Einasleigh Copper Mine and Smelter is a heritage-listed mine at Daintree Road, Einasleigh, Shire of Etheridge, Queensland, Australia. It was built from 1867 to 1922. It is also known as Lynd Copper Mine and New Einasleigh Copper Mine. It was added to the Queensland Heritage Register on 11 December 2006.
History
The Einasleigh Mine and Smelter is located in Etheridge Shire, some from Cairns. The site is an area of around , situated north of Einasleigh Township, on the west bank of the Copperfield River at its junction with the Einasleigh River. It is located about north of the Copperfield Gorge.
Australia's copper industry was in its infancy when Richard Daintree discovered the copper deposit near the basalt wall at the head of the Copperfield River watershed in 1867. He secured a freehold title over . The lode was stripped by open-cut where it protruded from the river bank and picked ore was sent to smelters at Cockle Creek for a return of 22% copper with of silver and of gold per .
Although located adjacent to the confluence of the Copperfield and the Einasleigh Rivers this mine was initially known as the Lynd Copper Mine as Daintree believed that the adjacent river was the Lynd River.
The Lynd Mine was a small operation. According to one account a shaft was sunk in 1867 and "a drive at the 30-ft level showed the lode to be 23 feet in width and to consist of spongy metallic copper." Daintree and his partner William Hann worked the mine in a "desultory fashion" for a few years but by 1898 the site was reported as deserted by surveyor Robert Logan Jack.
By 1900 the mine was back in production when William Woodhead from Broken Hill acquired freehold title and floated it publicly. Now known as Einasleigh Freehold Copper Mines Ltd, development of the mine began with a new shaft sunk to . A new headframe was erected, along with a boiler stack and gantry. Machinery including winding gear and a water-jacket blast furnace at a cost of was brought from Mareeba. The smelter's furnace was blown-in in 1901 but the operation was soon closed down because of the siliceous nature of the ore, transportation costs and the high cost of fuel. Prior to the opening of the Chillagoe rail line in 1910, fuel for the smelters was brought in by camel trains.
The mine reopened in 1906 as the New Einasleigh Copper Mine, a subsidiary of the Chillagoe Company. Number 3 level was developed in 1908 and 50 men were employed on the mine site. Employee numbers doubled in 1909 to 105 men and productivity leapt to an impressive of ore.
The isolation of the mine again made the operation marginal. All supplies had to come either overland from Townsville or via Cairns for along the Chillagoe line to Almaden, and then carted by bullock team another to the mine. Coke, which was vital for smelting cost from to to land at the mine and limestone had to be carted for over . After treating of ore, smelting was abandoned even though of copper matte had been produced.
The mines on the Chillagoe field had proved inadequate even to keep the Chillgoe smelter supplied, let alone make a profit, and it became increasingly urgent that the Chillagoe Company obtain ore supplies elsewhere. In 1907 construction began on a railway to the Etheridge field, principally to bring ore from the Einasleigh mine and tap known copper deposits around Charleston (later Forsayth). Once the railway was opened in 1910 Einasleigh ore could be railed directly to Chillagoe.
The opening of the new Etheridge railway to Forsayth in 1910 allowed for the daily transportation of ore to Chillagoe as the route passed by the Einasleigh Mine. This boosted development of the site: new offices and houses were built. The main shaft was extended to and worked from 4 levels by 87 men, while a further 30 men were employed above ground. A change-house with a concrete floor was erected. Machinery was upgraded, including a new Babcock and Wilcox boiler, and construction of a concentrating plant large enough to deal with the expected of ore a day, was started.
By 1911 ore production was not meeting expectations and the Chillagoe Company bought out the mine from its subsidiary and installed an Elmore flotation unit. Until the invention of the flotation process, the extraction of metal depended upon being able to handpick the material in order to be economical.
The flotation process depends on the properties of minerals surfaces and the manner in which they differ in the degree by which their surfaces can be wetted. It takes best advantage of such differences by suitable choice of the solution. Ore is first ground to a powder, which is introduced to a series of tanks (known as flotation cells) holding a solution containing oils. This solution is constantly agitated and air is pumped through. In the resulting froth the particles of copper minerals adhere to the raft of air bubbles on the surface, while the majority of worthless rock (gangue) sinks. The material is skimmed from the surface froth.
Lionel Clive Ball, assistant government geologist, deemed the installation of the floatation unit a "complete failure". Mine development continued in an unsystematic manner and the quality of the ore produced declined. Untreated ore was sent direct to the Company's smelter, away, and in 1911 the Company had to reduce railway freight on ore by 50% to keep the mine working. This seemingly uneconomical and inefficient practice was, according to Ball, due to the Mine's small reserves and the great expense of erecting smelters at Einasleigh. The Chillagoe Company's motives were largely due to its need for the Etheridge's ore and railway revenue, and to further open up the Etheridge field. Whatever the case, by 1913 the Einasleigh Mine was the main supplier of copper ore to the Chillagoe Smelters.
Development of the mine continued to progress throughout 1913 in most levels of the mine and the mineshaft was being extended. Below ground, No. 1 level () extended beneath the river and was stulled to reduce the risk of ingress from the river. No. 2 level () had various drives linked to the south shaft and included the "Big Stope" ( long and up to wide) below this level with copper contents as high as 10%. No. 3 level () had five almost continuous stopes in one formation. The ore-bodies at No. 4 level were below payable limit and at No. 5 level () the "Big ore-body" was distant from the shaft. No. 6 level () was under development.
The Chillagoe Smelters closed in February 1914 along with the Einasleigh Mine.
In 1919 the Queensland Government took over the Chillagoe Smelter and reopened the Einasleigh Mine under the terms of the Chillagoe and Etheridge Railways Purchase Act 1918, at a cost of . By December it was at full output, providing three-quarters of the copper ore treated at the smelters thereby keeping the Chillagoe Smelters going. By 1920 the mine employed 100 men and was producing 450 - of copper ore per week. However, the drop in metal prices in 1920 from to per , and the drain on the mine's reserves, led to the mine being closed in 1922.
At this time the whole of the Chillagoe Field, the Chillagoe Smelter and mining operations generally in State-owned enterprises were losing considerable amounts of money. The Smelter was closed in 1927 due to inadequate ore supplies, but was reopened in 1929 as a means of relieving unemployment. Mining on the Etheridge as a whole generally declined after this time despite the reopening of the Chillagoe Smelter. While other mines on the Etheridge were rejuvenated periodically after this time, no attempts to mine the Einasleigh occurred until the early 1970s. This was due to the heavy depletion of its reserves in the 1920s by the Chillagoe Smelters.
In the early 1970s Combined Mining and Exploration N.L conducted operations at the Einasleigh Mine to reinitiate earlier mining works. By the end of 1970 the Mine had produced of ore returning of copper (overall grade 6.04%), of silver ( per ), and of gold ( per ). Maximum staffing during this period was 16 employees, and a manager, W.J. Collins.
Development of the mine by Combined Mining and Exploration was undertaken over a 13-month period from October 1970 to November 1971, including "mine rehabilitation and exploration" and activities which were regarded as rectifying the site. Due to more stringent occupational health and safety measures much of the site had to be upgraded to comply with safety standards. Where suitable foundations were already present from previous operations, structures were built over the top, thus reusing existing infrastructure.
During the early part of 1971 activities included the installation of bearers for an air winch, installation of of polythene plastic water liner to work as a reticulation system for the camp, and a concrete floor for the power house being poured to the south of the main shaft and an area cleared for a garage/workshop. The workshop/storeroom area was completed and an ablution block was adapted from concrete engine beds remaining from previous operations. Mullock, soil and oxidised material were spread over much of the site during this time to provide a safer working surface. Mullock was also spread out between the main shaft and river, covering the Daintree shaft mouth.
In February 1971 the steel tripod was put over the main shaft, and in March a tramway was installed between the main shaft and the river bank. A flat-top trolley was acquired to run on the railway.
In June 1971, a new steel headframe was built over the shaft collar with a cross head made up to run in the main shaft. It is not known what the cross head was supporting. The air winch was repositioned and a winch house almost directly west of the main shaft was made. Extra timber and lagging was placed at the entrance of the mine shaft due to fears of falling rocks. Safety concerns also led to replacement of the old pulley-sheave with a new gin-wheel. Ladder ways and timbering in the shafts were substantially upgraded as most had split due to water logging. Most of the metal infrastructure such as pipe work and bolts had corroded due to their long period of saturation, and were replaced.
From March to November 1971, the mine was continuously dewatered in stages, ultimately down to , No. 6 level. Water samples taken from showed very low copper content, and when "two diamond- drill holes directed to intersect the main ore body at approximately 700 ft failed to intersect ore," operations at the mine ceased.
In 2006 an area including the site of the former Einasleigh Mine was leased by Copper Strike Ltd to develop a new mine. In December 2011, Copper Strike sold its Einasleigh Project to Kagara Limited for AU$16million and Kagara's 22.6 million shares in Copper Strike. Kagara sold the Einasleigh Project to Snow Peak Mining in January 2013. Snow Peak Mining owns a major stake in Consolidated Tin Mines Limited, which is undertaking exploratory activity in Einasleigh in 2016.
Description The Einasleigh Copper Mine site is a mix of very early workings and those of the exploration crews in the 1970s and the past year or so. Concrete engine mounts, the mill, a slag "floor", ore dumps, steel framed sheds and evidence of the change rooms and toilets from the 1970s are intersected by drill pads from exploration in 2005.
In the grass beyond the main mine site are traces of the 1970s work camp: a concrete slab floor and a power pole. They are adjacent to an elaborate concrete fountain derived from an earlier occupation period.
Sitting out on the flats are the remains of a stonewalled building, which retained its corrugated iron roof into the 1960s. It is presumed to have been an explosives store.