Cashbook and Claypan
Share in the tribulations of the admin manager as he balances the books from his Office-in-a-Blitz

Birdsville or Bust
Learn how French know-how and Australian muscle carved the French Line through the Simpson

East From Oodna
Marvel at the initiative of the early pathfinders who solved the mysteries of the Red Centre

Alive in the Dead Heart
Recollections from the crew who first burst the road through Australia's One True Desert

B-line for Birdsville
Join the CGG veterans on their return journeys to the French Line. Take their tip and travel with experts

Shooting Up the Simpson

International R190's using DC3 tyres for the ultimate in sand traction, were used as platforms to carry the Mayhew 1000 portable drilling rigs from shotpoint to shotpoint.  For the reflection shots required, patterns of 20' deep holes were drilled into which the shooters loaded their charges of geophex (TNT).

The recording traces carried impulses back from geophones (jugs) laid by the juggies.   The jugs were each joined up to the charges and in turn linked through the trace lines to the laboratory (labo) or recording truck, which acted as the control centre.   The labo communicated with the shooting trucks and its attendant LandRovers per medium of lowband VHF two-way radio sets installed in each of the vehicles to help coordinate the shoot.

There were plenty of things to go wrong when men mixed with explosives and mining gear.  Handling geophex and high-octane fuels on a day-to-day basis could lead to complacency and there was no place more remote than the Simpson Desert.   To emphasise their particular vulnerability, men in the field were generally up to twenty miles distant from the base camp.  The labo radio net barely covered its own work-fleet and so it could not be hoped to quickly summon help from the camp in the event of a serious mishap.

The First-Aid post in the camp office, although in daily contact with one or two distant RFDS bases by more powerful SSB radio, could only be expected to prepare injured persons for evacuation.   Not all aircraft pilots could manage landing and take-off on desert claypans so the first course of action usually meant evacuating victims to the main centres like Alice Springs and Birdsville on the back of a LandRover, a two-day prospect from the centre of the Simpson.

A reflection shot goes off early, nearly taking the French Petroleum Lannie with it.    In patterns of up to 36, placed either side of the shotline, the normal reflection (down-hole) shots used five pound sticks of Geophex with an electrical detonator at each hole.

The French were chosen for the Simpson Desert job by PM Menzies on the strength of their performance in the Sahara Desert.  They were acknowledged as the pioneers of refraction (surface) shooting, at a time when all the world relied on reflection results.  Experience in the Simpson allowed the French to further refine their techniques as CGG began combining refraction with reflection.  In tough conditions, they learned to cut their costs to one sixth of that of the Sahara work.

Thommo couldn't get away quick enough before this refraction shot went off.  He dives for safety behind the wheel of the labo truck and escapes unhurt.  Typically, the shooters made a pack of five tons of geophex but sometimes to save the good stuff for reflection shots, the shooters made do with hundred-weight bags of ammonium nitrate mixed with a gallon of distillate and laid 48 bags each side of the traverse.  This lethal mix was then primed with a stick of gelignite and a detonator.  When the party reached the Channel Country the Bedourie hotel publican, Joe Condon, reckoned he could hear French refraction shots from thirty miles away.

Claude Gauthier was the 'Chef de Labo'.   He recorded all the shots in his mobile laboratory on a portable seismograph and the results were interpreted on a computer in the office caravan at night.  These findings were then produced in printed form on a 36" plotter and the overall findings summarised into technical jargon and incorporated into a telegram for dispatch via RFDS radio the next morning.  Pretty slick for 1963, eh?

Seismic surveys are carried out by means of shallow underground explosions.  In effect, CGG was photographing the first cross-section of the desert from the surface to the very deep basement rock of the Great Artesian Basin, which was once a sea.  All valves and whistles, the task nevertheless was not beyond the capability of the technically-challenged labo unit.

On the reunion crossing along the French Line in 1998, the group of CGG veterans able to make the trip (out of forty-five originals), numbered just six.  As could be expected, the men busied themselves at every chance in looking for artifacts that might have survived 35 years by the track.  Extraordinarily, among the most minute of items actually recovered by the CGG survivors was a spent radio-type valve found on the French Line itself, which could be sourced nowhere else but to the labo truck and probably jettisoned by Claude himself.

One would expect explosions of this magnitude would have a deleterious effect upon the Simpson Desert and its inhabitant wildlife yet there remains no evidence that this was the case.  In an era without rules or even guidelines on ecology, the CGG workers were particular in burying camp-site refuse and mechanics' waste and diligently recovered all of their drums, tyres and other expendables.  

But that is where our care stopped.  CGG did not safely dispose of the cardboard and wooden explosive and detonator boxes we used.  These were left strewn haphazardly throughout the desert and as good luck would have it, not a trace remains of these neglectful acts due to the attention of the above-ground vertebrates that have obviously long ago ran out of this most-welcome CGG fodder to feast upon.  Nor is there any sign of damage around the camp-sites because we could not locate a single site, nor are there any cavernous excavations that remain obvious.  

Shooter John Blaney-Murphy and office manager Kevin Murphy locate and recover one of the CGG steel permanent markers from its hiding place under the gidgee bushes during their return trip in 1998.  The Simpson Desert reluctantly gives up one of its least harmful records of a past misdemeanour.

Perhaps all that will be found one day of Leichhardt's party will be their bones, plus steel artifacts of belt buckles and stirrups and rifle barrels.  It seems certain that even if buried by shifting sands, items of clothing, wood or paper will not survive the ravages of the below-ground invertebrates.