A failed proposal from the 1970's

In March 1976, the Commonwealth Bureau of Roads presented its report on the proposal to construct a new highway between Broken Hill and Mt Isa, passing through Tibooburra, Cordillo Downs and Boulia. This proposal was known as the "Silver City Highway Extension" or the "North-South Highway connecting Darwin to Melbourne via Mt Isa". The second title outlines the highway's ultimate purpose, and encompasses the existing Calder, Silver City, Barkly and Stuart Highways.

This proposal was a refinement of the intial Fedral Inland Development Organisation (FIDO) proposal for a "Pioneer's Highway" linking Darwin and Melbourne through Hay, Cobar, Bourke, Windorah, Bedourie and Boulia. The ultimate plan was to construct the highway to National Highway standards and include the highway (and the Calder and Silver City Highways) in the National Highway system but the CBR also assessed the merits of construction of this highway to beef road standards or as an improved unsealed route.

Right: Map from the CBR report, showing the proposed route of the highway. March 1976.
(Click to enlarge)

The following extracts are from "Commonwealth Bureau of Roads - Report on a north-south highway connecting Darwin to Melbourne via Mt Isa and Broken Hill - March 1976."

Study recommendations -
(a) At this time the suggested development of a north-south highway as an addition to the National Highway system does not warrant further consideration.
(b) A sealed road of lower standard than that required for a National Highway should not proceed at this time.
(c) The construction of an unsealed road, with minimal waterway crossing improvements, for the full distance between Tibooburra and Boulia with the object of providing a through road is not warranted on information available at the present time and should not proceed.

Factors influencing this decision -
(a) The suggested route was longer than the existing routes from Darwin to Melbourne and Sydney by some 140km and 370km respectively. Expected improvements to the Stuart Hwy would further shorten the distance to Melbourne by some 200km.
(b) The distance from Darwin to Broken Hill and Mildura by the suggested route was longer than by an improved Stuart Highway.
(c) By the time that a north-south highway could be constructed, both the Darwin-Adelaide and Darwin-Brisbane links should have been upgraded to all-weather capability.
(d) The suggested route would require new construction of 1306km between Boulia and a point 16km north of Broken Hill.
(e) This section of the suggested route would pass through areas posing road construction problems. It would cross three major watercourses (Diamantina River/Hamilton River/Coopers Creek) and many small flood-prone areas. These rivers flood once every five years and can cause disruption for periods of up to three months. South of Boulia the route crosses areas of cracking clay soils and near Cordillo Downs it crosses sand dunes which could cause road maintenance problems.
(f) The estimated cost of constructing the full length of the route from Mt Isa to Broken Hill is $160 million (1976 prices). This includes $6 million for the existing sealed sections of the route.
(g) The benefits derived from the provision of a north-south highway would be too small to warrant its cost. Little long-distance traffic would be diverted from other routes. Some benefit would be gained by local people in the tourist industry. The cattle industry would not require a road of this standard.
(h) Although the highway could improve the defence strategy for Australia, the development of other routes to northern Australia would appear to have higher priority and in any case the road could not be supported on defence benefits alone.
(i) The north-south highway would pass through an environmentally sensitive area with a delicately balanced ecosystem. The consequences of highway construction on the area are not fully known, could be severe in some aspects and would need careful investigation before permitting such a project to proceed.

History of Proposal:
1967 - FIDO raises proposal for ‘Pioneers Highway’ to link Darwin to Melbourne through Hay, Cobar, Bourke, Windorah, Bedourie and Boulia
July 1972 - AGM of ‘Federal Inland Development Organisation’ discussed and referred for investigation a submission on the extension of the Silver City Hwy to Mt Isa.
August 1975 - Mayor of Darwin suggested to Parliamentary Standing Committee on Public Works that the proposed highway was a better alternative for access to Darwin than either the Landsborough or Stuart Highways and presented a submission
December 1975 - North-South Highway Committee wrote to various ministers putting forward the advantages of the scheme and requesting interviews to discuss it further
September 1975 - Army given directive by Minister for Defence to carry out ground reconnaissance to select appropriate route
February 1976 - Scheme referred to CBR for investigation