High-Grade Cobalt and Nickel Results Underpin DFS Advancement at Goongarrie
- In-fill drilling confirms near-surface, high-grade cobalt and nickel mineralisation at Patricia Anne orebody
- Results include the following:
o AGSR0055 42 m at 0.16 % Co, 1.43 % Ni and 46 g/t Sc from 2 m
o AGSR0059 26 m at 0.18 % Co, 1.13 % Ni and 36 g/t Sc from 12 m
o AGSR0061 42 m at 0.15 % Co, 0.86 % Ni and 35 g/t Sc from 8 m
including 14 m at 0.25 % Co, 1.01 % Ni and 46 g/t Sc from 10 m
- Excellent results show lateral continuity of mineralisation at Patricia Anne, a hallmark of goethitic laterite deposits like Goongarrie
- The high-grade Patricia Anne orebody is earmarked as the start-up deposit at Goongarrie, providing rapid payback opportunities
- Significant scandium mineralisation evident from surface providing potential additional by-product benefits within the cobalt-nickel zones
- The sonic drill rig used to provide "run-of-mine"-grade samples suitable for future pilot-plant testing
- Drill result interpretation from Elsie Tynan, Elsie North, Pamela West and Canegrass expected shortly
- The ongoing 80x40m infill drilling is part of early-stage DFS work for Goongarrie, following the successful PFS
Patricia Anne has been outlined as the starting deposit when Ardea commences production at Goongarrie. The high-grade and low strip ratio of Patricia Anne will offer Ardea a robust early capital payback in the initial years of mine life.
Continuity of mineralisation at Patricia Anne ensures predictability and accuracy for mine scheduling which significantly diminishes operational start-up risk at Goongarrie.
The drilling has also confirmed extensive, near-surface scandium mineralisation both overlying and within the cobalt-nickel zone. Current metallurgical programs indicate a scandium credit ranging from 30-100g/t with extractions exceeding 90% which provides a significant benefit to project cashflow.
Additionally, the current GNCP DFS drilling has confirmed significant neutraliser carbonate and kaolin clay within Tertiary-aged channel sands overlying the cobalt-nickel mineralisation. The ability to source an onsite neutraliser supply has the potential to provide significant cost benefits to the project. Metallurgical evaluation is continuing using wide diameter diamond drill core.
Commenting on the successful drill results, Ardea Managing Director Brett Clark stated this was a significant step forward for the early-stage DFS program. "We are extremely pleased with the results received from Patricia Anne, as they confirm both the reliable continuity of the mineralisation whilst offering an exceptional orebody to begin mining at Goongarrie. With such high-grades demonstrated at surface, this will ensure the financial fundamentals of the project remain extremely positive and will allow Ardea to ensure rapid payback of initial start-up costs. The identification of scandium and potential onsite neutraliser source gives Ardea further encouragement as we continue with the various DFS workstreams."
About the Patricia Anne orebody
Patricia Anne is one of the constituent lateritic orebodies that contributes to the reserves defined at the Goongarrie Nickel Cobalt Project. It is located at the northern end of the Goongarrie South area and is one of the 13 defined deposits modelled for mining at Goongarrie (see Appendix 1 in link below).
The Patricia Anne deposit measures approximately 1,400 metres by 300 metres and is characterised by near-surface, high-grade, flat-lying mineralisation with minimal overburden. These characteristics are ideal for commencement of mining, so start-up Pits 1 & 2 of the Goongarrie Nickel Cobalt Project mining schedule will be located at Patricia Anne.
Drill results from Patricia Anne
Ardea's recent drilling shows conclusively that laterally continuous, shallow high-grade cobalt and nickel laterite mineralisation is located at Patricia Anne.
Continuity of mineralisation is strong between drill holes (Figures 2-4 in link below). This is a hallmark of the Goongarrie Project in particular and of 'goethite´ style (yellow-brown) laterite nickel-cobalt deposits in general (yellow-brown "limonite" of tropical laterites). It contrasts sharply with the more nontronitic clay style (green "saprolite" of tropical laterite) deposits which can exhibit marked variation between holes and are more difficult to mine and process.
Remodelling of the current orebody to understand the scandium resource is underway including a rework of the full KNP resource. A scandium JORC 2012 resource will be defined using the results of the current drill programs over the coming months.
Some of the shallow high-grade mineralisation is illustrated by recent results, which include:
6671440 mN section
AGSR0054 - 14 m at 0.27 % cobalt, 1.18 % nickel and 21 g/t scandium from 6 m
6 m at 0.59 % cobalt, 1.95 % nickel and 27 g/t scandium from 8 m
AGSR0055 - 42 m at 0.16 % cobalt, 1.43 % nickel and 46 g/t scandium from 2 m
34 m at 0.19 % cobalt, 1.60% nickel and 50 g/t scandium from 8 m
6670960 mN section
AGSR0059 - 26 m at 0.18 % cobalt, 1.13 % nickel and 36 g/t scandium from 12 m
12 m at 57 g/t scandium from surface
AGSR0058 - 38 m at 0.04 % cobalt and 1.08 % nickel and 46 g/t scandium from 6 m
2m at 0.11 % cobalt, 1.21 % nickel and 50 g/t scandium from 30 m
6 m at 567 g/t scandium from surface
6670880 mN section
AGSR0061 - 42 m at 0.15 % cobalt, 0.86 % nickel and 35 g/t scandium from 8 m
14m at 0.25 % cobalt, 1.01 % nickel and 46 g/t scandium from 10 m
8 m at 100 g/t scandium from surface
All defined intercepts from the Patricia Anne drill program are listed in Appendix 3.
Scandium by-product potential at Goongarrie
As can be seen above the nickel and cobalt results were supported by scandium mineralisation from surface. Scandium grades are modest but are of a grade sufficient for recovery through a modification to the flowsheet defined in the PFS, with no impact on cobalt and nickel recovery.
Ardea is buoyed by the potential for scandium be a high value by-product at Goongarrie.
Other metals at Patricia Anne
The current drilling has also highlighted other by-product metals. In particular, anomalous levels of chromium, vanadium, aluminium and gold (see Appendix 5) are distributed throughout the profile:
- Aluminium is abundant in many sections and the precipitation of aluminium sulphate or high purity alumina (HPA) for battery or sapphire glass manufacture is under metallurgical evaluation as part of the variability program
- Chromium and vanadium are evident at low- to medium-levels, however their extraction as a by-product is being investigated
- Gold is present in highly anomalous numbers in some areas. Though not expected to be extracted using the Goongarrie flowsheet, Ardea will use the geological knowledge as part of the adjacent Bardoc Tectonic Zone (BTZ) gold project exploration.
Ongoing drill program at Goongarrie
This first phase of RC drilling at Goongarrie (3,700m of drilling in 96 drill holes) is now complete. Data collected from this program will bring specific areas of the future open pit mine down to a 40mE x 80mN drilling density.
The second phase of drilling (199 drill holes for over 7,600m) is underway and is bringing the drilling density down to 40mE x 40mN in specific areas.
The ongoing drill program is designed to:
- Upgrade resources and reserves through higher density drilling. This will allow better accuracy and greater confidence in defining mining schedules for the planned Goongarrie mine.
- Provide continuing core samples for variability testing of mineralised zones. This will ensure that variations of the main style of mineralisation will perform to the same high standard or higher as that tested to date. This will also provide greater confidence for mine scheduling.
- Provide sample for production of cobalt sulphate and nickel sulphate marketing samples. Production of high-quality cobalt sulphate and nickel sulphate is required for appraisal for potential off-takers and strategic partners. There has been strong interest from several parties to receive such samples as soon as possible.
The sonic drill rig used for bulk core sampling is capable of coherent sample recovery from very loose or soft materials like that at Goongarrie.
Announcements are pending for drilling results at the Elsie Tynan and Elsie North orebodies as well as Pamela West orebody at Goongarrie South, and the Canegrass deposits further south in the Big Four area (see Appendix 1 in link below for locations). Results are showing continuity of high-grade mineralisation as expected, and will be released upon completion of quality assurance programs, data processing, analysis, interpretation and modelling.
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About Ardea Resources Ltd
Ardea Resources Ltd (ASX:ARL) (OTCMKTS:ARRRF) (FRA:A91) is an Australian resources company with an extensive Western Australia and New South Wales "battery metal" portfolio of nickel, cobalt and zinc, with associated scandium, High Purity Alumina and gold. Ardea owns 100% of the Kalgoorlie Nickel Project (KNP), a globally significant series of nickel-cobalt-scandium laterite deposits which host the largest cobalt resource in the developed world. Ardea is focused on the development of the Goongarrie Nickel Cobalt Project (GNCP) within the KNP, 80km north of Kalgoorlie WA. In March 2018 Ardea released a PFS on the GNCP and has commenced Definitive Feasibility Study programs. In June 2018 Ardea retained KPMG Australia Corporate Finance to assist in securing a Strategic Partner to jointly develop the GNCP.
The current piloting is the culmination at semi-commercial scale of two years of intense bench-scale Research and Development with Simulus using Ardea drill samples. The piloting is testing multiple new metallurgical concepts involving the uniquely endowed Goongarrie mineralisation.
Ardea Resources Ltd