I can remember the "Readymix" sign from 1969 and 1970, whilst flying back and forth over the Long Paddock in B707's.
The story behind the Readymix sign and the Readymix diamond logo, actually make a sizeable story. The full story is in the link below.
The diamond in the desert: the story of the giant Readymix logo on the Nullarbor. - Free Online Library
The Readymix company was contracted to carry out quarrying works for hard rock aggregate for ballasting for the Transcontinental Railway - and for the construction, re-alignment and sealing of the Eyre Hwy, from Norseman to the W.A./S.A. border - starting in July 1964.
Shortly after commencing work, the Readymix bosses decided to install a large, highly visible Readymix company logo (a diamond shape with "Readymix" wording in the centre) in the soil just North of the 225 mile marker, almost halfway between Norseman and the W.A. border.
As Readymix regularly used light aircraft for urgent parts supply, and for transport of senior executives who regularly visited work sites, the diamond section of the Readymix logo was claimed by Readymix to be intended primarily as a dual-direction unsealed airstrip for light aircraft.
However, it appears the graded logo area was never registered as an airstrip, nor does it appear it was ever used as such.
It's been suggested the primary aim of the name and logo was just for Readymix advertising purposes.
Readymix did construct several other airstrips along the Eyre Hwy, that were utilised as airstrips.
This logo and the Readymix wording was constructed over a weekend by Allan Hoare, a MRDWA grader driver. Allan peeled back the low vegetation and thin topsoil with the grader moldboard, to expose the bright white underlying limestone rock - thus creating a highly visible aerial landmark.
This work was done, typical of that era, without reference to, or approval of, any Govt authority.
By the late 1960's the logo and wording was becoming degraded as vegetation grew back. The Readymix name and logo was regraded at some time in the late 1960's or early 1970's.
Attempts to regrade the name and logo in the early 1980's, met with fierce opposition by the local Station (Ranch) lessee owner, Hugh MacLachlan - whose station manager, had initially allowed the regrading.
MacLachlan started to become angry about the damage to the Stations already-sparse, semi-desert vegetation by the logo and name - and perhaps some dry seasons brought the problem into sharp focus. 1980 was the driest year on record, since the huge drought of 1899-1902.
Then the Dept of Land and Surveys became involved and requested information from Readymix bosses as to who provided the authority to construct the name and logo.
It appears likely the "airstrip" story was concocted to try and smooth over a Dept that was angry about unauthorised work on land under its control (think BLM in the U.S.
)
The increase in "environmental responsibility" demands, and the fact that the Marree Man, the Mundi Man, and the Readymix logo were all constructed on land that is easily and rapidly degraded by vegetation removal (it's illegal to use or drive any tracked equipment in undisturbed natural vegetation areas, without Departmental authority in S.A. - and it has been, since the mid-1970's), means that none of these large visible features will ever be reworked again.
Anyone who tried to do so (illegally) today would most certainly go to jail when caught, and the full weight of a police investigation would fall upon them.
The constructions were all illegally carried out - but the enforcement of the laws of the day were much more lax than it is today, and the constructions were not regarded as being destructive, back then - as they are today.