MINING HISTORY
Pluton’s Tasmanian tenements include some of the earliest gold workings in the State’s history. James ‘Philosopher’ Smith discovered alluvial gold in the Forth River near Golden Point in 1859. Subsequently Campbells Reward and the Middlesex Goldfield (Five Mile Rise) were found upstream. A summary of the major workings is described below.
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The Campbells Reward Goldmine
Campbells Reward opened by Malcolm and Alex Campbell in 1882 and was the first hard rock gold mine in the Cethana-Moina district. It is located on the eastern side of the Forth River and about a kilometre upstream from where alluvial gold was first discovered at Golden Point by James Smith in 1859.
The Campbell Reward workings are mentioned in a number of government reports. However, their isolation meant that they were rarely visited and never described in any geological detail. The mine was used to float a company in about 1890. However, this venture appears to have lasted only a few years, and by 1893 A.Montgomery described the workings as abandoned. Montgomery’s parliamentary report goes on to say….”From the amount of gold taken from it [Campbells Reward], it will no doubt continue to be prospected and likely enough good reefs will yet be discovered”
Total gold production from Campbells Reward is unknown. In a 1913 report, government geologist W.H.Twelvetrees describes the mine as producing free gold in a barbed and wire form from a kaolin and quartz vein of up to 15 inches width. Twelvetrees goes on to state that mining ceased because of the high silver content to the gold and the mines remote location. In fact, Twelvetrees had never entered the mine. By the time he visited the area the mine had deteriorated and was showing signs of collapse. Instead, he had to rely on descriptions made by the Campbell brothers.
Twelvetrees also describes other occurrences of gold in the region, including ‘fair deposits of flaky gold’ within the Forth River at Golden Point, the site at which Smith had made his discovery some 50 years earlier. Perhaps with some humour, Twelvetrees goes on to mention exploratory workings within Lorinna itself and how ducks were known to collect small pellets of gold from creeks in adjacent areas. Other workings in the area described by Twelvetrees include gold workings on the ridge above Campbells Reward and in the nearby Five Mile Rise and Dove mineral fields.
Little is known about activity at Campbells Reward up until the 1960’s. Old mine plans dated 1922, show application for a 40ac Mining Lease over Campbells Reward in the name of William Jackson. It is not known how much work was done in the area or if any gold was actually mined. However in 1963 government geologist I.B.Jennings, described the mine as being cleared out since it was visited by Twelvetrees.
Jennings goes on to describe the Campbells Reward adit as being 230 ft (73m) long, beyond which it was blocked. He could not access the original vein worked by the Campbell brothers but notes numerous other altered feldspar veins exposed in the adit walls.
Campbells Reward sits on the flank of the Cethana Aeromagnetic anomaly.
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Five Mile Rise Goldfield
It was not until 1887 that a discovery at Five Mile Rise (previously termed the Middlesex Goldfield) was made by J Aylett at the “Great Caledonian” Mine. A number of leases at Five Mile Rise were pegged around the initial discovery in the following year, however the alluvial prospects were quickly ‘worked out’ due to the shallow nature of the alluvial wash.
Hard rock sources were soon located and developed by underground workings on the auriferous lodes. The lodes were gold rich in the oxide zones near the surface with gold not recoverable from the sulphide lodes at depth using techniques available at the time. By 1891 work had all but ceased on the gold field due to the rush at Bell Mount to the north (outside the licence area) and only three mines returned to production before work again ceased in 1901.
Six prospects on the Five Mile Rise mineral field constitute the main hard rock workings; they are the Great Caledonian, Glynn, Thistle, Golden Hill, Golden Cliff and Union Mines all of which were originally developed between 1887 and 1901. The only form of exploration on these prospects as individual targets has been by prospecting via adits and shafts. All but the Great Caledonian were accessed by adits, with the flat ground around the Great Caledonian only allowing access by a shaft. All the lodes in the goldfield are said to occupy small faults that strike northwest-southeast.
Twelvetrees re-examined the Five Mile Rise Goldfield in 1913. The workings were abandoned, however by 1919 when government geologist A.McIntosh-Reid visited Five Mile Rise the Thistle mine was once again being worked for lead ore. Alluvial gold was also being taken from “O’Rourkes Hydraulic” lease (East of the Glynn Mine) where a two sluice head water right on ‘Big Creek” was sourced by way of a water race about half a mile long.
The Five Mile Rise Goldfield was prospected by several hopeful bushmen in the early 1960’s, but has long since been abandoned and was cut off from the original VDL company track to the east when the Forth River valley was flooded to form Lake Cethana (a hydro electric storage).
There are a number of geophysical and geochemical anomalies associated with the goldfield.
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Devon Mine
The Devon Mine was historically mined for galena from clean 7 to 40cm veins which contained high grade hand picked silver-lead ore. Consequently the Devon Mine has long been considered and reported as a lead-silver deposit, however appreciable gold and copper grades accompanied the lode material and the mixed sulfide portion of the lodes and any associated disseminated sulphide was never recovered. The mine was the only prospect in the district to pay it’s way despite the restrictive location and associated transport costs of horse-packing it’s clean galena ore to market. Pluton has drilled under the Devon Mine with drill holes indicating the lodes pinch out at depth.
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Powerful Mine
The Powerful Mine is first referred to in Geological Survey Bulletin 14 (Twelvetrees, 1913) as Reardon and Days Mine. The mine is located approximately three kilometres south of Lorinna. The lode is in granite opposite the Dove River where it now enters Lake Cethana. The lode is comprised of quartz, specular haematite and pyrite. Two samples produced assays of 1.5 g/t gold and silver and no trace of gold and 6 g/t of silver. A bulk sample produced a trace of gold and 7.5 g/t silver. Pluton has since drilled this lode system with weakly anomalous metal grades.