawk, Grey Goshawk (magnetite) and Bearded Vulture. Intersections included: high-grade hematite and magnetite, hematised BIF and lower grade, friable hematite/magnetite. Further drilling is required to understand the extent of mineralisation and to define potential resources at these prospects.
- Drilling over Tui and Buzzard prospects. At Tui, drilling consisted of two drillholes (344 m) targeting up-dip extension of mineralisation and a gravity high to the northeast. At Buzzard, drilling consisted of 30 RC holes (3,891 m). Drilling was to the southwest where mineralisation style and species were similar to Buzzard but also contained considerable goethite, possibly representing supergene enrichment. Some holes were drilled inside the resource area to confirm interpretation and continuity of mineralisation.
- An MRE was completed by Arrium Mining over Kestrel. The deposit had been drilled on lines 100 m apart over a strike length of some 1,200 m. Drilling consists of 16 diamond and 93 RC percussion holes. Holes were generally 50 m apart on section. Most holes were limited to a depth of 135 m below surface. The estimate comprised 231.5 Mt grading 36.5% Fe (30% Fe cut-off), 38.5% SiO2, 0.88% Al2O3, 0.06% P, 0.09% S and 0.84% LOI.
2016:
- Arrium goes into voluntary administration.
- Exploration work completed included:
- Desktop studies as part of a regional geological review of Central Iron and Southern Iron tenements and targets, particularly in the light of the insights from the recent GSSA Eastern-Central Gawler Craton Solid Geology interpretation
- Data compilation and review with potential farm-in parties
- Continued rehabilitation of drillholes with 148 rehabilitated drill sites (including historical drilling) to date.
2017:
- Arrium acquired by Liberty House Group, an industrial and metals company founded in the United Kingdom in 1992 by industrialist, Sanjeev Gupta.
- Liberty House Group purchase all except Central and Southern Iron.
- Exploration work completed included:
- Desktop studies as part of a regional geological review of Central Iron and Southern Iron tenements and targets, particularly in the light of the insights from the recent GSSA Eastern-Central Gawler Craton Solid Geology interpretation
- Data compilation and review with potential farm-in parties
- Magnetite target review
- Continued rehabilitation of drill sites.
2018:
- Exploration work completed included:
- Desktop studies as part of a regional geological review of Central Iron and Southern Iron tenements and targets, particularly in the light of the insights from the recent GSSA Eastern-Central Gawler Craton Solid Geology interpretation.
- Magnetite target review.
- Continued rehabilitation of drill sites.
- Diamond drilling at a Kestrel target to obtain sample for further metallurgical testwork. Four drillholes completed for a total of 353.1 m.
2019:
- Exploration work completed included:
- Desktop studies as part of a regional geological review of Central Iron and Southern Iron tenements and targets, particularly in the light of the insights from the recent GSSA Eastern-Central Gawler Craton Solid Geology interpretation.
- Magnetite target review.
- Continued rehabilitation of drill sites.
- Diamond drilling at Kestrel project (two drillholes for 148.4 m).
RC drilling at Harrier project including 10 RC holes for a total of 1,612 m to test a magnetic anomaly and for metallurgical testwork. None of the Harrier drillholes intersected any mineralisation grading greater than 50% Fe.
Area 1 / Hawks Nest East
Area 1 located on the Hawks Nest exploration license contains both the defined high grade DSO hematite deposits at Buzzard and Tui, as well as the Kestrel and Goshawk large tonnage magnetite projects.
Significant additional exploration targets of both DSO hematite, coincident with gravity highs and magnetic lows, as well as further magnetite potential, coincident with magnetic highs, have been defined through geophysical and drilling exploration
Area 2 / Hawks Nest West
Area 2 defined by a north-south trending magnetic and gravity anomaly contains the identified high grade magnetite resources including Kite, Whistling Kite, Falcon and Raptor. A number of exploration targets have been identified that are prospective for additional high grade mineralisation in addition to extensions to the known deposits.
Peak intends to conduct a drill program to further define the known resources as well as identify additional deposits in the area.
Area | Classification | Tonnes (Mt) | Fe % |
SiO2 % |
Al2O3 % |
LOI% |
P % |
---|---|---|---|---|---|---|---|
Kestrel Magnetite (Hawks Nest) |
Indicated Inferred Subtotal |
144.9 |
37.00 |
37.50 |
0.90 |
0.06 |
|
|
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Exploration Targets | |||||||
Goshawk Magnetite |
Inferred | 149.0 | 35 | ||||
Harrier Magnetite |
Inferred | 54.0 | 35 | ||||
Kite Magnetite |
30.0 | 51 | |||||
Falcon Magnetite |
25.0 | 32 | |||||
Eagle Magnetite |
92.0 | 31 |