From blot to beauty: How open-pit mines are being transformed into lakes and wetlands.
Open-pit mines are being transformed into lakes and wetlands. Jo Lines-MacKenzie reports.
Once just a scar on the landscape, open-pit mines are being given a new lease of life.
Huntly couple Murray and Jennifer Allen are transforming a North Waikato mine into an environmentally acceptable recreation area.
They bought Solid Energy’s Huntly East mine in 2018 and are working towards creating a lake and adjacent wetland.
Solid Energy’s Huntly East Mine was closed and sealed in 2017 following the collapse of the company in 2015.
The Allens, who took over earlier this year, are pleased with the progress they’re making.
‘‘The lake is catching us by surprise,’’ Murray said. ‘‘It’s filling at eight times the rainfall – so we’ve actually lost quite a few trees that we were going to cut out before the water got to them. They’re getting drowned in the lake.’’
They had thought it would take about 25 years for the lake to fill from rainwater.
It will eventually be a deep-water lake and, at 1.2km long, it will be big enough to hold international waka ama contests and rowing races.
The lake already has a large number of eels and the Allens will encourage more wildlife.
‘‘We don’t want any motor sports unless they were electrical – we don’t want any pollution in the lake,’’ Murray said.
‘‘We’ve just ordered 6000 wetland plants that we are going to be planting in the next couple of weeks.’’
They’ve also got a digger working to cover the tracks on the property, along with 80 cows that are cleaning up the pampas.
It’s not the first time the couple have reclaimed a mine. Their farm had two clay quarries that they rehabilitated.
All going to plan, they’ll hold their first event – a music, arts and craft festival – in February.
Eventually, Murray said they’d like to get clubs and organisations interested in setting up facilities at the rehabilitated mine.
‘‘I want organisations that are looking at doing something that could involve Hamilton, Tauranga and Auckland.
‘‘In an hour-and-a-half drive, we’ve got over half the population in New Zealand. The idea is to have Huntly to be a playground for the three cities.
‘‘It’s just a nice day trip for people to come down and have some space to run around on – they’re being forced out of the cities at the moment.’’
Theirs won’t be the first rehabilitated coal-mine pit. Lake Puketirini in Huntly is another.
Puketirini is about 54 hectares, about half the size of the volcanic Lake Pupuke in Auckland, but slightly deeper, since Puketirini’s deepest point is 64m. It covers the same area as Lake Rotoroa – Hamilton’s lake – which has a maximum depth of 6m but averages 2m.
Puketirini was predominantly in private ownership before being obtained by the Crown for coal-mining operations and state-housing purposes between 1940 and 1980.
The original lake, Lake Rotoiti, became Crown land in 1865 and was earmarked for coal mining in 1929.
Lake Rotoiti was eventually considered dry land in 1986, after being drained for mining. Mining ended at Weavers Opencast Mine in December
1993, after which Solid Energy began a project to rehabilitate the disused mine and recreate the lake.
It was the first New Zealand coal pit of its size to be transformed. It opened in
2003 for off-water recreational activities. In December 2006, Waikato District Council acquired from Solid Energy approximately 104ha under the Public Works Act 1981.
Once the coal mine was closed, the tributary Puketirini Stream, previously diverted around the pit, was realigned to drain into the pit so that, combined with rainfall and run-off, the lake would fill. It took 11 years.
Along with the development of the lake, the land was reshaped in the early 1990s and over 30,000 trees and shrubs were planted. An extensive network of walkways and mountain-bike trails were also developed.
Puketirini Management Committee provides strategic oversight and community input into the development of the park and user issues.
The day-to-day running of Puketirini is managed by the district council’s parks and facilities staff, who also undertake the maintenance and development of the reserve, and deal with planned and reactive issues related to the park.
Lake Puketirini was opened for on-