Nelson Silos delivered a lime silo to the Karlawinda Gold Project at Newman in Western Australia. ABHR speaks to Eric Nelson, the company’s Managing Director, to learn more about the 8000-kilometre round trip.
A gold mine, 30 kilometres south of Newman, Western Australia, needed new infrastructure as part of a site expansion.
The site’s ball mill, which uses a mixture of lime and water to separate the gold from the other material, required a new silo to feed the lime.
Lime, part of the cement range of materials, is a high-density product. Where grain can reach 750 kilograms per cubic metre, lime can reach one tonne per cubic metre.
Eric Nelson, director of silo manufacturer Nelson Silos, says the system requires a robust pressure vessel to handle the dense, heavy material.
“Material is added to the silo through a pneumatic conveyor, which uses a heavy blower pipe and special, wear-resistant bends. Lime is a very abrasive material, so everything handling must be able to handle it,” he says.
“Aeration pads at the cone of the silo introduce compressed air at various time intervals to dislodge the lime and make it act like a fluid. Without this, the lime won’t flow on its own.
“It then reaches a rotary valve which measures the quantity required then drops it onto a conveyor.”
Nelson Silos was chosen to deliver the new silos along with all of its associated fittings, including the rotary valve. As part of its offering, the company also provided the civil foundation design.
Ease of maintenance was also a critical component of the silo’s design. The silo stands at about 25 metres tall, measuring in at about 4.6 metres in diameter and features mezzanine level access platforms to allow site staff easy access to service the rotary valves and vibropad equipment. Ladders and platforms to the roof deck are also included to provide access to the dust collection and extraction unit, and an over/under pressure valve was installed. To help change out the bends of the blower pipes that will wear with time, the roof deck has walk around access.
As the mine is located thousands of kilometres from Perth, the site was provided with a suite of spare parts for most of the mechanical items and wear-heavy components.
Nelson Silo’s engineers also took the location’s environmental conditions into account, ensuring the temperature variations between the Pilbara’s sweltering days and chilly nights wouldn’t affect the silo.
Nelson says the installation only took a couple of people three days to complete, thanks to the prefabricated nature of the company’s silos.
“The silo was transported in two, large pieces – about 18 metres long. Each section is manufactured, tested and fitted together in the factory environment, meaning we know the end product will be installed as intended,” he says.
“This significantly reduces the amount of site work required. That means less time working at heights around heavy equipment, making the work much safer.
“Traditionally, when buying a silo, it could take weeks or even months to be installed, costing an enormous amount in disrupted productions and labour. This method keeps it all simple, safe and effective.”
Nelson Silos supply pre-manufactured silos for a number of different industries, from agricultural, to food, cement, plastics and mining.
With modern courier dispatch times, Nelson Silos can provide delivery of any spare parts required within a week. The company has made the conscious effort to source its components from Australian manufacturers and suppliers to support local business and reduce turnarounds.
Transport is a major part of the business, which is why the company has a number of full-time employees dedicated to logistics. Based in Rochester, Victoria, the company has delivered multiple silos to places thousands of kilometres away, like Darwin, Port Headland and Kalgoorlie.
“We don’t use contractors because it gives us more control over the customer experience,” Nelson says. “Our delivery team can also do the installation side of things, with staff in the pilot cars for heavy transport vehicles able to get out and build them.”
“That’s one of our secrets for reducing time spent on site. The people handling the installation have done it literally 50 to 60 times before.”