Tonkin & Taylor Report.
Page v

This report was prepared for Winstones

Quote:
"Additional settlements have been detected beyond the volcanic centre in response to a wider groundwater influence than initially predicted. Settlements of up to 15 mm have occurred in area underlain by East Coast Bays Formation rocks (ECBF) and up to 19 mm in areas underlain by both Tauranga Group Deposits and ECBF."
Comment:
The subsidence is worse than previously predicted and it is occurring in areas outside the volcanic crater.
Tonkin & Taylor Report.

Page v "

Quote:
"Higher settlements have been predicted where Tauranga Group Deposits are known to exist within the dewatering zone and the potential for a centre of higher settlements (Zone IIB) has been identified for further investigation.
Comment:
Winstones don't want to investigate this zone at the present time. They would rather leave it for later. Perhaps they are too afraid of what they might find.
Tonkin & Taylor Report.
Page 4
Quote:
"Following the commencement of groundwater pumping from below the quarry in March 1999, the observed groundwater response soon began to show divergence from that predicted in the groundwater model beyond the edge of the volcanic complex."
Comment:
Things went wrong from the beginning.
Tonkin & Taylor Report.
Page 12
Quote:
"Detectable surface settlements were expected to be confined to within approximately 350m from the quarry based on predicted groundwater effects from the pre pumping groundwater model. Peak settlements of just over 15 mm were expected adjacent to the quarry with reduced settlement away from the quarry."
Comment:
The subsidence was to be confined to within the volcanic crater.
Tonkin & Taylor Report.
Page 21
Quote:
"If potential settlements are determined using laboratory testing alone, our calculations indicate that over 200mm of settlement should have occurred due to the current 20m of drawdown. This greatly exceeds the observed deformations and suggests that the rockmass at depth is considerably stiffer or there is a delay in the observed settlements."
Comment:
If there is a time delay between dewatering and subsidence, then the eventual subsidence could be massive. The area being discussed here is Zone 2.
Tonkin & Taylor Report.
Page 27
Quote:
"Where the dewatered Tauranga Group soils are about 5 m thick (this being the maximum known thickness of Tauranga Group in the area) this may result in a settlement delay of between 3 months to 12 months."
Comment:
In Zones 2A, 2B, 3A and 3B the ground may continue sinking for up to 12 months after the dewatering has stopped.
Tonkin & Taylor Report.
Page 31
Quote:
"The trend data also shows up a possible location of higher settlements on Mt Eden Rd (near Shackleton Rd). At this site potential settlements of 70 mm to 190 mm are extrapolated for groundwater and settlement trends to October 2002."
Comment:
This is the Black Hole area that Winstones are choosing not to investigate at the present time.
Pattle Delamore Report.
Page 3

This report was prepared for Winstones

Quote:
"It was also found that a zone of higher permeability Waitematas surrounded the volcanic crater, a zone in which groundwater drawdown matched drawdown levels recorded within the crater. It was suggested that this zone was due to effects of the volcanic explosion, however the aerial extent of this zone was not determined due to insufficient field data (i.e. the zone was not delineated). Nonetheless, this zone was incorporated into the volcanic computer model."
Comment:
This is the "Ring of Sorrow". This ring around the crater makes up most of Zone 2. It was meant to be impervious to water but in actual fact it leaks like a sieve and is subsiding quickly.
Pattle Delamore Report.
Page 8
Quote:
"There is a definite zone within the Waitematas where groundwater drawdown levels reflect those seen within the volcanic crater wells. This zone appears to extend roughly 700 m radially outward from the volcanic centre (Figure 2)."
Comment:
This is the "Ring of Sorrow" again. Figure 2 shows that this ring extends out to Buckley Road, the steep part of Landscape Road, Fulljames Street, McCullough Ave, Hayr Road and the end of Hillsborough Road.
Pattle Delamore Report.
Page 9
Quote:
"The presence of vertical gradients may reflect several characteristics of the system, including the layered strata of the Waitematas creating a fragmented drainage effect within the upper sections of the formation and/or vertical variability in either the vent materials or the Waitematas themselves. Resolution of this aspect would require further field information."
Comment:
This is the "Ring of Sorrow" again. The experts were definitely not expecting to find "vertical gradients". They are guessing what it means and they think maybe they "require further field information". There are about 1000 homes in the "Ring of Sorrow" with a property valuation of at least 400 million dollars.
Pattle Delamore Report.

Quotes from Pages 12, 13 and 17

Quote:
"No site-specific information is available regarding vertical hydraulic conductivity values within the Waitematas surrounding the quarry. Groundwater modelling of the Waitematas from other PDP sites suggests that vertical conductivities within the lower permeability Waitematas may be approximately one order of magnitude less than the horizontal conductivities (PDP 2000)."

"There is little to no information available regarding recharge to the lower permeability Waitematas."

"No information is available to allow the recharge rates to be correlated to the nature of the cover geology. Hence, a gross percentage figure has been used in this report as this is the best that can be achieved at this stage."

"Little site-specific information is available regarding storativity values for the Waitematas in and around the Three Kings Quarry."

"In all cases, drawdown levels are very responsive to changes in the storage coefficients, a parameter for which there is little site-specific field information currently available."

Comment:
They don't have the test measurements they need so they copy the measurements from other places. This is the sort of fiddling of results that caused all the problems in the first place. Altogether, the lack of test measurements is alarming. It appears that this whole report is based on guesswork.
Pattle Delamore Report.
Page 28
Quote:
"One aspect, not able to be addressed within the scope of this report is the suitability of the present model to provide acceptable calibration with the settlement data."
Comment:
Their computer model of the dewatering doesn't work. It doesn't match up with the known settlement data. How on earth can it predict the future when it can't even predict the past? They have obviously made a lot of wrong guesses earlier in the report, but hey, who cares? The ARC accepted Winstones earlier set of reports and they were all wrong as well.
Grant Fisher Report.
Page 7

This report was prepared for Winstones

Quote:
"However, obscured or thicker than expected areas of potentially compressible soils could occur between the data points, particularly in the vicinity of the intersections of Buckley and Mt Albert Roads, Marie/Warren Avenues, Carr Road, Bremner Avenue and the Harold Long Reserve."
Comment:
The geologist is predicting some areas, of up to a few dozen houses each, which could have more serious subsidence. These localised problem areas could be in between the existing survey points and so would not be detected until after the damage was done.
URS Report.
Page 3

This report was prepared for Winstones

Quote:
"The groundwater modelling presented focuses on the Waitemata Group rocks and has not been extended to the overlying compressible materials where most settlement is likely to develop."
Comment:
The computer model doesn't cover the problem areas. But hey, who cares?
URS Report.
Page 3
Quote:
"Alternatively, consideration could be given to use of a different model code to provide the data necessary for the settlement calculations."
Comment:
If they used a better computer model they might get better results. Is this rocket science, or what?
URS Report.
Page 5
Quote:
"The results of T&T's back analyses, presented in Table 3 of their report, however, do not appear to correlate with the input parameters . . ."
Comment:
What's this, fiddling the results. Score zero out of 10 for cheating.
Earthtech Report.
Page 1

This report was prepared for the ARC

Quote:
"Alternative settlement calculations (attached in Appendix A) show that with further dewatering, potential differential settlement may develop to levels that would start to cause building damage."
Comment:
Earthtech were commissioned by the ARC to review the T+T, Pattle Delamore and Grant Fisher reports. Earthtech's calculations are predicting building damage if dewatering continues.
Earthtech Report.
Page 2
Quote:
"We are confident that the current dewatering of approximately 20m drawdown has not, and will not, have an adverse effect on buildings or services but are not convinced that there will be no adverse effect if dewatering continues to 60m depth."
Comment:
No damage if the dewatering stops now; but damage if it continues. Winstones have quoted the first half of Earthtech's sentence in their public advertising, but have carefully avoided the second half of the sentence.

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