Is this New Zealand’s most challenging site?
Western Bay of Plenty quarry Poplar Lane is known as New Zealand’s most challenging site. The team finds anything from andesite to rhyolitic material, to ash and clays.
Located in the Western Bay of Plenty, the Poplar Lane site and team of 14 is overseen by Dave Loach. Dave has been there since 2017, moving north from Fulton Hogan Masterton following a few years mining coal underground in Australia.
The site itself has been in operation since the 1940s but it wasn’t until the early sixties that the area of the current site began, cranking into full operation within a decade. Formerly known as Maketu Quarries, Fulton Hogan acquired the operation in the early 2000s. The quarry has around 50 years of life remaining.
Due to variation of the rock and consenting restrictions, Poplar Lane is one the most challenging quarries in the country. The rock is andesite – an extrusive intermediate volcanic rock in composition between rhyolite and basalt, common in the Western Bay of Plenty. Poplar Lane sits on the Central Volcanic Zone which runs through Rotorua, Te Puke, Taupō and beyond – the same fault that Whakaari / White Island sits on.
The nature of the rock means it is variable and challenging. The team finds anything from andesite to rhyolitic material, to ash and clays. A variety of additional manufacturing processes are required at Poplar Lane; in particular, a lot of washing.
All run of pit (face material) is washed following blasting. The site has an extensive water clarifying system and a water catchment area of 250 hectares drains towards the pit. There are many consent conditions to which the site must comply and all water must be processed before it flows out towards the Kaituna River catchment.
The current bottom level of the pond at the bottom of the pit is RL-55 (below sea level). The top is RL125. There’s a pūrākau about a speed boat and some jetskis. “There’s a rowboat down there,” says Dave. “We need access because of the amount of water that leaches into the place. We have to pump quite a lot of water to maintain the levels. Otherwise we’ll drown the pit.”
The water is pumped from -55 meters to 70 meters, where the plant is located. There, the water is treated before it heads to the Kaituna River catchment.
Most of the products produced are roading subbases. An important project for Poplar Lane was the Tauranga Eastern Link, the Bay of Plenty’s largest roading project and a key strategic transport corridor for the region. Poplar Lane provided most of the rock for the basecourses, asphalt, subbase and topcourse material. The quarry also produces chip and concrete aggregates for the Tauranga, Rotorua and Whakatane markets.
Poplar Lane has historical heritage value. “We want to ensure we’re in compliance so we work closely with both archaeologists and Heritage NZ,” says Dave. The site is situated in an area of cultural significance.
“There are pā sites located on our finished boundaries, and these are areas we will never mine”. The surrounding land is untouched and following an archaeological process, consent allows the top soils to be removed while ensuring any archaeologically significant areas are avoided.
Some of the original site land was recently sold to the Bay of Plenty Regional Council. Poplar Lane Quarry, Fulton Hogan and Stevenson have a longstanding and sound relationship with the Council. The portion of land is now being used as a regional park with a bike track and walking reserve.