OPEN LETTER TO:
Malcolm Hyde, Commissioner of Police-
My name is Edward Cranswick (formerly US Geological Survey), now a resident of Adelaide, and I am presently at Olympic Dam/Roxby Downs to investigate the magnitude 4 earthquake that occurred here on 25MAR2012 UTC (see attached PDF <M4EarthquakeInvalidatesBHPB_OlympicDamExpansionEIS_AEES2012abs&Map20120702.pdf>)
and participate in the anti-nuclear protest.
In walking back & forth today/tonight between Roxby and the protest camp, I was stopped several times on the Olympic Way by police who asked me for ID and my purpose for being there. When I explained my scientific interest in the recent earthquake, none of them knew what I was talking about — they have not been briefed about the most serious physical threat to the engineered structures and related infrastructure at the mine and vicinity.
The magnitude 4 earthquake occurred local time on Monday morning 26MAR2012 — Olympic Dam and Roxby lost electrical power for about 30 minutes, there were reports of an “explosion” (Gary Bentel, former Geotechnical Manager at BHP Billiton, 2012, personal communication), and the mine was shut down for some period.
How would your forces react if a similar earthquake occurred during the protest? How would you respond to the loss of electricity and reports of an explosion? Who would you immediately blame for these life & property threatening events and how would the uninformed non-Roxby police officers respond?
Ironically, the only people who would not be directly impacted by such an earthquake would be the protestors who are not, unlike everyone else in Roxby, dependent upon the engineered infrastructure.
If the mining continues, we can expect even larger earthquakes that could damage the water pipelines from the Olympic Dam borefields — imagine this place without the 42 megalitres a day that it sucks from the GAB.
Were you also ignorant of these facts — because of the BHP Billiton and SA Government secrecy about so much of the mining operations here — or did you deliberately not inform the hundreds of police officers that you have sent to Roxby to control the peaceful protest?
Either way, the ignorance of the police force deployed here regarding the most serious threat to life & property is a serious dereliction of your duty and makes a mockery of your motto: SOUTH AUSTRALIA POLICE — KEEPING SA SAFE.
Australian Earthquake Engineering Society 2012 Conference, 7-9 Dec, Gold Coast
Magnitude 4 Earthquake Invalidates BHP Billiton Olympic Dam Expansion EIS
Public Seismic Network Adelaide
Hawthorn, South Australia 5062
SPECIFICATION – The design earthquakes and corresponding design ground motions specified in the BHP Billiton Olympic Dam Expansion Supplementary Environmental Impact Statement 2011 (EIS) are: “the peak ground acceleration values for the return periods of 475 years, 1,000 years and 10,000 years are 0.022 g, 0.032 g and 0.10 g respectively.” Hence, the maximum design earthquake (MDE) has a peak ground acceleration (PGA) of 0.10 g. With respect to the planned excavation of Earth’s largest open pit, 4.1 x 3.5 x 1 km deep, the EIS states that “mining-induced seismicity … is … unlikely to exceed magnitude 4 even using worst-case modeling assumptions … The potential consequences of a magnitude 4 earthquake would be limited to a temporary (five to 10 second) increase in vibration, similar in magnitude to that presented by a passing truck, with little if any damage, even to local facilities and structures.”
OBSERVATION – A magnitude 4 (M4), “MINE INDUCED” earthquake occurred at the Olympic Dam Mine on 25MAR2012 (Government of South Australia: Origin Time = 20:53:20 UTC; Coordinates = -30.44,+136.85; Depth = 0.0 km). Reports of an “explosion” followed by ground shaking suggest the high-frequency content, and hence, high accelerations, of the ground motions. The electricity in Roxby Downs and Olympic Dam went off for about 30 minutes, and the mine shut down for some period – indicating the disruptive effect of the event.
IMPLICATION – The ground motions at the mine generated by this earthquake probably exceed those of the MDE specified in the EIS. The attenuation relation of Sadigh, Chang, Egan, Makdisi and Youngs (1997) predicts PGA values > 0.1 g at epicentral distances < 5 km from an M4 earthquake. Because an MDE event has already occurred – prior to digging the open pit – the concluding EIS statement about the seismic hazard of digging the pit, “the risk [sic] rating for a greater than magnitude 5.7 event resulting in surface faulting and infrastructure damage is ‘low’ (representing a ‘rare’ likelihood and a ‘moderate’ consequence)”, is not creditable. Cranswick (2009) predicts that the open pit expansion could cause earthquakes as large as M6 and, if mining triggers slip on the Mashers Fault, as large as M7. These considerations potentially invalidate the fundamental design basis of engineered structures at Olympic Dam, including the tailings dams (i.e., TSF), ore processing plant, and large-scale water and gas pipelines
. The mine has an advanced seismic data acquisition system – these records need to be released to demonstrate that the mining complies with the EIS.
Keywords: BHP Billiton, Olympic Dam, mine, earthquake, open pit, EIS, tailings dam, TSF, design exceedance, MDE, PGA
Map of seismicity within ~40 km of the Olympic Dam Mine (SARIG, Government of South Australia; accessed-23JUN2012). The epicentre of the magnitude 4 (M4 – magnitudes reported for this event range from 3.9 to 4.1) mine-induced earthquake on 25MAR2012 is shown as the RedOrange-filled circle centred on the mine. The other coloured solid circles mark smaller seismic events: Blue = M<2, possibly explosions; Green = 2<M<3, possibly mine-induced earthquakes. Geoscience Australia posted a preliminary location of the M4 event, now “finalised”, that is approximately 10 km north of the assumed more accurate location determined by SARIG using proprietary data. Much of the scatter of the smaller events away from the mine is undoubtedly caused by similar mislocation.