Even though the practice of reinforcing concrete with steel rods was established in the late 1800s, the term ‘reinforced concrete’ only came into general use in the early 1900s. Concrete has been one of the most widely used building materials since then. It has made possible numerous complex structures, ranging from bridges, monuments and buildings, to civil engineering works.
Nowadays we have better knowledge of the chemical processes involved in the hardening of concrete and can predict its ultimate strength. Mixing concrete is now a science, not an art as it was in its early days. Nevertheless its placement and treatment after pouring to maximise its structural strength requires skill and diligence.
One of the key checks before a concrete pour was to confirm that the steel reinforcement had been correctly fixed in position and would not be displaced during placement of the concrete. Even though we had a good team of concrete workers on the project the inspectors needed to be vigilant. My presence at the placement of the concrete ensured that the inspectors were also on their toes.
But I was not there just to be a policeman. I got a deep satisfaction from seeing the creation of a structure. The transforming of an idea on paper to a physical reality. Whether it was the pouring of concrete, the erection of structural steel columns and beams or installing and commissioning a large item of equipment, I got a feeling of achievement. I guess it could be called job satisfaction. Today, being the second last major concrete pour, the completion of the crusher and Mill foundations, was a project milestone.
As I stood there watching the concrete workers complete cleaning up and applying the finishing touches to the poured concrete I was aware that I now had another decision to make. The aggregate used in the twenty thousand cubic metres of concrete poured to date was crushed limestone that had been quarried onsite.
I had had a battle to get approval to quarry the aggregate on the mine site. Initially I had been prompted to look for an onsite solution when the Mareeba Shire Council quarry, thinking that they had us over a barrel, had quoted an excessively high price for concrete aggregate. Then the Council had claimed that we did not have the right to quarry our own aggregate on the mine site, but that was soon refuted.
Initially a number of rock outcrops onsite had been tested but proved to be unsuitable for concrete making. They were either too soft, too mineralised or not in a convenient location. Eventually though, Ted Brennan, a mine geologist involved in the development of the open pit, located a source of stable limestone in a convenient location. I thought that the matter had been resolved when engineering tests showed that it was suitable as concrete aggregate but the design engineers then vetoed its use. They claimed that limestone would react adversely with the cement in the long term and weaken the concrete. After several weeks of argument I was able to produce engineering studies that confirmed that the opposite was true. The design engineers had consequently conceded but with I thought was rather bad grace.
I had been aware that the design engineers were annoyed because I had challenged their expertise in the past and would not concede that I had been wrong. Even so I was surprised when they had intervened in an attempt to prevent me using crushed limestone as concrete aggregate. Eventually when the stated grounds for their intervention had been shown to be invalid I discovered that they had been acting on instructions from the Project Manager.
But in spite of the initial opposition, quarrying our own concrete aggregate had worked out well. Very well in fact. But we now had adequate stockpiles of crushed limestone to satisfy the remaining requirement for concrete to finish the processing plant plus the outstanding road and drainage works. Today, I no longer needed to continue producing concrete aggregate. I now had the opportunity to close down the quarrying of limestone and return the hired crushing and screening plant to its owner.
***
But now I had another issue to resolve. The risk of flooding of the processing plant area. Perhaps it would be better to say, my perception of the risk of flooding.
Strictly speaking it was not my responsibility. I should just let it go. I had made my reservations clear and proposed a corrective course of action. But, my suggestions had been rejected. When I had persisted and continued to present my case I had been given specific instructions to construct the mine site drainage plan exactly as designed.
Nevertheless I was the man on site. To me it was not just a distant location drawn on a plan. I could see the contours of the land and the nature of the valley floor. Very little of any rainfall would be absorbed in the soil. Most of it would flow down the valley, along the southern edge leading to the mine site.
If an engineer decides to design a drainage system to handle stormwater by-the-book it is a fairly simple task. There are Australian Standards that specify the intensity and duration of rain storms that should be provided for. The engineer then, when he has contour plans available, has the simple task of calculating the rainfall catchment area. Finally he would look up some reference books to find factors to allow for the slope of the land and the ability of the topsoil to soak up at least some of the rainfall. Using simple arithmetic he will calculate a theoretical maximum flow of stormwater and look up another table to find what sized drainage pipe, or open channel, is required. Eventually he would have an impressive set of calculations to support his conclusions. Later, if problems occurred, he could deflect criticism by claiming that it had been done by-the-book.
The by-the-book approach is simple. Too simple. But that was how the design engineers had carried out the calculations for the Red Rock mine site drainage plan. I did not deny that this approach had its place in hydrology. But it should only be regarded as a ball-park estimate.
An experienced engineer would then look more closely at the consequences if the stormwater drains turned out to be inadequate to prevent flooding. If the cost to repair flooded facilities, or the cost of lost production, is highly significant then a higher safety factor should be included in the calculations. Also, instead of designing a drainage system to accommodate a standard rainfall intensity, the engineer should provide for a given storm scenario. In the case of Red Rock the logical design storm would be a Category 5 cyclone crossing the coast near Cairns and continuing inland to pass to the south of Red Rock.
Due to the clockwise circulation of wind around the centre of a cyclone the rain would approach Red Rock from the east. As the storm travelled down the valley towards Red Rock the runoff on the ground would be travelling with the storm thus maximising the peak stormwater runoff as the storm passed over Red Rock.
If the same cyclone passed to the north of Red Rock then the storm would advance on Red Rock from the east, travelling up the stormwater catchment. In that case the total rainfall would be the same but the peak stormwater flow at Red Rock would be less.
My view was that the risk of flooding the processing plant and causing a significant loss of production could, and should, be avoided.
The drainage plan that I was obliged to construct was a badly flawed concept. The planned collection of the stormwater runoff, and piping it through the processing plant area, was bad engineering. It was not just that the main drainage pipe might be too small. It meant that all the eggs were in one basket.
There should be a plan B option to handle the runoff if the pipe got blocked.
I was at a decision point now because there was no longer a need to keep producing concrete aggregate. The connection being that limestone had been quarried for concrete aggregate from a deposit that outcropped on the ridge leading to Lookout Hill. Not only had we produced cheap aggregate but the first stage of a stormwater discharge channel had been created. A channel that, if completed, would ensure that storm water runoff could be discharged at no risk to the open pit mine or the processing plant.
I had been instructed to construct the mine site drainage scheme exactly as designed and that was what I had done. But I was not told that I shouldn’t excavate a bypass channel, I just hadn’t been given the funds to do so.
Jack Gilmore had fully supported the under-the-radar excavation of the stormwater discharge channel. So did Ted Brennan, the Red Rock mine planning geologist. They were the only other persons aware of the ploy.
When I gave Ted Brennan the brief to find a rock deposit suitable for quarrying for concrete aggregate there had been a basic requirement. If at all possible, the deposit had to be located in the ridge leading to Lookout Hill. As it turned out he found a stable limestone deposit on the perfect alignment for a cutting that could serve as a open channel for stormwater discharge. It was during a mini trek by the two of us to inspect the limestone deposit that he and I had walked to the top of Lookout Hill. The intention was to get an overview of the mine site and the proposed limestone quarry, aka the stormwater discharge channel. But Ted’s deep interest in gold exploration geology emerged and he proceeded to give me a lecture on gold mineralogy and exploration that I had found inspiring.
Ted Brennan was a friendly, affable character in sharp contrast to his earnest demeanour when talking about geology. Sweeping an arm to encompass the panorama spread out below us he said, “Somewhere out there lays a mother lode. A body of rich, gold-bearing rock from which the gold has been leached and disseminated by geological processes over millions of years. Gold that we will extract from the open pit down there. One day we will find that rich mother lode and the Red Rock Mine will evolve into a major gold mine.”
I looked out over the desolate looking landscape. There was little vegetation and no visible animal life. It seemed to be incredible that anything of value existed in that wilderness. Much less gold-bearing material that was sufficiently valuable to justify the spending of more than $200 million to develop a mine to extract it.
Seeing that he had my attention Ted Brennan proceeded to give me a lecture on geology as it applied to the Red Rock deposit. He explained how a pocket of very high grade gold bearing rock, a mother lode, had been formed during volcanic activity tens of millions of years ago. Subsequently gold bearing material leaked from the mother lode due to pressure and tectonic movements of earth’s upper mantle. In time, it was widely distributed without any surface evidence of its existence.
I was curious and asked, “What makes you think that a high grade mother lode exists here? As you say, there is no indication of it on the surface. All that you have found so far is moderate grade ore. No mother lode. Why do you think that it exists?”
He replied, “Well, it must exist somewhere. The widespread distribution of moderate to low grade ore has to have come from somewhere. The probability is that the mother lode is lurking nearby. Perhaps it is too deep. Our immediate exploration objective is to find a high grade zone below, or adjacent to, the planned open pit on which to base an underground mine. We need to think outside the square and challenge the basic assumptions made when analysing drill core samples to locate a mother lode. We should not rely on ore grade quite so much but look more closely at variations in chemical binding and crystal formation for clues to its source.”
We stood looking at the panorama spread out below us for a few moments in a pensive silence. Something had stirred in my consciousness. Developing an open pit mine with moderate grade ore is a second best option. It means that the search for the mother lode has failed. Even though the mother lode is rarely found explorers should not give up looking. I looked across at Ted thoughtfully. During the past year I had learned much about gold mining and processing. But now I could visualise the story of gold before it is discovered and exploited. Gold mining was unique. It did not just produce a valuable product. It produced money. There was never a problem in being able to sell gold. Marketing the product from a gold mine was simple and sure. The only uncertainty was the price which was set by outside factors.
The memory of Ted Brennan’s lecture to me atop Lookout Hill that day remained with me and was to have an influence on me in the distant future.
***
Looking back I can see that there never was any doubt that I would eventually opt to complete the cutting through the ridge to provide a channel to discharge stormwater away from the processing plant. We are all captives by our sense of duty and sometimes forced to act by circumstances.
I was the man on the spot and had identified what I believed to be a problem. But that was not all, I also believed that I had a solution at my fingertips. My sense of duty was telling me that I should accept responsibility and do what I knew to be needed. Even so I had put off making the final commitment until the last minute just in case I was somehow overtaken by events and did not have to make a decision. A decision that would exceed my delegated powers and would almost certainly rebound on me.
Nevertheless I could not back off. Perhaps the design engineers were correct and I was arrogantly dismissive of views contrary to my own. I did not have to do anything as my backside was definitely covered if the plant was flooded. On the other hand, even if I was off the hook, Gibson Construction would be exposed to substantial damages if the drainage system was later proven to be inadequate and the plant was flooded. They were at risk not just during construction but later as well, during operation of the plant. The turn-key contract required Gibson Construction to design, construct and deliver a processing plant and facilities for a lump sum price. If the plant was shown to be inadequate in any way, including being subject to flooding, Gibson Construction would be liable to pay damages and also rectify the problem.
Unfortunately for Gibson Construction, if there is a costly flood in the future, they could not deny knowledge of a potential problem with the stormwater drainage scheme. My correspondence identifying the risk of flooding would ensure that they would be held to be liable.
I had been employed to use my judgement so that was what I would do. As soon as I had returned to my office I sent an email to Jack Gilmore stating that I would continue work on the stormwater discharge cutting until it was completed. It was a formal request for him to have the work carried out by the mining contractor and have the cost charged to me as had been done to date. Five minutes later he replied with an email confirming my request and his agreement to have the work carried out.
The die was cast. Whatever the outcome it was the only course of action acceptable to me. I would have no regrets, no matter the consequences.
***
Friday October 16
Red Rock Project Site
During the past week I had not been aware of anyone looking at me sideways or acting suspiciously. It was now almost seven days since I was attacked and I still had no idea who my assailants were or why I had been targeted. Admittedly I had not gone around the whole week thinking only of events the previous Friday. I had enough on my plate to keep me occupied.
Project milestones incorporated in my revised construction schedule were weather-centric, taking the expected seasonal heavy rainfall into account. February was usually the peak rainfall month but heavy rain storms could hit the project anytime from late November through to late April. A common misconception held by lawyers drawing up construction contracts is that one day of bad weather should not delay a construction schedule more than a single day. In fact most standard building contracts provide for wet weather adjustments to the target completion date by just one day for each day of rainfall. However, in the real world, one day of heavy rain could lead to project delays of several weeks. The actual impact on the project would depend on what stage the project was at when the rain storm occurred. If foundations were exposed and roads and drains incomplete then heavy rain could cause storm damage that might take days to repair. Sometimes a day of heavy rain might prevent access by heavy equipment for a week or more.
Consequently I planned to complete all the foundations, drainage and site works before November. Also the import of heavy equipment onto the site was scheduled to avoid the January to March period if at all possible.
Apart from completion of the stormwater diversion cutting, which wouldn’t be completed before January, I was satisfied with progress of all the critical p
roject activities. I had also been satisfied with our efforts to keep the project within budget. As far as I was concerned the project was ahead of schedule and under budget. But as I logged on to check the latest project cost figures I was surprised to learn that although the project was still under budget the savings were nowhere near as substantial as I had expected. Something was wrong. I knew that I had saved more than $300,000 on the concrete aggregate alone. All around the site I had been making gains. It just didn’t add up. Costs to date should have been much further below that budget.
Maybe I had taken my eye off the ball somehow. I walked out of my office along to the project accountant’s cubicle. But I was too late. She had joined the weekend exodus on the Friday afternoon flight to Cairns. I would have to wait until Monday to get her explanation, if she had one.
***
I often spent the weekend on the project site. Especially after a major concrete pour late during the week. That was usually the weekend that the number of workers on site was much reduced. It gave me the chance to wander around and check out the work done during the week unimpeded. It also gave me the opportunity to talk to some of the workers and get their feedback on an informal basis.
Initially I was not particularly concerned about the project’s budget situation as I expected it to be easily resolved when I sat down with the accountant. I monitored project expenditure on a contract by contract basis whereas the accountants recorded costs in accordance with the Chart of Accounts. I did expect that there would be timing differences on occasion but they would sort themselves out eventually.
I had developed a series of financial analysis computer programs in my own time. It was just a hobby, an intellectual exercise, but I used one of the programs to collate project costs and update the forecast of the final total capital expenditure. Initially I had used Excel to develop the logic but later switched to a computer programming language. I could now compile the programs so that they would run on a range of computers.
Smoking Gun (Adam Cartwright Trilogy Book 1) Page 8
