Northparkes began as an open pit mine but, in 1997, used the block cave method to extract ore for the first time in Australia. All images Northparkes Mines.
NORTHPARKES has a big year ahead of it with construction underway at a new copper-gold project that will continue its block cave mining method that has set it apart. Under the fresh leadership of Hubert Lehman, Northparkes was also focussed on continued investment in the community in which it operates.
Northparkes Mines started 2019 on a high, with the green light for a new project, and a new managing director appointed to lead it through its next growth phase.
In early January, the joint venture (JV) between China Molybdenum Company (CMOC) and Sumitomo announced that its new $200 million block cave project, E26 Lift 1 North (E26L1N), had received final approval, and would begin construction immediately – with full production expected by mid-2022.
The project would deliver about 40 million tonnes of ore over a 10-year period, and comprised 11km of underground development, an underground primary crusher, conveying systems and associated infrastructure, and an upgraded ventilation system to provide the mine with sufficient airflow to support development and production activities.
CMOC Group chief executive Steele Li said the JV was “really excited to see this project come to fruition” and to watch Northparkes continue to grow.
“Northparkes plays a pivotal role in our strong and long-term presence in Australia as an internationally renowned mining company,” Mr Li said.
The Northparkes’ project, previously owned by Rio Tinto, was about 27 kilometres north of Parkes in NSW and sat on 6000 hectares with a 1630 hectare mining lease.
Interestingly, the site also comprised a farm, which planted canola, wheat, barley, chickpeas and lentils.
Newly appointed managing director Hubert Lehman said Northparkes’ new E26L1N mine would be designed to utilise an increased level of automation and digitisation, to help deliver a safer and more productive mine.
“This is a major investment in the future of our business and a very exciting time for Northparkes,” Mr Lehman said.
Mr Lehman was officially appointed managing director of the company in February, after taking over from Jim Fowler in August last year when Mr Fowler was appointed chief executive of CMOC’s Tenke Fungurume mine in the Democratic Republic of Congo.
Mr Lehman joined the company as manager asset management in 2011, and as a member of the leadership team was responsible for overseeing the planning and execution of key elements associated with Northparkes’ strategic plan, and had been instrumental in the lead up to its new project at E26L1N.
Mr Lehman said the new E26L1N mine required up to 180 new staff at peak construction, and the additional personnel would largely be a mixture of Northparkes mine workers and central west contractors.
In a January newsletter, the company said employment opportunities included a mine surveying; drill and blasting; crushing and conveyor package engineering; mine technician and hydrofracturing monitoring; document controlling; underground training advising, and more.
The Block Cave Method
As the world’s easily accessible copper and gold deposits continued to be exhausted, Northparkes said mining companies increasingly turned to the block cave method as a simplified and more systematic way to mine and process large, low-grade ore bodies.
The method relied on gravity and natural rock stresses to fragment and recover the ore using minimal explosives.
Northparkes was the first mine to utilise the method in Australia, which is deployed in 1997.
And in 2015, Northparkes’ E48 Lift 1 block cave mine became the world’s most automated underground mine with 100 per cent of its production to come from automated loaders.
According to Northparkes, its block caving method began by digging an access ramp and a vertical extraction shaft to gain access to the ore body.
Then, a series of parallel extraction drives would be developed from one side of the ore body to the other, and between the extraction drives, a series of draw bells would be developed, while an undercut level would be developed at the same time.
Drill holes would then be charged and fired from one side of the ore body to the other, and the draw bells would be drilled and blasted to create a series of funnels to feed ore into a draw point.
The blasting would leave a large unsupported area that would cave under its own weight.
Once the ore was removed from the draw bells, the ore body becomes unstable and collapses into the funnels that continues to feed ore into the draw point.
From then on, the mining process was relatively simple.
The ore was collected and processes underground into smaller rocks before being transported to the surface for processing in the mill, and the blasting process was repeated.
The method would eventually process the whole ore body that would leave a deep depression from the top as the mine slowly caved in on itself.
Northparkes said the block cave mining method was “highly efficient” and had a number of advantages over conventional mining methods, such as greatly reducing the footprint by minimising waste mining; reducing greenhouse gas emissions through minimising ore re-handling; and minimising the use of explosives to fragment the ore.
In addition to its block cave mines, Northparkes also operated the E26 sub level cave, which began production in August 2016.
A Century of Mining Together
In 2018, Northparkes continued to invest in the local community in which it operates.
“We look forward to continuing to contribute to the local community in which we live and work for years to come,” Mr Lehman said.
While E26L1N would directly provide new jobs for the community, the company also provided events and social opportunities for local residents and workers, such as the Parkes Show, the Central West Pride March, the Boy’s Night In and the Central West Met Fest.
Northparkes also provided scholarships to students, sponsored the Mental Health Month, R U Ok? day and a Women in Mining event.
The company’s mine rescue team also performed strongly in the Victorian Mines Rescue Competition.
“The mine has been operating for 24 years and we have a vision of a century of mining together here in NSW’s Central West,” Mr Lehman said.
Good news continued with recent development consent approval to mine until 2032.
“We know the exploration potential of Northparkes and we believe we will discover more copper and gold deposits to take us even further into the future,” Mr Lehman said.
