The King Battery site is 47 km south-south-east of Kalgoorlie, Western Australia (WA) on Woolibar (originally Wollubar) Station. It is accessed from a track off the eastern side of the Kalgoorlie-Kambalda Road, approximately 45 km south of Kalgoorlie/Boulder. King Battery has strong links with Ernest Lidgey, an early President of the Australasian Institute of Mining Engineers (AIME, now AusIMM).
Heritage status of the site
The site’s heritage significance and importance is due to the rarity of the remains of its gold treatment plant, dating from the early 1900s. It was listed as a Permanent Entry on the Register of Heritage Places by the Heritage Council of Western Australia on 13 May 2005. The relevant ‘Assessment’ and ‘Permanent Entry’ documents give little technical information on the site and contain several errors of fact, while a paper written by Gerard MacGill in 2004 gives only background information.
This article provides an explanation and description of the site – as it was most likely operated and as it is today – based on the writer’s knowledge of the technology of gold treatment plants in the late 1800s-early 1900s.
It is ironic that the site survives today because the project was a failure. It is the last remnant near Kalgoorlie of the new cyanide technology introduced in the 1890s-1900s which contributed greatly to the development and success of the Golden Mile and surrounding goldfields. The Cyanide Process, first patented in 1887, enabled greater recovery of gold than was possible by just using stamps and amalgamation and thus changed the economics of gold ore treatment around the world.
Ernest Lidgey and Hampton Plains Estate Ltd
The site is closely connected with Ernest Lidgey, born in Adelaide in 1863 and later educated in Cornwall, England. He returned to Australia in 1891 and joined the Victorian Department of Mines, becoming Assistant Government Geologist in 1897. In 1898 he was appointed Government Mining Representative in London then returned to Australia in July 1899. His connection with the Hampton Plains Group commenced in 1900 and the Coolgardie Miner reported Lidgey’s view that, ‘with thorough and careful development the Hampton Plains Estate should become the largest gold producing property in Western Australia.’ He was President of the AIME in 1901 and he and his wife were resident at ‘Wombra’ on Block 48, Hampton Plains, where visitors to the AIME 1901 Conference were entertained.
By then a 20-head battery had been ordered for the King Battery site. It began operating in early 1902 and while its builder is unknown, the adjacent cyanide plant is known to have been built by S G Turrell and W G Manners. This was completed in October 1902 and included what was reported to be the largest tailings wheel in the state, with a diameter of 54 ft.
It is obvious in examining the limited remains of the plant today that the original design was not optimal and that elements of the plant were not well sited. Most plants at the time were designed to take advantage of gravity as much as possible but not the King Battery. The remains of the cyanide plant itself also suggest an inefficient layout. These recent observations were ultimately confirmed by a comment of W G Manners, reported by his grandson Ron Manners that ‘their engineer insisted that we build the plant upside down.’ There are further comments in the press of the time which cast considerable doubt on Lidgey’s actions and his over-optimistic promotion regarding the possibility of rich gold ores in the area.
By mid-1902 Lidgey was already being questioned by the Board of the Hampton Plains Estate Limited for failing to make sufficient returns from the operations to justify the heavy expenditure and in September 1902 he resigned and left Kalgoorlie for London. However, despite the amount of money he essentially wasted on the plant, the Board absolved him of blame. At the company’s sixth annual general meeting in London on 18 December 1902, Lidgey was present and the Chairman advised that ‘unhappily the sanguine expectations of Mr Lidgey have not been fulfilled, and he is here today to answer any questions.’ The Chairman also said that he ‘must in justice to Mr Lidgey tell you, with the entire concurrence of my colleagues, that our faith in his honor and integrity is undiminished.’ It was also reported that ‘a vote of thanks to Mr Lidgey closed the proceedings.’ Various comments in the local press of the day by those who had observed the situation close up were not so forgiving.
As well as poor plant design, the material treated was not of sufficiently high grade to be treated economically; that is, it was not technically ‘ore’. Others battled on after Lidgey left, the local press reporting that ‘…they have produced order out of something approaching near chaos’ and ‘… the present management …to their credit… are doing good work with bad tools.’ But by 1904 the plant had closed. Despite Lidgey’s unimpressive performance, in 1903 he was already back in the area promoting an electric ore finder.
The King Battery
The King Battery was erected on Block 48 of the properties owned by Hampton Plains Estate Limited. The treatment plant complex was designed to treat ores from several mines in the area, with the ore to be transported by rail from these to the centrally located mill. Although it was erected to treat ores from several deposits, these were essentially owned by the same company, so it was a ‘central’ not a ‘custom’ mill. The name came from the nearby King mine that was named, ‘in honour of the new ruler on the British throne.’
A single photograph has been discovered showing an overview of the site in 1903. As far as can be ascertained there is nothing particularly unusual about the equipment and methods that were employed in the plant, other than that it was not well designed and laid out. It appears that more money was spent on the plant than necessary – for example, the photograph shows a large structure built above the site’s tailings wheel, which is much more elaborate than on other similar tailings wheels.
The stamp battery
Ore was trammed to the mill. It would probably have been tipped through a grizzly, before being fed to one or more rock breakers to reduce its size to no more than a few inches. Then, most likely it passed to a Challenge feeder, one for every five head of stamp, which provided a steady feed of ore to the mortar boxes. After wet crushing in the boxes with the stamps, the slurry or pulp, consisting of finely crushed ore particles and water, passed through screens which ensured that oversize particles were retained and subjected to further crushing by the stamps. Then the pulp would have been passed over copper plates coated with mercury, whereby some of the gold amalgamated with the mercury, with the plates being scraped periodically to remove the amalgam. The amalgam would have been heated in a retort, so that the mercury was vaporised, then cooled and collected for reuse, while the gold remained in the bowl of the retort, to be recovered and further purified by heating in a crucible with flux, then poured into moulds to produce gold doré bars ready to be sent to a refinery.
The excavation for the stamps and associated equipment, hewn out of solid rock, today forms a distinctive feature on the western side of the site but no equipment or foundations remain.
However, as was typical in many plants, it is possible that the pulp was also passed over Wilfley (shaking) tables, with the gold-rich fraction being recovered for further amalgamation in a Berdan or other grinding pan, prior to retorting. Perhaps classifiers such as spitzkasten may also have been used. But there is no evidence of what was actually done.
The tailings wheel
The pulp was then sent to the cyanide plant via a launder (a long trough) to a tailings wheel 54 ft in diameter, where it was elevated about 40-42 ft. The substantial masonry and brick pillars that supported the wheel remain intact today, as does the central portion of the wheel, with its spindle still attached to the tops of the supporting pillars. The spokes and ‘buckets’ are no longer there. What was most unusual was the substantial roofed building covering the upper part of the wheel which seems rather unnecessary and would have been an added expense.
Tailings wheels, which were used in South Africa, were only erected in Australia for a very limited period in the late 1890s and early 1900s. Many plants favoured pumps instead and it was not long before tailings wheels went out of fashion. Several were used on Western Australian goldfields including Great Boulder Main Reef (~ 24 ft diameter), Brownhill (32 ft), Lake View Consols (42 ft), Golden Horseshoe No 1 plant (40 ft), Great Fingall (40 ft), and Sons of Gwalia (56 ft). In addition, the Cosmopolitan Mine at Kookynie had a tailings wheel that was claimed to elevate the pulp 50 ft. Its supporting pillars are the only other ones that remain intact, contrary to the claim in the WA heritage documentation that the only remaining tailings wheel pillars are at the King Battery.
The cyanide plant – treatment of sands by percolation
After being elevated by the tailings wheel, the pulp was conveyed by a launder that dispersed it to one of six Butters and Mein distributors that sat atop six vats, the masonry foundations of which are still intact today. Six vats, as at King Battery, was a common number in many smaller plants, providing one vat for each day of the working week, with each vat being filled, treated with the various solutions and then emptied on a rotating basis. A Butters and Mein distributor comprised a central collecting cone into which the pulp poured from the launder, with the cone having pipes of different lengths attached. This all rotated on a vertical axis due to the flow of the pulp and thereby the material was evenly distributed in the vat from the rotating arms of differing lengths. This simple but effective method was widely adopted after it was developed by Charles Butters and Captain Mein in Johannesburg in 1894.
In the Kalgoorlie area, vats were constructed of curved steel plates that were riveted together, with flat steel plates on the base. At the King site the diameter of each vat is estimated to have been approximately 24-25 ft and the height probably 5-6 ft, sitting on foundations around 6 ft high.
Fortunately, the masonry foundations of the six vats are essentially intact at the King site, although partially buried by sand and loose fill. Each vat had its own set of foundations, comprising four supporting walls running north-south, around 6 ft high, with all six adjacent vats aligned north-south, so a tramway could run along the central spine beneath the vats. The vats would have been laid on wooden supports above the masonry foundations and evidence for this is clear, with lengths of timber still remaining, cemented into the top of the foundations with small gaps to allow for various pipes.
Once filled with pulp, the water was drained from the vat and then the contents were subjected to cyanide treatment. This usually comprised three different washes – a stronger cyanide wash (~0.3-0.5 per cent potassium or later sodium cyanide), a weaker cyanide wash (approximately 0.15 per cent potassium or sodium cyanide) and a water wash. In each case the cyanide solution was left to percolate through the crushed ore before being drained and the next solution run on.
Each vat was fitted with a filter on its base, comprising a combination of pebble beds, canvas, burlap, coconut matting and the like that were overlain with wooden battens. The battens provided protection when the spent material was removed. Pipes were fitted at the base of the vats to enable introduction and removal of solutions, with draining often assisted by suction.
The different cyanide solutions were contained in separate solution tanks. After being applied and then run off the vats, the gold-bearing solution was passed through zinc boxes, usually dedicated to the different solution strengths. These boxes were of a standard design as first described in the patents related to the MacArthur-Forrest Cyanide Process. The pregnant liquor passed through a series of compartments in a long wooden box, which had several screens fitted that contained zinc filings. The gold was precipitated and dropped to the base of each compartment while the zinc went into solution. The gold sludge was cleaned out periodically, then dried and heated in a crucible with flux in a furnace to produce gold doré bars.
After passing through the zinc box(es) relevant for the strength of the solution, the liquid was collected in sumps. Usually three sumps were provided – with strong solution, weak solution and water wash being kept separately. At the King site one of these sumps, 4 ft 3 inches square and of similar depth, has been excavated and is located east of the fourth vat foundation near the corner of a flat area assumed to be the floor of a building. This would have been the building where the zinc boxes were located and it is highly probable that two other sumps can be found, adjacent to the one excavated. The solutions from the sumps were reused and were usually sent to three larger solution tanks, where extra cyanide was added if needed, to make up the required strength before the solution was applied to a new charge in a vat. However, at the King site there is now no evidence of where these solution tanks may have been located.
Emptying the vats
When the percolation process was complete and the cyanide solutions containing the gold recovered for treatment, the spent material from each vat was emptied. Normally, in many similar plants, there were circular bottom discharge doors in the base of the vats that were opened so that the spent ore could be shovelled through the open doors into small trucks. These trucks ran on a narrow tramway, with rails laid between the middle two masonry foundations of each vat. The men working at the battery trucked away and emptied the contents from the vats.
However, in the case of the King Battery it is not clear if this typical working method was applied and there is insufficient information to determine the actual method used. Some evidence suggests that the vats were sluiced out with water.
There is a single set of different tank foundations on the lower ground immediately south of the plant and below a 91 ft long retaining wall, at its eastern end. These comprise a series of eight low ‘walls’ 1 ft wide and approximately 1 ft high constructed of masonry, finished on the upper surface with mortar work for timbers. They may well have been for a water tank.
There would have been a laboratory on site which also included a furnace. Broken glass and broken crucibles and cupolas can be found today near the excavated sump. There are various smaller remains dotted around the site, probably foundations and the like for pieces of equipment and for launder supports and so on.
Today, while it is clear that pulp consisting primarily of sands was treated by percolation, it is impossible to tell if there was a slimes plant, where pulp consisting of fines would have been agitated – there is no evidence of a slimes plant. Neither is there any evidence of any roasting of ores or concentrates. Unlike Kalgoorlie, the local gold-bearing material may have been relatively free milling, not too talcose and not refractory.
It is ironic that the King Battery site should remain today and be of considerable heritage significance – essentially because it was a failure in the early years of the 20th century, due to it being erected where there was insufficient ore for it to be worked economically and also to the fact that it was poorly designed.
It survives as a rare example of a gold treatment plant, including a cyanide plant, which operated at the start of the 20th century. Such plants were commonplace on gold fields around Australia in the early years following the introduction of the Macarthur-Forrest Cyanide Process, which had changed the economics of gold processing around the world. At the King site today there are sufficient remains, mostly consisting of masonry foundations, to allow some understanding of the plant. Although little-written information is available, much can be inferred as to how the plant was worked.
A detailed survey of the site would assist in better understanding its original works and its remains today.