Charters Towers, Queensland, Australia
On 29 April 2005, Tamaya Resources [as SMC Gold] poured its last gold bar from the Rishton mill, which it then handed over to BMA Gold for $2.75 million plus a buy-back option. An equipment auction and subsequent rehabilitation effectively closed a ten-year history of mining in the Rishton Mine Corridor and associated areas. During the period, the company milled 1,338,550 tonnes of ore at 3.82 g/t Au and produced 173,000 ounces of gold. The bulk of this ore, 961,000 tonnes at 4.19 g/t Au for 129,300 ounces, was mined from the Hadleigh Castle underground mine 210 to 425 metres below the surface.Tamaya’s gold properties are located 30 km east of Charters Towers on the Burdekin River, within the historic Charters Towers goldfields as per Figure 1. Administratively, they are under the jurisdiction of the Dalrymple Shire.
Figure 1 – Tamaya Resources Charters Towers Exploration Properties
In all, Tamaya Resources owns 23 mining leases, covering an area of 21 km2 (2,144 Ha) and three exploration permits covering 341 km2 (Figure 2) The largest of these, EPM 10,585 is 100 blocks, or 320 km2, and covers the Rishton Mine Corridor and Cornishman prospect areas. These properties give Tamaya effective control of the historical Rishton-Hadleigh gold field.
Prospectivity
The gold deposits located within Tamaya’s leases are hosted by ~400 million year old granodiorite-granite intrusive complexes, which are part of the Ravenswood Batholith. Locally the host-rock is a magnetite-rich granodiorite.
Interestingly, the leases occur at the intersection of two significant gold trends: the east-west Mosgardies shear zone which links gold deposits at Nolans in the Ravenswood gold field with Charters Towers, and the NE-striking Mt Leyshon trend.
On Tamaya’s tenements, the main targets for exploration are high-grade gold-quartz veins and lower-grade breccia zones, which are associated with east-west planes of structural weakness, fault intersections and dilation zones, which could have provided a focus for the migration of gold-bearing fluids.
The quartz veins are sheathed within sericite-clay envelope. Associated with the gold are small amounts of pyrite as well as other base metal sulphides (chalcopyrite, sphalerite and galena). The sericite envelopes are relatively incompetent compared to the fresh granite, and non-magnetic. These are evidence of the shear-controlled hydrothermal activity which generated the mineralisation.
Figure 2 – Tamaya Resources Current Mine Leases and Tenements
The area of immediate interest is EPM 10,585 which is a very large area covering the Rishton Mine Corridor and the Cornishman sector (Figure 3). The former is a term referring to an east-west structural lineament characterised by gold-quartz veins, and incorporating a series of historical workings and recent gold mining activities by SMC Gold and its predecessors (North Queensland Mining, Ashton Mining and Aurora Gold) at Hadleigh Castle, The Captain, Robinson Crusoe, Disraeli and Joes’ Delight.
A field visit and inspection of the data by the company shows that despite significant historical activity, most of which was small scale, the area is under-explored, with insufficient drill hole coverage for the size of the field, with 65% of holes less than 40 metres in depth and limited ground geophysics over the Rishton Mine Corridor and soil geochemistry over the Rishton Mine Corridor and part of the Cornishman sector.
Figure 3 – The Mosgardies shear zone and Mt Leyshon trends intersect at Rishton
It is the intention of the company to begin an exploration programme during April 2007. The first stage of the exploration programme will involve a programme of ground geophysics including ground magnetics and IP to identify drill targets over the Cornishman Breccia Zone, as well as a series of RC holes drilled in the Hadleigh East area of the mine corridor, adjacent to the abandoned Hadleigh Castle open pit area.