Exploring the twists and turns of Bulmer Cavern

Success!: Cavers. from left, Gavin Holden, Jonathon Raven, Bruce Mutton and Kieran McKay, front, on finding the  link ...
NEIL SILVERWOOD

Success!: Cavers. from left, Gavin Holden, Jonathon Raven, Bruce Mutton and Kieran McKay, front, on finding the link between Mt Arthur's Nettlebed and Stormy Pot cave systems.

In a world where the surface is mapped so closely you can spot a street sign from space, it's easy to think of cavers as the last true explorers. Burrowing deep into the ground, recording and naming everything new that they find, they're the first and sometimes only humans to see what's secreted under the skin of the earth.

It is 30 years since Nelson's John 'Oz' Patterson and friends found the entrance into Bulmer Cavern, and together with some of those original cavers - Lindsay Main, Joe Arts and Alice Shanks - he continues to return, helping grow the known passage from an impressive entrance chamber to a 72km-long series of passages reaching north into the mountain. Now a group of cavers are hoping to lengthen it even further.

This week, Kieran Mckay and his wife Pip Rees will venture from their home in Takaka up to the pitted outcrops of Mt Owen, in the Kahurangi National Park near Nelson, on the latest leg of an effort to grow the Bulmer Cavern to what Mckay hopes will one day be 100km. The longest cave in the Southern Hemisphere is currently the 120km-long Burke's Back Yard system in Australia's Northern Territory, but though that seems a lofty goal right now, Mckay thinks there's also a good chance that title could one day be ours, putting Bulmer into the top 20 longest caves in the world.

River start: Caver Kieran McKay at the entrance to the Nettlebed system where the Pearse River emerges from   the Mt ...
NEIL SILVERWOOD/FAIRFAX NZ

River start: Caver Kieran McKay at the entrance to the Nettlebed system where the Pearse River emerges from the Mt Arthur Range.

Northwest Nelson is already a caving mecca: all but one of the country's 30 deepest caves and a good chunk of the 30 longest lie in the hokey pokey-like marble of Mt Owen, Mt Arthur and the Takaka Hill.

Bulmer Cavern, on the southern side of Mt Owen near Murchison, is 750m deep and more than twice the length of its nearest rival, the Nettlebed/Stormy Pot system, which Mckay recently connected to make the Southern Hemisphere's second-deepest system. Mckay and Rees will be joined by other caving friends on multiple trips this year, all of them the latest links in a chain of people stretching back decades, who have collectively spent tens of thousands of hours exploring and surveying underground.

But the sport doesn't come cheap. Expeditions cost thousands of dollars in helicopter transport, food, gear, and lost wages while underground, and the team's latest bids for Bulmer sponsorship have mostly failed so far - except for loyal Nelson sponsor Absolute Wilderness, which provides high-performance freeze-dried meals so good that Mckay and Rees sometimes have them for dinner at home.

Arrived: With his feet in the Nettlebed  ystem and his head in Stormy Pot, caver Kieran McKay  was among a team of ...
NEIL SILVERWOOD/FAIRFAX NZ

Arrived: With his feet in the Nettlebed ystem and his head in Stormy Pot, caver Kieran McKay was among a team of cavers who have linked Mt Arthur's massive cave system.

The recent expedition connecting Stormy Pot and Nettlebed attracted support from SPARC, the New Zealand Geographical Society, Red Bull and National Geographic, as well as documentary The Cave Connection, which has swept film festival awards all around the world.

This one hasn't managed that. But Mckay - a wiry figure with abraded knuckles and a thatch of brown hair - just shrugs, despite his estimation that the trip will cost the team between $30,000 and $40,000. They'll just have to do it themselves - as cavers always have.

"It's certainly not going to stop us. When you ask for sponsorship, people always say 'Well, would you go if you didn't get it?' The answer's always of course you do. It's just that we'll have to scale it down and it'll take a lot more time."

Because caving is not a spectator sport, Nelson Speleological Group member John Patterson points out: "It's never been glamorous". Cavers are private people, and there's a natural tension over publicity. They don't do it for the spotlight and would prefer to stay out of it entirely. They're also wary of single people gaining recognition for long-term group efforts. Caving is not a sport you can do alone, and it's not one that has easy goals.

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"We can put huge efforts in and find nothing, and then one day, serendipitously, you might find a new way on," Shanks says. "It requires perseverance and endurance. People who want to explore caves have to be in it for the long term.

"It is very much a group sport because you need a team to find the way on and rig the ropes, and if anything goes wrong when you're caving you have to rely on your mates to get you out. Hundreds of cavers have enjoyed Bulmer and each one has contributed."

On New Year's Day 1985, Shanks, Patterson, Main and Arts had gone out searching for caves after a prominent Australian geologist said it was unlikely there would be any of significant size on Mt Owen's southern slopes, fractured as the land is by plate tectonics. "That was certainly proved to be wrong," Patterson says.

He recalls peering down a large hole and noticing some light glowing at the bottom, which meant a side shaft and a possible entrance. Sure enough, they were soon exploring passages containing spectacular metre-long, finger-thick, wiggly helictites growing out of the cave wall. They'd never seen anything like it. A strong wind hinted at a big system beyond, but Patterson says they had no idea at the time it would get as big as it has. The longest cave in New Zealand back then was only about 25km.

From that first shaft, the cavern has slowly grown as cavers spent days squeezing through tubes, swimming and paddling through underground rivers and waterfalls, and walking wonderstruck through cathedral-like spaces, with ceilings, walls, and floors covered in spires; Castles of the Underworld, as a 1991 TV doco once put it.

This week, the team's attention is focused on a 500m stretch of unmapped space between an arm of Bulmer, and that of a neighbouring cave, Bohemia, which if linked would gain the former a big jump in distance. For years, Mckay has wondered if there could be a connection, and he's now confident there is. Lay a map of the two neighbouring systems on top of each other and it's easy to see why. All they have to do, he says, is dig and squeeze and wriggle until the straggly ends of this massive underground puzzle become one.

Last year, a group spent five days underground, investigating. They dumped a special bright green dye into a small stream at the end of Bulmer, and stationed lookouts at water exits around the base of Mt Owen. A day and a half later, the rush of dye came gushing out of the streambed at a place called Blue Creek Resurgence, about 8km away as the crow flies on the northern side of the mountain.

"That took everyone by surprise," Patterson says. "We weren't expecting that at all."

Water flows were high, but still, 1 1/2 days is quick. Mckay says the tiny stream probably empties into a much bigger underground river, which hopefully means one huge system, water flowing through large open passages under Mt Owen. Probably over 100km long. Maybe even 200km. It has, Mckay says, made cavers rethink the parameters of what they thought possible. It's the kind of system cavers dream about, but to explore it, they're going to have to learn to dive, as if the thought of forcing your ribcage through a sharp, tight squeeze, tonnes of rock above and below, wasn't claustrophobic enough.

The exploration team will have to dive an underground river to get through the drowned passages to dry caves beyond. They don't yet know how long the river is, though it's not expected to be more than 100m. There aren't many dive sites in the world as isolated as this one.

"It's not so much the dive, but what happens if something goes wrong?" Mckay asks, rhetorically and quite cheerfully. "Who's going to come and help us?"

That's not forgetting that Bulmer Cavern is, like many New Zealand caves, prone to rockfalls, and was once described by a caver as like "a huge block of Weet-Bix that's had weevils through it". Mckay himself had an abseiling fall there in 1999, breaking his arm and smashing his jaw. An 80-strong team rushed to help rescue him, but he was able to walk out of the cave. He hasn't had an accident that bad since, touch wood.

His answer to the danger is to just go do it. "Cavers are very good at coming up with a solution for problems. You just have to, otherwise you don't do anything. It's just another obstacle, even though it's a little dangerous."

Why do this at all? As well as the thrill of going somewhere that few people have been before, John Patterson points out that underground rivers in Tasman have the same protection as above-ground ones, and the more that is known about them, the better, as they could affect water rights and mining applications.

A chief aim of cavers is to protect them - ironically, from too many cavers. The sport is not just about recreation and physical challenges, Shanks says, but also to alert scientists to unusual and new records from deep underground where they cannot easily go.

Mckay is quick to point out that they're just the latest to hit the rock in an effort to find something new. They'll do what they can - and when they've gone as far as they're able, someone else will come along and pick up the reins.

"We're creating a pathway for someone else to carry it on if we don't manage it," he says. "We've just got to keep up the momentum."

 - Sunday Star Times

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