JUDGMENT

Ontario Court of Justice (Toronto Region)

Between:

Her Majesty the Queen in Right of Ontario (Ministry of Labour)

-and-

Advanced Construction Techniques Ltd.

Justice: B. Knazan

Date: August 3, 2016

Appearances

Mr. David McCaskill – Counsel for the Ministry of Labour

Mr. Norm Keith – Counsel for Advanced Construction Techniques Ltd.

Table of Contents

• Factual Background
• The Charges and Relevant Legislation
• Preliminary Discussion of the Three Charges
• How the Drilling Process Worked
• The drill rig that collapsed
• Change in platform design from Shaft 1 to Shaft 2
• The rig operator
• The Operation on the Day of the Accident
• The Accident
• Events Following the Accident
• Analysis: Application of Facts to the Charges

Factual Background

This prosecution arose after a 24-year-old worker, Kyle Knox, died while building the Toronto Transit Commission's extension of the Spadina subway line at York University. On October 11, 2011, a drill rig owned and operated by the defendant, Advanced Construction Techniques Ltd. (A.C.T.), fell over and crushed Mr. Knox's backhoe as well as an excavator that Danny Deluca operated for a different company. Mr. Deluca was so badly injured that he could not work for almost three years.

The Ontario Ministry of Labour ("the Ministry" or "the prosecution") charged the general contractor and the defendant, its subcontractor, with violating the Occupational Health and Safety Act (OHSA). After two weeks of trial before me, the contractor ("constructor" under OHSA) pleaded guilty before a different judge.

All three charges allege a failure by A.C.T. to provide a proper platform for the drill rig. This platform had three parts: the ground, a circular concrete guidewall for a shaft that the rig was there to build, and four steel plates placed on the ground under the rig. Knowing what work was occurring when the rig fell over is essential to assessing whether the platform was adequate.

I begin with the charges and the relevant legislation. I will then describe the purpose and design of the platform and review the evidence, including from the accident itself, regarding the adequacy of its design. Then I will analyze the evidence in the light of applicable legal principles to determine if the prosecution has proven beyond a reasonable doubt that A.C.T. violated OHSA. If I find that it did in relation to any of the counts, I will consider if A.C.T. has established on a balance of probabilities that it exercised due diligence such that it is absolved of liability.

The Charges and Relevant Legislation

The defendant was not charged with counts 1 through 4 on the information, which does allege that A.C.T., on or about the 11th day of October, 2011:

Count 5: did commit the offence of failing, as an employer, to take every precaution reasonable in the circumstances for the protection of workers, at a workplace located at 4700 Keele Street, Toronto, Ontario M3J 2S5, contrary to s. 25(2)(h) of the OHSA.

Particulars: The Defendant failed to design an adequate work platform for the drill rig RTG RG25S #176 by identifying the soil bearing capacity as required by the manufacturer's specifications for stability.

Count 6: did commit the offence of failing, as an employer, to ensure that a part of the workplace located at 4700 Keele Street, Toronto, Ontario M3J 2S5 was capable of supporting any loads that may be applied to it in accordance with good engineering practice, contrary to s. 25(1)(e)(iii) of the OHSA.

Particulars: The part of the workplace referred to is the ground based work platform, the soil base upon which the project was taking place.

Count 7: did commit the offence of failing, as an employer, to ensure that the measures and procedures prescribed were carried out at a workplace located at 4700 Keele Street, Toronto, Ontario M3J 2S5, contrary to s. 25(1)(c) of the OHSA.

Particulars: The Defendant failed to ensure that a machine, to wit, a drill rig RTG RG25S #176, was operated in accordance with the operator's manual issued by the manufacturer, contrary to s. 93(3) of Ont. Reg. 213/91.

Applicable Legislation

The applicable provisions of the Occupational Health and Safety Act (OHSA, R.S.O. 1990, c.O.1) and regulations are:

Section 25(1) – An employer shall ensure that:

(c) the measures and procedures prescribed are carried out in the workplace.

(e) a building, structure, or any part thereof, or any other part of a workplace, whether temporary or permanent, is capable of supporting any loads that may be applied to it,

(iii) in accordance with good engineering practice

Section 25(2)(h) – An employer shall take every precaution reasonable in the circumstances for the protection of a worker

Ontario Regulation 213/91:

Section 93(3) – All vehicles, machines, tools and equipment shall be used in accordance with any operating manuals issued by the manufacturers.

Preliminary Discussion of the Three Charges

The prosecution has particularized the three charges. Having done so, it must prove the particulars as well as each element of the offence beyond a reasonable doubt.

For count 5, the prosecution must prove that (1) A.C.T. failed to take every precaution reasonable in the circumstances for the protection of workers, (2) the failure consisted of failing to design an adequate work platform for the drill rig, and (3) the particular manner in which it failed to design the adequate work platform was its failure to identify "the soil bearing capacity as required by the manufacturer's specifications".

The third element particularizes within the particular how the defendant failed to design an adequate work platform. "[A]s required" must refer to "identifying", not the soil's bearing capacity; it does not make sense that the manufacturer's specifications would refer to the soil at particular workplace. The allegation is that the employer designed a platform that was not adequate because the soil base was unable to withstand the weight and pressure created by the drill rig. The Crown must further prove that one of the ways the defendant failed to design an adequate platform was its failure to identify (determine) that the soil could bear the weight and the pressure that the rig applied, as was required by the manufacturer's specification of the pressure that needed to be supported.

Count 6 requires that the prosecution prove (1) that the employer failed to ensure that the ground-based work platform was capable of supporting any loads that may be applied to it and (2) that in failing to do so, the employer did not act in accordance with good engineering practice. It is again obvious that "good engineering practice" refers to the ensuring the platform's capability and not "any loads that may be applied to it." Further, the prosecution must prove (3) what is good engineering practice.

The elements of count 7 include (1) that the employer failed to ensure that the drill rig was operated in accordance with the operator's manual. Although not appearing in the charge, the prosecution agreed that this failure amounted to (2) not operating the rig on level ground as the operator's manual required.

Thus, the three counts against the defendant contain two allegations: that A.C.T. did not provide a platform that could support the drill rig, in general in count 6 and specifically because it did not identify the soil's bearing capacity in count 5, and that the drill rig was operated on ground that was not level. The following reviews the evidence relating to these allegations.

How the Drilling Process Worked

The evidence establishes that A.C.T. is a reputable and responsible company that among other services specializes in working underground. It primarily works with ground water remediation, and says it can "fix anything underground that has water leaking into it". As well, it is a recognized expert in providing compensation grouting, which is inserted underneath a structure to ensure its stability during and after digging or tunnelling nearby. The grout to be used in this project was a slurry, liquefied bentonite, a wettish concrete that stabilizes soil.

The rig that toppled and killed Mr. Knox and injured Mr. Deluca was at York University where a TTC subway station was to be built. The Toronto Transit Commission had awarded the contract for the Spadina subway extension to a joint venture of two Spanish companies, Obrascón Huarte Lain, S.A. ("OHL") and Fomento de Construcciones y Contratas Canada, S.A. ("FCC"). I will refer to the contractor, "constructor" under OHSA, as OHL-FCC.

Extending the subway line required tunnelling underground, parallel to the surface and near existing buildings, particularly York's Schulich School of Business. Compensation grouting was required to ensure the stability of the building, both during tunnelling for the subway and into the future. OHL-FCC subcontracted the grouting job, a complex and sophisticated project, to A.C.T.

In order to place the grout under the Schulich building, A.C.T. needed to build a system of underground pipes into which grout could be pumped from an on-site grout-batching plant. To protect the Schulich building, A.C.T. "put up a high-tech monitoring system that would monitor the building" during the tunnelling and afterward, according to A.C.T. supervisor Darrell Miller. This system consisted of sensors in the building that detected settling or movement.

In order to provide grout to the 121 horizontal pipes, fanning out under the building parallel to the ground surface, A.C.T. had to construct three concrete and circular compensation grouting shafts, 21 metres in vertical depth and about 6 metres in diameter, according to Ministry of Labour investigator David Duncan. Building such shafts is an intermediate and necessary step to the principal specialized job of providing stabilization by grouting, and is itself a specialized job.

Shafts were created by sinking in a circle 40 interlocking concrete piles of the same 21-metre depth as the large shaft they were to encircle. These piles were 0.813 metres (about two feet, eight inches) in diameter.

These were not ordinary piles but secant piles. (A secant is a line between two points of a circle's arc, thereby defining two sections.) A small portion of each circular pile interlocked with the next pile, as after each concrete pile was poured – as a full circle – a small curved section was removed so the next pile could be poured to interlock with it. When all the secant piles are placed, interlocking each to the next, the result is concrete piles 21 metres into the ground interlocking to form the inner circular wall of the large 6-metre grout compensation shaft.

Though measurements are important here, exact precision is difficult to achieve as witnesses testified variously in metric and imperial measures. Tab 6 of Exhibit 1 has drawings to scale, but the diagrams are difficult to measure. Witnesses testified to different decimal places, and counsel were often content with approximations. Accordingly I qualify some measurements with "about" or "approximately", but if a measurement was specified as being accurate I rely on it.

Regarding the diameter of the shaft, I rely on A.C.T.'s specification from its response to a request from TTC engineers for the diameter (provided at tab 3 of Exhibit 2). It stated that its measure of the shaft diameter, 6.81 metres, was from the midpoints of two opposite secant piles. Subtracting the diameter of one pile (0.813 metres, or two half-piles) therefore leaves approximately 6 metres as the size of the final shaft, slightly different from Mr. Duncan's diameter. I use about 6 metres in this judgment.

Several steps preceded the building or sinking of the secant piles, all within the expertise and contractual obligations of the defendant A.C.T. Patrick Byrne, a union steward from the Labourers' International Union of North America (LIUNA) in charge of worker health and safety, exaggeratingly described the process as 200 steps. I accept his evidence when it is not inconsistent with actual physical evidence.

The process commenced with form work, building a circular guidewall. Labourers used mini-excavators to dig a ring 6 feet deep in the ground and 6 feet wide, leaving a circular centre. (Mr. Byrne testified that the ring was 40 feet, but other measurements show that this could be neither the diameter nor the circumference of the inner or outer ditch. Accordingly, I am disregarding his estimate.) The inner unexcavated circle would ultimately be replaced by the large vertical grout shaft. The outer part of the excavated circle would be filled to build the guidewall, inside which would in turn be drilled smaller holes to make the concrete secant piles, which would ultimately form the wall of the large vertical grout shaft.

The area enclosed by the guidewall built into this ring was also the work platform at issue in the three counts, because the drill rig sat on it to drill the holes to be filled with concrete, the secant piles, to form the shaft wall. The defendant, a company with acknowledged and undeniable expertise in supporting buildings long term with complex grouting systems, is charged with failing to design a proper platform under the machine that it used to build a grouting system.

After digging the circle, labourers must ensure that the grade of the bottom of the circle is level. A surveyor assists in this. The labourers then put down a layer of clear stone and compact the soil with a heavy tamper. This layer is tamped down in the excavated part, the ring, not on top of the circular centre that remains. That inner portion is covered with a layer of concrete, according to Mr. Byrne "about a half inch thick up to five inches at the most".

The next step was, working to an engineer's specifications, to build rough steel rectangles that curve around the circle. Then Styrofoam cylinders each with one curved section cut out – the exact shape of the concrete piles to be built – would be placed inside the steel frame. Additional steel reinforcement would be added every four cylinders.

This steel frame with the cylinders inserted is not built to the outside of the 6-foot-wide circular trench. It takes up part of the middle of this excavation, more specifically, the diameter of the Styrofoam cylinders, 2 feet, 8 inches (0.813 metres). The labourers then pour concrete into the two remaining spaces, i.e., between the Styrofoam cylinders and the inner and outer edges of the circular trench.

At each stage, according to Mr. Byrne, the workers levelled the ground, both before and after placing the Styrofoam guides, as well after fastening the timber parts of the frame with steel. They checked the grade with a "surveyor laser pointer" to make sure it was level, added clear stone and compacted it.

These steps completed, the result is a concrete guidewall with 40 cylindrical Styrofoam guides where the piles can be built. From above, and as clearly depicted in photographs recording the building of the large shafts (exhibit 21, photos 5 and 10), is a centre section of earth, a ring of concrete, a ring of the Styrofoam circular guides fitting together that become concrete piles as each pile hole is dug and filled, and another ring of concrete. The two rings of concrete fill in the curving or flower petal pattern created by the joined circular Styrofoam guides.

I consider these concentric circles for consistency. From the outside in is the outer edge of the guidewall, that is, Styrofoam guides with curves where they meet and filled in with concrete. This is the outer guidewall, with a diameter of approximately 7.6 metres (the 6-metre shaft wall plus the diameter of a pile at each end, 6 + 2 x 0.813). The next circle is the inner guidewall, with a diameter of approximately 6 metres (the outer guidewall less the diameters of two Styrofoam cylinders). Inside that is a concrete ring of undetermined width because the 0.813-metre guidewall doesn't fill the whole six-foot trench excavated to build it. Enclosed by all these is what I call the unexcavated centre, meaning it was not excavated during the building of the guidewall, though OHL-FCC did remove the topsoil and place crushed stone on it. There is no measure of this circle, which was covered with concrete.

The Drill Rig That Collapsed

A.C.T. purchased a rig for this job from Bauer, a company based in Schrobenhausen, Germany. The RTG RG25S #176 drill rig was specially designed in Germany with a double-head drilling system for installing piles immediately adjacent to buildings, a method known as "against the wall".

The dimensions of the machine convey its huge size. Its mast – an outer drill casing and an inner auger – is 30.7 metres high. Its base is on tracks that resemble tank tracks: 5.7 metres long (of which 4.64 metres makes contact with the ground) and 0.8 metres wide. The gauge, the distance between the tracks, is 3.7 metres, though the evidence is not clear regarding which two points it is measured from. The top of the track is about four feet high.

The RTG RG25S rig weighed 111.5 tonnes, though the important measure was not weight but the downward pressure it exerted as specified in units of force, expert witness Dr. Myint Win Bo explained. The pressure given by the manufacturer for a fully equipped machine with the auger 70% full of soil was 1,237.3 kilonewtons (1kN = 1000 newtons).

A.C.T. bought this machine new from Bauer-Pileco, Bauer's sales wing in Houston, Texas. A Bauer employee from Germany, Manfred Fischer, who operated the rig and also trained others, travelled to Texas and then to Toronto to train and prepare A.C.T. employees on it. Those trained were Darrell Miller, mechanic Ray Nelson, operator Mike Hensen and Jeffrey Prewitt, who operated the machine at the moment that it fell over.

Mr. Miller described the training and preparation of the machine both in Conroy, Texas, where A.C.T. set up a small site and trained employees, including Mr. Prewitt, for over a month and at the York University site. Mr. Fischer commissioned the drill as suitable for making piles, once in Texas and again on site at York University.

The rig could use different-sized casing and auger systems. Mr. Miller estimated that the casing on A.C.T.'s rig could go 72 feet into the ground; indeed, Bauer's specifications give a length of 23.1 metres or about 76 feet. The casing's diameter was exactly the diameter of the piles and the Styrofoam guides: 0.813 metres.

Inside the casing was an auger system that trapped the drilled material, known as the spoils, and forced them up the casing to a big evacuation vent at one side of the casing's top. The dirt fell to the side of the machine. So as the rig drilled a hole to create a pile, the hole's contents were brought up at the same time for disposal.

This rig had a special feature that allowed A.C.T. to complete three parts of pile construction at the same time. As the machine brought up the spoils, a hose was attached atop the casing-auger boom to pump concrete into the drilled hole and thus create the pile at the same time.

This was the first time that A.C.T. had used this rig, as it was the first that Bauer had sold in North America after many years of successful use in Europe. It was specially equipped to permit drilling near large buildings – which it was doing at the time of the accident.

As outlined in Bauer's letter of commission issued September 11 in Texas, Manfred Fischer inspected, set up, demonstrated and trained others on the rig. Mr. Fischer signed the confirmation on behalf of Bauer and attached an extensive, detailed list of every significant part and aspect of the machine. Most were checked off. The items that generally related to the platform or the soil's bearing capacity were under Part 3: "The client has been introduced to the following points", "operator instructed in operating of machine", "operator instructed in handling of operation manual and maintenance manual". Regarding stability for the rig, the manufacturer specified "[e]ven, horizontal surface with the necessary load-bearing capacity". There is no issue that Mr. Fischer was qualified to train and did train Messrs. Miller, Hensen and Prewitt properly, and that he set up and inspected the machine properly.

When the machine arrived in Toronto, A.C.T. modified it with the knowledge of Bauer. As the underlying soil was wetter and heavier than what the crew practiced on in Texas, A.C.T. added an air valve to the top of the auger-mast casing to hook up a compressor in order to introduce air to force the heavier dirt up. A.C.T. also redesigned the counterweight system, adding some counterweight, and then tested the machine.

When setting up the rig at York University, A.C.T. originally set it up in the area of Shaft 2. The crew and machine then moved it to a confined sector on the other side of the Schulich building, to the south and east of the accident site, and successfully completed Shaft 1 following the procedure described above. In other words, the operator used the machine to drill and build by filling with concrete 40 secant piles while positioned in the centre of the circular guidewall. No steel plates were used underneath the rig.

Before October 11, 2011, the rig was moved back from Shaft 1 to Shaft 2. Instead of taking it down and then reassembling it, the crew 'walked' the rig, which means to drive it, onto the street beside the Schulich building and then westward to the site of Shaft 2.

In operation, the machine was equipped with a safety switch to turn it off if it ever was off level by more than 2.5 degrees. A bubble device in the cab showed the operator that the machine was level.

Change in Platform Design from Shaft 1 to Shaft 2

At Shaft 2, unlike at Shaft 1, A.C.T. used steel plates under the rig. There was more room at Shaft 2, Mr. Miller explained. At Shaft 1, in order to line up the drill casing over the guide to drill the pile hole, the operator had to move the rig on and off the concrete form. If driving the machine over the wall chipped it and damaged the foam guides, the guidewall had to be levelled, as happened at Shaft 1.

At Shaft 2, the crew used steel plates to "track over the guidewall and get [the rig] out in the centre of the shaft," Mr. Miller said, in order to avoid damaging the Styrofoam guides. After they walked the rig over the guidewall into the centre of the shaft using the steel plates, they noticed that the back of the track still had some steel plate under it. This meant the machine was not level because the front of the track had no steel plate under it. As there were more steel plates near the Shaft 2 site, I infer from what Mr. Miller said, the crew "played it all the way out into the middle of the shaft" in order to level it.

The steel plates were rectangular, measuring 1.5 metres wide by 3 metres long. A.C.T. workers originally placed the plates lengthways in the direction of the tracks. That did not work, so they turned the plates sideways near front of the track and then put the other steel plates crossing over the concrete guidewall in the same direction of the tracks.

Therefore the two steel plates that A.C.T. placed perpendicular to the rig tracks occupied 3 metres of width if adjacent at their long side, 1.5 metres if adjacent at their short sides, and the two steel plates placed in the same direction of the tracks would occupy another 3 metres. Mr. Miller testified that the tracks were on the plates and no part of the plates were on the guidewall at the front of the tracks.

In this way, according to Mr. Miller, all parts of all tracks were on steel plates, some of the plates over the middle of the centre of the circle enclosed by the guidewall and two of them covering the guidewall at the back of the tracks. There were no gaps or spaces between the four steel plates under the rig, but they remained separate as they were not rigidly attached.

Mr. Miller testified that no considerable part of the tracks were outside the guidewall unsupported by the steel plates, though he never said no parts of them were. In any event, they were never outside the west side of the circular guidewall.

The Rig Operator

Jeffrey Prewitt operated the rig on October 11, 2011. Patrick Byrne described the team of Mr. Miller and Mr. Prewitt as "so good" at what they did. Mr. Prewitt supervised the labourers, under Mr. Miller, when he was not operating the machine. Along with the mechanics he performed a safety check on the rig every day before it operated, and a mechanical inspection before he used it.

This was Mr. Prewitt's first time operating the rig at the York University site, but he had been trained by Manfred Fischer in Texas. He did not testify, and I did not admit his statement for reasons delivered during the trial. He returned to the site a few months after the accident and completed making the secant piles for Shaft 2 using the same model rig as the one that collapsed. There is no evidence that he made a mistake operating the machine.

The Operation on the Day of the Accident

On Tuesday October 11, 2011, the rig was over Shaft 2. The day began at 7 a.m. with a toolbox or safety meeting. A.C.T.'s main boss or superintendent, Victor Chiasson, assigned the tasks for the day. After that Mr. Prewitt checked the rig.

Four piles had been made on October 6 at Shaft 2, and four more were planned for October 11. For each pile, while the operator moved the casing (some witnesses used the term caisson, but I shall generally use casing) over the Styrofoam guide (which is the same size as the casing), a man on the ground, in this case Mr. Byrne, gave hand signals to guide the operator, who was skilful enough to place the 0.813-metre circular casing over the Styrofoam guide within a quarter of an inch. Mr. Prewitt then lowered the cutting teeth on the cutter-head press into the Styrofoam guide, and then lifted it so that the man on the ground could confirm that it was lined up with the Styrofoam guide. Workers managed the hose for pumping concrete into the hole, the third function that the machine performed after drilling the hole and bringing up the dirt spoils.

At the start of the drilling, the 23.1-metre-long casing was fully extended above the ground. Once it was over the guide a final time, the operator began to drill straight down until the hole was completed. At the same time, the machine was expelling the spoils that it forced up while drilling.

Once the casing drilled right into the ground, the team, under the operator's direction, started to pump concrete into the hole to create the pile. The drilling took about two hours and pumping concrete another 20 or 30 minutes. The operator then raised the casing out of the hole so that the machine's mast was straight up, as it was when he began.

Although there was a mechanism for turning off the cement pouring, the machine still had extra cement in the casing after the pile was full. So in an operation related to the drilling but separate, Danny Deluca was operating an excavator to haul the excess cement away. Mr. Deluca, assigned by OHL-FCC to A.C.T. that day, was working under the direction of Mr. Byrne. He used the teeth on his excavator to scrape a 5- or 6-foot dispersal hole where the supervising labourer directed him to, outside the circular guidewall. Mr. Prewitt then slowly turned the auger and spilled the excess cement into the dispersal hole, from where Mr. Deluca removed it and trucks transported it off the site.

Yet another labourer, Eddie Lopes, was assigned to work on Shaft 2, keeping the area around the shaft clean. Meanwhile, more of the team covered the drilled and filled pile, mostly using plywood, and one of every four piles was reinforced with steel. A.C.T. drilled and completed two piles in the morning of October 11, and in the afternoon began to work on a third pile, identified as number 5.

Prior to starting Shaft 2, Mr. Miller said, he was not satisfied that the rig was well protected, judging from answers he received from OHL-FCC. So he had OHL-FCC excavate the topsoil and replace it with crushed stone. He said Gholamreza Hosseinzadeh, an OHL supervisor, assured him that only the topsoil had been disturbed, so he was not concerned about the proper depth and sufficiency of the crushed stone.

The Accident

Three witnesses to the accident testified – Danny Deluca, Patrick Byrne and Darrell Miller – plus evidence was adduced of what Mr. Prewitt experienced from a statement by him that Mr. Miller heard. I found all three witnesses honest and credible, but not all their evidence can be reconciled with the others' or the physical evidence. To explain what can be determined and what I have determined happened, I will deal with the witnesses by first setting out their testimony.

Danny Deluca

Mr. Deluca saw the rig tip over onto him. He was seriously injured and pinned in his crushed excavator for hours before rescue workers could release him and take him to hospital.

Mr. Deluca was employed by Python Construction Inc./Dibco Underground Ltd. ("Dibco"), but was assigned to work for A.C.T. on October 11, 2011. Using an excavator, he was transferring spoils from the rig casing into trucks to haul way. In order to do this he would make a small hole in the ground near the rig. Mixing dry material with the wet spoils, he would scoop up small buckets (trying to stay on grade by not scooping big buckets), lift the mixture and carry it to a truck.

He testified that he had some concerns about the stability of the rig. He perceived that the operator was moving it back and forth too quickly, so he moved his excavator.

Mr. Deluca described the accident, starting with the rig beginning to drill the hole for the pile. Describing his memory as "not that good", he recalled that the rig's casing went only 10 feet into the ground and then came back out again. The whole machine then moved back, and then came back toward the hole it was digging. The operator seemed to look at something and then drove the rig forward. The casing tilted toward Mr. Deluca, who was to the west of the rig. He saw that the rig was in what he called a bad rut. He recalled that the tracks were in ruts inside the circle, having slipped off the steel plates into the mud. This memory was more than just an impression, he said.

Then the rig fell. Mr. Deluca expected the casing to miss his excavator, but the operator swung the machine, though "not the tracks" of the rig, and that is how the casing hit Mr. Deluca's machine. The casing was originally not swinging.

Mr. Deluca testified that on Darrell Miller's instructions he had moved the steel plates, and they were not under the rig after lunch. He testified that the rig's tracks were not on steel plates when the accident occurred (about 2:30 p.m.), but agreed in cross-examination that he was not sure that the steel plates were not under the rig. He saw Mr. Miller on the catwalk of the rig and said it appeared that Mr. Miller was talking to Jeff Prewitt before the accident.

When cross-examined about not saying in his statement or examination-in-chief that he saw Mr. Miller on the catwalk, he rightly said that nobody had asked him. He held to his testimony that he saw the rig moving on the tracks just before the accident. He also confirmed that the tracks were inside the circle formed by the Styrofoam guides because if they were outside, the operator would not be able to drill.

Mr. Deluca was an honest witness. He did not attempt to answer what he could not answer: he admitted not knowing south from north on the site, and would not guess measurements when he could not, nor identify objects that he could not. He revised his answer on cross-examination about the steel plates. He was badly injured and traumatized, but there was no indication that that affected his memory of the accident. I accept his evidence except when other facts that I find demonstrate that his memory is wrong in any respect. Importantly, he was working right in front of the rig – the casing, tracks and cab – when the accident occurred. He was uniquely situated to see what was happening to the tracks.

Patrick Byrne

Patrick Byrne was a steward and labourer sent from the Labourers' International Union of North America (LiUNA). He was involved in all aspects of the guidewall construction and preparation of the platform.

At the time of the accident he was working on a late stage of secant pile construction, clearing excess concrete at the top of the previously filled pile. As there was a danger of falling into the hole just drilled, he tied himself to the rig using a harness that gave him 12 feet of movement on a lanyard. The rig's cab was perpendicular to the tracks, which were lined up more or less east-west, parallel to the Schulich building.

Mr. Byrne was to the back of the machine on the south side towards the building. He saw Mr. Miller walk up to the catwalk on the rig to talk to Mr. Prewitt. He heard a screeching noise like fingernails on a chalkboard or steel on concrete. The noise was on the left side of the rig, to which he was tied. He did not know if the noise was from the tracks sliding along the steel plate or the concrete, but heard it as a loud scraping.

Mr. Byrne looked up at the mast and saw that it was already tilting forward. The casing was all the way up, its bottom inches above ground. His 12-foot lanyard went taut as he was pulled with the rig. He saw Mr. Miller trying to jump off of the machine. The boom (as he called the casing) gave way once, but only to 5 degrees forward, before going back to straight. Then it fell over, continuously and for good. Mr. Byrne unhooked his lanyard. After the slack in it disappeared, the momentum from being pulled catapulted him in front of the left track of the tipped rig, which was pointing up into the sky. He saw that Mr. Miller had been ejected 15 feet to the other side of the rig, over the cab, and that Mr. Prewitt had gone out the door or the windshield of the cab. The whole collapse took about eight seconds, he thought.

Mr. Byrne followed the mast along the ground with his eyes. Mr. Deluca was screaming in agony, Mr. Miller was out cold, and Kyle Knox was dead. The grout machine that had been attached to the rig by the concrete hose used to fill the pile came whipping across and hit two other workers.

Darrell Miller

Mr. Miller was working along with Jeff Prewitt on October 11, 2011, as site supervisor. He had extensive experience in drilling, construction, grout and structure support, having worked on complex projects throughout North America. The crew also included Rupert (last name not known) running the pump, a trainee named Francis, Gonzo and Fernando. Mr. DeLuca was removing the spoils and loading them onto trucks. As he did so, he "dressed" the spot that he scraped the spoils from with fresh crushed stone. The rig was where it had been brought into the shaft, he said; its tracks were not outside the guidewall on dirt or ground.

When Mr. Prewitt was drilling a hole for the pile, Mr. Miller said he was concerned about the teeth on the crown, that is, a piece on the bottom of the casing that does the actual digging. He felt vibrations in the ground in the soles of his feet. Not wanting to interrupt the drilling, he left Mr. Prewitt to finish pumping the concrete. Mr. Prewitt, as rig operator, had lifted the casing from the ground a couple of feet at most and moved it to his right so that the crew could strike the top of the concrete off level with the form.

Using established practice, Mr. Miller got Prewitt's attention and Mr. Prewitt nodded, making a show of taking his hands off of the controls and putting them in his lap to show that it was safe to approach. Mr. Miller, on the catwalk, walked over to Mr. Prewitt and heard something hit or bang off the casing overhead. He knew something was moving, but said he had no idea what had caused it. He looked up and said Mr. Prewitt looked up and said, "It's going over."

Hearing the bang and then Mr. Prewitt saying, "It's going over" all happened in a split second, Mr. Miller testified. Until then, he had not felt any movement. Walking on a catwalk parallel to the ground, Mr. Miller then saw the ground quickly receding away from him. He thought that the rig's mast would fall into the Schulich building because he thought it was pointed partially towards it to the south and west, and he understood that any rig falls towards its load. But it fell parallel to the Schulich building, and the collapse of the rig threw Mr. Miller over the top of the rig to the north of the mast. Mr. Miller was seriously injured.

Events Following the Accident

After the accident, the rig was on its side with the tracks pointing up and embedded in the ground, the right track penetrating about four feet and the left track, nearer the south, less. Rescue services from several agencies saved Mr. Deluca, whose excavator was crushed under the mast of the rig. Mr. Knox, working nearby for Anchor Shoring and Caissons Ltd., died at the scene, doing his job building the Spadina subway extension, when the mast demolished his backhoe.

The mast broke. Rescuers apparently had to work on the rig from the side opposite the fallen mast, that is, the underbody of the rig because heavy machinery was brought on to the circle where the rig had sat. Rescue workers are permitted by law to disturb accident scenes in order to save lives.

The configuration of the steel plates shown in police photographs after the accident is not the same as before the accident, according to Mr. Miller. Indeed the police photos are not time-stamped as such photographs usually are. A photograph taken after the accident seems to show a steel plate parallel to the tracks on and outside the guidewall to the north (Exhibit 6(c)), while Mr. Miller said that no plates were outside the guidewall except to the east side. Another photo shows a plate right on the guidewall. The steel plates and soil were disturbed during the rescue operation.

It was not possible to determine the position of the plates before the accident, according to one of the first Ministry of Labour employees at the scene, engineer Saeed Khorsand. He attended the scene the day of the accident and was later assigned to conduct an engineering study of it for the Ministry. His investigation focused on four areas: the broken mast, the rig, the soil underneath the rig, and the slope of the ground under it. His findings are essential to the prosecution's case, as well as to my analysis of the charges and the defences available to A.C.T. I will deal with each in turn.

Saeed Khorsand's Evidence

Mr. Khorsand was introduced as an expert in mechanical and geotechnical engineering, which studies the reaction of a structure to the soil beneath it. I determined that he could not give an opinion on the final cause of the accident, as he had demonstrated a bias in speaking with expert witness Dr. Bo about his findings while Dr. Bo was under examination. I did permit Mr. Khorsand to give his opinion on engineering, particularly geotechnical engineering.

Although A.C.T. attacked his investigation and methods, Mr. Khorsand provided helpful explanations of technical evidence, particularly respecting the soil underneath the rig. Eliminating alternate causes of the accident is relevant to the analysis of inferences and circumstantial evidence in this case. In fairness to A.C.T. and in keeping with my ruling, I have confined myself to relying on Mr. Khorsand's description of his investigation, and explanation of technical terms, his own observations, and his conclusions on engineering matters. Apart from his gathering of information relevant to other potential causes of the accident, I excluded his opinions on the cause of the accident, including any that could be considered indirectly about the cause.

I also ruled that the police evidence on which Mr. Khorsand based his conclusion regarding the slope under the machine was inadmissible, because of the late manner in which it was disclosed. That ruling eliminated the underlying facts on which Mr. Khorsand calculated the slope. Therefore I discuss only his evidence relating to the mast, the rig and the load-bearing capacity of the soil underneath the rig.

When Mr. Khorsand arrived on the accident site, his first concern was not the cause but the safety of the Schulich building and the street. He was concerned about other equipment that had been hit and also feared the rig falling over more. But he took photographs and made notes for later diagrams. He measured the steel plates and drew them in a configuration that was nothing like what Mr. Miller described, but he arrived after rescue operations had occurred.

The Broken Mast

The Ministry of Labour retained an expert metallurgical firm, Acuren, to determine whether the drill casing was broken before the accident or the break was caused by the accident. The metallurgical firm determined that the break in the mast resulted from the accident rather than preceded it. Similarly there was damage to the rig's backstay cylinder, which is used to adjust the angle of the mast. He determined that this damage was due to impact.

The Rig in General

Mr. Khorsand reviewed the computer in the rig, which registers not only flaws but operations performed. The manufacturer's manual and Mr. Khorsand explained that the times recorded are not necessarily real time but from the beginning of the machine's operation. However, the error message record that he appended to his report did show four messages about five seconds apart at 2:31 p.m. on October 11, 2011.

Mr. Khorsand consulted the manufacturer's explanations of error messages and found that one was unique in the history of this machine. He requested an interpretation from Bauer, which the company provided in a letter dated January 24, 2012. Bauer said a system called B-tronic in the rig that records error messages is not a black box to tell what happened but a guide to the operator. Explaining the last four error messages, the letter said message 31 indicated a rake in the mast's Y axis (its forward and backward inclination) that went beyond its measuring range of -45 to +45 degrees.

Apart from damage caused by the fall, Mr. Khorsand's investigation learned of no other problems with the drill rig.

On behalf of the Ministry of Labour, Mr. Khorsand commissioned DST Consulting Engineers Inc. to estimate the soil's bearing capacity and consider the possibility of a disturbance in the soil (whether he meant before, as a result of, or after the accident was unclear). He obtained a report from Dr. Myint Win Bo of DST, an expert in geological engineering, and as a geotechnical engineer assisted the court in interpreting it. Mr. Khorsand had directed Dr. Bo and DST as to what the Ministry was looking for concerning the soil around Shaft 2. Dr. Bo's report said the assignment was to "provide geotechnical information as part of the ongoing investigation of the likely cause of the accident."

Based partly on the excluded statement from Mr. Prewitt and the excluded police evidence regarding the soil topology, Mr. Khorsand reached an opinion on the cause of the accident that I ruled he could not give, as he was not objective. Therefore I have limited the use of his evidence to descriptions of what he saw and did, and his reporting the results of inquiries to Acuren and Bauer. I have accepted the conclusion he reached that the damage to the backstay cylinder was caused by the collapse. It was a step that he took in the course of his investigation before he had formed an opinion of the accident's cause, was not challenged, and comes within the scope of the limitations I placed on his expert evidence.

The real significance of A.C.T.'s attack on Mr. Khorsand's evidence is not about its substance but its effect on the trial, and particularly on the opinion of the expert that he retained, Dr. Bo. Mr. Khorsand did not inform Dr. Bo that OHL-FCC had left a watermain in the ground in the area under Shaft 2. Mr. Khorsand also did not show Dr. Bo a picture of the rescue equipment that had disturbed the soil in the circle.

Dr. Myint Win Bo

Dr. Bo is a world-renowned engineer in the field of geology, having a postgraduate diploma and Master of Science in Hydrogeology and a PhD in Civil Engineering. He has co-authored five books, two of whose titles – Ground Investigation Manual and Laboratory Testing of Soils, Rocks and Aggregates – are directly relevant to the report that he prepared for the Ministry of Labour. He is an adjunct professor at three universities, and an outside examiner and research supervisor at others in Canada and Australia. He has written or contributed to articles in more than 70 refereed journals and written more than 70 more papers for conferences, all in the area of geology.

The Ministry of Labour retained Dr. Bo to "investigate subsurface conditions in the area of the collapse, review available information, and provide a professional opinion regarding the adequacy of site preparation prior to the collapse".

His qualifications as a geotechnical engineer were not challenged. Although he had never testified in a court before (as opposed to private arbitrations), he was qualified on consent to give his opinion on geotechnical engineering including the structure and property of soils, the abilities and load-bearing capacities of soil, the allowable bearing capacity of soil and its ability to withstand loads and pressures applied to it, and anything that takes place within the soil affecting its capacity to bear loads below, above and at grade.

In court he fulfilled the requirements of an expert witness; his impartiality was unassailable. He set out his assumptions and the scientifically accepted methods that he used, explained them clearly, and provided his opinion. In cross-examination he agreed that the information that Mr. Khorsand failed to provide could have affected the soil's bearing capacity around the rig, demonstrating that he fulfilled the duty of an expert witness to assist the Court and not any party to the case. For these reasons I accept his opinion and rely on it in reaching factual conclusions about the element of the charge.

I now turn to that opinion, briefly describing the methods that Dr. Bo used in reaching it. Except for the misdating of his written report and one mislabelling of a slide in his in-court presentation, his report and slide show are clear and helpful.

My comments refer to Dr. Bo's investigation of the soil. In a colleague's description of the scope of the work that he sent to Mr. Khorsand (Appendix A to Exhibit 25), he also proposed to do a level survey of the ground surface near the accident. Although the report refers to "Site Topography" and surveys done by others, it does not appear that DST performed a level survey of the site.

Dr. Bo analyzed the soil below and immediately surrounding Shaft 2 using two methods, auger boreholes (BH) and cone penetration testing (CPT). The first method collects samples of the soil below the ground to analyze in the laboratory. Dr. Bo's employees took a sample every metre from points outside the shaft circle through the circle. The second method involves pushing a cone into the ground without drilling with equipment to sense the resistance of the ground.

Considering the results of both methods, Dr. Bo formed an opinion on the types of soil below the work site, the strength of the soil, and the pressure that it could withstand. He integrated all this in an opinion that he expressed verbally and backed up with diagrams and tables showing results from the two methods. His calculations relied on accepted standards in his field, each of which the text of his report referenced. With respect to the soil, there was no challenge to his methods or the accuracy of his results based on the information he had. But the way he measured the grade of the ground was challenged.

Borehole and cone pressure tests were conducted both inside and outside the guidewall circle. For instance, CPT1 and 2 were outside the guidewall circle, as was BH1. But CPT3 and CPT4 were fully inside the inner guidewall circle. BH3 was right at the edge of the inner guidewall circle. It appears from the scale on Dr. Bo's map (disclosure page 4659) that BH3 was not only within the guidewall but also within or on the margin of the inner unexcavated circle.

Ground investigations had already been done for the Toronto subway extension in 2009 and 2010 using the borehole method. Dr. Bo reviewed the borehole logs of those investigations and described the ground conditions that obtained then. He found variable fill material to a depth of 4.57 meters, underlain by more than 20 metres of till described as silty clay with some sand and gravel and thin, inter-bedded layers of clayey silt, silt or silty clay.

Dr. Bo analyzed the samples and the bearing pressures from the BH and CPT operations. He relied on information provided to him by Mr. Khorsand that included Jeff Prewitt's statement that is not evidence in this trial. Accordingly, I have ignored any facts in Dr. Bo's report that he took from Jeff Prewitt's statement; some were presented by Messrs. Miller, Byrne and Lopes.

In his report Dr. Bo stated, after referring to a statement by Mr. Miller that the tracks were on top of steel plates: "It seems from the above statement that the piling platform consisted entirely of steel plates. It is not clear when and how the suitability of the soil conditions beneath the plates was examined prior to placement of the steel plates."

I note this statement for two reasons. First, it is almost the only evidence about good engineering practice in the whole case in relation to count 6, though it was made only by implication in a report that is an exhibit but was not restated by Dr. Bo in testimony. Second, it elegantly states A.C.T.'s alleged failure in count 5.

Dr. Bo's results are accessible to the lay reader, even if the steps in reaching them are not, because of the clear prose of his report to the Ministry. Section 5.2.2 explains that he calculated the allowable bearing capacity for each stratum of soil he encountered, and that bearing capacity is not a fixed value even for the same soil type with the same strength.

Using the rig's weight provided by the manufacturer, Dr. Bo calculated the weight or load for the machine. From that he could calculate the pressure or stress on the surface in kilonewtons (kN) per square metre.

Though the Ministry provided him with Bauer's specifications of maximum bearing pressure exerted by the rig, Dr. Bo did not use them but rather those that he calculated that the ground could bear. He also back-calculated from the manufacturer's bearing pressure applied to the ground what they would be with steel plates, either of 6 by 1.5 metres (two plates) or 3 by 1.5 metres (one plate). He also calculated bearing pressure that would have been applied without steel plates.

He found that the allowable bearing capacity of the ground was far below the pressure that the rig applied at CP2 outside the circle with either one or two steel plates per track, and that it was not sufficient for the pressure applied at the other points if there was one steel plate of 3 x 1.5 per track but sufficient if there were two. Comparing the bearing pressures of the rig provided by Bauer – which ranged up to 730 kilonewtons per square metre – he found that even with two steel plates arranged end to end (6 by 1.5 metres) the allowable bearing capacity of the soil at all of the points except for BH1 that had granular fill would be exceeded by the bearing pressures that the manufacturer provided.

Dr. Bo's calculations assumed the tracks of the rig each being supported by two end-to-end steel plates (6 by 1.5 metres). His report did not say whether he assumed them placed adjacent lengthwise or widthwise, but stated that the connection of two plates should be rigid or they wouldn't distribute pressure equally. He was also of the opinion that given the manufacturer's statement of the pressure exerted by the rig, bigger steel plates (longer and wider) were needed to match the pressure on them. In his opinion, "the possibility of the tracks being partly on the steel plates and partly directly on the ground during operation could have induced instability with consequent bearing failure."

Dr. Bo also calculated the shear pressure – the strength of the soil – for each of the points that he tested. He found it low in some points and reasonable in others.

Integrating all the information that he had and his results, Dr. Bo gave an opinion that the most likely reason that the rig fell over was that in some conditions and at some locations, the pressure that the rig exerted on the ground exceeded the allowable bearing capacity. In interpreting his own results, Dr. Bo did not rely on the particular failure of any one point under the rig as the basis for his opinion. He stressed that CP2, where the rig's track penetrated the ground, was outside the outer guidewall, but he agreed that he did not know if the softness there caused the failure or was caused by the tipping of the track into the ground.

Dr. Bo's opinion was that the pressure exerted by the rig exceeded the allowable bearing capacity and was the most likely of the rig failure, but he agreed that there could be other causes. I accept his evidence and his expert opinion, subject to my findings about the underlying basis of his assumptions and his own qualifications of his opinion. Though important, his opinion is but one part of the evidence and is not conclusive regarding the cause of the accident.

Information That Dr. Bo Did Not Have for His Report

Dr. Bo was not advised of all of the disturbance to the surface of Shaft 2, the rig's platform base, caused by the heavy machinery used during rescue efforts on October 11. Shown a photo of what appeared to be an excavator on wheels, he agreed that if in the hours after the accident it had been on the circle where he later took some of his measurements, it may have affected his results. If the excavator's wheels were on the steel plates that appear in the photo, he noted, that would lessen the disturbance of the soil.

Dr. Bo knew that a watermain had been rerouted around Shaft 2 but was not aware that an abandoned part had been left in the ground directly under the guidewall circles, a plastic pipe of undetermined thickness between 9 and 12 inches in diameter. He learned about it only during the first day of Mr. Khorsand's testimony. Dr. Bo agreed that it could have been relevant to his opinion, but his words warrant attention. He did not say, as A.C.T. argued, that "since the pipe was plastic and not made of steel, it would likely have impacted the ground conditions." I acknowledge that counsel prefaced his submissions by stating that any discrepancy between his summary of the evidence and the actual evidence at trial was inadvertent, and here the warning is relevant. Dr. Bo agreed that knowing whether a plastic pipe at a depth of 2 or 3 metres could "possibly have some impact on soil stability" and that access to the pipe or an expert's determination of its stiffness and strength would have been "of some assistance" to help understand the effect of any plastic pipe in the ground.

No one told Dr. Bo that 12 days before the accident, a hydrant broke about 200 to 300 feet from Shaft 2 and that water flowed toward Shaft 2 for 1.5 to 6 hours. Dr. Bo's opinion was that this flood would have had little effect on the ground stability, or his results and opinion. I similarly disagree with A.C.T.'s submission that Dr. Bo admitted that the water concentration in the soil should have been a consideration in his overall assessment and opinion. Dr. Bo's opinion was that even water running into sector D, the area around Shaft 2, for 6.5 hours would not have been an important factor. "If they have a sufficient thickness of granular material, it should not [a]ffect", that is, decrease, the bearing capacity. He agreed that it was only "a little bit necessary" to consider the effect of water on the soil, and to that extent agreed that if there was excess water it could have weakened the soil. He stood by his calculations as reliable even if he did not consider the water factor. And he did not retreat from his final judgment. As well, Mr. Hosseinzadeh testified that he diverted the water to the street, and that the water from the flood did not reach Shaft 2.

The Contract Between OHL-FCC and A.C.T.

In the contract signed June 2, 2011, with the contractor OHL-FCC, the subcontractor, A.C.T, agreed to a scope of work for the compensation grouting for the Schulich building that included "design and construction of (3) grout access shafts". The contract had several exclusions relevant to A.C.T.'s position regarding its compliance with the Occupational Health and Safety Act (OHSA), including this statement:

The following services will be performed by others at no additional cost to A.C.T.:

1. Staging and Grout Batching area
2. Site work
3. Hardscaping and Drainage
4. Obstructions
5. Utilities
6. Survey
7. Clean up

Under point 4, Obstructions, removal and relocation of all below-grade and surface obstructions were excluded. Under point 8, Utilities, all inspection, locating and relocating of existing utilities were excluded. In the body of the contract, under the heading 7.2 Safety Loads, the contract stated:

Safety Loads. Subcontractor has an affirmative duty not to overload the structures or conditions at the site, and shall take reasonable steps not to load any part of the structures on site so as to give rise to an unsafe condition or create a risk of personal injury or property damage.

The Broken Hydrant

On September 29, 2011 – twelve days before the accident – a front-end loader operated by Anchor Shoring hit a hydrant near Shaft 3 approximately 200 to 300 feet east of Shaft 2. The water ran for 1.5 to 6 hours before it was shut off. The water gushed from the broken pipe and covered the ground between shafts 3 and 2, where it occurred.

The Abandoned Watermain

Around July 28, 2011, OHL-FCC, in keeping with its responsibilities and contract with the Toronto Transit Commission, arranged for the watermain that ran under Shaft 2 to be rerouted and the ground to be simultaneously prepared. One foot of topsoil was removed, a filter cloth was placed in the ground and then two inches of crushed concrete was added to the soil. The watermain ran east to west right through the middle of the proposed Shaft 2, and thus also through some shafts of the secant pile wall. No work could be started without checking the "locates" (utility locations in construction), because as OHL-FCC supervisor Gholamreza Hosseinzadeh put it, "Because you wanna go do something on the ground, excavating, drilling or something, first of all you should know what was happened – the area you couldn't see".

While A.C.T. was making Shaft 1, a company known as Metric relocated the watermain. This was a major job requiring a major excavation of a 40-foot-long trench about 6 feet wide and 7 or 8 feet (2 to 2.5 metres) deep. After diverting the watermain, OHL-FCC took several steps to determine suitable fill material and filled the trench with a granular fill, compacting it down in layers, according to Mr. Hosseinzadeh.

Mr. Hosseinzadeh testified that OHL-FCC decided to leave the abandoned watermain in the ground so as not to disturb the soil. He testified that he discussed it with A.C.T. site supervisor Owen Organ, who told him that A.C.T. would have no problem drilling through this pipe.

OHL-FCC did not measure the ground contact pressure after the rerouting, and no one saw anything that was unsafe.

Analysis: Application of Facts to the Charges

Count 7: Operation in Accordance with the Manual

Count 7 is quickly dealt with.

The preponderance of evidence is that the rig was level on the steel plates. Both Mr. Miller and Mr. Byrne swore to that, and Mr. Miller particularized each step that A.C.T. took in constructing the guidewall to make sure that first the base, then the guidewall and then the concrete were level. This attention by A.C.T. to making sure that the guidewall and concrete were level was in part independent of the use of the circle as the platform for the rig. As Mr. Miller explained, "if you get out of level anywhere then it continually gets worse as you keep putting the foam pieces in". Mr. Hosseinzadeh walked by on the morning of October 11 and saw that the ground was level. There is evidence that the machine would stop if it was operating on an "unallowable" slope.

The only evidence of uneven ground under the steel plates is from Dr. Bo's reliance on previous surveys done at the site. If the tracks were partially off and partially on the steel plates, as I find below, that meant that they would have been off level, according to Mr. Miller's testimony. But the manufacturer's specifications allow for a departure from level to 2.5 degrees. The evidence does not prove beyond a reasonable doubt that the rig was not operated on level ground according to the manufacturer's specification.

Count 7 is dismissed.

Count 5: Adequacy of the Work Platform

The case against A.C.T. that it failed to design an adequate work platform is circumstantial, based on evidence of different types. There is directly observable and measurable evidence, such as photographs of the accident scene and measurements of the circle, the rig specifications and the steel plates. Then there are facts that I must determine based on inference and in some cases credibility, which may turn on other facts determined the same way. Expert opinion evidence, in this case, Dr. Bo's, is another category of evidence.

In a circumstantial case, the evidence can only prove an element of the offence, in this case the adequacy of the platform, beyond a reasonable doubt if there is no rational explanation for that evidence other than the guilt of the accused. And the pieces of evidence and categories of evidence I have referred to must be considered along with and in the context of all the evidence, rather than in isolation. The conclusion reached when following these two legal principles comes at the end of the consideration and is a judgment on the whole, even if set out as linear reasoning.

Measurable and Visible Facts

The evidence that the tracks could not be entirely on the plates is the measurements of the plates and the width of the rig. The plates under the rig that in Dr. Bo's calculations increased the allowable bearing pressure of the ground were 1.5 by 3 metres, and when he combined two he obtained a plate of 6 by 1.5 metres. (Mr. Khorsand measured the plates, as did Dr. Bo's employees.)

I will call the plates laid perpendicular to the tracks the perpendicular plates, and the plates parallel to the tracks the parallel plates. Given Mr. Miller's description of the configuration, the maximum width of two parallel plates was 3 metres, but each track was 0.8 metres wide and the gauge was 3.7 metres, according to Mr. Duncan.

There is no evidence that the gauge is measured from the centre of one track to the centre of the other, as one might expect. So I cannot assume that the gauge Mr. Duncan provided was measured that way – or between the inner parts of the tracks, or from the outside.

By any measure, the width of the tracks on which the rig was based was at least 0.7 metres more than any configuration of two steel plates placed together parallel to the tracks without a gap. The back two tracks that Mr. Miller testified were left parallel ("we took two of them and turned them sideways and put those out where the front of the track would be, and then we had the other two crossing over the concrete guidewall") could not have been together without a gap or space (as he testified) and still contain the whole width of both tracks. From the measurements, therefore, one of his answers was incorrect.

Mr. Miller did not testify as to whether the two perpendicular plates nearest the front were joined at the short side of their rectangles (end to end) or the long side (side by side). But he agreed that together they would be 10 feet long, suggesting they were joined at their long side east and west of each other. He also referred to a photograph that shows them east and west, and commented on their position in the circle but not on their arrangement. If they were arranged in that position, their combined width of 3 metres was too short for the width of the tracks (3.7 metres measured by gauge).

If the parallel plates were placed side by side, and met the perpendicular plates, their combined length (parallel to the tracks) could only be 4.5 metres lengthwise if the perpendicular plates were side by side joined at their short side. But the surface contact length of the tracks was 4.64 metres. So one way or another, the tracks were partially off the steel rigs, whether placed lengthwise or widthwise or both.

Dr. Bo's calculations show that without any steel plates, the rig's downward bearing pressure would exceed the allowable bearing capacity of the soil at BH 1, 2 and 3, as well as CPT2. And with a single 3 x 1.5-metre plate under each track, the bearing pressure would exceed the load capacity at all points. (The bearing pressure is significantly increased by the unbalanced condition a single plate entails.)

His calculations based on two end-to-end plates of 6 by 1.5 metres showed sufficient bearing capacity for all points except CPT2. However, his calculations presumed rigidly attached plates or just single plates per track and all the rig's tracks on the plates, conditions that did not pertain. With just one plate per track, even doubled to 6 metres long, the rig would have been unbalanced.

I am not competent to determine the calculation for the real conditions, but Dr. Bo's projection is contained in his opinions that a) the tracks were not completely under the plates and b) the tracks should be rigid to provide the bearing capacity that he calculated. That is, in the real conditions as I have found them – that is the tracks partially off the plates and the plates not rigidly attached and possibly not adjacent – the plates most likely did not compensate for the lack of bearing capacity in the soil.

The tracks being partially off the steel plates is also consistent with the testimony of Danny Deluca that Mr. Prewitt, i.e., the rig, "was in a big rut." I accept Mr. Deluca's evidence. He suffered devastating trauma and physical injury but was an excellent witness. He was right in front of the accident. He did not try to answer what he could not, and had a good memory of some points confirmed by other evidence; his description of the mast coming forward and then going back and then going for good is consistent with Mr. Byrne's and Mr. Miller's evidence. At first it appeared that his memory was poor because he said that Mr. Prewitt had just "pulled up" from drilling and had not gone in deep, and he did not see any steel plates.

The clearly incorrect observation that Mr. Prewitt had just pulled up the casing does not diminish his observation that the rig was in a rut: Mr. Prewitt had just finished the previous pile and had moved the casing, which was low to the ground, so that the crew could clean the excess concrete. Mr. Deluca initially testified that there were no steel plates, but under cross-examination said he didn't see any steel plates. This did not amount to impeachment but buttressed his credibility, as he was not categorical. But he testified that Mr. Prewitt as rig operator was in a big rut as the rig came forward. Mr. Deluca drove an excavator, so his description of a vehicle with tank tracks has extra weight in my opinion. I accept this evidence.

Every way that Mr. Deluca's observation of the rig being in a rut is considered contributes to the inference that the platform could not support the rig, to be considered along with and in relation to Dr. Bo's opinion and the other evidence. The rig could not have been in a rut if the tracks were entirely on steel plates. Or if Mr. Deluca saw a rut and the tracks were on steel plates, the rig was pushing plates down into the ground, implying that the soil below could not support the rig. Or if he saw a rut after the rig somehow left the steel plates and was coming forward as he described, then it slid forward, because Miller testified that it did not move in the sense of driving forward. Such sliding also supports an inference of the soil it was on being insufficient to support it.

Mr. Deluca's evidence that the rig came forward is supported by other evidence. He seemed to mean that Mr. Prewitt was moving it back and forth. Whether by being driven or sliding forward on the plates, it did move forward as it ended up outside the guidewall. Some part of the width of the tracks had to be off the steel plates, however the plates were configured; the totality of evidence considered together shows that the rig was partially on them and partially off.

Nor could the plates have been entirely inside the guidewall; they must have been at least partially on it. They may even have been outside the outer edge of the guidewall. In response to a question, Mr. Miller agreed that no considerable part of the plates were outside the wall.

Further, the plates were not rigidly attached, as Dr. Bo testified was required to properly distribute the load's bearing pressure. As there were four plates, they were unattached at four or more meeting points: where the two perpendicular plates met, where each parallel plate met a perpendicular plate, and where the two parallel plates met.

I conclude that the platform consisted in part of steel plates that were not completely under the rig's tracks, were not rigidly connected, were not together without a gap if the width of the tracks were all on the plates, and themselves sat on ground that consisted of parts of the concentric circles: the guidewall (and possibly the area outside the guidewall), the area between the inner part of the guidewall and the non-excavated centre that had concrete poured into it, and the unexcavated centre itself.

This unexcavated centre had between half an inch and five inches of concrete on top. Though Dr. Bo noticed no concrete in his samples, without the measurement of the unexcavated centre it is not possible to tell if he took samples from directly below it. But from the samples he took, he projected that a portion underneath the unexcavated centre had very little granular fill. A.C.T. never filled or worked on this unexcavated centre during the guidewall construction except to put the concrete on top. The only evidence of work on it was that OHL-FCC filled the area around Shaft 2 with filter cloths and granular fill to a depth of 1 foot after removing the topsoil. Mr. Miller was not concerned for the depth and sufficiency of that crushed stone because OHL-FCC's Mr. Hosseinzadeh had assured him that it was only replacing topsoil residue. When it put the crushed stone down and compacted the centre, Mr. Miller was confident that it was safe.

Furthermore, not all the secant piles had been made. Work had only started, so except for six piles, the secant pile part of the guide wall was Styrofoam, not yet concrete, set in concrete and iron frames. So the steel plates rested on four different types of ground quite apart from the strength of the soil underneath, and the rig's tracks did not rest completely on the steel plates.

The steel plates were not placed or designed to support the rig. They had not been used at Shaft 1, and were placed at Shaft 2 to facilitate entry of the rig into the circle, not to support the rig when drilling. A.C.T. had not designed a platform using steel plates with respect to the bearing capacity of the soil below.

One other piece of evidence indicates that the platform, consisting of the ground and steel plates, was not properly designed: the rig fell over. To hold that because the rig fell over the platform was not proper would be circular reasoning. But if a rig that is stable in the right conditions is in proper working order, has no equipment failure, is operated properly, is on level ground – and no external event or other circumstance explains its tipping over, independent of the failure to provide an adequate platform – then the very fact of the fall is evidence to be considered.

Alternative Explanations

I now turn to alternative explanations, starting with operator error. The evidence is that Mr. Prewitt was trained, knew what he was doing, was one of the best in the business, and had just successfully drilled two pile holes that day. A few months later, A.C.T. employed him to operate the same rig model when it successfully constructed Shaft 2. His hands were off the controls when the accident occurred; he had just moved the casing after completing the concrete filling of a pile. As good as he is, he may have made a mistake. But there is no evidence that he did, and operator error is not a reasonable explanation of why the rig tipped.

Whether the rig was on level ground is also straightforward. The greatest departure from level that is proven is 0.025 metres, almost exactly an inch (the thickness of the steel plates), from one point of the platform to another. The fact of the tracks being partially off the plates has not been translated into a meaningful slope that the rig was on. In raising a reasonable doubt about the ground being steeper than the slope permitted by the manufacturer's specifications, the defendant adduced evidence from Messrs. Byrne, Miller and Hosseinzadeh to show that the crew levelled the ground under the guidewall at every turn, was using the steel plates so as not to chip the guidewall when the rig moved on it, and that the ground appeared level to the eye. As well, the operator had an instrument that showed him if the machine was off level, and the machine would turn off if the slope was greater than allowed. The defendant has eliminated unlevel ground as a reasonable alternate explanation for the rig falling over.

There is no evidence of high wind or any other environmental or external forces that could have caused the rig to fall over.

Next: was the rig in proper working order? The investigation regarding this involved Mr. Khorsand gathering information from the manufacturer, Bauer. But he did not make notes of any conversations with Bauer. The defendant challenged this as neglectful and submitted that any information he relied on and conveyed to the Court about the proper working order of the rig was hearsay. I agree that the information Mr. Khorsand received, apart from his relating the results of the Acuren examination of the mast, is not admissible to show that equipment failure did not cause the collapse.

But there is other evidence as to the soundness of the machine. This was a new machine with only 400 hours of operation. It had operated successfully during training in Texas, and in completing 40 piles in Shaft 1. It was commissioned by Bauer trainer Mr. Fischer, an expert in its use, not once but twice. It had successfully completed four piles on October 6 and two on the day of the accident.

No one noticed anything amiss prior to the accident. Mr. Miller heard a noise above him like something hitting the mast, but the equipment at the top of the mast is unique and this occurred seconds before the mast was seen to tilt, so it is no evidence of a defect in the machine. Mr. Byrne testified that he used his level to make sure that the rig's bottom edge was levelled from top to bottom.

This total absence of any observed defect, combined with evidence of proper operation and being commissioned by the manufacturer, leaves equipment failure as a speculative explanation for the accident; there is no evidence to support it.

Similarly, the abandoned watermain that OHL-FCC left in the ground and that Mr. Khorsand did not disclose to Dr. Bo does not give rise to a reasonable inference that the reason the rig tipped was the watermain and not the inadequate platform design. There is no evidence whether the watermain pipe was stiff or not, as Dr. Bo agreed would be relevant. Dr. Bo said he would have wanted to know it was there, but did not go further than agreeing it "possibly" could have some impact on soil stability.

A.C.T. correctly points out that OHL-FCC had left the watermain in the ground after contracting with TTC to remove it, and that Mr. Khorsand did not tell Dr. Bo about it. But neither OHL-FCC's nor Mr. Khorsand's omissions explain the accident independent of the soil's bearing capacity and the alleged failure to identify it. No one identified the soil's bearing capacity in relation to the rig's requirements. Had OHL-FCC done so, the significance of the abandoned watermain could have been assessed. Had A.C.T. done so, it would not be guilty of failing to design an adequate working platform.

In further arguing that the actus reus has not been proven, A.C.T. points to the successful drilling of Shaft 2 a few months after the accident as proof that the platform was adequate. I do not find that Mr. Miller's evidence establishes that nothing changed between October 11, 2011, and the second drilling. But if, as argued, A.C.T. or OHL-FCC did nothing to the soil between the accident and the successful making of Shaft 2, then it would prove that the abandoned watermain is irrelevant because it was found during excavation of the shaft and obviously did not cause the second rig to collapse.

The absence of any alternative reasons for the accident strengthens the inference that the collapse itself contributes to the circumstantial case that A.C.T. failed to design a proper working platform.

In addition to Dr. Bo's opinion, the implications of the measurements of the rig and the steel plates, and the rig falling over, other evidence supports the conclusion that the ground beneath the rig could not support it. Mr. Byrne heard a screeching noise like metal on concrete, indicating that the plates were moving. The ground was level, but the tracks penetrated the ground approximately a metre past the guidewall. Mr. Miller testified that the guide wall was not damaged when A.C.T. drilled it in February 2012. He also testified that Mr. Prewitt did not drive forward or at all. As prosecution counsel somewhat dramatically but pertinently submitted, the rig did not fly over the wall.

Inferences from the evidence, including that of Dr. Bo, support the conclusion that the rig's tracks slid alone or with the plates so that at least the front of the track reached its final resting place as the rig tipped. As well, the collapse was sudden, within seconds. This is consistent with a failure due to inadequate soil base, Dr. Bo testified in answer to the Court.

The prosecution has proven the first particular – "failed to design an adequate work platform" – beyond a reasonable doubt. In the particulars it provided, the prosecution joined that failure to "by identifying the soil bearing capacity as required by the manufacturer's specifications for stability".

Load-Bearing Capacity

The only steps that A.C.T. took whatsoever with respect to determine the ground's bearing capacity was to send the manufacturer's stability requirements to OHL-FCC and to assemble the rig – empty of spoils – near the proposed Shaft 2. Mr. Miller also observed that Anchor Shoring was operating other Bauer rigs, some of them heavier than A.C.T.'s, in the area.

There is similarly no evidence that OHL-FCC used the specifications in preparing the ground where A.C.T. was to construct Shaft 2, either when it removed the topsoil and placed filter cloth and then granular fill or when it put granular fill into the centre during construction of the guidewall.

There is no evidence that Mr. Fischer, in explaining the rig's operation and use of the manual, made any reference to the load-bearing capacity of the soil, the particular in count 5, and except for the very general box to be ticked in the checklist that he gave to A.C.T., there is no reference to the soil or the ground's bearing capacity or the work platform.

The prosecution's case on that particular is that A.C.T. took no steps other than sending the specifications to OHL-FCC. A.C.T.'S position is that once OHL-FCC had the specifications, OHL-FCC was contractually responsible to make sure that the soil's bearing capacity was sufficient. The legal issue of whether an employer can contract out its obligations under the Occupational Health and Safety Act or excuse a failure to comply by showing that another responsible party also failed to comply with its duty has been decided: R. v. Structform International Ltd. confirms that every employer is responsible for taking every precaution.

The concept of failure appears twice in count 5, once in the particular that the defendant failed to design an adequate work platform and once in the allegation of the offence that it failed to take every reasonable precaution. ACT's position is that providing the specifications to and relying on OHL-FCC to identify the soil's bearing capacity as required by the manufacturer's specifications is reasonable. This raises the issue of what is reasonably required of a subcontracting employer such as A.C.T.

"Reasonable" is ubiquitous in all aspects of the law, from police powers to appellate review to the test for conviction, and cannot be interpreted with resort to other words. It is self-defining and specific to the context and circumstances. In this case "in the circumstances" is stated in the section cited from OHSA and the charge.

I would include the circumstances that: the model of the rig with its specialized functions was new; the rig itself and no other rig of that model had ever operated in North America; testing had been done in Texas and A.C.T. had noted differences in the soil when it set up at York University; minor modifications to the rig could have added to its weight; A.C.T. was changing the platform configuration from the successful operation at Shaft 1 without steel plates for a different purpose than ground stability, that is, to protect the Styrofoam guidewall but without regard to how the plates needed to be under the tracks; the size of the machine and its location close to a building and a work site with many workers; and A.C.T. had no idea of the soil's weight-bearing capacity on the site.

In these circumstances, A.C.T. had to identify the soil's bearing capacity underneath its rig as required by the manufacturer's specifications or confirm that OHL-FCC had done so. Although this case is not about contractual interpretation between the contractor and the subcontractor, the contract on which A.C.T. relies, like the charge, did address the design of the platform in clause 7.2.

Even if A.C.T. could rely as a matter of law on another party with the contractual responsibility for ground preparation, and offer its reliance on the contract as a reasonable precaution, that raises a reasonable doubt as to their failure to take every reasonable precaution, I still must deal with the word "every" in s. 25(2)(h) ("take every precaution reasonable in the circumstances") and the charge. Having sent the specifications as its reasonable step in taking precautions for the protection of workers and designing an adequate platform by identifying the soil's bearing capacity, A.C.T. had to follow up and ask if OHL-FCC had identified the soil's bearing capacity in order to make OHL-FCC's action its own.

I emphasize that "identifying the soil bearing capacity" refers to the soil, not to the specifications. There is no evidence that anyone ever identified the soil's bearing capacity to compare it to the manufacturer's specifications and requirements before operating the rig on the platform, as opposed to reading or conveying what the requirements were, before Dr. Bo did so after the accident.

I do not hold that every constructor and employer putting a machine on a platform must conduct the scientific investigation and analysis that Dr. Bo did during his investigation. They must of course follow good engineering practice (of which there is none in evidence in relation to this point). But I do hold that they had to do something reasonable in the circumstances. Sending specifications to OHL-FCC could only be a reasonable first step toward ensuring that the work platform was adequate.

The next necessary step was to become informed about whether the underlying soil's bearing capacity had been identified and was adequate. Dr. Bo's report (section 2.5) said ground investigations had been done for the overall project; some information was available. The answer from OHL-FCC would have been one of: 'Yes, we identified the capacity and it is adequate" (which would raise a doubt about a failure by A.C.T. if the rig collapsed); "Yes, we identified the capacity and it is inadequate"; or "No, we have done nothing about it" (either of which would have led A.C.T. to not put the rig over Shaft 2). That is a reasonable approach.

I need not resolve the dispute in argument and the conflicting evidence as to whether OHL-FCC could be trusted or whether A.C.T. had justifiably trusted it. A.C.T. simply failed to take any steps to identify the soil's bearing capacity. As that is the particularized way that it is alleged to have failed to design an adequate work platform, A.C.T. thus failed to take every precaution reasonable in the circumstances.

Leaving aside A.C.T.'s affirmative duty in clause 7.2 of its contract with OHL-FCC not to overload structures, this technical case and the searing tragedy involved comes down to this question: If a constructor is responsible for ensuring that the ground or platform is adequate to support a subcontractor's equipment, and the subcontractor transmits to the constructor the information respecting the pressure that the equipment applies to the ground, has the subcontractor taken every reasonable step to protect workers if it doesn't follow up and ask the constructor if the ground will support the equipment?

In my opinion, given the purpose of the OHSA – safety and the protection of workers – the answer to this question is no. Requiring companies to verify safe use of their equipment will act as a check on any company to which a contract has assigned the duty to protect the workers' safety.

I find that the soil could not bear the pressure of the rig without steel plates properly designed and placed, and that those used were not.

I reject the argument that because A.C.T. later finished the secant piles using the same model of machine and again operated by Mr. Prewitt without any changes to the site, as Mr. Miller said, that it demonstrates that the soil was adequate. Putting it forward shows how tightly the circumstantial case has been proven. Mr. Miller's evidence does not establish him as being at a level in the A.C.T. hierarchy and in relation to OHL-FCC to invest him with knowledge of how A.C.T. dealt with the accident. And I agree with the prosecution that it is absurd to infer that after the collapse of a new rig in a fatal accident of this magnitude and with serious rescue operations, that any company would continue using a rig that weighs the same and is the same without at least attending to the platform. I do not draw that inference.

The prosecution has proven count 5 beyond a reasonable doubt.

Count 6: Good Engineering Practice

I have determined that A.C.T. failed as an employer to ensure that the soil base upon which the project was taking place, as count 6 puts it, was capable of supporting any loads that may be applied to it. This charge adds "in accordance with good engineering practice." These words seem superfluous, as any engineer in any field – as any lay person – would state that a platform must support any load expected to be applied to it.

But on the principle that the legislature does not legislate redundantly, I must give effect to its terms. Therefore some evidence of good engineering practice must be available with respect to constructing a platform to support a load. Only with that can I evaluate whether A.C.T.'s failure to ensure that the platform was capable of supporting the load, which my conclusion regarding count 5 establishes, came about because of its failure to comply with good engineering practice. I disagree with the prosecution that "good engineering practice" is not a term of art and requires no expert interpretation.

The issue is not whether the words need interpretation; they are words in a statute for a judge to interpret. R. v. MBI/Smurfit is not applicable, as that case dealt with words not in a statute that the trial justice erroneously held needed evidence to interpret. A judge can use a dictionary.

A.C.T. submits that no expert evidence of good engineering practices was adduced in relation to the ground-based work platform's ability to support any loads that could be applied to it. But there was.

Dr. Bo provided evidence as to what A.C.T. should have done when using steel plates: make sure that they were attached and therefore rigid. Dr. Bo, an engineer and expert, was cross-examined with a view to showing that he was a geotechnical engineer rather than a mechanical or a construction engineer. But from the whole of his evidence, he had to know many aspects of engineering in order to be a geochemical engineer.

No doubt the guidewall and the circle it contained was expertly built as a guidewall and ultimate shaft wall. But as a platform base for the rig, it was lacking. Implicit in Dr. Bo's evidence is that good engineering practice requires comparing the soil's bearing capacity to either the manufacturer's specified requirements or the load's actual bearing pressure, and explicit in Dr. Bo's evidence is that to effectively decrease the load's bearing pressure on the platform, metal plates must be entirely under the rig's tracks and be rigidly attached to one another. But there was no evidence as to how this should have been done before the job apart from the example of what Dr. Bo did after the job.

The term "good engineering practice" is in the legislation and in the charge. I have no evidence about it except in relation to the steel plates, but it could be a complex issue that includes the nature of the job, risks and resources. An example of this is Dr. Bo's comment that geotechnical engineers apply a safety factor only to the allowable bearing capacity, not to the load – otherwise "you gotta … construct everything with a[n] unnecessarily very conservative construction." Failure to act in accordance with good engineering practice is not proven here beyond a reasonable doubt.

Even if the prosecution was right that the term is self-defining, I would not enter a conviction on count 6 but stay the charge under the Kienapple doctrine, as at bottom it is the same delict as count 5. The prosecution agrees that there could not be convictions on both.

Count 6 is dismissed.

Due Diligence

Proof of the failures specified in the counts is proof of the actus reus, and the prosecution need not prove any mental element on the part of the defendant company, as the defendant recognizes.

However, to avoid punishing regulatory offenders who are not deserving of sanction, the Supreme Court of Canada created the concept of strict liability offences in the regulatory context. These charges are in that category. Although it failed to provide a safe work platform, as I have found in two counts, A.C.T. is not guilty if either (1) it "reasonably believed in a mistaken set of facts which if true, would render the act or omission innocent", as the Supreme Court put it, and (2) if it took all reasonable precautions to avoid the particular event.

With respect to both aspects of the defence, it is necessary to establish that that the defendant subjectively believed in the state of affairs that renders its act innocent and that the belief is objectively reasonable. The onus is on the defendant to establish that it exercised due diligence on a balance of probabilities. If there is no evidence of due diligence or the issue is evenly balanced, the defence cannot be established.

Mistake of Fact

The belief required for this state of mind is usually associated with an individual. The only individual who testified who could speak for the corporation was Darrell Miller. A.C.T. offers five facts to establish this defence, but as two are relevant only to the defence of count 7 that I have dismissed, I omit them. The three facts that A.C.T. urges it believed true that would come within the mistake-of-fact defence are:

1) A.C.T. reasonably believed that the rig used at the project was suitable, safe and stable as a result of the Bauer recommendation in the purchase, training, set-up and commissioning of the rig by a Bauer representative, Manfred Fischer.

This alleged mistake of fact cannot support the defence, as there is no evidence that it is mistaken. I dealt with this above while considering whether the equipment was defective in my assessment of the circumstantial evidence. With no evidence of rig failure when the onus was on the prosecution, and the defendant producing no evidence of equipment failure, this can hardly amount to a proven mistake of fact when the onus is on the defendant on a balance of probabilities.

2) A.C.T. reasonably believed that the watermain running under Shaft 2 had been removed, according to OHL-FCC's contract with the TTC, as OHL-FCC's Mr. Hosseinzadeh told Mr. Miller. It further reasonably believed that proper Granular A gravel had been placed under Shaft 2 where the watermain was to be removed.

The only evidence that the abandoned watermain could have contributed to the collapse is Dr. Bo's testimony that any effect would depend on the stiffness of the plastic; he agreed that if the pipe was not stiff it could "possibly" have had an impact.

In defending itself on the basis that the prosecution had not established an actus reus, A.C.T. was completely within its rights. But at this stage of the trial the defendant must adduce evidence from witnesses or otherwise to show on a balance of probabilities that the platform was adequate but for the abandoned watermain. And A.C.T. called no evidence to show that the abandoned watermain was not stiff plastic.

There is evidence that the ground supported the same model rig without steel plates when A.C.T. finished constructing the shaft in 2012. And the watermain was not found until the main shaft was drilled. A.C.T.'s belief is irrelevant to arguing innocence unless it establishes on a balance of probabilities that the ground was a proper platform but for the abandoned watermain. But it has not established on a balance of probabilities that the abandoned watermain contributed at all to the rig's collapse.

Therefore it is not necessary to deal with any perceived conflict between Mr. Hosseinzadeh's testimony that Owen Organ of A.C.T. was present when OHL-FCC decided to leave the watermain because of the disturbance to the soil that removing it would cause, and Mr. Miller's evidence that Mr. Hosseinzadeh told him that it had been removed. That latter conversation was never put to Mr. Hosseinzadeh, as it should have been if A.C.T. intended to contradict him. But Mr. Miller is not the only knowledgeable A.C.T. employee; Mr. Organ was also. No mistake-of-fact defence arises from the abandoned watermain.

3) A.C.T. reasonably believed the ground was sound.

In determining whether A.C.T. took every reasonable precaution in establishing the actus reus of Count 5, I discussed A.C.T.'s failure to ask OHL-FCC if it had determined the soil's allowable bearing capacity after A.C.T. sent it the manufacturer's specifications for stability. This failure to follow up and ask was not reasonable. So A.C.T.'s belief was not reasonable; it was created by one of the omissions that make up the charge.

The due diligence defence does not succeed on the first branch, mistake of fact.

The Second Branch of Due Diligence

Justice Dickson described this branch in R. v. Sault Ste. Marie:

… whether the accused exercised all reasonable care by establishing a proper system to prevent commission of the offence and by taking all reasonable steps to ensure the effective operation of the system.

The due diligence offence is therefore about the offence at issue, not the employer's general safety policy. A safe company with thorough safety procedures can err in one regard, and the issue will be whether its system was directed to avoiding that mistake. A.C.T. has a good safety record, a thorough safety policy in writing, was up to the standards of the Labourers' Union (as confirmed by an experienced health and safety steward, Patrick Byrne) and held daily safety meetings that it documented.

But its reasonable precautions must be specific to the hazard in play, or the delict alleged: R. v. London Excavating and Trucking Ltd. ACT's proof of its safety policy and methods does not establish that it exercised due diligence in relation to the design of the platform and the soil's bearing capacity. In fact, the contrast between its attitude and methods regarding safety in general and its failure in this case to identify the soil's bearing capacity as required by the manufacturer's stability specifications demonstrates that it did not exercise due diligence in this regard.

The company's policies included three aspects that it recorded in writing: Job Hazard Analysis Reports, which were reviewed with employees, on-site safety meetings called "toolbox talks", and its general safety policy. But there is no evidence that it took any steps to confirm that the platform at the York campus could support the drill rig in accordance with its specifications for stability, and no record of it being confirmed – because it was not.

Two steps that ACT offers as evidence of due diligence reveal the deficiency in its handling of the specific failure that it is charged with and that I have found occurred. The "specific training on the equipment from the manufacturer's representative, review and commissioning of the rig for the specific project at York University by the Bauer representative" has no relation to the soil's bearing capacity at the Shaft 2 location. If the check boxes on Mr. Fischer's commissioning statement that I have referred to could include support for the rig, there is no evidence that Mr. Fischer ever knew the exact location of the three shafts or that he commissioned the rig as safe to work on all of them. A.C.T. did not relate the specifications to the site but relied on OHL-FCC to identify the soil's bearing capacity at the drill site.

And to the extent that it relied on OHL-FCC, there is no evidence that A.C.T. confirmed with OHL-FCC that the ground had been prepared sufficiently to support the rig, after its "provision of the relevant and required information to OHL-FCC … regarding the platform requirements of the Rig and its operations", another specific act on which A.C.T. relies to show due diligence. A.C.T. never asked.

In an OHSA charge under 25(2)(h) of failing as an employer to take every precaution reasonable in the circumstances for the protection of workers, which must be established beyond a reasonable doubt, there is less room for the second branch of the due diligence defence to benefit the defendant. It must establish on a balance of probabilities that it took reasonable precautions, but the question arose only after it was proven that it did not. I agree that the expression "all reasonable care" means "all reasonable care that a reasonable [person] would have taken in the circumstances." But here A.C.T. did not take the precaution of verifying with the contractor that the ground could support its rig.

I find A.C.T. guilty of count 5, and not guilty of counts 6 and 7.

Footnotes

[1] R. v. Charemski, [1998] 1 S.C.R. 679

[2] R. v. B. (G.), [1990] 2 R.C.S. 57 at para 40

[3] R. v. Structform International Ltd., [1992] O.J. No. 171

[4] R. v. MBI/Smurfit, [2008] O.J. No. 541

[5] Kienapple v. The Queen, [1975] 1 S.C.R. 729

[6] R. v. Sault Ste. Marie, [1978] 2 S.C.R. 1299

[7] R. v. Sault Ste. Marie, supra

[8] R. v. London Excavating and Trucking Ltd., 40 O.R. (3d) 32

[9] R. v. Thomas G. Fuller & Sons Ltd., [2012] O.J. No. 5590