This article isn’t about one person’s struggle. It’s not even about one company’s struggle. Nor is it about a town or region’s struggle in incredibly difficult times. It’s a look at how a family quarrying company in particular, and Australia as a whole, responded to a chain of cascading disasters. This company didn’t necessarily suffer the most nor should any comparison be made with other regions, industries or people. Rain started in one area, moved to another, a separate source of precipitation appeared, and before we knew it, southern, northern and central New South Wales was flooded. Rockhampton and other parts of northern Queensland were hit by a cyclone that flooded areas as large as France. Then we saw cars tumbling down the streets of Toowoomba and piers and docks “flowing” down the Brisbane River on the news.
Floods in South Australia, fires in Western Australia, floods in Victoria – for once Tasmania probably felt good about being ignored! The year 2010 covered a range of devastating natural disasters, eg the loss of up to 250,000 lives in Haiti’s earthquake, heat waves in Russia, more floods in France, Pakistan and China, and earthquakes in China and Indonesia, to mention just a few.
When we thought the Earth couldn’t throw any more at us, we were stunned as Christchurch was hit once again in early 2011 and Japan experienced one of the largest earthquakes known, with an attendant tsunami, as well. In acknowledging all the devastation across Australia and the world, a glimpse into one operation from the quarrying industry dealing with its own difficulties is appropriate, a year on from these devastating events. Nothing can diminish the suffering that has been experienced, the world over, during the preceding 12 to 18 months.
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MURRUMBIDGEE FLOODS
Parts of NSW and eastern Australia experienced an El Nino-related drought for several years in the last decade. As is commonplace throughout Australia, some areas had the drought broken by flooding. Gundagai is a historical town, approximately halfway between Melbourne and Sydney, on the Hume Highway. Our pioneering ancestors recognised it as a good location for crossing the Murrumbidgee River. Gundagai has a colourful history of bushrangers, a gold rush and the infamous dog on the tuckerbox. Prior to mid-2010, Gundagai had not experienced flooding of the Murrumbidgee for some years.
The headwaters of the Murrumbidgee River are now part of the Snowy Mountain Scheme, with the Tantangara dam retaining most of the water at its source. The remnant catchment meanders out of the Snowy Mountains, and begins a long journey leading in nearly every direction of the compass, heading towards Cooma, turning north and running alongside the Monaro Highway and crossing into the Australian Capital Territory, south of Queanbeyan. In the ACT, the river passes through the “Murrumbidgee River Corridor”. The Molonglo River joins as a tributary before it crosses back into NSW. The river feeds into Lake Burrinjuck, south of Yass (NSW’s first dam constructed for irrigation, first completed in 1928). Downstream of the Burrinjuck, the Murrumbidgee widens again, drifting out to the Hume Highway. At Jugiong, it turns and heads south once again. A major tributary, the Tumut River, bringing water from the “other” side of the Snowy Mountains, joins northeast of Gundagai.
Rain fell in the various catchment areas upstream of Gundagai in late 2010. A “below minor” flood peak of the river was reached in early September at Gundagai (these terms are related to the height of the river). Heavy rain fell in the catchment area in October and a “minor” flood was experienced with the river height peaking at just over seven metres. November saw rains below the Burrinjuck Dam and another “minor” flood, with a peak of 6.5 metres. Rain continued to fall on both sides of Lake Burrinjuck, water began to overlap the dam. The catchment area of Blowering Dam on the Tumut River received heavy downpours, as well. Jugiong Creek was in flood, upstream of the township of Jugiong. Adelong Creek only has a small catchment area but it received significant rainfall in this period and fed into the Murrumbidgee as well. On 3 December, 2010, water was released in stages from the Burrinjuck Dam. The Murrumbidgee reached a “major” flood peak of 10.2 metres at Gundagai on 4 December, 2010.
A FAMILY QUARRY’S TRIALS
Tegra Australia is a family-owned quarry and concrete business based in southern NSW. Tegra manufactures, supplies and delivers quality aggregates, sands, soils, river stones, river pebbles and pre-mixed concrete, including decorative, everyday, special and high performance mix designs. It operates four quarries, seven concrete plants and two mobile batch plants. Tegra purchased the Jugiong operation in 1980 and the Gundagai operation in 2001. Both quarries are four kilometres from the Hume Highway. Significantly, both quarries are “surrounded” by bends of the Murrumbidgee River.
Tegra installed a wash plant at its Gundagai quarry six years ago. This operation utilises a 30-tonne excavator and a 30-tonne dump truck. The truck loads a feeder, which sends material to a scalping screen, with a 50mm aperture. The oversize is sold as river rock or is crushed and screened to appropriate sizes. The throughs of the scalping screen are fed to a triple-deck inclined screen, with apertures of 20mm, 10mm and 5mm; the minus 5mm goes to a sand screw. Tegra can make a range of natural aggregates and washed sand from its primary feed. Alternatively, with a portable crusher, it is able to crush the oversize and make a similar range of crushed aggregates and wash the crusher dust to make manufactured sand.
Tegra have an older fixed crushing and screening circuit at Jugiong, along with a cyclone sand plant, as well as a fine sand plant (cyclone). This site can produce similar products to Gundagai.
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On 3 December, 2010, with rain continuing to fall and the river rising, Tegra were formally advised that 48,000 megalitres would be released from the Burrinjuck Dam. The quarry personnel moved the mobile equipment to appropriate height ground, based on the advice of water releases and forecasts by the Bureau of Meteorology, but left the submersible pumps as they were.
Unknown to the locals, a landslide occurred on the road to Burrinjuck Dam, leading to a loss of communications. As well, gauges that could be monitored via the internet were knocked out. Ultimately, 184,000 megalitres of water was released from Burrinjuck Dam. Both of Tegra’s quarry operations alongside the river were virtually encircled by the existing riverbed. When the floodwaters came, the river claimed back its former riverbed. The floodwaters rose quickly and sliced through both properties, wiping out machinery, work areas, contaminating stockpiles and in some instances, washing stockpiles completely away.
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In the final “wash up”, Tegra lost a fine sand plant (sump, pump, cyclone plus tower and skid) at Jugiong and the retaining wall and feeder were wiped out at Gundagai. Three diesel pumps, a 33,000 litre fuel tank, 1100 volt power lines, pole and transformer were also lost at both sites. Jugiong was “out of action” for a week, Gundagai did not operate for six weeks. Gundagai had several stockpiles that had been certified ready for use. While they could not access them, the silt meant they had to wash the material again. This amounted to 60,000 tonnes of contamination, while approximately 10,000 tonnes were simply washed away. Jugiong lost 30,000 tonnes of product, with another 30,000 tonnes contaminated.
At the end of the disasters, the Australian spirit rose up as it has so many times before. Wagga Wagga was affected by the same flooding downstream, as were other areas. The small town of Eugowra, in NSW’s central west was flooded four times; when the media asked for a comment, most locals passed off their problems with a joke or a humorous comment. Who could not feel pride in seeing Brisbane and southeast Queensland residents picking up mops and shovels and heading off to help clean neighbours’ properties. Coal mines were shut for so long in central Queensland, the Australian GDP took a battering. Along with that, we had banana-induced inflation! Australia showed, once again, it is a land of extremes, and when we were knocked down, we stood back up, and in many cases, our neighbours helped us get back on our feet, once again.
{{image5-a:c}} As with so many other communities, businesses and industries, Tegra Australia, went back to work, cleaned up what it could, recovered what it could and carried on. With some juggling, Tegra was able to supply its own internal concrete demands. Today, other than the odd high water mark, it would be difficult to know either quarry had been affected by the flood. Gundagai was not too badly affected by the floods, having had many terrible floods in its past. The local farmers lost stock and a lot of fencing, but no lives were lost in the area.
When rain falls, and falls in the “right” places, there is no doubt, all the rivers run!•
