Operation Brumby, the next phase of the withdrawal from Maralinga, was the main scheduled clean-up. Unlike Hercules, which had been undertaken using existing data, Brumby needed a more thorough understanding of the radiological properties of both Emu and Maralinga. The AWTSC asked the Australian Government for some direction on how to deal with the derelict range, but it never received a response. At its 133rd meeting on 14 May 1966, the AWTSC accepted the AWRE’s RADSUR proposal. The AWTSC still had no idea what the Australian Government wanted, but the plan proceeded anyway. On 21 December 1966 Moroney wrote rather forlornly to the Department of Supply saying, ‘In the absence of such a decision, the AWTSC will base its decision on complete evacuation of the range’. No-one in authority seemed to be interested in tying up the loose ends. Maralinga was a problem that just about everyone was trying to wish away.
RADSUR was carried out between October and December 1966 by about a dozen AWRE scientific personnel, assisted by six sappers from the Royal Engineers. The survey involved gamma and beta surveys at each of the major trial sites and the plutonium-contaminated areas around Taranaki, TM100 and TM101. With the exception of Marcoo, where the low-yield ground shot formed a crater, RADSUR noted that the major trial sites at both Emu and Maralinga had glass-like glazing produced because the intense heat from the blast had fused the soil. This strange shiny glazing covered a circular area with a radius of about 180 metres at each major site. The glass was alive with beta radiation, largely from the strontium-90 trapped in it. However, there was not much in the way of gamma radiation, and what little there was fell away sharply as one moved away from ground zero. Most of the radioactivity associated with the big bomb sites was in the upper layer of soil, between 30 and 40 centimetres deep, close to ground zero and approached the surface as the distance from ground zero increased.
RADSUR established a colour-code system that helped to map contamination. The Pearce Report used this system to explain the state of each part of the site. Yellow areas had the highest contamination – above 400 kilobecquerels (10 microcuries) per square metre – while red areas had between 40 and 400 kilobecquerels per square metre. Everything else was white. During RADSUR, the Taranaki site was sampled, as it was known to contain the most contamination. The Pearce Report later outlined this part of the operation:
The samples were in the form of a core approximately 16 cm deep by 7 cm diameter obtained by driving a tube into the ground. The sample was divided into layers 4 cm deep and the plutonium content determined by the scintillation counting method which was used for the measurement of surface soil samples. At some sampling points the rock substratum was near to the surface of this ground and prevented the sampling tool from being driven in to its full depth. This resulted in fewer soil samples in the lower layers.
Some of the samples were taken to Aldermaston for analysis, while others were analysed on site. Ernest Titterton had travelled to Aldermaston in June 1966 to confer with Pearce, and between them they had apparently agreed to keep the sampling to a minimum. That Pearce and the AWRE wanted this done as quickly and efficiently as possible is clear from the correspondence between Pearce and the AWTSC in the lead-up to RADSUR. Moroney had been offering his suggestions about what needed to be done. In a letter to Moroney in August 1966, Pearce said that he agreed with Titterton, who, he felt, wanted to keep sampling to the minimum necessary. Pearce also told Moroney he wanted to minimise the personnel involved and suggested that CSIRO not take part, although it had offered to help.
Pearce’s letter to Moroney prompted the latter to write an annoyed letter to Titterton, reacting to the suggestion that he was being over-zealous. Moroney said:
From Noah’s letter and from your one comment to me when you came back, I get the impression that both of you are somewhat fearful that I am wanting to grow the sampling into a major and disproportionate effort. Noah recalls his conversation with you at Aldermaston and writes of ‘not letting the soil sampling get out of hand and tailoring it to the minimum necessary to establish the conditions obtaining at the various sites’. This is a pretty strong comment, and I certainly didn’t regard the suggestions I have made as being extravagant and warranting such a reaction.
Titterton replied more or less endorsing a quick sampling regime, while blaming Pearce for any misunderstanding:
Noah’s interpretation of his discussion with me in June in England has been translated in a very free fashion. I certainly am not enthusiastic to have groups of CSIRO, AAEC [Australian Atomic Energy Commission] or anyone else charging around the site. Nor am I enthusiastic for you, plus supporting staff, to spend a lot of time on the job… As we discussed in the past, our policy should be to get sufficient information for our purposes but not to make a big project of it.
Moroney was not as dismissive of these issues as his boss. In a letter to Bill Gibbs, director of the Bureau of Meteorology, he said:
There may be several points of principle wrapped up in all of this. The first is that we must be sure that we are getting all of the information we believe to be necessary for taking the decisions and to provide the essential data for the archives in the future. The second point is really a question of whether we should become directly involved ourselves in the clean-up operations; I can see that if one of us is actually there doing some work whilst the AWRE team is also on site, we will obtain direct confirmation of what we already believe, namely, that they will carry out the operation very thoroughly indeed. However, it may be worthwhile doing this simply because of the finality of the whole procedure.
Was there a hint of irony in this comment? There may have been, although it was a couple of decades before Moroney accepted that the operation was not carried out ‘very thoroughly indeed’.
Apart from sampling, other forms of measurement were undertaken. For example, RADSUR deployed an x-ray device. The monitor had a strap that the user slung over his shoulder and a jig to standardise the distance it was held above the ground. The user would stand still every 90 metres and wait for the needle on the meter of the instrument to arrive at a steady value. Once it stopped, this number would be recorded as counts per second. The grid was coarse since it would take too long, even with this over-shoulder device, to sample more frequently. Later events proved this was unfortunate since it missed much contamination.
For all its up-to-date measuring equipment, RADSUR did not capture the right information because its field data gathering was not properly thought through. Moroney came to the view that Operation Brumby was based on RADSUR data that were ‘so poor as to be useless’. Nevertheless, RADSUR formed the basis of Operation Brumby, which was intended to put the atomic test sites to rights.
Emu Field also underwent a cursory clean-up as part of Operation Brumby. The Totem bombs at Emu had produced local fallout, and, in addition, the Kittens initiator tests had left behind beryllium and polonium. The grey metal beryllium is chemically toxic, though not radioactive. It should have been removed from Kittens test sites at both Emu and Maralinga. It was not. By the time of the clean-up, the polonium, which is radioactive, had decayed. When the ARL team visited in 1984, radiation levels from both Totem and Kittens had dropped, but Emu was still unsuited for continuous occupancy and will be until about 2025.
The Pearce Report documented, quite briefly, the actions taken to survey and remediate the many sites of bomb tests. The 51-page report had numerous diagrams showing schematically what was done at each site. At Emu, the Totem 1 and 2 sites were hand-scavenged to remove metal debris and the larger pieces of glazing. An area of approximately 130 metres radius was graded and disc-ploughed at each site. All of the fences and signs put up during Hercules 5 were removed in an effort to return the site to its pre-test appearance – to spirit away the British presence.