31 The absence of any evidence from Mr Dreske does not assist the prosecution. Counsel for the prosecutor submitted that I should accept Mr Carfi's evidence on this issue. To the extent that Mr Carfi was adamant as to his recollection, it is accepted. However, balanced against that is the totally contrary evidence of Mr Bradley. His evidence on this issue was equally firm and he was not tested in relation to it. I have nothing to suggest that his evidence should not also be accepted at face value.
32 In the absence of any corroborating evidence from Mr Dreske, I cannot accept Mr Carfi's evidence as evidence establishing beyond reasonable doubt the facts that he asserts. If anything, there was other evidence given before me that, when taken together, would point against accepting the veracity or accuracy of Mr Carfi's recollection on important matters. Before detailing those, it is necessary to set out the events of 18 and 19 January 2003 relevant to this offence.
33 On Saturday, 18 January 2003 employees of Newtown commenced excavation work. As instructed by Mr Carfi, they did the work manually using digging tools such as 'picks, shuffles (sic) and crow bars'. They were digging a trench along the boundary line and cutting away any of the solidified grouting that may have extruded into the trench line.
34 The work was being overseen by Mr Nivone Thipdavong. He was the site foreman for Newtown at the Belmont Street site. Mr Thipdavong had prior experience as site foreman on construction sites for his parent's construction company. At the time he worked for Newtown, he was part way through a degree in civil engineering which he has now completed.
35 In addition to himself, Mr Thipdavong recorded in his site diary that other employees on site that day were:
Tino, Foong, Peter, Phil, Marko, Nick, Kenny and Adam.
36 Reference to 'Tino' is Mr Carfi and 'Foong' is Mr Foong Takounlao, the company manager for Newtown at the time. He is still with Newtown in the position of Project Manager.
37 Excluding Mr Carfi and Mr Takounlao, both of whom visited the site briefly on 18 January 2004, there were five labourers actually doing the trench digging. Beyond the names listed by Mr Thipdavong in his site diary, there is no other evidence to confirm whether they correlate with those persons cited in the particulars of the offence charged as being specifically exposed to risk. They are named as Ken Hong, Phillip Walzinski, Nivone Thipadavong, Adam Hong, Tino Carfi, Kite Richards and Pauline Piper.
38 Mr Richards and Ms Piper were the tenants living at 160 Belmont Street. Mr Carfi and Mr Thipdavong have been clearly identified as Construction Manager and site foreman respectively for Newtown. Although it is more likely than not that reference in Mr Thipdavong's site diary for 18 January 2003 to 'Phil' is Mr Phillip Walzinski, 'Kenny' is Mr Ken Hong and 'Adam' is Mr Adam Hong, that issue was never clarified in evidence before me. Further, I have no idea who 'Peter', 'Marko' and 'Nick' are as far as being employees of Newtown on site on 18 January 2005 who may have been exposed to risks to their safety.
39 Ultimately, the only persons I can be satisfied beyond reasonable doubt as being specifically exposed to risks to their health and safety on the dates of the alleged offence are Mr Thipdavong, Mr Carfi and Mr Kite Richards. Although I assume Ms Piper was present in the house at 160 Belmont Street when structural problems emerged with the wall of the house, I have no evidence as to her presence or otherwise.
40 Mr Thipdavong gave evidence that he participated in a tool box meeting on the afternoon of Friday 17 January which Mr Carfi attended. According to Mr Thipdavong, it was at that meeting that Mr Carfi told him to proceed with the excavation of the trench at the boundary line of 160 and 162 Belmont Street the next day. Mr Carfi confirmed that discussion although his evidence differed as to where the tool box meeting was held. Mr Thipdavong said it was at the Spectrum development site at McAvoy Street whereas Mr Carfi said it was at the Belmont Street site.
41 As site foreman, Mr Thipdavong had not been involved in discussions with Mr Bradley or Mr Paterson about the silicone grouting process. He was not familiar with the process. When Mr Carfi told him about it at the tool box meeting on Friday 17, Mr Thipdavong said he:
... asked Tino for advice on the actual specification of the product and what's it used (sic) and how was the cost in comparison with concrete underpinning or grout injections.
42 According to Mr Thipdavong, Mr Carfi assured him that he had previously used the product, that it worked well with sand and was cost effective.
43 The only additional instruction Mr Carfi gave was that the digging of the trench and the cutting away of any extruded silicone grouted material should be done by hand using digging tools such as picks and crow bars.
44 According to Mr Thipdavong, the excavation work and trimming of the extruded silicone grouted material proceeded relatively uneventfully in the area adjacent to the footings of the house that had been underpinned by the silicone grouted material. In other words, the side wall of the house at 160 Belmont Street gave no indication of any untoward movement.
45 At some point, however, the workers did encounter what Mr Thipdavong described in his site diary as follows:
Found the silicone to be quite soft half way between Grid (9-8).
46 Reference to Grid (9-8) refers to grid lines on structural plans of the proposed development. The proposed development consisted of a row of terrace houses fronting Belmont Street and extending back to Belmont Lane. Commencing with the front of the proposed terraces in Belmont Street, the structural plans depict each house to be built as falling within denoted grid lines running horizontally across the plans. Starting with Belmont Street, each house had a front courtyard area depicted between grid lines 10 to 9. The residential or main section of each proposed house fell between grid lines 9 to 8, the back courtyard between grid lines 8 to 7 and the garage between grid lines 7 to 6. As I understand it, the house at 160 Belmont Street corresponded more or less with the same structural outline as the proposed terrace development adjoining it. Accordingly, while the need to provide underpinning to 160 Belmont Street using the silicone grouting process was done along the full length of the boundary, the underpinning between grid lines 9 to 8, being the residential area of the house at 160 Belmont Street, was obviously particularly important.
47 Despite Mr Thipdavong's entry in his site diary as to the silicone being 'quite soft' between grid lines 9-8, he did not report it to Mr Carfi or anybody else for that matter.
48 According to Mr Bradley, he and Mr Dreske did not complete the grouting under the residential section of the house until Friday 17 January at a time said to be between 11:30am and 2:00pm.
49 As is evident, based on the recommendation of Mr Paterson in his discussions with Mr Bradley, once the grouting process was completed by approximately midday on Friday 17, the sodium silicate grout should have been left for a minimum period of forty eight hours in order to properly permeate and set. Mr Bradley certainly knew that and it was his evidence that Mr Carfi was also aware of that. Further, Mr Bradley stated it was his belief, based on his discussion with Mr Carfi on Friday 17 January, that no attempt would be made to excavate the boundary trench and trim the extruded silicone grouting until Monday 20 January. As events transpired, Mr Thipdavong and his workers did the job on Saturday 18 January, less than twenty four hours after grouting had been completed.
50 Given the relatively shortened period that elapsed before excavation commenced, it was not surprising that Mr Thipdavong observed the silicone 'to be quite soft' between grid lines 9 to 8. Between grid lines 10 to 9, Mr Thipdavong said the 'solidness of the silicone was hard'.
51 In addition to noticing the silicone was soft between grid lines 9 to 8, Mr Thipdavong noticed some areas of black silt in that area that had not bonded well with the silicone.
52 In short, as would now seem evident, two problems were encountered on Saturday 18 January. The first was that the silicone grouting had not had time to properly harden. The second was that due to the presence of silica with the sand in some areas, the silicone grouting had not properly permeated and bonded before setting. The extent of that is not clear.
53 It is not disputed that problems with the structural stability of the side wall of 160 Belmont Street, adjacent as it was to the boundary line and the excavated trench, surfaced early on Sunday, 18 January 2003. As Mr Carfi described:
Q. ... When did you first know there was a problem?
A. About 6 o'clock Sunday morning.
Q. How did you know?
A. The tenant, Kite, rang me and said he couldn't open his front door and that the house was creaking.