Derek Grzelewski

Tales of the underworld

Suspended between two worlds, a caver ponders the enormity of Harwood’s Hole—one of the grander entrances to the unseen labyrinths that riddle the marble mountains of north-west Nelson.

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In motueka—a small town renowned for its fruit, housetrucks and organically conscious hippies—the stress level was undetectable. Along the main road muscle cars lazily rumbled for attention, and some­where a child was hammering out a chore of piano scales. The town felt safe and friendly, like a place where nothing can ever go wrong.

That was an hour ago. Now, with the clammy hand of fear at my throat, I am starting to wish I had stayed in town. Though only 10 kilometres away, I am in a world so different that I could well be on another planet. Under­ground and underwater, inside the bowels of a marble mountain, I am finning against the gentle current of the Riwaka River. My hand slides along a nylon version of Ariadne’s thread, strung out by my guide. All I can hear is my breath hissing in and gurgling out through the mouth­piece of my air supply—until the steel air cylinder on my back hits the rock ceiling with a loud clang. In this silent, liquid gloom, the slightest sound has the intensity of a Chinese gong.

My torchlight zigzags across the grey walls, revealing an austere and surreal landscape like a derelict railway tunnel. The passage—its walls as cold as glacial ice—slants down, then turns upwards and opens like the wide end of a horn. I surface next to my guide, Sean Mitchell, resting on a pile of boulders, and take a draught of moist cave air.

We are in a chamber the size of a circus tent. When we turn off our lights, the darkness is absolute, and so thick I can feel it pressing against my face. These walls have never seen sunlight, yet we have only passed the entrance sumps, flooded siphon-like passages that form a kind of Lewis Carroll mirror gate into another world. Ahead, through clay-coated chambers and tunnels, through twisting squeezes which corkscrew like deformed keyholes, and through yet more sumps, the cave continues for no one knows how far.

Sprawled on the riverside rocks in total darkness—monsters with black wet suit skins, flippered feet and faces distorted by hoods and masks—we may look a natural part of this subterranean world, but it’s only an illusion. Caves make you feel alien and out of place in a way that no other earthly landscape does. They are black holes in the imagi­nation; cold, eternally dark places inhabited by creeping and slithering creatures, places where early explorers found themselves involuntarily slicing the air with crosses and mumbling paternosters. They epitomise our fear of dark­ness, of confined spaces, of unfathomable depths and, ulti­mately, of the unknown.

Since ancient times, caves have been considered the domain of death and suffering. If mountains, with their grand, airy vistas, were the abode of the gods, caves sym­bolised the darker side of human experience. Here was the kingdom of Hades guarded by three-headed Cerberus. Here lived bloodthirsty bats and dragons, trolls and gob­lins, the Greek Minotaur and Austrian Tazzelwurm—in fact, most of the monsters and nasties any folklore has ever produced. Occasional discoveries of prehistoric mammoth size bones and skulls within caves only strengthened such beliefs.

Proteus, a blind, pale-pink, 20 cm-long cave salaman­der found in Slovenia, was said to be the freshly-hatched offspring of a dragon, soon to be spitting fire and terroris­ing villages in search of toothsome virgins. How else could the unearthly adaptations of the creature be explained? It has both lungs and external gills, and can detect light and scents through its skin, change colour when brought into the daylight and survive without food for three years!

Perhaps it was a cave similar to Riwaka where the Tolkienian hero Bilbo Baggins traded riddles with the wretched Gollum: “Is it nice, my preciousss? Is it juicy? Is it scrumptiously crunchable?” I could almost hear Gollum hissing at me in the dark. “If precious asks, and it doesn’t answer, we eats it, my preciouss. If it asks us, and we doesn’t answer . . . We show it the way out, yes!”

I flick on my torch to dispel the monsters. Sean grins his beachboy smile at me; he’s no Gollum and I don’t have to bargain for my life. We dive into the gloom and follow our rope back towards the sunlight.

[Chapter Break]

Around the world, caves are almost as common as mountains, but because they are out of sight we are hardly aware of their existence. “Under the Earth’s crust, in absolute darkness, there exists such an enormously great world, that we can with sonic justice speak of a new continent,” wrote Swiss speleologist Alfred Bogli.

The dimensions of that continent are staggering. Un­der Mount Api in northern Borneo is a chamber so large that it could accommodate 17 football fields side by side. One of the chamber’s original explorers, an accomplished and well-travelled speleologist, suffered an acute attack of agoraphobia while he was inside.

The world’s longest cave, in Mammoth-Flint Ridge, Kentucky, has passages totalling 563 kilometres in length—equivalent to a return trip from Auckland to Taupo.

A cave in Mexico boasts a 410-metre shaft, Sotano de las Golonclrinas, smooth like a canon and aimed at the sky.

Most caves are found in limestone and marble, sedi­mentary rocks formed from the calcium-rich shells of dead molluscs which, over millions of years, have been com­pressed and solidified. Although the two rock types are chemically identical (calcium carbonate), they differ in their genesis and physical appearance. Usually matte white or light grey, limestone remains relatively unaltered once it has been laid down, and shells of prehistoric animals can often be seen in the rock.

Marble is limestone that has been metamorphosed by high temperatures or pressure deep within the Earth’s crust and then pushed back up to the surface by tectonic movement. Such traumas produce a harder, crystalline rock, frequently tinted with grey, brown or pink hues lent by traces of other minerals. Together, limestone and mar­ble constitute 5-10 per cent of the Earth’s surface.

Although there are caves in many parts of New Zea­land, the deepest, longest and probably oldest cave sys­tems are to be found within a 90 km-long belt of marble arching from Abel Tasman National Park towards  Murchison, across Kahurangi National Park. This layer of rock, formed in the Ordovician era over 440 million years ago, is not continuous but resembles a chain of chunky, steeply rising islands embedded in the underlaying shales, phyllites and schists. The highest of them are Mt Owen (1875 m) and Mt Arthur (1795 m). Their bald, ice-scoured tops, about 100 and 80 square kilometres respectively, are an otherworldly landscape of bulging rock slabs cut by rifts and crevices, dotted with shafts and craters.

The rock, sharp as coral, is weathered by rainfall aver­aging over 2100 mm annually, but these rugged marble tablelands have the dry air of a desert about them. You can walk for hours and not find any surface water. But the water—streams and rivers, waterfalls and pools—is there all right, deep underground.

Landscapes like these, collectively known as karst (after a region in Slovenia), usually indicate extensive subterra­nean labyrinths, “plumbing systems” draining entire mountains. One such area, at the northernmost tip of the marble belt between Motueka and Takaka, is Takaka Hill, where I’ve come to see the New Zealand equivalent of Sotano de las Golondrinas, the 176-metre-deep entrance shaft to Harwood’s Hole.

In the picnic area at the end of Canaan Road, I meet Kerry Silverwood and his son Neil, my caving guides. Together, they make a good team: youthful daring tem­pered by the hard-bitten wisdom and resourcefulness of the seasoned West Coaster.

The Hole is roughly the shape of an hourglass, and the long rope descent begins just above its narrowest part. Our 200-metre rope weighs close to 20 kg and feels as taut as a cello string. As I inch my way down, fear creeps in and imagination offers scenarios in which the rope snaps with a twang, there is a moment of zero gravity and then an endless fall, a fall where you suffer from motion sickness long before you reach the bottom.

But the titanic size of Harwood’s Hole overwhelms all other emotions. If you could stack two Christchurch Ca­thedrals inside the pit, the upper steeple would still be 40 metres below ground level.

Abseiling on a rope this long has its fine points. Go too slowly and the harness will cut the blood circulation so effectively that your legs will be numb before you reach the bottom. Go too fast and the abseiling rack can over­heat until it’s too hot to touch.

“Don’t stop at the bottom,” Kerry warned me. “Keep walking down the slope as you untie the rack or it might melt the rope!”

Should you speed out of control, it is virtually impossi­ble to stop or even slow down. The last accident here happened just like that. The victim suffered severe rope burns and a fractured thigh bone. The rescue, Herculean in its scope, took nearly 12 hours.

During the first part of the descent, life is abundant all around me. Bonsai-like trees reach out for sunlight from their cracks in near-vertical rock; layers of spongy moss absorb the water constantly dripping from above. Swal­lows dart towards their hidden nests through a multitude of insects enjoying this unusual ecological niche. But fur­ther down, as the daylight recedes, so do the last plants and animals. Finally, I can see nothing but bare rocks with an occasional hint of algae.

At the bottom, in a chamber some 50 metres across, Neil explains the techniques of caving: “Forget all about grace, about trying to stay clean and dry. You have to move quickly and safely, but without unnecessary aesthet­ics. Think ferret; ferrets would make good cavers.”

We are wearing standard caving attire: white meat-workers’ gumboots, one-piece Cordura overalls with lay­ers of fleece underwear, a harness with an abseiling rack and a carbide light generator, backed up by two or three electric torches.

The generator is one piece of equipment which cavers both love and hate. In a pint-sized, pressure-proof container worn on a waist belt, calcium carbide is mixed with drip-fed water, producing acetylene gas which is channelled by a hose to the front of the helmet and lit with a built-in lighter. It’s like carrying a welding torch on your forehead. The entire contraption can be temperamental and is prone to untimely malfunction, but it also produces a pleasantly warm and powerful light far outlasting its electric counterparts. On long caving escapades-20 hours or more—carbide is the only practical light source.

We climb down a slope of loose rocks, then follow an underground river, our hands and legs spread-eagled against the tubular walls of the passage. Crystal pools of water so clear it is impossible to judge their depth cascade into one another. We abseil through the resultant water­falls, climbing down or jumping smaller steps and chutes.

“I’m not much of a swimmer,” Kerry admitted before setting out, “I’ve brought a few of these.” He produced an impressive range of empty soft-drink bottles. “Three or four inside the overalls make a fellow float quite well.”

It seems incredible that what today is the deepest natu­ral shaft this side of the Equator began life as a bowl-shaped pond littered with rotting vegetation. Water read­ily absorbs carbon dioxide—some from the air, but much more from soil, where plant metabolism produces con­centrations of the gas which are ten times higher than that in the atmosphere—forming a weak solution of carbonic acid. Marble and limestone, being alkaline, are readily dissolved by the acid. As water seeps downwards into the ground, it dissolves rock as it follows the lines of natural weakness—cracks and hairline fissures—widening them until, many thousands of years later, they become tunnels and chambers of astonishing shapes and sizes.

Warm temperature, heavy rainfall and steep land are all accelerating factors. In Riwaka Basin, scientists estimate that in a single year around 100 cubic metres of marble can be dissolved from each square kilometre; in the King Country, with similar rainfall but less dramatic verti­cal relief, the rate of removal of rock is estimated to be 70 cubic metres. Both are moderately rapid on a world scale.

The first stage of the cave-making process, when the nascent caves are completely filled with water, is known as the phreatic phase, and, because all walls dissolve at a simi­lar rate, the resultant passages often have a tubelike sym­metry. In time, as the water keeps working its way down­wards, the upper walls of the phreatic tubes become ex­posed to air, while their bottoms act as riverbeds. Depend­ing on the amount of water in the system and the gradient of the tubes, these underground rivers can be meandering streams or, as in Harwood’s Hole, gushing torrents. At this stage of cave development, known as vadose, rock is not only dissolved by acid, but also, even more vigorously, eroded by the physical force of moving water. Often the river flowing along a phreatic tube gouges a deep rift, so that a cross section of the passage comes to resemble an old-fashioned keyhole.

As long as the water continues to percolate from above, the cave is “alive” and constantly changing. Dripping, trickling, chiming, roaring, the underground water tire­lessly wears away the obstacles along its way, creating a labyrinth of passages. Caves themselves become under­ground watersheds, with their own rivers and tributaries, white-water rapids, waterfalls and crystal lakes so still that they, too, seem made of stone.

We climb further down into the cave. The pools grow deeper, and occasionally Kerry adds another bottle to his already bulging bust. The walls around us bristle with stalactites and stalagmites. Some are fragile, like spun glass; others solid Greek columns. Sometimes they join together to form intricate chandeliers, curtains and “dwarf’s beards”—waterfalls of white rock frozen in mid-air.

These structures, collectively known as speleothems, are by-products of the cave-building process. As the cal­cium carbonate-laden water seeps and flows through the passages, much of the carbon dioxide bubbles out—the way a fizzy drink goes flat if constantly agitated—and the solution becomes supersaturated with calcium. The dis­solving reaction is now reversed, and the calcium carbon­ate recrystallises as a solid. With the regularity of pendu­lum clocks, beads of water drip from roofs and arches, and thin rings of crystalline calcium carbonate build around each droplet like salt patches from evaporating salt water. With time, the stacked-up rings form hollow tubes called soda straws. These tubes eventually disappear under new growth of crystals and become stalactites. The water drip­ping from their tips releases still more calcium carbonate as it hits the floor directly below, forming stalagmites, sometimes mirror images of the stalactites above.

This process, repeated in its infinite variations, can produce an exquisite cave decor, a tantalising display of beauty comparable perhaps only with the artwork of hoar­frost. But the “stals,” as they are commonly known, are not just aesthetic; stored within them is a wealth of geological and climatic information.

“The cross section of a stal shows annual growth rings just like those of a tree trunk,” says Trevor Worthy, a Nelson-based caver and palaeontologist. “Because the tem­perature in deep caves equals the average annual tempera­ture above ground, by analysing the ratio of oxygen iso­topes across the growth rings, we can learn how the tem­perature has changed over thousands of years. We can also compare the results with similar analyses from Antarctic ice cores and cores from the seabed in deep trenches—the methods verify each other.”

Near the end of the cave we leave the increasingly narrow streamway and climb up towards the exit known as Starlight Cave. Suddenly, we find ourselves in the middle of a Hans Christian Andersen fairy tale. Awoken by our lights, the walls, the stalagmited floor and the ceiling thick with stalactites—this entire shark’s jaw interior—glitter with delicate stardust: tiny crystals embedded in the rock.

Through the last waist-deep pool we wade into day­light. After four hours in a cave never warmer than 4°C, the outside world greets us with the heat of a sauna, the pungent smell of the forest and the blue, blue sky.

Every year, towards the end of December, some of the most enthusiastic cavers from all over the country gather for a sort of “Black Christmas” at Bulmer Lake in the Mt Owen karstfield. This wild and inhospitable place combines the harsh climate of the Southern Alps with heavy West Coast rainfall. A trip up here is always an expedition requiring military-style logistics and helicopter transport. On occasions, unable to cross the often-impassable Owen River, cavers have been trapped for several days in their base camp.

Within the karstfield lies a vast cave complex called the Bulmer Cavern. Since its discovery in January 1985, over 40 km of passages have been explored and surveyed, mak­ing it the longest cave in New Zealand. Yet there are still so many new “leads,” so many question marks on the cave’s mural-size map, that, as Lindsay Main, the expedi­tion organiser, tells me, it is rare to go into Bulmer and not find at least a few hundred metres of unexplored territory.

The cave comprises upper and lower levels which could almost be separate systems were it not for a 100-metre­deep connecting shaft known as the Lion’s Den. Climbing up this mega-tunnel at the end of a 20-hour exploration blitz is a daunting prospect even for the most experienced cavers, so a short cut into the lower level has been eagerly sought. One possibility, tenderly referred to as the “Dig,” is a narrow, horizontal fissure filled with sediment, about two hours from the main entrance. If penetrated, it could bypass not only the Lion’s Den, but its decidedly awkward extension, the 200-metre-long Castration Corridor.

Cavers got down on their knees and began to dig.

Digging is the darker side of caving and not everyone’s idea of adventure. You kneel or lie in a constricted “squeeze,” gnawing at it with a sawn-off shovel and filling up a plastic rubbish bag with the debris. When the bag is full, you crawl out backwards, pulling it as you go. With a bit of luck, there is someone to take over, but not always.”I once spent five days on the Dig,” Neil Silverwood told me. “Sometimes the dust was so thick you couldn’t see your hand in front of you.”

Eventually, the Dig reached 40 metres in length, with no breakthrough in sight. Meanwhile, an extremely tight bypass of the Lion’s Den, christened Memory Lane (only 100 metres long, it takes 40 minutes to traverse), was discovered. The new bypass revealed that another 100 metres of digging would have been required to make the connection via the Dig, so it has now been abandoned.

But why dig at all, if there are so many other big caves nearby? Indeed, of the 30 deepest caves in New Zealand (the depth being the difference in altitude between the cave’s entrance and its lowest point), only one—Aurora, in Fiordland—does not lie within the Mt Owen-Mt Arthur­Takaka Hill karst. The answer goes to the heart of what caving is about—why it is more than just a sport. The thought that just beyond this choked squeeze might be cavern upon cavern of unseen, uncharted splendour is a powerful motivation.

Witness the fact that 24 of the 25 kilometres of passages that make up Nettlebed Cave (at -889 metres, New Zea­land’s deepest cave so far) was found on the other side of a successful dig. The nearby Ellis Basin System is 28.7 km long, 775 metres deep and “growing” rapidly.

And yet cavers count the discoveries to date as mere reconnaissance, for the surrounding mountains are as full of holes as a block of Emmental cheese.

The vertical relief of Mt Arthur and Mt Owen karst indicates potential for caves 1200 metres deep. That would make them some of the deepest in the world. It is known, for example, that Nettlebed Cave contributes only one-eighth of all the water which comes out at the Pearse Resurgence, the river draining the side of Mt Arthur. If you translate the remaining seven-eighths into caves, it means systems totalling over 100 km.

Cavers are under no illusion that the mountains will give up their secrets easily. Many high-altitude cave en­trances—often deep, narrow shafts—are permanently choked with snow which, accumulating year after year, turns into a sort of underground glacier. Low-altitude entrances, on the other hand, are often inconspicuous and uninviting potholes camouflaged with mud and rotten vegetation and guarded by forested bluffs.

Although cave prospecting and exploration happen both in expeditionary outbursts of activity and quiet weekend potholing, major discoveries still take everyone by sur­prise. In 1990, a group of Czechoslovakian cavers arrived on the south side of Mt Owen, a short stroll from our Bulmer campsite. “We steered them away from our own leads and sent them where we thought it was safe,” one Nelson caver told me. “They went off and, on a shortcut between two campsites, found Bohemia, over seven kilo­meters long and, at -662 m, the fourth deepest cave in New Zealand. We had walked past the entrance many times. No one ever thought of looking in there.”

The discovery touched a raw nerve of nationalism among some of the local cavers, who cursed not loud but deep. It was as if the Trinidad & Tobago rugby team had thrashed the All Blacks at Carisbrook. Chris Pugsley, the editor of the New Zealand Speleological Bulletin, explained their viewpoint: “Unexplored caves are a limited national resource; why should we let someone else come and ex­plore them for us? If you inherit a cellar full of good wine you don’t throw a big party and drink it all at once. So with the caves, you want to savour the experience of explora­tion, a little bit at a time.”

The liberals among cavers think that there are plenty of caves for everyone. “In New Zealand you can still wander off into the bush and find a completely new cave—your cave!—a place where no one has been before!” said an enthusiastic British ex-pat. “You can name it, explore it, map it—all the Captain Cook stuff. I guess cavers are explorers born a couple of centuries too late.”

Too late to discover new islands and mountains, per­haps, but just in time to explore caves. Just in time, because our largest systems, like the upper levels of Bulmer, are in the last stage of their geological lifespan. When the water, constantly seeking the most direct way down, recedes to the lower levels, the caves begin to dry out and collapse. The once-smooth passages fill with the rubble of boulders peeling from the roof. The weakened underground struc­tures slowly give way, causing implosions and slumping on the surface. Finally, after a million of years of incessant erosion, the caves fill up flush with the ground, as though they never were.

But here we are talking in geological terms, where a millennium is the blink of an eye and a million years a handy unit with which to reconstruct the past. On our human time-scale, caves seem eternal. There is no danger of their disappearing any time soon, and, indeed, they can be considered valuable pieces of real estate.

[Chapter Break]

What would you do  if you dis­covered a cave under your property? According to Roman land law, en­shrined in New Zealand law, you own everything within the bounda­ries of your land and the centre of the Earth, except minerals, but including caves.

You could turn a small cave into a wine cellar—some­thing the French call la cave, a cool, musty place full of patinaed bottles. But suppose the cave was a huge laby­rinth encrusted with candelabras of stals—an asset of un­known value and possible business potential? Would you let cavers come and go as they please, build a ticket booth and charge tourists for going into your cave, or would you just bolt the entrances and keep the place pristine?

This is the dilemma faced by over 20 landowners farm­ing the Waitomo karst. They call their land—grassy hills cratered with sinkholes—”rolling country,” meaning that it’s easy to roll a farm bike here. The underlying caves are mainly horizontal, often with steep entrance shafts known as tomos (wai means water, tomo a hole in the ground).

Located near major population centres, these caves have been the cradle of New Zealand caving. When the New Zealand Speleological Society (NZSS) was formed in 1949, Waitomo was its first playground, and the following two decades yielded several milestones of underground exploration, caves like the 12 km-long Gardner’s Gut, Waipuna and Lost World, Ringlefall/St Benedict’s and Hollow Hill. Here, most cavers learnt to crawl before walking into the more challenging marble caves of the northern South Island.

Then, five years ago, caving in Waitomo took a deep and sudden dive.

On a steamy day in late February I met the man whose decision brought about this change, a farmer named James Haggas. When I drove up, he was carving slabs of raw meat from a cow’s carcass and throwing them to his dogs. Retiring the knife to a hip sheath, he eyed me defiantly while I explained my business.

“The cavers shot themselves in the foot,” he explained. “They overstayed their welcome.” He told me how, on a busy weekend, up to 50 cavers could be wandering around his paddocks making nuisances of themselves: gates left open, stock scattered, a calf dying a horrible death after swallowing a canister of spent carbide. He started charg­ing $5 per head—”Not a fortune, you agree?”—but some cavers were unwilling to pay.

There were two rescues and plenty of scope for more. Haggas began to wonder if the caves were an asset or a liability. The final straw was his own visit to one of his caves. He saw the damage which had accumulated over the years: broken stals, mud smeared over pristine flowstone, discarded carbide and broken glass. All this in his cave!

Haggas saw red. There would be no more recreational cavers on or under his land, he declared. He leased exclu­sive rights to three of his caves to a commercial caving company, Waitomo Adventures. They would take care of the caves and cave safety, conduct paying clients through them, and he would pocket a handsome commission. The only party left out of the deal were recreational cavers.

All this might seem a storm in a teacup, if not for the fact that the Haggas property contains at least 10 signifi­cant caves, some say the best caves in the North Island. Their closure was a shock to the caving community. As they saw it, these were their caves as much as they were Haggas’s. They had found, explored and mapped them. They took the access for granted, true, but this was how it had always been. They pleaded and begged, and even offered to help Haggas fence off his tomos, but to no avail. When the dust of the dispute had settled, James Haggas stood unmoved by his gate like a bouncer, arms across his chest. His caves remain off-limits to recreational cavers.

[Chapter Break]

James haggas was not the first to appreciate the tourist potential of Waitomo’s caves. In 1887, Tane Tinorau of the Maniapoto tribe and English surveyor Fred Mace drifted through what would become the famous Glowworm Grotto on a raft made of korari, flax flower stalks. Before their two candles burnt out, they had seen enough of the cave to realise that it was a profitable discovery. A year earlier, the eruption of Mt Tarawera had obliterated the world-renowned Pink and White Terraces of Rotorua; now the glow-worms could steal the limelight.

The uniqueness of the Waitomo caves was soon recog­nised by the Tourist and Health Resorts Department, and Tinorau became one of the first caving guides. Inside the caves, tracks of ponga logs were laid, and wooden ladders opened up higher levels. Although the early admission price was only a candle, by 1900 the visitors were charged two shillings. Accommodation and stables mushroomed around the embryo village of Waitomo, soon to become the focal point of the district.

Tourists have been paddling through Waitomo ever since, beneath a firmament of insect lights, and the caves have become a world-class attraction. Recently, with the advent of adventure tourism, more challenging ways of seeing them have evolved. Almost anyone can now abseil into the 100-metre-deep entrance shaft of Mangapu Cave, better known as The Lost World, raft underground rivers in a truck’s inner tube, walk along keyhole streamways, squeeze through low passages half-filled with water and generally experience real caving without becoming a caver.

Such attractions have made Waitomo a major stopover for foreign tourists, on a par with Milford Sound and the Westland glaciers. During the day the village is a parking lot full of cars and coaches. Their passengers are invariably underground.

There are six commercial caving companies operating around Waitomo, all competing for a finite number of visitors—though there are more caves that could be devel­oped. “Couldn’t unregulated competition lead to a local version of the Kentucky Cave Wars?” I asked John Ash, a seasoned caver and co-owner of Black Water Rafting.

He knew the Cave Wars story well. In the United States in the 1920s, a quick and easy way to get rich was by luring paying tourists on sightseeing trips through some of the world’s largest and most spectacular caves. Competition between neighbouring cave owners was fierce. Touts and hustlers strove to outwit each other by wearing police­men’s uniforms and putting out “Road Closed. Detour This Way” signs to divert traffic towards their caves. Fist fights broke out, ticket booths were torched and barbed wire was used to delineate cave boundaries. The war ended when the entire area was declared a national park in 1941. Could Waitomo be heading in the same direction?

The case of Ruakuri might suggest so. Developed and operated by the Tourist Hotel Corporation (THC), Ruakuri was turning a healthy profit until nearby land­owners realised that the cave was actually under their land. Wanting a slice of the action, and having failed in negotia­tions with the THC, they erected an underground “No Trespassing” sign and halted the tourist operation.

In the meantime, local Maori claimed the entrance to be an ancestral burial cave and declared it wahi tapu, effectively off-limits to everyone else. Thus the cave own­ers found themselves with a cave but no entrance. They considered drilling a 90-metre-long tunnel to open the cave, but the costs must have been prohibitive. Ruakuri, with its electric lights awaiting only a flick of a switch, remains closed and dark.

At a meeting I attended on Waitomo’s Tokikapu Marae to discuss cave issues, the participants seemed eager to avoid a repetition of that kind of impasse. Their concerns were many. The threat of too much success hung over the 200-plus community. Last year some 450,000 visitors passed through the Glowworm Grotto, leaving a financial residue benefiting many. The locals liked having their children mingle with foreigners, soaking up news from the world, and they wanted Waitomo to remain a cosmopoli­tan oasis. But they feared that if the tourism development were to run amok, Waitomo could become another Queenstown: prosperous and glitzy, but with its soul mis­placed. They feared hit ‘n’ run tourist operators and ruth­less offshore investors. Most of all, they feared that if anything unwholesome happened to the glow-worms, Waitomo would soon follow, becoming, as it once was, just another farming hamlet.

Local residents and tourism operators are not the only ones interested in the welfare of caves and glow-worms at Waitomo. The Department of Conservation (DOC) is also concerned to see that caves are not harmed by human activities, but it has no jurisdiction over caves on private land. Chris Pugsley, a DOC officer, caver and expert on Waitomo glow-worms, says that, despite their irreplaceability, caves fall into legislative cracks.

“Regional councils are responsible for waterways, and although all caves were once waterways, many sections of cave systems no longer carry water,” he says. “District councils can control earthworks, such as roads to cave entrances, but caves get no special mention in district schemes, even in areas where they are important, such as Waitomo, and therefore many activities in private caves are unregulated.”

The potential for damage is considerable—and injuries to caves are not easily healed. Caves are more fragile than any other landscape you can think of. Bootprints in snow or mud above ground are quickly erased by wind and rain, more slowly by falling leaves or new vegetation. Below ground, imprints in the dust on a cave floor may still be there in a thousand years. Scratches on the soft rocks, damage to stals, graffiti—all will endure, as will lolly wrap­pers, cigarette butts and all the other debris of human passage.

Serious cavers go to great lengths to preserve the integ­rity of the caves they frequent. They would no more consider snapping off a stalactite or crystal formation than they would cutting a stained-glass window from a cathe­dral. Some of them accuse tourism operators and weekend cavers of lacking cave ethics, and dismiss many of the more popular caving destinations as “sacrificial caves”—monu­ments to commercial exploitation.

The potential for damage to caves goes beyond direct human impact. Flex your imagination a little and you can consider caves to be living organisms. They “breathe”—in, when the outside atmospheric pressure is rising; out, when the barometer falls. (In caves with several entrances, particularly if these are at significantly different altitudes, such breathing can become a gale blowing through the constricted passages.) Like other living things, caves main­tain reasonably constant temperature, and water, carrying absorbed carbon dioxide, can be considered to be their lifeblood. But unlike living organisms, caves have no im­mune system. They are fragile, prone to dehydration and clogging by silt. You can damage them without even set­ting foot in them.

“Caves are not separate entities, somewhere deep un­derground. They are an integral part of a geological eco­system, the karst,” Dave Smith, once a caving guide, now a Te Kuiti DOC officer, told me. “Within a karst landscape, caves, forests, soil and water are all in a complex equilib­rium which can be easily upset. Denude the surface and resulting erosion may silt up caves and change the under­ground watercourses. Plant pine trees and they can dry out a cave. Use fertiliser and its run-off can upset the chemical characteristics of the water. Alter just one element in the karst and everything else can change. You can see why we’re concerned. Besides, 95 per cent of our drinking water comes from the Waitomo River catchment, which, at one stage or another, runs through the caves.”

In the past, reckless attitudes towards karst and caves often backfired. Until nearly the end of the 19th century in France and the USA, large quantities of refuse—even putrefying carcasses of animals which died during fre­quent plagues—were customarily dumped into the seem­ingly bottomless pits which pockmark karst landscapes. Often, spring water many kilometres away would be found to be contaminated and the cause of widespread epidemics of typhoid and cholera. Thousands of people died. The two facts were not linked until cavers and geologists dis­covered that both the dumps and the springs were parts of the same water system, the Earth’s natural plumbing now turned into a sewer.

A milder version of the same scenario happened in Waitomo in the 1960s. Sludge from the THC hotel’s septic tank was emptied into a tomo, only to re-emerge as a noisome seepage into the tourist caves. It took days for the water to clear. Fortunately, glow-worms don’t have much of a sense of smell.

I left my visit to the Glowworm Grotto—Waitomo’s highlight for over a century—until the end of my stay in the village. Obviously, others had the same idea, for there was a long line of buses parked outside the entrance.

I was sandwiched between a group of Japanese, evidently annoyed at not being allowed to use their cameras here, and a group of French, who strolled with the same cool dignity they might display in the halls of the Louvre. After making our way through the sepulchral interior of the cave, we boarded a flat-bottomed boat which the guide pulled along a rope. The artificial lights faded out and we drifted into the perpetual cave night.

“Regarde fa, maman!” a young French boy at my side whispered to his mother. “Tenement d’lumiere! Ils sont comme les etoiles!” So many lights. They are like the stars.

Gliding through perfect silence, we found ourselves in one of Antoine de Saint-Exupery’s night flights, mesmerised by the light of galaxies. Yet here the cool, blue lights were clustered so close together it was impossible to group them into imaginary constellations. It was as if the Milky Way had spilled across the entire sky.

Keeping all those lights burning brightly involves some deft behind-the‑scenes       management. What the tourist doesn’t know is that, in the dark, instruments set up by the scien­tists of the National Institute of Water & Atmospheric Research are keeping an eye on the stability of the cave environment, taking continuous measurements of rock and air temperature and relative humidity. If, for example, the humidity drops too low, in-cave sprinklers can be turned on. The instruments are not unlike those you can see in corners of museums and art galleries. Unique, if odd, masterpieces of Nature’s art, the glow-worms are too valu­able to be taken for granted.

As we drifted out of the cave into blinding sunlight, the Kentucky Cave Wars seemed far away indeed. As long as the glow-worms continue to glow, I mused, Waitomo’s future looks bright.

[Chapter Break]

Whenever i have been under­ground, I’ve always had a guide—a professional, a friend, sometimes both—for entering caves without ex­perience and local knowledge can be a risky venture. In caves, my sense of direction, not infallible at the best of times, would leave me literally in the dark.

But getting lost is only one of many potential perils. Cavers jammed in vertical squeezes—narrow passages through which you have to wriggle—have been strangled by the chin straps of their own helmets. They have been poisoned by carbide making its way into food or drinking water, burnt by an exploding carbide generator and knocked unconscious by rocks thrown down a shaft by tourists testing the force of gravity. In wet caves, drowning and hypothermia are constant threats, and there is a con­stant danger of ropes wearing through on abrasive rocks.

Caving is not for the claustrophobic. On our way out of Hollywood Cave, on the northern fringe of Paparoa Na­tional Park, we came to a cul-de-sac with a narrow rift cleaving the ceiling. Without hesitation, Neil Silverwood weaselled his way up with a mixture of brute force and sinuous contortions. His gumbooted feet wriggled vio­lently above my head. I could hear the rasping of Cordura against rock. Minutes passed. There was much panting and grunting. Then I heard his muffled voice: “I’m through; come on up!”

I made a mere two metres of upward progress before the walls seized my upper body with the grip of a hydraulic press. My feet dangled in the air and I could no longer turn my head, as the helmet became wedged as well. I remembered all too well an incident in Waitomo’s Rum­bling Gut, when a female caver got so severely stuck in a squeeze known as the Last Minute Crawl, that it took 19 hours of drilling and chiselling to get her out.

“Undo your helmet buckle first,” Neil advised. “Breathe out and then push your chest through one rib at a time.” I tried. Five centimetres . . . 10 . . . 20 . . . Slowly the walls receded and I was through.

“Thin people around 60 kg can usually squeeze through a `letterbox’ 180 mm high,” I read later in a caving-made-easy book by British caver Ben Lyon. “For those near 80 kg the limit is likely to be around 225 mm.” A squeeze the height of this page-276 mm—would be a comfortable passage, a “crawlway,” he’d say.

When facing a particularly uninviting squeeze, I always followed Neil Silverwood’s pointers closely. He had learned the hard way. One squeeze nearly cost him his life.

Three years ago, with novice caver Chris Manuel, he was prospecting for new caves in dense bush near Charleston, on the West Coast. They found a steep-sided sinkhole with a small opening at the bottom. Neil, eager to be its first explorer, lowered himself feet-first into the hole. He was about a metre in, his head already below the floor, when the sides caved in and he was wedged tight.

Both his hands—he kept them above his head to stream­line his body—were jammed between the crumbling walls and his helmet. He tried to wriggle himself out, but his feet were treading only air, and with every movement his body sank deeper into the squeeze, turning the chin strap of his immobilised helmet into a tightening noose.

Without a knife to cut the strap, Chris was unable to do much for the wedged man. The sides of the hole were loose, and his attempts at rescue only brought down more debris. With only two hours of daylight left, they both agreed that Chris should go for help.

He set out towards the road through trackless bush, marking his way with strips of red tape. The going was hard, for bush-covered karst is full of sudden cliffs, ravines and holes camouflaged by vegetation. An hour-and-a-half later he was still in the bush and had run out of tape.

It began to rain. Neil’s sinkhole soon flooded, washing more and more debris into the squeeze. “I couldn’t move, and the water was pouring into the funnel and down my body,” he recounted. “I was stuck in the middle of a stream. It got very cold and I wasn’t sure if Chris would ever make it back. I had to constantly fight off panic and despair. I thought of all the reasons for living, all the things I still wanted to do, all the people I love. I really wanted to live!”

Eventually, Chris reached the road and stirred up a full-scale rescue, but in the darkness, bush and pouring rain he could not find his way back to the hole. For eight hours Neil remained buried while 30 rescuers combed the bush for bits of red tape. Shortly after midnight they found one, and Kerry Silverwood was the first to reach the hole. All he could see were his son’s fingers sticking out of the mud.

“Are you still there, son?” asked the old man, reaching for what he feared were lifeless fingers.

“Dad? DAD!” Neil sobbed, his tears mixing with the rainwater that ran down his face.

Kerry scraped away the dirt, reached down and, with his pocketknife, cut the helmet strap. It took another two hours of digging to remove the debris, stone by stone, until the rescuers could place a sling around Neil’s shoul­ders and pull him out to safety. “These things make you grow up real fast,” Kerry told me.

Neil was just 16 at the time.

[Chapter Break]

Eraphs the most extreme form of un­derground exploration is not caving per se but cave diving. According to an American cave-diving manual, regardless of fitness or experi­ence, “anyone can die at any time on any cave dive.” Even the renowned Jacques Cousteau described his debut cave dive as the “worst experience in five thousand dives.”

In cave diving, the balance between acceptable risk and sheer madness is so fine that the sport’s history reads like a book of horrors, where scenarios of disorientation, entan­glement in safety lines, out-of-control panic and subse­quent drownings seem more common than the occasional happy ending. But it is also a remarkable account of hu­man ingenuity and endeavour.

In 1934, two decades before the invention of the aqua­lung, Jack Sheppard and Graham Balcombe braved the sumps of Swildon’s Hole in England, armed with motorcycling goggles, nose clips, a bicycle pump and 12 metres of garden hose. One held the hose in his mouth while the other used the pump as a compressor. They could hardly have imagined that, 50 years later, their fol­lowers would look more like astronauts on a space walk than cavers.

To the caver, sumps are liquid barricades which block access to the passages that lie beyond. Because “connect­ing”—finding links between known systems—is one of the most gratifying and accolade-generating accomplishments in exploration caving, breaking down those barricades has become an all-important mission.

This is why Kieran McKay, indisputably the most ac­tive and daring of New Zealand cavers, took up scuba diving seven years ago. The beginnings, he admits, were humble, and certainly dangerous, for experience is hard to acquire, and those without sufficient know-how or sang­froid are weeded out quickly and mercilessly.

“The main danger in cave diving is that if anything goes wrong, you can’t simply surface and sort yourself out. The slightest problem can turn into a life-threatening situation,” McKay tells me. “There are not many places where you can learn to cave-dive, and all of them are overseas, so out of necessity I had to teach myself.

“I read all the available books, set up the gear, then played for hours in lakes and rivers at night. I’d learn to lay out and retrieve the guideline, to deal with emergencies, to manage my air supply—the rule of thirds is an unbreachable standard: one-third on the way in, another on the way out, the last third as a reserve. My first dive was 15 metres long, and seemed endless. Now, with three tanks, I can dive 400 metres and more.”

So far, McKay has clocked up some 400 subterranean dives—more than those of the rest of the country’s cave divers put together. Most of his diving takes place in Waitomo, where he works as a guide, but he has also made a number of pioneering dives in the South Island marbles.

He almost always dives alone, adhering to another bru­tal cave-diving truth, that down there, if you can’t help yourself, no one else will. And, yes, he has had his share of mishaps.

McKay: “I was diving the Rangitaawa sump. The vis­ibility was about two metres and I was blindly following my line. I still had another 300 metres to swim, and to keep off the bottom I decided to add some air to my buoyancy compensator. With three tanks, it is quite a tangle—regulators and gauges everywhere—and somehow the guideline slipped out of my hand.

“‘I’ve lost the line!’ I thought. My only link to the surface. It was like a nightmare that continues after you wake up. Imagine: you’re blind and lost, and with every breath you’re exhausting your air supply.

“I dropped back to the bottom to keep myself oriented. The water was like a cold brown soup, thick with silt. I started groping this way and that, and was about to tie off one of my tanks like an anchor and start a circular search when I felt it again. Man, the LINE! It was like seeing the sunlight again.”

Malfunctions are the greatest dread of cave divers. “You must minimise your dependency on a single piece of equip­ment, particularly an air tank,” says McKay. “That’s why you have two or three, and you constantly ‘rotate’ them, breathing a little bit out of each tank, so that if one mal­functions you can detect it early enough.

“One time I was in a spacious tunnel with tremendous visibility, though, moments beforehand, I had been swim­ming along the silty bottom. The spare mouthpiece must have got clogged up with mud, because, as I swapped the regulators and took a deep breath, I got a lungful of sludge. I started choking, and felt as if I was about to cough my lungs out. I was at a depth of 30 metres, with a 100-metre swim to the entrance. Eventually I managed to get myself together and breathe normally, but getting back to the surface was surely a relief.”

“Isn’t that enough to make you want to take up some­thing safer—say, shark-feeding?” I ask.

He smiles: “That’s the point. In cave diving there’s nothing malicious out there trying to get you. All my near misses were my own fault. That I can fix, because I can’t afford to repeat these mistakes.” He pauses. “Out there is a world that defies imagination.”

I know. The continent.

[Chapter Break]

So far, while exploring New Zealand’s under­ground landscapes, I’d always followed some­one else’s more or less well-trodden path. The caves I had visited were explored and mapped. Some, like the by-permit-only Hollow Hill in Waitomo, receive only a handful of visitors a year; others seemed as busy as pedestrian subways.

Then, one clear autumn day, I took part in the most rewarding and exciting type of caving: the exploration of a new system. As our heavily-laden helicopter hummed above the Heaphy River in Kahurangi National Park, Neil Silverwood pointed out a broad slot gaping in the forest. It was during a similar flight in 1994 that he had found this entrance and a cave which he named Megamania. The exploration that followed revealed over 15 km of passages, making the cave the fourth longest in the country. Still, as Neil assured me, there was plenty yet to be found.

For the next five days we lived in Megamania, just beyond the edge of daylight. Every morning I shook out my overalls and gumboots in fear of spelungulas, local cave spiders which, I was told, can grow as big as the palm of your hand. Day after day we explored the maze of known passages, hoping to find some new ones. We abseiled down tomos, pushed through muddy squeezes and ran along tubular tunnels that could accommodate a narrow country highway.

Every night we came back, tired and dirty, like miners after a long shift, to sleep under the false firmament of glow-worms, lullabied by the roar of an underground river. Carbide torches were our daylight, and mud, like dark­ness, became an inseparable part of our lives. This wasn’t the countryside mud of wet roads and farm paddocks, but the primordial ooze that threatens to swallow you whole and forces you to leave a desperate trail of Yeti-like foot­prints. It taints food and water, penetrates sleeping bags, cakes skin. It can drive you crazy, this mudness; like a fosse, it is the cave’s formidable first line of defence.

Although the names of Megamania’s passages betray the awe and excitement of their discoverers—Great Wall, Mega Blast, Goldrush, Fake and True Orgasmia—the cave seemed determined not to give away any more secrets. Neil set out on a lengthy dig but found only 150 metres of new cave. Another caver found a new tomo, but its bottom was choked by a rockfall. This time we had to settle for what was already known.

For me, that was still plenty, and occasional glimpses of unearthly beauty made up for the dirt and discomfort. In one calcite room, bristling with more rock spines than a porcupine, I peeped between stalactites that formed a low-roofed cage. Inside was a garden of crystal flowers, white amaranths hanging upside down on long, slender stalks, glistening as if made of diamond. Their beauty seemed ironic and unfulfilled, for they were doomed to exist in perpetual darkness, like an old master in the safe of a private collector.

Poring over cave maps full of question marks, trying to make out which way the cave may “go” is like putting together a three-dimensional puzzle where you know nei­ther the shape of the whole nor the details of individual pieces. Nonetheless, missing links are often predicted long before they are found.

“In Takaka Hill, already thoroughly explored, we still haven’t found the main cave system,” Trevor Worthy told me. “We know that the cave must be there, but we just can’t find an entrance.”

So caves remain an open frontier, and finding The Big One is every caver’s dream. Even in a country as compact as New Zealand, a casual caving trip can result in a discov­ery of a completely new system, perhaps larger than all those known so far, a geographical equivalent of finding a mountain higher than Mount Cook or a glacier longer than the Tasman.

A day after our Megamania expedition, I was relaxing with Neil and Kerry Silverwood in their cosy home, just north of Westport. Their dog, Silver, was fast asleep at our feet, and the smouldering West Coast coal guarded us against the chill of an autumn evening. Our caving adven­ture was already becoming a memory, a tale to be told on nights like this, when the passage of time had erased the misery and mud, leaving only the splendour and beauty.

The phone rang. It was Danielle Gemenis, a Hamilton doctor and a caver of hard-to-match enthusiasm. She had been prospecting for new caves near the summit of Mt Arthur, she said, and found a massive hole. “We threw a small rock down the shaft,” her voice grew excited, “and it came back! The draught was that strong!” A quick topo­graphical calculation established that the cave could be the long-predicted but still not found Mt Arthur Master System, possibly over 1000 metres deep.

Could this be The Big One? Danielle was already or­ganising an expedition and Neil promptly invited himself. Would I come as well?

I looked outside at the pile of soiled caving gear, the mud so fresh it hadn’t caked up yet, and felt the cave grit still grinding between my teeth. I could see why there were only about 300 cavers in New Zealand, and only half of them active. Admission to the underworld was pricy—dirt, fear, danger and exhaustion—but for the elite of cav­ing addicts no effort is too great. They are the cutting-edge explorers, and they will continue disappearing under­ground to emerge wide-eyed with wonder and full of strange tales.

Perhaps I won’t accompany them to Mt Arthur. But I’d love to hear their stories.