Company Projects
Tiwi Islands | Cape York | Carnarvon | Pender
Tiwi Island Project, Northern Territory
Location and Geography | Exploration | Reserves/Resources | Mining and Processing Methodology | Construction progress photographsLocation and Geography
The Tiwi Islands, comprising Melville and Bathurst Islands, are located 50 kilometres north of Darwin, in the Northern Territory of Australia. The islands cover 3000 square kilometres and have a permanent population of approximately 2000. The major settlements are Nguiu on Bathurst Island and Milikapiti (Snake Bay) and Pirlangimpi (Garden Point) on Melville Island.
Exploration
Matilda is currently exploring 16 prospects on Melville and Bathurst Islands and has identified good heavy mineral targets at several of them.
Brief exploration in the 1960s by United Exploration highlighted the Tiwi Islands as having deposits potentially rich in zircon and rutile. Numerous HM accumulations were noted on beaches and at the base of the Tertiary sandstone scarps.
In the early 1990s, exploration by RGC demonstrated the potential for small, but rich, zircon and rutile dominated deposits similar to those mined on the east coast of Australia two to three decades earlier. Only limited exploration was undertaken on the younger Quaternary coastal plains with the primary focus on the Tertiary sandstone in the quest for world-class deposits. RGC tested only about 20% of the coastal plains before deciding that although the deposits had excellent zircon/rutile assemblages, the potential size of the deposits was apparently too small for a large mineral sands company and therefore did not meet its corporate criteria.
Since the end of 2004, Matilda Minerals has actively explored many of the coastal plains and identified reserves and resources at Andranangoo Creek West, Andranangoo Creek East, Goose Creek East and West (Andranangoo project) Lethbridge Bay West, Lethbridge Bay South and Radford Point (Lethbridge Project) and at Puwanapi on Bathurst Island.
Major targets currently being explored are: Lethbridge South and Robinson Inlet on Melville Island, and One tree Point on Bathurst Island.
Reserves/Resources
IDENTIFIED MINERAL RESOURCESTiwi IslandsMineral Sands Project
September 2006
Resources (inc Reserves) |
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| Deposit | Category | Cut-off | M Tonnes | % HM | % VHM |
| Andranangoo | Measured | 1% | 2.68 | 3.6% | 93% |
| Andranangoo | Indicated | 1% | 0.54 | 5.5% | 92% |
| Andranangoo | Inferred | 1% | 0.30 | 3% | |
| Lethbridge | Measured | 1% | 0.41 | 5.2% | 87% |
| Lethbridge | Indicated | 1% | 1.13 | 3.6% | 86% |
| Lethbridge | Inferred | 1% | 0.03 | 4% | |
| Puwanapi | Measured | 1% | 1.77 | 5.8% | 81% |
| Puwanapi | Inferred | 1% | 0.12 | 6.0% | |
| Total | Measured | 1% | 4.86 | 4.5% | 87% |
| Total | Indicated | 1% | 1.67 | 4.2% | 89% |
| Total | Inferred | 1% | 0.45 | 3.9% | |
| Total | 1% | 6.98 | 4.4% | ||
Reserves |
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| Deposit | Category | Cut-off | M Tonnes | % HM | % VHM |
| Andranangoo | Proven | 1% | 2.68 | 3.6% | 93% |
| Andranangoo | Probable | 1% | 0.54 | 5.5% | 92% |
| Lethbridge | Proven | 1% | 0.41 | 5.2% | 87% |
| Lethbridge | Probable | 1% | 1.13 | 3.6% | 86% |
| Puwanapi | Proven | 1% | 1.77 | 5.8% | 81% |
| Total | Proven | 1% | 4.86 | 4.5% | 87% |
| Total | Probable | 1% | 1.67 | 4.2% | 88% |
| Total | 6.53 | 4.5% | 87% | ||
Contained VHM in Reserves (tonnes) |
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| Deposit | Zircon | Rutile | Leucoxene | Ilmenite | Total |
| Andranangoo | 60,000 | 31,000 | 17,000 | 9,000 | 117,000 |
| Lethbridge | 26,000 | 14,000 | 10,000 | 5,000 | 55,000 |
| Puwanapi | 20,000 | 11,000 | 7,000 | 45,000 | 83,000 |
| Total | 106,000 | 56,000 | 34,000 | 59,000 | 255,000 |
The exploration results have been prepared by Mr Peter Schwann (Ass App Geol), FAusIMM, CP (Geology), a consultant to Matilda, who has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2004 Edition of the "Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves". Mr Schwann consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.
Mining and Processing Methodology
Mining started at Andranangoo Creek West in October 2006.
The mineral sands mining method being used at Andranangoo is a form of slot mining, which minimises the excavation footprint at any one time. Mining is done by a 45 t excavator and two 35 t articulated 6-wheel drive trucks on a day shift basis only, whilst processing operates on a double shift basis. The ore zones at Andranangoo are variable in width (25m to 150m – typically 80-100m) and depth (1 to 3m). Ore is stockpiled and screened before being slurried and pumped to the HM concentrator where a simple wet gravity circulate separates valuable heavy mineral from waste sand.
At Andranangoo 96% of the sand is returned immediately to the mined out areas.
A visual description of the full mining method, water recycling, tailings disposal and rehabilitation is shown below. The mining technique is aimed at minimising environmental impact and also costs.
