Tennant Creek
engineering heRitage tour Tennant Creek has an interesting and varied history including some fascinating Engineering Heritage sites. This brochure suggests 14 sites, the location of which are shown on the maps in this brochure. There is also a brief description of each site and a photograph for most sites. A car and a Tennant Creek street directory are essential.
Tennant Creek Engineering Heritage Brochure
A brief history on the evolution of government administration of the Northern Territory is required to explain the changing government responsibilities mentioned in this brochure. In European times the Northern Territory was initially part of the Colony of New South Wales. After John McDouall Stuart commenced his exploration through the centre of Australia the colony of South Australia applied to the Colonial Office in London for responsibility for the Northern Territory to be transferred to it; SA assumed responsibility for the NT on 6 July 1863. SA invested heavily in development of the NT, in addition to the Overland Telegraph SA commenced construction of a transcontinental railway from Port Augusta in the south and Palmerston (Port Darwin) in the north and constructed public buildings and other infrastructure in Palmerston / Port Darwin. In the late 1800’s the development of the NT became a drain on the SA economy and as part of the Federation negotiations to form the Commonwealth of Australia the SA govt negotiated that the Commonwealth take over responsibility for the NT, the negotiations took some time and then to legislate; the NT was transferred as the NT of SA to the NT of Australia on 2 January 1911. The NT was administered by the Commonwealth until 1 July 1978 when after the establishment of limited self-government NT politicians and departments took over administration of most Territory affairs.
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1 Overland Telegraph Station
The Overland Telegraph was constructed in 1871/72 by the South Australian government. At the time each of the Australian Colonies was in competition with the others over telegraph lines and traffic. The Colonies of Victoria and New South Wales wanted a link with Asia through to London. Routes for a telegraph line through Queensland and Western Australia were considered however South Australia with a proposed line through the centre of Australia linking with a submarine cable from Java clinched the deal. John McDouall Stuart had crossed Australia from south to north in 1862; based on his reports of the potential of the country he had crossed, South Australia applied in 1863 to the Colonial Office in London to have the Northern Territory made a South Australian responsibility. South Australia had appointed Charles Todd as Government Astronomer and Superintendent of Telegraphs, Todd convinced the South Australian government to enter the competition. The SA government were successful and over a two year period constructed the Overland Telegraph following the exploration route of John McDouall Stuart and connecting with the undersea cable from Java operated by the British Australia Telegraph Company. The Tennant Creek repeater station is a remnant of the original infrastructure, several Oppenhiemer poles and copper conductor exist in the vicinity of the repeater station. The Northern Territory government maintains this valuable piece of our history, interpretive signs are located around the Telegraph Station The Overland Telegraph was originally constructed as a single 8 SWG galvanised steel wire, with earth return, supported by a porcelain insulator on a wood pole cut from local timber. Poles were 80 metres apart with Repeater Stations located at around 250 kilometres. The Tennant Creek repeater station was sited near water holes on Tennant Creek. Staff received and retransmitted messages using Morse code. Power was provided by Meidinger cells producing 1.5 volts per cell for an operating voltage of 120 to 180 volts. Battery maintenance was a large component of the daily operations at a telegraph station. Automation in the form of repeaters was developed so messages could be automatically forwarded, from repeater station to repeater station, without human input. The time taken for a message to pass from Adelaide to London was 7 hours. Compared to the 3 months for a message to be transported by ship; telegraphic communication was relatively rapid. The Telegraph Station was manned until 1935 when the telephonists moved into Post Office facilities in Patterson Street in the recently established town of Tennant Creek. The overland telegraph facilities had a large Government Reserve around them which prevented development near the telegraph station; so Joe Kilgariff constructed his hotel where the truck carrying supplies was bogged south of the telegraph station. The alignment of the telegraph line had a direct impact on the road through the town of Tennant Creek. All construction had to be a Chain (66 ft. or one cricket pitch length.) off the telegraph line, so a two chain wide road reserve evolved as the road through the town.
2 Telephone Lines North of Tennant Creek
The single steel wire of the Overland Telegraph was upgraded with a return circuit in 1898, copper wire was used. Voice communication from Darwin to selected Southern stations was made available in addition to Morse code telegraphy in 1925, data transmission teleprinters were installed at Darwin and Alice Springs in 1938. The single circuit was upgraded to four circuits by the Military authorities in 1940’s at the same time the alignment was changed to follow the north south road. Oppenhiemer poles were relocated from the Overland Telegraph line or light section rolled steel joists were used as poles, cross arms were creosote treated eucalyptus and insulators were simple porcelain pin type; single strand copper conductor was used. A section of single wire copper conductor on Oppenhiemer poles exists adjacent to the telegraph station. A section of the poles, cross arms, and remnant conductor that can be seen to the east of the Stuart Highway just North of Tennant Creek is a remnant of the lines that ran from Adelaide to Darwin and from Three Ways to Mt Isa. Multiplexing allowed 24 different conversations / data transmissions to be carried on the one line pair. Voice and telex communications were the bulk of the data transmitted. Local calls were connected by a telephonist without delay; however trunk calls to the south needed to be booked and in the late 1960’s delays of a day were not uncommon in peak times. The introduction of the radio relay / microwave system in 1972 ended Tennant Creeks and the North’s reliance on telephone land lines. It was not until 1979 however; that Tennant Creek subscribers were able to dial a telephone number either for a local call or interstate by STD (Subscriber Trunk Dialling)
3 Mt Isa - Darwin Microwave System
Tennant Creek was a major repeater station on the Mt Isa - Darwin radio relay system constructed by the Post Master Generals Department in 1971/2, a further microwave link from Tennant Creek to Alice Springs was completed
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in 1979. The tower on the range of hills to the north east of town, along with other towers, no longer functions as part of the trunk communication system; optic fibre technology has replaced it. The electronic and generation equipment and shelters have been removed from remote sites. The Tennant Creek tower does however still transmit television signals and supports antennas and aerials for radio repeaters for local telephone services. The micro wave system consisted of two bearer’s one active the other a stand by. Forty five towers between Mt Isa and Darwin were spaced at approx. 40 km with a maximum tower height of 70 metres. The opening of the microwave revolutionised communications and brought live “Southern” television to Tennant Creek, Katherine and Darwin. Problems were experienced with the system in the early years of operation with “atmospherics” in the early morning after sunrise causing fading of the signal; the problem was partially corrected by diversity using frequency and spacing. Problems were also experienced with the generating sets, apart from people stealing distillate; the diesel engines which were a PMG “standard” failed prematurely. The problem was that the fuel supplied through Darwin was different (higher sulphur content) to southern fuel which caused corrosion and premature wear. By the late 1980’s optic fibre technology was replacing the microwave system commencing in the north between Darwin and Katherine and rapidly in the south.
The outbreak of war in the Pacific resulted in troops and equipment from the United States of America coming to the north of Australia, equipment was landed in the east and south and was railed to Mt Isa from where it was trucked across the Barkly Tableland to join the North South road approx. 25 km north of Tennant. The Australian military brought considerable volumes of materials and troops from the south via Port Augusta and Alice Springs. The military, who had taken over control of the North of Australia from Civil authorities, decided that the North South Road should be surfaced with a bituminous layer. The Country Roads Board (CRB) of Victoria was engaged to seal the road from Alice Springs to Larrimah. Owing to the worn condition of the road the CRB recommended that a 25 mm layer of asphalt be laid over the “existing” pavement. Work started at the Three Ways intersection north of Tennant Creek heading north, this was the most heavily trafficked section of road. Three specialised Barber Green mixing plants were identified as being required however only two were delivered. Work on regravelling the road and surfacing was interrupted in 1942 after the Bombing of Darwin when effort was transferred to bituminous surfacing of facilities for fighter and bomber aircraft in the North; in 1943 surfacing of roads recommenced and the North South Road from Three Ways to Alice Springs was finally sealed in December 1943. The current Stuart Highway to the south of Tennant Creek was constructed over the World War II pavement, in places the old pavement was widened. In other places a relatively thin sheeting of gravel was constructed over the old pavement. To the North of Tennant Creek at the crossing of Tennant Creek a new alignment was adopted; the World War II highway and floodway crossing of Tennant Creek is still visible just to the west of the bridge on the new highway. Two other interesting heritage items exist in the area just north of the Stuart Highway crossing of Tennant Creek:
4 Water Supply
The development of Tennant Creek and the surrounding mining activities was undertaken with an ongoing shortage of water, initially water was obtained from surface sources in creeks and dams. In 1935 after a public protest on lack of water; a bore was sunk and equipped at Seven Mile Creek, however water continued to be in short supply until bores were developed south of town. In 1962, bores and infrastructure were installed in the Cabbage Gum locality. A bore at Cabbage Gum was used by the military as part of its convoy activities during World War II, remnants of military activity remain in the form of a Sidney Williams hut and fencing. Two series of bores were drilled in the Kelly Well area further to the west to provide increased volumes of water to supplement the Cabbage Gum bore field. Tennant Creek water supply consists of tanks on the hills to the east and west of the township; the Kelly Well and Cabbage Gum bore field infrastructure consisting of bores equipped with submersible pumps, power supply and rising mains, bore field tanks, transfer pumps and delivery mains. The infrastructure has been upgraded and expanded over time, the original delivery main to town was a 150 mm cast iron pipe; the current system comprises a 250 CICL and a 375 DICL main. The initial town water storage was a 2.25 Ml tank on Aerodrome Hill, a second tank of similar volume but of different diameter and height was constructed beside the original tank in 1974. The different operating levels caused operational problems so the walls of the shallower tank were raised in 1981/2. A third tank of 5 Ml was constructed in 1975 near Battery Hill. Automatic chlorination of the water supply was to be introduced in 2014. Prior to that the residents of Tennant Creek had decided that the water supply should not be chlorinated and that chlorine dosing should only occur when necessary. Flouride is not added as it occurs naturally in the bore water. The shortage of water at Tennant Creek meant that water borne sewerage system could not be used to service the town, a pan / night cart service was used. Laneways were included in the Town Plan to provide rear access to lots for the collection of pans. These laneways were used to provide a location for the sewers when the town was sewered in the 1970’s. The system installed was a gravity system with treatment by ponds / lagoons.
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5 Mary Ann Dam
The Mary Ann Dam was constructed as a recreation water body by the Northern Territory government in 1979-80. Mary Ann Creek was named after a mining lease, the site of the dam was investigated as a water supply for Tennant Creek and the Peko mines in the 1940’s and 50’s. In 1977 local residents proposed a recreation lake on the creek. The local member Ian Tuxworth, a senior member of the Everingham CLP government, ensured that the proposal proceeded. The proposal was subject to much controversy with sceptics predicting that the dam would never fill. Much discourse took place between the CLP Territory government and the Labour dominated local government over the practicality of the dam; however discussion ended when wet season rains filled the dam before the wall was finished. The contractor MacMahon Construction Pty Ltd had to pump the water out of the dam twice in order to complete the concrete facing of the wall! The structure was designed by Guttridge Haskin and Davey, with construction by MacMahon Construction Pty Ltd, supervision was by the Department of Transport and Works. The concrete faced, rock fill wall is 11 metres high 143 metres long and contains 17,000 cubic metres of rock fill, surface area of the dam when full is 17.6 ha and the catchment area 5 sq. kilometres. A 50 metre long spillway exists adjacent to the wall. The dam has revolutionised recreation opportunities for local residents and visitors.
6a Stuart Highway
The completion of the Overland Telegraph created a track that was used by the people maintaining the line and by anyone wishing to cross Australia from north to south. This was the case for the track through Tennant Creek for the first sixty years; the discovery of economic gold deposits near Tennant Creek in 1932 lead to increased traffic along the OT from Alice Springs. The Commonwealth government through the Department of the Interior realigned and upgraded sections of the track; by 1940 a fire plough had been used over 217 miles and gravel pavements constructed for 97 miles of the section between Alice and Tennant. DD Smith was the Resident Engineer based in Alice Springs with the responsibility, amongst other duties, for survey and construction of roads. Surveys and designs of sections of the road north of Tennant Creek were also being prepared. The deteriorating world situation lead military authorities to request in mid1940 that upgrading of the road from Tennant Creek to the railhead at Birdum be carried out as a priority. The Commonwealth government requested assistance from the SA, NSW and Queensland roads departments for each of them to upgrade one third of the 300 mile section by December 1940. Men and machines were mobilised and work completed in the required time. This initial work was the commencement of five years of intense road construction and maintenance activity much of it centred in the Tennant Creek area. The State road authorities maintained their sections of road north of Tennant Creek for the next twelve months; the Department of Interior continued to maintain the road south to Alice Springs.
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Tyre wear and failure due to heat was a major problem with convoys using the North South Road. A trial was carried out involving running trucks through a water filled concrete bath to cool the tyres, it was not successful as the tyres dried out in a short time and returned to high operating temperatures. The concrete bath still exists adjacent to the tanks and wind mill - see second image 6a
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A vertical shaft wind mill and water storage tank was installed near the tyre bath to supply water, the tanks still exist, and the wind mill was recently removed.
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6b Barkly Highway
The Barkly Highway was constructed in 1942 by the Queensland Main Roads Department. Qld Main Roads had previously constructed a section of the North South Road as part of the priority 1940 operation. The Qld MRD Commissioner had offered to the Commonwealth authorities to form a road from the North South Road back to Mt Isa as his equipment returned to Mt Isa; the offer was declined so Qld MRD returned to Mt Isa via the Barkly Stock Route. Within a year the defence situation had degenerated and with US authorities wishing to transport material from the east coast to Darwin a road was required. Qld Main Roads constructed the road including bridges over the Georgina and Rankin Rivers. The road was sealed with bitumen emulsion and stone from natural gravel. The Barkly Highway was upgraded to National Highway standard commencing in 1979.
7 Mining
Gold and copper was first recorded in the Tennant Creek region in 1925. It was not until 1932 that a boy herding cattle found a gold nugget which he took to one of the workers at the Telegraph Station. This discovery set off Australia’s last “gold rush”, the Overland Telegraph station became the base for exploration activities in the area. In excess of 120 mines with ore bodies of varying sizes and grades were developed in the Tennant Creek area; “exotic” names such as Burnt Shirt, Golden Kangaroo, Black Angel, White Devil, Whippett, The Mammoth and The Nipples were given to the mines. Greater details of Tennant Creeks mining history can be found at the Battery Hill Mining Museum. The mines which had the longest economic effect on Tennant Creek were those developed by Peko Mines NL Peko / Wallsend and Australian Development. Peko went on to explore and develop the Orlando, Juno, Ivanhoe, Warrego and Geko mines. These mines produced copper, gold, bismuth and silver. The vagaries of the world economic climate on mining companies were demonstrated by the Warrego Smelter; Peko had shipped concentrates by truck to Townsville, a decision was made to refine the minerals at Tennant Creek. Peko constructed a smelter in 1973 to refine copper and bismuth, the structure was located beside the Warrego Road between Warrego and Geko mines. The smelter had technical difficulties and could not achieve the required copper concentrations so it was closed down and modified. It was recommissioned however it was fuelled by imported oil so it became uneconomic during the “first” (1979) Arab oil embargo and was mothballed, then demolished. Driving down the Warrego Road it is now difficult to see where the smelter was. The Nobles Nob mine commenced as a small underground mine. It had high grade ore, a story of its early operation was that a reef of high grade ore was discovered and closed off with a security gate; when the accountants needed a cash flow boost the gate was opened, some high grade removed and processed and the cash flowed. The mine was purchased by Australian Development in 1935. The mine infrastructure was upgrades after World War II; a collapse of the underground diggings in 1968 resulted in the mine being converted to an open cut mine.
8 Electricity Supply
Government reticulated electricity supply was first provided to Tennant Creek in March 1945 from 2 x 25kVA Southern Cross generating sets that had been installed by the CRB during World War II. Additional equipment was moved from Alice Springs to Tennant Creek to augment the original equipment. Later on power generation by the Government ceased and an agreement was signed with Peko Mines N.L to supply Tennant Creek electricity needs from the Peko Mine Power Station. In 1967 the need to continue purchasing electricity from Peko Mines NL was questioned in the Commonwealth Department of Works Northern Territory Electricity Supply Undertaking Annual Report. The Commonwealth Government funded construction of a diesel fuelled power station. The station was located in Standley Street and initially had four
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