Established in 1986, Blackhead Quarries is a joint venture between Palmer & Son and Fulton Hogan and operates a number of quarries in the region surrounding Dunedin, in New Zealand’s South Island. Opened in the 1950s, the company’s Blackhead Quarry, located on Green Island, produces 300,000 tonnes of aggregate per year.
The company also operates quarries at Logan Point, Dunedin, as well as Balclutha and the Walton Park sand plant in Fairfield. The Balclutha quarry, located approximately 80km south-west of Dunedin, is the largest producer of quality aggregates in the South Otago area and supplies around 30 different products.
With a population of 130,000 people, Dunedin is the second largest city of New Zealand’s South Island and is the principle city of the Otago region, with the harbour and the hills surrounding it being the remnants of an extinct volcano. It has a diverse economy, but the city’s most important activity centres around tertiary education. It is home to the University of Otago, New Zealand’s oldest university (established in 1869), and the Otago Polytechnic.
While primary industries are the main drivers of New Zealand’s economy, in recent years the Otago region has experienced a large increase in tourism. As a result, local government authorities have increased their expenditure on infrastructure in the region, driving strong demand for quarry products.
Investing in the future
Until recently, Blackhead Quarry’s Balclutha quarry operated a fixed crushing plant that required rock to be transported up to 5km from its primary sources to the ageing facility. In the interest of improving operational flexibility and safety, the company decided to invest in a new mobile crushing and screening plant for its Balclutha operations.
Blackhead Quarries has worked with plant specialist Metso in the past, having bought its first Lokotrack mobile impact crusher in 2005 from the company. With its latest acquisition, Blackhead operates the largest fleet of Metso mobile crushing and screening equipment in New Zealand. But the company’s relationship with Metso and Mimico, Metso’s dealer in New Zealand, dates back further. Much of the equipment in the company’s original fixed plants includes Nordberg, Allis Chalmers and Barmac machines, which can all be traced back to Metso origins.
Tony Hunter is the general manager of Blackhead Quarries and has been involved in the industry for over 30 years. He is a fifth-generation descendant of one of the company’s original founders. Tony has overall operational responsibility for all of the company’s quarries.
He said that being near the sea, Blackhead quarry’s fixed plant was suffering from extensive corrosion issues. Management was worried about the safety of fixed walkways and the quarry’s 23 conveyors.
“Five years ago, we decided it was best to build a new plant at Blackhead with only nine conveyors and no walkways,” he said. In doing so, the existing Nordberg C100 jaw crusher, a cone crusher and Barmac 9600 crusher were relocated.
The new plant is fully automated and was designed to keep the amount of structural steel work to a minimum, which led to the elimination of walkways.
“For maintenance we use cherry pickers, which give better access to the equipment than walkways, and, in our opinion, are much safer for our maintenance staff,” he said.
Hard rock drives need for reliable wear part supply
Gavin Hartley is the quarry manager at Blackhead quarry, and has 10 years’ experience with the company. He describes his job as, “making stones as cheaply and efficiently as possible while ensuring that his staff is safe.”
“Staff compatibility and continuity are very important, as is giving our people the right tools for the job,” he said.
The Blackhead quarry produces a range of quarry products, including base courses (for road base), sealing chip, asphalt dust and railway ballast. The rock quarried in the Otago area is a heavy, fine-grained rock that is hard, brittle and abrasive.
“Jaws and liners typically last about 3500 hours, and Barmac tips only about 500 hours,” Hartley said. “Bucket teeth can last anything from 800 to 2000 hours.”
The reliable, local supply of wear and spare parts is important.
The importance of local support
“Here in New Zealand we are a long way from Finland, or other countries where rock crushers are manufactured,” said Hunter. “It’s important that we can get ready access to the support we need, because a crushing equipment failure can stop our production.”
“New Zealand is a small country and Dunedin is a small community,” said Garth Taylor, crushing and screening business manager at Mimico. “If Blackhead Quarries has two LT106 jaw crushers they only need one set of spare parts. They have two of New Zealand’s 12 LT1213 impact crushers. The number of Metso machines in New Zealand means that we keep a range of spare parts to support our customers.”
While there are more brands of crusher available, Hunter likes to work with organisations that support the local quarrying industry.
“The large number of Metso crushers in New Zealand means that there’s good support locally,” he said. “Wear parts are one thing, but these technically advanced machines can be stopped by the failure of a small component like a sensor. While we perform most of the maintenance ourselves, it is good to have local technical support. Mimico provides all that we need and we have a great relationship.”
Blackhead Quarries experienced the benefits of crushing and screening at the quarry face when it introduced its first mobile crusher in 2005. The company has been growing its fleet of Metso Lokotrack mobile equipment ever since, gradually reducing its reliance on fixed plant.
“You can’t bust a rock without energy and even though it is fuel efficient, the mobile plant uses a lot of diesel – the machines have large motors to move them around, as well as for processing rock,” said Hunter. “With our move to mobile equipment and reduction in the number of trucks, our diesel usage has remained about the same, but we no longer consume electricity in our fixed plants – so overall, our energy costs have gone down in the order of $100k per annum.”
According to Hunter, the reduction in truck usage has also delivered benefits in respect to staffing levels, site safety and maintenance costs.
Blackhead Quarries now owns a total of 10 Lokotracks across its sites, and is the largest user of these machines in New Zealand.
“The Lokotrack fleet has become important to our business,” said Hunter. “Our original LT1213 unit was the first one in New Zealand and is still operating – and now we have more across our quarries. They are the core of our mobile fleet.”
Going mobile at Balclutha
The company’s most recent addition to its Lokotrack fleet took place in 2017 at its Balclutha quarry, which mostly produces road and construction materials as well as manufactured sand. Part of the quarry’s production also feeds the concrete plant next door. The quarry’s demand tends to be seasonal – the Clutha District Council, for example, has an annual road sealing season, and there are periodic maintenance gravel contracts.
Craig Upston, quarry manager at the Balclutha quarry, is a veteran of the industry. Having been with the company for 25 years, he is a third-generation employee.
“The shape of the product is critical for our customers – if we don’t get it right it will be rejected,” he said. “Our Barmac crusher helps us to achieve consistent product shape and quality.”
The Metso Barmac vertical impact crusher uses an autogenous (rock-on-rock) crushing method. Its adjustable rotor speed and feed rate give operators precise control of the grade and shape of the final product. From Upston’s perspective, moving from fixed to mobile plant was a matter of future-proofing the quarry.
“We were planning to replace our older Barmac with a new one, and because the market for Balclutha’s product has a lot of ups and downs, being able to move the crusher around to different sites creates better business flexibility,” he said.
The quarry was originally opened some distance from the town of Balclutha, but with the growth of the town bringing suburbia closer to the quarry, the issue of dust has become a problem. By eliminating the fixed plant that was close to the road and moving to Lokotrack machines, quarry staff can choose where crushing occurs. The reduction of truck movement and decommissioning of the fixed plant has made it easier for the company to manage dust.
At first Upston proposed putting a new Barmac on tracks then in five years’ time adding a tracked cone and jaw crusher as well. As it turns out, the company’s management loved the idea and acquired all three Lokotrack versions in the same year.
Uptson’s first exposure to Metso crushers was the Nordberg GP300 when Blackhead Quarries took over from Fulton Hogan around 2003.
“We already had a lot of Metso gear and had a great run with the crushers, so it made sense to keep on dealing with the same company,” he said. “As we were happy with the Metso equipment that we already owned, it was a no-brainer.”
The decision to move to tracked equipment was driven by the need to quarry without access to electricity. Additionally, if the quarry had to relocate, it would be easy to move the equipment elsewhere.
“If you bolt it to the ground there is no flexibility,” he said. “All the mobile plant is self-powered. We don’t have any three-phase power at the new quarry face, so mobile, diesel-powered crushing and screening is the only way to go.”
Reducing dependence on fixed plant
In July 2017, Mimico supplied a Metso Lokotrack LT106 mobile jaw crusher along with an LT200HP mobile cone crusher and a ST3.5 mobile screen for the Balclutha quarry. An additional ST3.5 and a LT7150 mobile Barmac VSI (impact) crusher were supplied in October.
At a time of increasing infrastructure expenditure in the growing Otago region, being able to produce large quantities of quality aggregate in a more flexible way allows the company to be responsive to market fluctuations, which is important for Blackhead’s future business success.
The company also deploys some of its Lokotrack mobile crushers and screens in contract crushing operations around the Dunedin area and is now looking to purchase another LT106 for a new job that will deliver half a million tonnes of aggregate for a major road building project.
In a world where concern for the environment means that people look at mining and quarrying with an increasingly critical eye, Hunter has a positive outlook on the future. “This is a simple business. You can’t have a city without stones, and so we are lucky to be a mature company in a mature local economy, that will always need infrastructure,” he said. “In buying the Lokotrack equipment, I am trying to set the company on a good path for whatever may happen over the next 10 to 15 years to come and beyond.”