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Mt Todd, Yimuyn Manjerr - Batman, Quigleys, Tollis, Golf |
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Northern Territory, NT, Australia |
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Au Ag
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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The Mount Todd gold mine ( also known as Yimuyn Manjerr ) is located within the Palaeoproterozoic Pine Creek Inlier of the Northern Territory, Australia, approximately 40 km north-west of Katherine and 220 km south-east of Darwin. The operation comprises a series of pits, including Batman (the largest past producer), Tollis, Golf and Quigleys distributed over a north-east trending interval of approximately 6 km.
(#Location: 14° 8' 26"S, 132° 6' 28"E).
The Batman gold deposit is part of a goldfield that was worked from early in the 20th century. Gold and tin were discovered in the Mt Todd area in 1889. Most deposits were worked in the period from 1902 to 1914. The Yinberrie Wolfram field, which was discovered in 1913, is located 5 km west of Mt Todd. It comprised tungsten, molybdenum and bismuth mineralisation hosted in greisenised aplite dykes and quartz veins in a small stock of the Cullen Batholith. Exploration for uranium began in the 1950s discovered some small uranium prospects were in sheared or greisenized portions of the Cullen Batholith in the vicinity of the Edith River. In 1975, a joint venture between Australian Ores and Minerals Limited (AOM), Wandaroo Mining Corporation and Esso Standard Oil were granted a number of mining leases in the Mt Todd area. Exploration concentrated on alluvial tin and, later, auriferous reefs culminated in two drill holes at the Quigleys prospect. Despite promising gold results, the tenements were relinquished by the joint venture. A number of companies further explored the area between 1975 and 1983. In late 1981, CRA Exploration mapped the area and drilled 14 diamond holes program, for an aggregate of 676.5 m, testing Quigleys Reef over a strike length of 800 m. Following this program, no further work was undertaken. In late 1986, Pacific Gold Mines NL undertook further drilling, culminating in development of a small-scale open pit on the Quigleys and Golf reefs, and limited test mining at the Alpha, Bravo, Charlie and Delta pits. Ore was trucked to a carbon-in-pulp (CIP) plant owned by Pacific Gold Mines at Moline. This continued until December 1987 when Pacific Gold Mines ceased operations in the area, having produced ~86,000 tonnes @ 4 g/t Au. Subsequent negotiations between Pacific Gold Mines and the Mt Todd Joint Venture partners, the Shell Company of Australia (as Billiton) and Zapopan NL who were investigating opportunities in the Mount Todd area resulted in the former's tenements being incorporated into the joint venture. Drilling of a number of prospects in the area culminated, managed by Billiton, resulted in the discvery of the Batman deposit in May 1988. Zapopan acquired Billiton’s interest in 1992 by way of placement of shares to Pegasus Gold Australia Pty. Ltd.. Pegasus progressively increased their shareholding until they acquired full ownership of Zapopan and Mt Todd in July 1995. Studies for a heap leach operation focused predominately on the oxide portion of the deposit, commenced during 1992 culminating in a mine coming on stream in late 1993. A second phase involved treatment through a flotation and carbon-in-leach (CIL) circuit, with commissioning commencing in November 1996. However, a slump in gold prices in conjunction with underperformance of the project, led to the mine being closed and placed on care and maintenance on November 14, 1997. Administrators were appointed in 1997, and in February 1999, General Gold Resources Pty. Ltd. agreed to purchase the mine and form a joint venture with Multiplex Resources Pty Ltd and Pegasus to own, operate, and explore the mine. General Gold operated the mine from March 1999 to July 2000 when the mine closed again and went into liquidation. Pegasus Gold, regained possession of various of the mine assets to recoup the balance of purchase price owed to it, and most of the equipment was sold in June 2001 and removed from the mine. The Deed Administrators, Pegasus Gold Australia Pty Ltd, the Government of the Northern Territory, and the Jawoyn Association Aboriginal Corporation were deemed owners of the property. In 2006, Vista Gold Corp. acquired the mineral lease rights from the Deed Administrators. From 2006 to 2021 Vista Gold Corp. carried out a drilling campaign, produces environmental, economic, geotechnical, regulatory and required studies and completed its remediation of Batman Pit. Mineral Resources have been estimated in advance of seeking capital to re-commence mining (Vista Gold NI 43-101 Technical Report, 2021).
The Mt Todd operation comprises several discrete orebodies striking NNE within a broad NE trending corridor of gold mineralisation in the central domain of the Inlier. The ore is hosted by the Palaeoproterozoic Burrell Creek Formation which is principally composed of greywacke, siltstone, sandstone and shale of delta to pro-delta facies. In the mine area greywackes are massive and blocky with beds from 0.2 to more than 1.5 m in thickness, siltstones are fine to massive as beds from a few mm to more than a metre thick, while the shales are commonly graphitic and occur as interbeds in the greywacke and siltstones. These sediments are conformably overlain by the 1890 Ma volcaniclastics and volcanolithic sediments of the Tollis Formation.
Between 1870 and 1780 Ma the region was subjected to three compressional events that together make up the Top End Orogeny. The first, the Nimbuwah Event or D1, corresponds to the Barramundi event seen right across northern Australia. It produced tight NE to N to NW trending asymmetric folds and continuous axial plane cleavage and is associated with the development of conjugate buck-quartz veins. These were formed prior to the emplacement of the Yenberrie Leucogranite which contact metamorphosed the Burrell Creek Formation to hornblende hornfels facies at much the same time a the peak regional metamorphism. The second deformation, D2, was the Maud Creek Event at 1850 Ma producing open westerly trending folds and a spaced disjunctive to fracture cleavage. This was preceded by the emplacement of the Tennyson Leucogranite phase of the 1835 to 1820 Ma Cullen Batholith which further contact metamorphosed the sediments and Yenberrie Leucogranite. The D3 Shoobridge Event deformation from 1780 to 1770 Ma is characterised by the reactivation of mostly sinistral strike slip faults and shears (such as the important NW trending Pine Creek Shear Zone), a steeply dipping foliation and mesoscopic en echelon folds. This was followed by the emplacement of shallow lopoliths of Oenpelli Dolerite at 1688 ±13 Ma.
Each of the first two compressional events was followed by extension, the development of shallow rift grabens which were the centres of deposition for clastics, volcanics and volcano-sediments.
Five main types of veining are recognised at Mt Todd, namely: i). Buck-quartz veins - early barren veining associated with D1, ii). Quartz-tourmaline veins - follow the buck quartz, but closely precede the sulphide veining, iii). Quartz-sulphide veins and lodes - which carry the gold mineralisation and predominantly strike NNE as zones of structurally controlled (in cataclasite zones) sheeted veining and anastomosing stockworks ranging from a mm to 10 cm in thickness and hosted by greywacke or siltstone dominated sections of the host sequence. Sulphides include pyrrhotite, chalcopyrite, arsenopyrite, pyrite, marcasite, löellingite, cubanite, galena, sphalerite, bismuth, bismuthinite, other related sulphides and gold. They define a zone that passes through the Batman, Golf and Tollis pits. This veining and mineralisation apparently post dated D1, but accompanied the emplacement of the Tennyson Leucogranite of the Cullen Batholith, following the peak metamorphism, but preceded D2. iv). Calcite-base metal veins - a set of NW striking veins occuring near faults and range from <1 mm to 3 cm in thickness with cockscomb and colloform calcite, carrying galena, sphalerite, pyrite, arsenopyrite and chalcopyrite and are of no economic interest, v). Epithermal style quartz veins - several late, large unmineralised quartz veins.
Greisen type W-Mo-Sn-Bi-Cu mineralisation in the carapace of the early, D1, Yenberrie Leucogranite suggests an earlier discrete mineralising event before the main gold phase.
The ore deposit at Batman has a length of 1500 m and has been delineated to a depth of 500 m. It has a central thickness of 150 m tapering towards either extremity and dips at 75° E. The main ore envelope strikes at 10°, while the host lithologies strike approximately NW and dip at around 45°SW.
In 1986-1987 Pacific Gold Mines mined ~86,000 tonnes @ 4 g/t Au and trucked it to their carbon-in-pulp (CIP) plant at Moline.
Open pit mining commenced at Batman in 1993 with a total production to the end of 1996 of 13.2 Mt @ 0.96 g/t Au.
Recovery averaged 53.8%, with a total of 7 tonnes of gold being recovered.
At the end of 1995 reserves at Batman were 97.6 Mt @ 1.07 g/t Au.
Production in 1996, included Tollis and Golf also and amounted to 8 Mt.
The mine was closed in 1997. Total production over the period was 13.7 tonnes of gold.
Ore Reserves and Mineral Resources as at 31 December, 2022 using a 0.35 g Au/t cutoff grade (Vista Gold Website, viewed July, 2023) were:
Batman deposit
Proved Ore Reserve - 81.277 Mt @ 0.84 g/t Au;
Probable Ore Reserve - 185.744 Mt @ 0.76 g/t Au;
Proved + Probable Ore Reserve - 267.021 Mt @ 0.79 g/t Au, for 210 tonnes of contained gold;
Measured + Indicated Mineral Resource - 277.837 Mt @ 0.82 g/t Au;
Inferred Mineral Resource - 61.323 Mt @ 0.72 g/t Au;
Measured + Indicated + Inferred Mineral Resource - 339.16 Mt @ 0.81 g/t Au, for 276 tonnes of contained gold;
Heap Leach deposit
Proved + Probable Ore Reserve - 13.354 Mt @ 0.54 g/t Au, for 7.2 tonnes of contained gold;
Measured + Indicated Mineral Resource - 13.354 Mt @ 0.54 g/t Au;
Measured + Indicated + Inferred Mineral Resource - 13.354 Mt @ 0.54 g/t Au, for 7.2 tonnes of contained gold;
Quigleys deposit
Measured + Indicated Mineral Resource - 7.895 Mt @ 1.11 g/t Au;
Inferred Mineral Resource - 3.981 Mt @ 1.46 g/t Au;
Measured + Indicated + Inferred Mineral Resource - 11.876 Mt @ 1.23 g/t Au, for 14.57 tonnes of contained gold;
TOTAL Reserves and Resources
Proved Ore Reserve - 81.277 Mt @ 0.84 g/t Au;
Probable Ore Reserve - 199.098 Mt @ 0.75 g/t Au;
Proved + Probable Ore Reserve - 280.375 Mt @ 0.77 g/t Au, for 217 tonnes of contained gold;
Measured + Indicated Mineral Resource - 299.086 Mt @ 0.82 g/t Au;
Inferred Mineral Resource - 65.304 Mt @ 0.77 g/t Au;
Measured + Indicated + Inferred Mineral Resource - 364.39 Mt @ 0.81 g/t Au, for 295 tonnes of contained gold.
For detail consult the reference(s) listed below.
The most recent source geological information used to prepare this decription was dated: 2021.
Record last updated: 11/7/2023
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
Mount Todd
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Selected References:
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Hein K A A 2003 - The Batman and Quigleys gold deposits of the Mt Todd (Yimuyn Manjerr) Mine, Australia: structural, petrographic and mineralogical investigations of coeval quartz sulphide vein and lode/stockwork systems: in Ore Geology Reviews v23 pp 3-33
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Hein K A A 2003 - Relative timing of deformational, metamorphic and mineralisation events at the Mt. Todd (Yimuyn Manjerr) Mine, Pine Creek Inlier, Northern Territory, Australia: in Ore Geology Reviews v22 pp 143-175
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Hein K A A, Zaw K and Mernagh T P 2006 - Linking mineral and fluid inclusion paragenetic studies: The Batman deposit, Mt. Todd (Yimuyn Manjerr) goldfield, Australia: in Ore Geology Reviews v28 pp 180-200
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Ormsby W R, Olzard K L, Whitworth D J, Fuller T A, Orton J E 1998 - Mount Todd gold deposit: in Berkman D A, Mackenzie D H (Ed.s), 1998 Geology of Australian & Papua New Guinean Mineral Deposits The AusIMM, Melbourne Mono 22 pp 427-432
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Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
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