Location: Northern Yorke Peninsula, South Australia
Geological Province: Olympic Dam Copper- Gold Province, Eastern Gawler Craton
Ground Holding: Exploration Licence 4961, 819 sq kms
Commodity: Copper, Gold
Ownership Status: Adelaide Resources 100% (713 sq kms) and 90% (106 sq kms) with option to acquire remaining 10% for $200,000 cash or shares
- Project lies at the southern end of the Olympic Copper-Gold Province, a world class copper belt
- Moonta has an historic copper mining heritage
- Previous explorers of the region have left behind a vast amount of exploration data that to reacquire would cost approximately $50M in today's dollars
- Ubiquitous but thin sediment cover has hidden deposits from previous explorers of the region, leaving significant opportunities for ADN using today's modern exploration tools and techniques
- shallow aircore drilling at Alford West has confirmed the presence of a single large IOCG mineral system
- the Moonta tenement has the potential to host multiple deposits to contribute to a project-wide resource base
The Moonta Copper Gold Project tenement EL 4961 covers an area of 819 sq kms on the northern Yorke Peninsula of South Australia.
The majority of the tenement (713 sq kms) is owned 100% by Adelaide Resources. The Company holds 90% equity (and holds a right to acquire 100% equity) in the 106 sq km Moonta Porphyry Joint Venture with Minotaur Exploration Limited. A number of small production leases owned by third parties fall within EL 4961 and are excised from the Company's tenement.
Moonta Copper Gold Project location plan
Geological Setting - The Olympic Copper-Gold Province
The Moonta Copper Gold Project falls near the southern end of the world class Olympic Copper-Gold Province in South Australia. The Olympic Copper-Gold Province is highly prospective for Iron Oxide Copper Gold (IOCG) deposits, with Olympic Dam, Prominent Hill and Moonta-Wallaroo the three mines with past or current production, Significant deposits in the pre-development stage include Carrapatenna, Khamsin and Hillside, while numerous other prospects are spread along the belt.
Approximately 75% of Australia's known copper resources are contained within the Olympic Copper-Gold Province evidencing its substantial endowment. Exploration ground within the belt is highly sought after and held by a range of large and emerging copper producers.
The IOCG deposits in the Olympic Copper Gold Province are thought to have formed around 1,590 million years ago and are genetically related to the Hiltaba Suite granites. Mineralisation is associated with often intense alteration (or metasomatism) of the host rocks, with metasomatic products including bodies of magnetite-hematite bearing iron-rich rock.
The depth to the top of the rocks considered prospective for IOCG deposits varies significantly along the belt, and in many places the thickness of the overlying barren cover sediments exceeds 300 metres. However, the depth of cover on the Moonta Copper Project is normally less than 10 metres, and while it has obscured deposits and delayed their discovery , it is thin enough to allow the application of a broad range of cost-efficient exploration methods including surface geochemistry and shallow aircore drilling.
The Moonta Project includes the Alford Copper Belt, a zone displaying intense alteration and structure immediatley south and east of a large body of Hiltaba grantite.
Alford Copper Belt interpreted basement geology
Copper was first discovered on the Yorke Peninsula in 1859, leading to the establishment of substantial mining operations at Moonta and Kadina, and smelting and export facilities at Wallaroo. Together these towns formed the famous "Copper Triangle" which was crucially important in the development of the early South Australian economy.
A characteristic of the deposits at both Kadina and Moonta, confrimed by past mining records, are the dimensions and continuity of the mineralised lodes. For example, the Main Lode of the Wallaroo Mines (somewhat confusingly located at Kadina) comprised a series of steeply plunging, high grade ore shoots that were mined from the surface to depths of over 900 metres. The figure below shows a long projection of the Wallaroo Main Lode including shafts and level development, and the areas of ore stoped up until December 1915. The stoped out areas reflect the steeply plunging ore shoots.
Long projection of the Wallaroo Main Lode, 1915
Mining of the Wallaroo Main Lode continued after 1915 and the old reports record that on the 2,980 foot level (908 metres below surface) the Main Lode varied in width from 4 to 30 feet (1.2 to 9.1 metres), assayed 3.5% copper, and was mined over a horizontal distance of 1,970 feet (600 metres).
Similar steeply plunging ore shoots were present in the majority of the historical mines in the district, reflecting a fundamental geological structual control on mineralisation that is likely to be repeated at new discoveries.
Since 1959, exploration in the district has been dominated by major mining houses including Western Mining Corporation Ltd, North Broken Hill Ltd, Broken Hill South Ltd, Mount Isa Mines Ltd, BHP Ltd and Phelps Dodge Corporation. In the period from 1988 to 1993, a joint venture between Amalg Syndicate and Melita Mining NL focussed on producing copper and gold from the Poona and Wheal Hughes mines located near Moonta.
Adelaide Resources entered into the Moonta Porphyry Joint Venture (then with Amalg Resources) prior to listing in 1996, with the 106 sq kms MPJV one of the assets included in the Adelaide Resources' Initial Public Offering. The Company also secured a "first right of refusal" over the larger part of the tenement and in 2003 exercised this right to acquire the bulk of the Project area and consolidate its ownership.
In 2002, Adelaide Resources formed a joint venture with major copper producer Phelps Dodge Corporation, which completed a significant exploration program of drilling, geochemistry and geophysics. Phelps Dodge withdrew from the joint venture in 2006 allowing Adelaide Resources to take control of the entire Project area.
The long and active exploration histroy of the district has generated a substantial volume of past exploration information including data generated from geochemical and geophysical surveys, and from past exploratory drilling. The Company estimates the present day cost of repeating the exploration programs completed by previous explorers would be in excess of $50 million demonstrating the significant value of this past work.
A timeline summarising the companies that have managed exploration of the Moonta Copper Project during the modern era, together with a graph of historical copper prices over this period, is presented below.
Moonta Copper Gold Project - Exploration history timeline
Adelaide Resources recommenced ist search for copper-gold deposits on the Moonta Project in 2009, delivering promising discoveries at Willamulka (2010/11) and Paskeville (2012). Its assessment of the historical exploration data from the Project highlighted what are now referred to as the Larwood and Bruce Zones at Alford West, with both returning significant exploration results in 2013 and 2014. Aircore drilling in 2014 discovered two more zones of mineralisation at Alford West (Six Ways and Blue Tongue). Ongoing assessment of historical exploration data in 2014 has also identified the West Doora prospect as a significant body of mineralisation.
In 2013 Adelaide Resources pioneered the use of highly cost efficeint Field Portable X-Ray Flourescence (FPXRF) geochemistry in the district. FPXRF was instrumental in the discovery of the Blue Tongue Zone at Alford West.
Alford West Prospect
The Alford West Prospect was first recognised through a review of historical exploration data which confirmed that limited past drilling had intersected attractive grades of copper amd gold mineralisation beneath a large copper geochemical anomaly defined by shallow auger drilling completed in the 1960's.
In April 2013, the Company completed am initial aircore drilling program of 25 holes over part of the prospect (now called the Larwood Zone), with a number of holes returning high grade intersections including:
- 20 metres at 4.20% copper and 0.27g/t gold from 32 metres in ALWAC007
- 45 metres at 1.56% copper and 1.83g/t gold from 13 metres in ALWAC008
The figure below presents a summary of the prospect's status in April 2013.
Alford West Prospect - April 2013
Following these outstanding initial exploration results, additional aircore drilling was completed at the Larwood Zone and over part of a second zone called Bruce, with further significant intersections returned from each.
In 2014, after FPXRF survey efforts had identified the Blue Tongue Zone and significantly increased the overall size of the Alford West geochemical anomaly, a further program of aircore drilling was completed to systematically cover the enlarged prospect. This drilling discovered a new zone of copper mineralisation at Six Ways, returned a nember of further attractive drill intersections from the Larwood and Bruce Zones, and confirmed the Blue Tongue anomaly to be sourced by underlying copper mineralisation.
The Company has constructed a 3-D model of the prospect incorporating the results of all of its aircore drilling and drawn the following conculsions:
- the Alford West Prospect is a single, large Iron Oxide Copper-Gold style mineralised system that extends over 3 kilometres in an east-west direction.
- there are four internal zones within the broader system that show potential to contribute to a mineral resource. These are named Larwood, Bruce, Six Ways and Blue Tongue. All four zones remain open at depth.
- the dimension of the currently modelled lodes confirm that potental for a substantial mineral resource if deeper exploratory drilling successfully demonstrates the mineralised zones persist to depth.
The Larwood and Bruce Zones both extend for 600 metres along strike and have sub-vertical dips. Mineralisation reaches thicknesses of up to 50 metres in places in each zone and both zones remain open at depth along their 600 metre strike lenghs.
Alford West Prospect 3-D mineralisation model
Confidence that mineralisation at the four zones at Alford West will continue to depth is enhanced by the large lateral extent of the system and the presence of mineralistion in limited historical deeper reverse circulation and diamond drill holes at the Bruce and Larwood Zones.
The typically steeply plunging ore shoot morphologies at historical mines in the district add to this confidence. A long projection of the 3-D Bruce Zone model built using the Company's aircore drill results and superimposed onto the Wallaroo Main Lode long projection shows that if the current mineralised zones at Alford West do display the same steeply plunging shoot character, the potential to grow the deposits down-plunge is significant.
During March/April 2015, an 8 hole deeper reverse circulation drilling program was conducted at both the Bruce and Larwood zones at Alford West and returned broad intersections of moderate grade copper mineralisation which confirmed the continuity of mineralisation at depth.
At the Bruce Zone results included 20 metres at 0.56% copper and 0.11g/t gold from 131 metres, including 6 metres at 1.12% copper and 0.17g/t gold from 135 metres, and 11 metres at 0.87% copper and 0.10g/t gold from 169 metres, including 9 metres at 1.01% copper and 0.08g/t gold from 170 metres. At the Larwood Zone, results achieved included 17 metres at 0.41% copper and 0.19g/t gold from 93 metres, and 11 metres at 0.54% copper and 0.12g/t gold from 166 metres.
Below is a summary of the current status of the Alford West
Alford West Prospect - current status
A review of often hand written old exploration records by Adelaide Resources, which led to the recognition of the opportunity at Alford West, has identified further potential targets such as the West Doora, Doora and Vulcan prospects within the Moonta Copper Gold Project.
At West Doora, southwest of the town of Kadina, between 1966 and 1974 drilling undertaken by the WMC/NBH joint venture intersected copper from depths as shallow as 20 metres below surface with significant intersections including 7.31 metres at 2.29% copper from 224.03 metres in DDH 38 and 71.02 metres at 0.82% copper from 276.15 metres in DDH 114.
To the southeast of West Doora lies the Doora and Vulcan prospects where significant intersections from historical drilling by WMC and its joint venture partners included in 8.38 metres at 1/20% copper from 380.24 metres in DDH 7. 2.44 metres at 7.64% copper from 182.42 metres in DDH 52, and 20.00 metres at 0.75% copper and 0.33g/t gold from 10.00 metres in MP 674.
These prospects add to a growing list of prospects within the Moonta Copper Gold Project that are 100% owned by Adelaide Resources and represent additional targets that show potential to contribute to a broader project resource inventory.