Deep Stream on the Denniston Plateau offers a spectacular journey into a rare sandstone world slated for destruction.

There’s a moment on the track to Deep Stream when you step out of the regenerating bush and onto a vast, undulating expanse of ancient sandstone. It feels like walking on the exposed bones of the land. It’s in the heart of the Buller Coal Plateaux, an uplifted landscape of mineral-rich sandstone pavements. 

It is also a landscape on borrowed time. 

The journey into this threatened world begins at Burnetts Face, a place steeped in the mining history of the West Coast. A 2km road walk leads to the impressive upper Waimangaroa River gorge where a track leads between the cliff bands. A couple of cairns guide the way to the river where an old iron bridge, once used to haul coal from the Taipo Mine, stands sentinel over the water. On the true right, look for track markers and a well-cut track heading uphill. After a short, steep climb you will drop down onto an old tramway. The track goes around a tunnel and keeps climbing until the foundations of old buildings are reached.  

The reward for your climb appears on your right: a beautiful sandstone creek, pooling to form a golden swimming hole. 

From here, you can cut directly across the open sandstone pavement towards Deep Stream gorge, where the area’s unique character is truly revealed. The landscape is a mosaic of tortured rock and hardy alpine vegetation, and has breathtaking views. It’s open, easy country to navigate and offers excellent campsites on the edge of the gorge. 

This isn’t just a fascinating landscape; it’s an ecosystem of immense value. Its harsh acidic soils, 600–800m elevation and high rainfall have created an environment where life has adapted in remarkable ways. Plants hunker down, resulting in bonsai-like forests where ancient southern rātā and pygmy pines hug the ground.   

This climate has also kept introduced predator numbers low, making it almost as precious as an offshore island sanctuary. It’s home to giant flatworms, snails and wētā, and is the only place where you’ll find the day-flying avatar moth. It’s a sanctuary for ancient velvet worms – living fossils older than tuatara – and it has a nationally significant population of geckos. It’s also a critical habitat for rōrōa great spotted kiwi and home to the endangered carnivorous land snail, Powelliphanta patrickensis.

And it’s all under threat. 

Though its public land, managed by DOC and Land Information New Zealand, a proposed mine expansion by Bathurst Resources would see the surface of these sandstone plateaux removed entirely. 

Bathurst’s proposal is for a 25-year open-cast mining operation to extract 20 million tonnes of coal. Modern open-cast mining is total ecosystem destruction. It involves completely removing everything from the surface – plants, soil and rock – to access the coal seam.   

The plan involves two new mining areas: expansion onto Mt Frederick south (the area the Deep Stream loop covers) and the Denniston Plateau, with a massive expansion of the mothballed Escarpment mine. Linking these would be a 20km haul road. This is a huge mine covering 1250ha – the equivalent of more than 1700 rugby fields will be stripped bare.

The extracted coal is destined for export and for use in steelmaking. It has no bearing on New Zealand’s domestic electricity supply. There are 6900 coal mines in the world and the International Energy Agency has said that declines in fossil fuel demand are so steep that there is no need for new mines or mine extensions. The world is moving to cleaner steel technology using electricity and hydrogen. 

Bathurst promises rehabilitation, but true restoration of this ancient, complex ecosystem after it has been strip-mined would be like trying to unscramble an egg. Rehabilitation efforts at nearby Stockton demonstrate that what is recreated is nothing like what was there before.   

The allure of jobs and prosperity for the West Coast is attractive, but the proposal is fragile, based on a boom-and-bust industry. We’ve seen it before, when Bathurst mothballed its original Denniston mine in 2016.  

Standing on the edge of Deep Stream, looking over the unmodified landscape, one can see what the entire Stockton Plateau once was. It is a profound and moving experience. It is also a call to action. Those who walk, climb and cherish these wild places must be their voice. This sandstone plateau needs us to speak up before the diggers arrive and this tramp becomes nothing more than a memory. 

Write to your MP, tell them you oppose the mine expansion and want to see this area of high conservation value permanently protected for its unique landscapes, biodiversity and recreation opportunities.