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Practice English Speaking&Listening with: Journey Towards The Center Of The Earth

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MALE SPEAKER: He was going to talk about caves.

He's a very famous--

I guess, I don't know this field--

cave explorer.

He's been responsible for discovery and exploration of

many caves, which he will cover, and

he will have pictures--

much better than what I can do.

He's also been involved a lot in aerospace, and underwater

exploration as well, which ties into the cave. And I'm

doing a terrible job of introduction, so I want him to

talk about this himself.

But remember, there is a 12:30 talk, which should be a so

fascinating one.

Thanks.

BILL STONE: I want to thank all of you for the opportunity

to come out here.

This is, for me, a rather eye-opening experience to see

what Silicon Valley has a metamorphosed into over the

last 10, 15 years or so.

I used to do some research work in

collaboration with Ames.

I've met a few of the people who have migrated here from

there, as the interest in the space arena change over time.

I've had the privilege over the past 25 years of being

involved, not only with space exploration related projects,

aerospace vehicle design and things like that at a national

lab, but also of leading some projects that deal with some

of the last untouched, truly unexplored terrain that exists

on this planet.

If you try to ask yourself where would you go if you

really wanted to go someplace that was truly unexplored, you

think about the mountains, right?

I've climbed some fairly high altitude peaks.

You can get satellite images of where you're going while

you're on the mountain.

You can call up people through sat phone.

You can get weather forecasts for the next day to try to

plan your summit assault.

That's how much the Alpine environment has changed over

the last 50 years.

Similarly, with pretty much all of the tropical rain

forests, the jungles, and the other places, the arid deserts

and things like that, as well as underwater.

Some may argue that the ocean is one of the least explored

places, at least when you get down to talking about touching

every square meter, that's quite true.

But as far as knowledge, we have really detailed benthic

maps of the entire floor of the ocean.

We visited the deepest spots, and pretty much like the plans

to return to the moon in 2020, people are talking still about

returning to the bottom of the Mariana Trenches, if

it were a big deal.

We ought to be able to do better than that.

But in one particular area, and this is something that's

taken me a long time to realize, what constitutes a

true frontier.

It's a place where, in my opinion, the exploration

consists of a process.

This is where many people try to wiggle out of the

definition.

To me, the definition of exploration is putting this in

terra incognita.

Nothing short of that.

Now, you can do it in many ways, by gaining scientific

knowledge, by using intelligent mechanical

surrogates.

Now we call these things robotic spacecraft, for

example, or robotic autonomous underwater vehicles.

The question then becomes a philosophical one.

Is it better to see a raster line appear on a television

screen of the image of a place that no one's seen before, or

is it better to be there in person to be able to look at

it and interactively touch it, feel it, experiment with it,

observe, satisfy the curiosity of the human species?

I tend to fall into the latter category, but there are places

where, indeed, it is too dangerous, too far, simply

because our limited knowledge of propulsion has not allowed

us to get there more easily, or perhaps it is, in fact, a

lethal environment.

Like for example, the surface of Europa is not a good place

for humans.

Five minutes there and you would have a lethal dose of

radiation, largely whipped up by particles from the Sun

going out and being spun up in the

gravitational sphere of Jupiter.

So what I'm going to talk about here now, and I hope a

couple of you will find your way over to the talk at 12:30

on Europa, because there's a lot of cool stuff that's going

on in the robotic area as well, as many of those in

California who have had any association with JPL or Ames

would know.

But this is about what's left on Earth.

It has to do with the exploration of extraordinarily

deep caves.

Everybody's probably at one time or another visited a

commercial cave.

What I'd like to show you today is a very unknown world,

at least unknown to almost everybody I know.

Except for a very small band of expeditionary groups,

they're around the world, who do know what's going on and

realize that this is, in fact, a finite, dwindling frontier.

and they're going for it now on expeditions pretty much as

much as two to three or four months a year until they run

out of time.

So what I'm going to show you is where things are happening.

There are largely three places in the world right now where

there is a competition going on, for lack of a better term,

between good-willed groups--

Russians are leading one in an area of Chechnya, which is a

bad place for Americans to go, unfortunately.

The US is leading a multinational team of about 10

countries to an area in Southern Mexico.

And there are pockets of work that are taking place at high

altitude in Austria and the French-Spanish border and

places like that.

But largely it is shaking out now to what we would call the

2,000 meter plus gain.

The deepest caves in the world for the longest times were

measured as a crossing of 1,000 meters, much in the same

measure as you would consider a high-alted peak to be an

8,000 meter peak.

There was this gradual push to where things slowly, slowly

grew towards 2,000 meters deep.

It was as much of a physical barrier as a psychological

barrier to think about it.

And I hope when you see these slides here, you'll get a feel

for the fact that these are not--

it's not like going to a National park.

These are projects where to gear up is equally or greater

than the logistics involved with the largest ever

expeditions that were ever put together.

Typically, you're looking at a 50-person team, on site for

four months.

It takes on the order of two to three weeks to get your

team to base camp.

It takes several weeks to initially begin to prepare a

place like this for travel, and you'll kind of see what

that travel is like.

And then there are a whole host of obstacles, at least

three or four or five that I would run in to the category

of extreme situations where we have had to invent technology.

And we've been doing this now for over 25 years, and you'll

get to see some of that here.

The place that we're working, where the US team is leading,

is in Southern Mexico.

If anybody's been down there, it's about 400 kilometers

Southeast of Mexico City in the Northeastern tip of the

State of Oaxaca.

The idea is that there is a large entrance up there called

Cueva Cheve, which was discovered about 20 years ago.

At that time, it was explored down for a certain distance.

The water that goes in these things, unlike a Jules Verne

journey, does not go to the center of the Earth.

They go towards the center of the Earth, but eventually with

most of the deep cave systems on the Earth, they have to

find a way for the water that creates-- and these are

created in limestone.

There are, in fact, lava type systems, but they don't go as

deep, at least not yet.

Most of them collapse because of the hydrostatic pressure.

In this particular case, in Cueva Cheve, we have the

possibility of hitting over 2,600 meters down over a

distance of about 20 kilometers.

And the waters come out in a spring down here in the depths

of this place called the Santa Domingo Canyon.

So those are kind of the topograph places that are

going on, and we have projects that are going up and down

this mountain range.

It's about 20 kilometers from left to right, about 6

kilometers across, and 2,600 meters deep.

The gain then is what's in between in the center of this

mountain, and how deep can you go in it.

Yeah?

AUDIENCE: What did you say was the depth of a cave?

BILL STONE: It's the vertical extent.

I'll show you here at the end.

In order to determine that, you actually have to survey

what you're doing inside the mountain.

So we actually have a three-dimensional computer

model of the inside of the mountain that I'll show you

right at the end here that shows where

everything sits inside.

If you go from point to point, for example, if you go from

the highest known point and you pop up in the resurgence

springs, you can go down there with phase differential GPS,

and within a centimeter you know exactly what the vertical

differential is.

So when we talk about depth, it's the vertical differential

from the highest point to the lowest point.

If you're talking about the length of a system, that's an

entirely different animal.

The stuff that's being found here will probably, when it

all winds up, be in excess of 150 or 200 kilometers worth of

passages that weave their way in through the interior of

this mountain.

To do that, however, is going to be a logistical challenge,

the likes of which we've really not dealt with yet here

on Earth, and I'll tell you why.

It's kind of a dramatic statement to weight, but when

you see what we've gone through to get the knowledge

that we have and what remains, you'll see that it is, in

fact, logistics that control the entire thing.

So basically, you can start many, many projects here by

trying to choose a target point to find your way inside

the mountain.

This one here is at the bottom of a canyon that is deeper

than the Grand Canyon.

It's called the Santa Domingo.

That's just a part of the ramparts of the plateau

surrounding each side.

They go up to over 3,000 meters in each direction.

This typical type of morphology that you find down

there, you're going through fairly dry type stuff.

Because you're at a resurgence spring, you're working upwards

through the mountain. these are of some local Mexicans

from in the village.

Just like in the US, you might have farmers that would own a

cave down here.

They're Mexican ranchers.

These are the kinds of things that people typically think

about when they think about caves.

They're relatively small, they have formations in them.

This is what you would find if you went to a typical tourist

type cavern.

When you get further in, you find out that you're dealing

with places that are flushed by seasonal rains.

This is one of the controlling factors in Southern Mexico is

that you really only have about a four month window

between the beginning of February and the end of May

when you can conduct any type of research here.

After that point, these things will flood right to the roof

and flush out, and so you're getting this nice, polished

scalloping going on here.

However, invariably in these things, you find yourself

confronted with obstacles that are a grade up.

There are several of them that I'll point out to you here.

One is that the strata that you're following can take a

minor hiccup.

It can just be a concave bend that goes downward.

The cave does not end.

These are carved out by water moving through them.

The water that's moving through them then collects--

you have the equivalent of a subtrap in a sink in your

bathroom or something like that, and the question is how

long are those things.

Well, in this particular case, we've been in this 450 meters

so far at 30 meters depth.

The little sketch in the lower right was taken from the

expedition base camp log that showed this guy had gone in

with two tanks and a re-breather.

Took the re-breather off, took one of the tanks off and was

pushing the other tank ahead of him with a hammer trying to

knock rocks out of the way.

That's the kind of mentality that you have going on to

explore these things.

At the same time that was going on, there was another

team that was saying, well, you know, if it stopped here

going down, there's still a possibility that there can be

multilevels.

These things are labyrinthine in nature.

The rivers find their courses from higher levels to lower

levels over time.

So this crew here on the--

well, all these slides--

started climbing above that underwater tunnel, and, in

fact, scaled 100 meters straight up using rock drills

and Yosemite-type climbing techniques.

To where they got to a point where the path onward was

blocked with boulders in the ceiling.

The curious thing was that there was a lot of air coming

out of these boulders.

Now, you had a choice there.

You're hanging off 100 meters worth of rope, over an

underwater tunnel, and if you decide to pull one of these

boulders out so that you can go past it, it may initiate a

landslide which then comes down and cuts all your ropes,

and might hurt you as well, or at the very least leave you

stranded hanging on the wall up there.

So we decided it was prudent at that point

not to go any further.

So here was kind of a cross-section of what's going

on in the bottom.

That's a section view, and on the top is the plan view.

There's about 12 kilometers of caves there.

The parts that are blue and red are under water, and that

is not uncommon in a deep cave system to find the fact that a

fair substantial amount is under water, some of it

involves climbing going up.

If we were exploring this from the top down, we would be

throwing ropes down these shafts as opposed to climbing

up from the bottom.

But this is starting at the bottom of the problem and

trying to see if we can explore into the mountain

going upwards.

Another thing that's rather curious and I always found

this funny when I looked at the history of exploration and

things like that is you would look at a map of a very deep

cave over in France, for example, and it would have

dates on it, 1898, 1930, 1952, 19--

these would be the places that over the course of time,

sometimes over 100 years in many cases, there would be

expansion of knowledge because technology had changed or

something like that.

So many of these things will go for a 10-year or 15-year

hiatus before somebody will say you know it's time to go

back and look again.

So this right here, Cheve 2003, was the first expedition

in seven years to what is certainly one of the great

caves of the world.

It would be like the equivalent of Everest getting

visited only once every seven years.

That's the nature of these places and the logistics of

getting to them.

This picture right here is rather curious.

You can see all these little white streaks there.

That's 3,000 meters of 9-millimeter nylon line that's

going to be used to rig this cave. And straightening it

out, and cutting it, and bagging, and things like that,

is one of the first little chores that you do on an

expedition.

The area is located just to the east of the well-known

Tehuacan Valley.

This is the place where corn was first discovered by

anthropologists back in the 1960s, well, proven to have

existed there as one of the earlier agricultural remnants

of a ancient society.

That was where it was first cultivated I should say.

This is Robert MacNeish and that crew.

In any event, you're going up from a desert through

deciduous, and then finally up into a Pine forest at 3,000

meters elevation.

One of the things you can see here is what looks to be a

giant valley.

In fact, that valley extends in five different directions

of about the same size.

And sitting at the very bottom is this little soccer field

with nice green grass growing in the bottom.

It's called a llano in Spanish, meaning meadow.

The curious thing about it is that this is up at 3,000

meters elevation.

All the water that drains within that 5 kilometer

diameter circle goes into this entrance right here.

When you find things like this, this is the kind of

things that people who are looking to discover a deep

cave somewhere in the world look for those kind of signs.

Does it capture a lot of water.

Is it very high elevation.

In this particular case, it's really sitting on top.

So what we saw before there was explorations in this thing

called the Cheve resurgence down at the

very base of the mountain.

We're now at the very far upper right at the entrance of

Cueva Cheve trying to go down.

In this year, 2003, the deepest point in the cave was

1,386 meters, and you see this thing called Cheve sump.

That means there's an underwater tunnel there.

And as soon as you start adding all of the rope work,

and the fact that you've got to do cave diving at the end

of this, you start to see that the logistics start to mount

up, which is why people don't do this every year.

Very typical here.

This is just going through a series of 120 shafts on the

way down and traverses.

They vary in size.

Most of them probably 15, 20, 30 meters.

A lot of them can get up as high as 50 to 150 meters.

This is at 320 meter level.

I hope everybody understands metric, because I'm not going

back to feet.

We made that conversion a long time ago at the National lab.

So this is the 500 meter level here.

This is where pretty much the limit of where you could get

on a single day's travel.

This would be about 24 hour journey to go down to this

point and back out with a backpack.

That's the beginning of a shaft.

If any of you guys, or people, saw, for example, some of the

Hollywood representations of what happens underground,

things like that.

Invariably they have something like a bottomless pit, and

they throw a rock in it and it goes forever.

Curiously enough, this one here is 150 meters.

If you throw a rock down this, it takes about six seconds of

free fall to hit the bottom.

That's really not much.

The current knowledge of this kind of thing is single drop,

not necessarily the deepest cave in the world, but a

single drop is now 600 meters over in Croatia for people who

are into morphological features.

It is, as far as I've heard from

colleagues, a straight drop.

It's got Alpine ice water that flows into it.

So it's not very pleasant place.

But 2,000 feet straight down-- oops, slipped.

Throw the catch me here.

One of the things about deep caves is that they are very

much like a--

to give you an analogy, it's like the limbs of a tree.

Very high up in the tree you have very small limbs.

They come down and they eventually

join to form a truck.

Think of each one of those things as the potential

entrance that collects water.

So the tops of a very deep cave frequently tend to be

small, unless they have a big focus mechanism-- that's the

term for that big sink hole that you saw there.

Frequently you don't have that.

So you end up with these very tiny passages, that as you get

deeper they get bigger after they join with another and

another and another.

But eventually in all these cases, by the time you get to

somewhere around the 800 to 1,000 meter level, you have a

substantial underground river that you are dealing with that

continues to build and become a danger, a physical danger.

So you find yourself building tension traverses and things

like that to bypass all this stuff.

AUDIENCE: This is the dry season?

BILL STONE: That is correct.

Rainy season, that water would probably be more than 5 meters

higher in that area, and you would not want to be there.

Some passages would flood completely shut.

This picture on the left here is something that's called a

taut line/slack line traverse, and it's a technique that we

picked up from the Europeans probably 10 years ago in which

you have a, what used to be called a Tyrolean line, which

is a diagonal line going down, and then you have a slack

repel line.

So you hook up a short cable onto the taut line and you

repel the slack line.

What it does is it carries you magically away from the place

you want to avoid, which in this

case is that big waterfall.

Coming back up is a little more complicated.

You have to put a pulley on the taut line and ascent the

slack line.

This kind of gives you an idea for the logistics here.

You'll note that there's distinctly different types of

suits going on here.

That's because we've got nine nations

involved on these projects.

Typically sometimes 10 or 11.

Right now it's mostly US, Mexico, England, France,

Switzerland, Germany, Poland, Canada, Australia, Portugal,

Spain are the main ones.

These guys right here with a light-colored yellow suits are

all the Polish team.

They're unloading tackle at camp two at minus 800 meters.

On the far right over there, the guy in the sleeping bag,

is on the lead rigging team.

He's out about two days from the entrance at that point.

These guys up there have just brought in a resupply of rope

and food to keep the lead team going.

AUDIENCE: Do you want a question?

BILL STONE: Yeah, sure.

Go right ahead.

AUDIENCE: What about communication?

How does the guy who's two days on the lead--

I mean he's not using his cell phone.

BILL STONE: No, that's a very good question.

In fact, up until I would say last year we did it all by

basically messenger.

You would send a message back with somebody from camp to

camp to camp, which offered tremendous--

it's like one of these games where you all sit in a circle

and you tell a message to the next guy and by the time you

get back, it's not anything close to what

this guy really wanted.

If it happened to be that he wanted a battery pack for a

drill because they weren't going to be able to rig

anymore, and what came out was I need a charger for a battery

pack, but it doesn't work with that one.

So the guy gets this charger for the battery pack and he

says, well, you know this only runs at 110 AC, we don't have

that down here.

We've seen stuff like that.

And that's a really good question because it bears on

what I'm going to show you at the very end of this thing.

It's this logistical pyramid that you're fighting, and the

question is can you cut the ties to the surface?

There are some things that you can cut, some you can't.

But the issue of communication is one that was dealt with

over the last year.

We have three solutions, one of which was to deal with

magnetic induction radio and actually put receiver stations

on the surface and then standard radio relays back.

The second one was to run a multi-hop internet in.

And the third one, which we ultimately ended up doing, was

using a single wire, low impedance com system that used

the Earth as the ground.

Very clever design.

Came out of Australia.

It's just a little tiny box the size of a pack of

cigarettes.

With that you got one hand on the wall for your ground and

you press the button and you've got communications and

it works like gangbusters.

So we've been using that since.

We ran seven kilometers of wire over the last year in one

system here.

But anyway, this is a typical large tunnel

when you're down there.

Everybody asks me what is its depth?

AUDIENCE: On one of those, you mentioned that GPS system

before wouldn't pick up the satellites either.

What's the technology?

BILL STONE: GPS would not work underground.

You put a piece of paper over--

AUDIENCE: You said you hit suspension depth.

BILL STONE: Oh, only between the open entrances.

So you could go from the highest entrance to the spring

provided you had made a link between them, and it would

serve as a correcter, an ultimate absolute correcter,

to whatever survey that you had done in between.

It only works if you have access to open entrances.

AUDIENCE: How do you measure the depth then?

BILL STONE: We survey in polar coordinates.

You have a metric, fiberglass tape, you have two optical

instruments, hand-held.

These are [? Symptose ?]

made in Finland.

Quarter-degree accuracy on compass angle, and roughly the

same on vertical inclination.

So if you think about it, our polar coordinate system, you

got all the information you need to convert back to

Cartesian or standard GPS type coordinates.

That's basically how we do it.

As you'll see here at the end here, we actually have a

computer model of the entire internal coordinates of the

mountain, and they're done in northeasting and op standard

UTM GPS coordinates.

So you could actually overlay those on a standard GIS model

and look at it.

Right now we're in the process of converting and getting the

digital terrain model for Oaxaca, and I don't

have it to show you.

But you can see what the surface looks

like on Google Earth.

I could give you the coordinates.

Anyways, one of the things that people always ask us here

is what does it take to get on one of these teams?

So the guy on the right over there is just doing the normal

test that we ask everybody to perform.

[LAUGHTER]

BILL STONE: So onward you go from camp to camp.

It takes roughly one day's travel, and by one day's

travel we're talking anywhere from 12 to 16 hours one way

travel time between camps.

So this is camp three.

You're down at the end 1,025 meter level, and you can get

an idea for the feel of the tunnel right there.

We're on the side of that on a little pocket over there.

Finding flat spaces is always a challenge in a deep system

because you have rivers that are flowing the place out

every year.

Yeah.

AUDIENCE: Are these strictly in an exploration and

surveying teams, or is there a biologic aspect to any of the

expedition?

BILL STONE: It is not uncommon to have a biologist along.

It is not an intentional search that we do to have a

biologist along, the same way that we would not necessarily

have a geologist along.

Most of the people who do this long enough recognize

instantly if there's something unusual, and they'll

frequently collect it.

Some people just carry a little vile of formaldehyde

because there are people who do this.

You have to watch that though because you're crossing a

curious boundary in certain countries, and

Mexico is one of them.

If you're doing scientific research, you have to have a

Scientific Visa, which is totally different from a

standard Tourist Visa, which is what most explorers go on.

AUDIENCE: So a lot of the teams that are working on the

[UNINTELLIGIBLE]

are looking for places that are sort of like

[UNINTELLIGIBLE]?

BILL STONE: That's an interesting connection you

make there.

Yes, people like Penny Boston and a few of these other

people who are fairly well-known.

Extremophile biologists and things like that, Norm Pace,

John Spear, people like that.

Some of the times they're finding these things in caves.

Frequently, they're finding them elsewhere in hot springs

and places like that.

There are a whole host of those, and that's a totally

different talk.

I will talk a little bit about the types of things that we're

designing apparatus to detect on Europa when we

do the 12:30 talk.

So again, the thing is when you're going down there,

you're picking up more water all the way, which means

you're constantly rigging more rope.

So about this point, you've run out of your 3,000 meters

of rope and you're getting ready to move on to doing the

final bits of exploration.

As we invariably find, the deeper you get, it seems like

the higher the probability is that you're going to find a

tunnel that is completely under water.

So in Cheve, you're now at a point where you can see the

waters is building up massively in

that left-hand slide.

Still doesn't mean that you can't hit small spots.

If you hit a hard layer of rock, you can usually hit a

fissure that's narrow.

That's actually not narrow.

Narrow would be something that would be compressing your

chest and your back at the same time and just barely

getting through.

So this is the typical place that you would get.

Up until probably 1970, '75, these places used to be called

terminal sumps, or terminal syphons, meaning that's it.

OK, that's the end, let's get out.

We'll de-rig the ropes and go home.

Until people started taking a dive mask along and sticking

their head under water and saying hey, you know the cave

doesn't end here, it's just full of water, man.

So that started a whole cascade over the last 30 years

of this skill, sport, whatever you want to call it, called

cave diving.

It's developed into two distinctly different factions.

If you go, for example, down to Cancun or the Yucatan, you

can actually take a sport course and do a cave dive down

there right now.

You can get an open water certification, then you do a

basic cave dive.

And you'll see what some of these cenotes and things like

that look like.

Very fascinating.

Also very deadly if you go much further without the

proper skills.

The other faction, which is perhaps, I would say, on the

order of one of them to 300 or 400 of these other types who

go and visit these springs and things like doing cave diving,

is what you would see the divers who would do

this kind of stuff.

The problem is that you have to have all these other skills

behind you to get to these locations.

The other problem is that to transport normal diving

apparatus, let's say a tank of compressed air to these

places, is enormous.

So when you get down there, if you don't find the way on on

the first crack, you've just shot all of your equipment and

all that has to go all the way back up.

Right now, this is at a point 8 kilometers from the entrance

one way, three and a half days travel time.

Very arduous.

And after it's rigged.

So you're about six weeks into the expedition right now just

to get to this point.

And that's with your one shot, right?

So to break that, what people have done is gone to closed

cycle life support systems that are now becoming

popularly known as re-breathers.

What those things do is close the metabolic loop and you can

get anywhere from 6 to 12 hours out of a backpack that

weighs the same amount as what you had before, and you can

take the recharge materials to give you another 12 hours.

So suddenly the distance underwater becomes less and

less important, as long as it's not too deep.

So in 2003 we were successful in passing

this first one here.

It was 120 meters long, about 12 meters deep, which by

diving standards is not much.

The second one, about a kilometer away, this was all a

large cascade canyon, again, with all that water that you

saw before.

280 meter dive there, and on the far end of that, there was

a place where the ceiling had collapsed and you couldn't go

any further.

So the problem then is now what do you do?

Well, you could, perhaps, put a team out there and camp on

that far side of that second underwater tunnel and see if

you can weasel your way through.

What everybody felt was you know, maybe it's time to start

looking for an alternative way into the

heart of the mountain.

So a year later, we had a three-month reconnaissance

expedition looking at areas in between that entrance and the

resurgence to try to find a way on.

This is kind of a topographic map of what's going on.

This is the main Cheve entrance right here.

The resurgence is right at the very top there.

That's over 18 kilometers a straight line distance

between those two.

The limestone band runs, it's a 5 kilometer wide chunk,

perhaps about that wide from here to there.

The idea then is can you find places where there are

entrances dropping in.

Well, this was one of the areas right here that seemed

most profitable for looking for new entrances.

And indeed, we found a lot of stuff while we were up there.

It's one of the few remaining true cloud

forests in Latin America.

It's up at about 2,600 meters elevation.

You can see everything is covered with green moss.

This is on a typical day where, or untypical day, where

the sun is actually out.

This is more typical, chopping your way through 10 meter high

vegetation to look for entrances.

But entrances, we did find, over 150 in the

space of three months.

Many of them quite spectacular from the entrance looking out,

things like that.

But ultimately, we ran across this one here, which

had the name J2.

Now, you might wonder where these names came from.

Well, since we're doing the original exploration--

in fact, the only people to ever have ventured into this

cloud forest before were a handful of local hunters from

this tiny remote village on the mountain down

there called El Ocotal.

So this was this pretty much cutting track where nobody had

ever been, even in the jungle on that mountain.

We had various groups breaking up to go do the surveys.

Well, the Americans went with a lot of the Mexicans, and we

would put a P for pozo, which means pit in Spanish, and we

were up to like P25 or 30, something like that.

The Poles, the Spanish and the Australians went off in

another group, and they used the term J, which in Polish

means Jaskinia, which means cave. So J2 was cave number

two in Polish.

That was where the name came from.

Now, we were able to get down a little over 340 meters,

something like that, during the course of that project.

The thing that made this very interesting was the fact that

there was a wind blowing into this entrance that exceeded 35

miles an hours, 35, 40 miles an hour.

And that alone was enough to drive a team to want to come

back and find out where the heck that was going, because

you don't get a wind that's 35 or 40 miles an hour in a cave

unless there's something enormous underneath.

It takes a huge hydrostatic differential in terms of

compressed air to cause that kind of air flow to form,

which also means that there's consequently a big cave, but a

very deep cave as well, attached to it.

So this is expedition life in the cloud forest. Gear is all

hung under tarps because it's always dripping and rainy.

Everybody hangs out in their tents when

they're not up and caving.

It is wet, it's dirty, you have to deal with a lot of

really strange characters who have attitudes, and they have

strange ways of resolving their problems. But in

general, I would say if I had to add up some of the

experiences that I've had through life, and what has

been the most valuable to me, it's the people that you do

these crazy things with.

A lot of people I've talked to about this said, well, it's

kind of like war.

You're out there with a platoon or something, you all

barely survive for some lucky reason, and you go back and

you have that experience to think about for the

rest of your life.

The difference is here is we meet every year.

This is my family.

It's my international family here, and they've all got

crazy ideas about what life is about and everything else.

So it's a good cultural diversity time for all of us.

So this is the exciting thing that got everybody to come

back there.

You might think that that's not so exciting.

But in fact--

and the first 400 meters really isn't exciting.

In fact, it's really terrible.

You're basically in a fissure.

It's one of these deals where unlike Cheve, it did not have

a huge drainage area, and so therefore you were working at

very high altitude, you're up in one of these tiny little

limbs that's small and leading on downward.

Ultimately, there's a series of shafts.

There's one that's about 140 meters long.

It's not nearly as big as the ones in Cheve, but is

controlled by the same geological straight and so it

tends to form shafts.

Just like all the other things, repeating the ideas.

Camp one was established at 500 meters about eight hours

from the entrance.

Not as far as normally we would like, but that was the

only place that we could actually put a camp.

Below that you're now in clean washed rock, you're picking up

streams. As soon as you have something about that size you

know you're going somewhere.

You know that you're definitely headed for a very,

very long, remote trip down into the core.

These are kind of like walking through mountain streams and

things like that with a slot canyon, except having a roof

over your head.

You don't really even think about the fact that there's a

roof over your head unless you're cave diving.

That's a more disciplined type situation where you really are

thinking about what are your options for getting out.

Whereas here you've got plenty of time to think about it.

You get tired, you can just sit down.

Same thing with being on rope.

It's again, J2, very similar to Cheve.

Two and a half kilometers to get to the moment of

exploration in 2005.

three and a half kilometers where we got to this year.

AUDIENCE: What's the temperature down there in

Centrigrade degrees?

BILL STONE: It starts off at about 10 to 12C at the

entrance, and by the time you're down 700 meters, it's

sitting at around 13, 14.

And it's not so much from geothermal heating as from the

fact that you get frost and snow and stuff like that at

high elevations that run down these valleys and dump into

the entrance.

You're really equilibrating with the mountain by the time

you get to that depth.

So again, a typical camp down there.

We have a wonderful relationship with the Nalgene

Labware Company.

[LAUGHTER]

BILL STONE: And we've had it for almost 25

years I would say.

You might wonder what do you use these things for?

Well, the thing is you're constantly in the rain, you're

swimming, you're diving, you're doing--

If you want to be happy underground, you don't want to

arrive there with your food soaked, your clothes soaked,

and your sleeping bad soaked.

Very, very bad karma.

Well, in this particular case, we found out a long time ago--

actually, not that long ago-- but we found a very good

synthetic sleeping bag that would fit in a four liter

bottle if you compressed it.

Now, it takes some extra effort to make it fit in

there, but it's worth it because these things are like

nuclear indestructible.

You can actually drop them down shafts and they just

bounce around at the bottom and off they go.

So you can carry your hammocks down there, you can carry your

clothes down there in these things, and basically you're

transporting these bottles through the cave until you get

to where you're going to go.

AUDIENCE: I don't see any advertising, so how much does

it cost, and who's funding?

BILL STONE: Very good question.

I've run projects like this that have run as little as

$25,000 to run an expedition when I was doing stuff in

college at UT Austin, to as much as over $2 million.

It depends a lot on the technology

that's being involved.

When we were first developing closed cycle life support

systems, we were building 8, 9, 10 prototype devices that

were running $50,000 to $80,000 a piece to small

process manufacture.

We had to design our own computers.

That's a whole different talk that I don't have an

opportunity, unfortunately, to get in to here.

But over the course of 15 years, we developed some

pretty high technology, and building

that stuff costs money.

So I would say generally a project like this you're

looking at around $100,000, and you've got roughly 40 to

50 people who are involved.

Typically on the order of 20, 25 industrial sponsors,

corporate sponsors put up most of that.

National Geographic has been very, very good to us.

We have probably been sponsored by them, I would

say, 7, 8 times.

They don't always do a story.

Once in a while we'll do a story in the yellow magazine,

the main one.

Frequently they'll do stories in Adventure

magazine, things like that.

Sometimes it'll come out on the web.

There's a great website that's still archived there on the

2004 expedition.

Rolex, another good sponsor there.

We've been very fortunate in the last couple of years to

have had some individual patrons who

put money into the--

you know, much like Lance Armstrong, built up the US

cycling team for the Tour de France and all that.

We had people who would put into a nonprofit corporation

to try to get the team out in the field.

And we've been pretty lucky the last couple years.

We've been pretty much been self-sponsored for

the last few years.

That will change if we have another high tech

need that pops up.

So somebody was asking how we know where we are.

This is really typical.

You have somebody who's a good artist/sketcher who's taking

the notes down.

And basically you're building maps of what the roadway looks

like ahead that you have to navigate through, and that's

information that you pass on to the next crew that's coming

in to change out with you when you want to

go back to the surface.

You might wonder how long you stay down.

I've accumulatively spent 397 days below 400 meters deep.

Typically, your run would be on the order of anywhere from

10 days to two weeks.

Maximum somewhere between 18 to 20 days.

As you'll see when I show you the slide at the end here,

we're extrapolating to complete this project probably

on the order of 35 to 40 days as a mission length of time at

distances over 30 kilometers from the entrance.

In 2005 we had a rather curious thing happen that

hadn't happened to me in 20 years because invariably we

took cave diving equipment with us, just in the off

chance that you ran into an underwater tunnel.

Well, we had so much wind in this cave J2 that we figured

why bring diving gear.

It's just an extra piece of stuff you're not going to use

because there's so much wind.

That means it's all open, it's deep, and we're just going to

be rigging rope this year.

So we had plenty of rope.

Until we hit the 700 meter run.

You see this guy here on the left up to his armpits there

in water in that fissure, which obviously, he's not

going to go any further in.

We didn't have any dive gear in base camp.

So we backed up and we tried the old climbing trick.

Go into the roof, see if you can find a place where the old

river went, and try to bypass the sump.

Well, we tried that for two weeks and it didn't work.

And then finally we drew straws in base camp, and four

lucky volunteers drove two and a half days back to

Brownsville where a team from Austin, whom we contacted on

sat phone, brought down enough dive gear for four people and

then they drove back.

So within five days we had dive gear at camp.

This is not your normal dive gear.

These are carbon epoxy tanks.

They run at 6,000 psi.

They weight about 8 pounds empty, about 16 pounds full.

So half the weight of the tank is the gas that you're putting

inside there.

AUDIENCE: And is that just compressed air?

BILL STONE: Yes, in this particular case.

These are shallow dives, so you don't need Helios or

anything else.

But again, that's a whole other subject we can talk

about if people are interested.

AUDIENCE: So why was there so much wind if the cave was

[UNINTELLIGIBLE]?

BILL STONE: Because there, in fact, were higher-level

fissures, but they were only a couple of centimeters wide.

But because they were on the order of 30, 40, 50 metres

tall, you've got enough cross-section there for it to

get through.

However, even with that, what we discovered, and I'll show

you something interesting here that happened just after this.

In order to do a dive, you noticed how narrow that

fissure was.

Well, underwater we found that, in fact, it was still

almost that narrow.

It was about a meter, less than a meter wide.

Maybe three-quarters of a meter wide.

And you had to get through that.

Well, the normal technique is to either have tanks on your

back or on your side.

But those wouldn't fit through.

We couldn't get through the thing with that.

So we ended up doing this thing where you strap two

tanks together, this neutral, you push it ahead of you and

then you basically slip through this tight crack

underwater while pushing that gear ahead of you.

Here's the phone we were talking about.

The first use that we saw with that was in 2005 where we ran

an underwater line through the underwater tunnel to talk to

the crews who were on the other side, just in case we

had a problem.

So this went from camp two to the crew that was on the lead

team on the other side of the sump.

What they discovered over there was something really

curious, and it's something that I haven't seen in 40

years of doing this stuff.

Is that where those guys are standing right there, there

used to be a gigantic pile of boulders, about

15 to 20 tons worth.

And they were small enough that they had backed up and

gotten silt on them and built a dam, which pulled the water

up in this fissure to a point where you had to dive through.

So they started pulling the rocks out and they found that,

indeed, they were lowering the water enough to eventually

lower it two and a half meters to where they had air space to

go through.

So this guy right here on the right is actually coming

through the place where we dived with those two tanks

just the previous day.

And beyond that, things are pretty much the same.

Just the kind of thing that you'd expect in a small

in-feeder into a gigantic cave system.

Again, doing lots of rigging along the walls.

Then finally you get to a fine point in the deep caver's

world where you still have all this gigantic wind and you run

out of rope at the end of some big shaft going down and

there's nothing but blackness below you.

And then you come back and you see where the heck you are.

It's at that point that you begin to cycle anew for the

next year's project.

So everybody says well, we're all out of time this year,

what are we going to do next year.

So you look at these things and you start thinking well,

are we coming back here or not?

In this particular case, we did.

And again, this is the cultural diversity of the

teams that we have up there.

When you're sitting at base camp and doing nothing but

either sitting in the rain forest or working in the muck,

you tend to have a curious psychological outtake and look

for ways to amuse yourself.

This is Artur Nowak on the left from Poland.

That's Mark Wilson on the lower left

over there from Australia.

And Tony Dwyer from Germany on the right.

And again, upper section, tight, narrow, dirty,

uncomfortable.

When you get down to about the 1,000 meter level,

you're in the water.

This year we did a couple things different this year

because we were trying to experiment with ways to break

this tie chain to the surface.

The first thing we did was try to reduce the amount of

clothing that you have to take down.

And one way we did that was by finding a way to introduce

heat into the sleeping environment here.

That's a silk tent, weighs about one pound.

Fits in one of those four liter Nalgene bottles.

And it raises the temperature of six people sleeping in

there by about 6 degrees C. 6 to 8 degrees C. It's quite

significant such that you can really cut down on the weight

of what you're bringing on down.

Again, typical camping environment here.

So we are not in a Gulag or a concentration camp here.

These are happy explorers reducing weight.

We've only got one spoon between the entire

four person crew here.

No bowls, no cups, one pot.

You even think to the level of where you either don't take a

toothbrush or you cut the toothbrush off to save the

weight of the handle when you're going down to places

like this because everything has to be carried out.

Here's another interesting experiment that went on.

Probably half of the weight that we carry--

this might be amusing or whatever--

is the fact that we've gotten away from the traditional way

that people used to use light underground,

which was calcium carbide.

Right up until about, I would say, 2001, 2002, this was the

standard way that we went.

Calcium carbide, you put it in a little container, you put

water on it.

It generates the acetylene.

You light the acetylene, you've got

this very bright flame.

Anybody who's used a welding torch knows how bright

acetylene is.

They used this, it was invented back in the early

1800s for miners.

We've not completely supplanted that.

We used to use 700 to 800 pounds of carbide for an

expedition.

700 to 800 pounds.

We now use less than 20 pounds of lithium ion batteries.

What you see right here are lithium ion batteries that

we've developed for drills.

The way that you rig is using the pneumatic impact drills.

Well, those used to use really big, heavy batteries.

And taking those out to the surface every time was

probably 25% of the mass that you were transporting up and

down. so what we did now, is by going to these batteries,

and using a hydroelectric power station to recharge them

by hanging in the water, we have snapped

that tie to the surface.

And off we go down in the big tunnel.

You're now at 6 and a half kilometers distance from the

entrance at about 1,100 meters down.

Geology is all around.

This is what's called a slickenside, for those who

have ever heard that term in a geology class.

It means a place where the Earth has been just

ripped up and down.

You can probably see it out on the San Andreas fault and

other places like that if you look very carefully.

But this is a graphic example where the left side has just

dropped down below the right side, and you can see the

signs of salacious materials like clay and stuff like that,

which have a nice color to them, that indicate the fact

that these walls have moved to some seismic event in the

past.

AUDIENCE: Also, we're seeing all these photos taken with a

flash, and presumably you're seeing this whole thing with

your Petzl headlamp and that's about it, right?

BILL STONE: Actually, not Petzl headlamp, we design our

own LED lights.

AUDIENCE: OK.

But with a Petzl band on it.

BILL STONE: Yeah.

AUDIENCE: So you're working on this with some cluster of LED

lights and you have like that 5 degrees of--

BILL STONE: Right, and that's a good point.

So if I go back up here--

I don't want to delay the end of this show too long--

You look at a slide like this, OK, you don't see that when

you're walking through it.

That's a multiflash thing.

Pretty much like from about five slides before this, until

this right here, all those previous slides were taken

with either bulb or large capacity underwater strobes

and Kodachrome 200 film using Nikon S5 cameras.

This year everybody has gone digital, and as a result of

it, the quality has gone down.

So we've gone from probably 20 megapixel, 25 megapixel

resolution, to these three and a half megapixel waterproof

cameras that you can put in your pocket.

So everybody likes them, but we haven't crossed that

frontier of bringing the quality back up in terms of

digital, because if you gave me the top of the line Nikon

15 megapixel digital camera right here, $6,000 camera, I

and 39 other people on that team could trash it for you in

less than a half a day in an environment like this.

So that's the problem that we're still working on there.

The environment can vary dramatically.

The rock here can just be as fluted as Swiss cheese.

You have to really watch yourself when you're walking

on stuff like this.

There's a term for it.

It's called [? xenolith. ?]

it means razor rock in Latin.

It's very peculiarly present in tropical

caves in certain areas.

This kind of looks like a pleasant area, but in fact,

everything they step on breaks off underneath

them as they go through.

Not everything is big.

These are the kind of things that you occasionally

have to deal with.

While you're doing that, of course, you're also passing

five or six duffel bags that you carry between

your team with them.

Frequently we don't have the sense to show those in the

pictures because they're in the way of the camera.

We're down at the 1,150 meter level here.

And finally we've arrived at camp three.

This is a far more arduous trip here.

You're about 7 and a half kilometers

now from the entrance.

1,150 meters down.

Same ideas again though.

The silk tent to keep you warm, lightweight stuff.

There's our happy crew.

This is the, we call this the DUS team.

That's the Dutch members of our team on the left there,

and myself, and Matt Covington who's from Stanford, are the

US members-- that was be Dutch-US team.

This is a typical night down at camp three again with the

single pot servings.

It looks suspiciously comfortable in this place.

And in fact, you can have nightmares because you wake up

and you go, what a great place, and you step outside

and realize where you are.

This is what you look like after 10 days down.

It gets to be a little wearing on you.

After about 20 days down, you don't look a whole lot

different, you just have a little more facial hair.

It just gets to be a place that you go to work.

You get up every morning and do it.

Again, things that you don't see on the surface.

Just razor-like little things with popcorn growing on them

in the middle of a big tunnel.

Stuff like that.

And, of course, the ubiquitous underwater tunnel, which

marked the end of this year's exploration at

1,210 meters down.

That's our lead diver for this year, Jim Brown, coming back.

This was not a re-breather dive.

In order to get off a quick recon right at the very end of

the trip, we just had two carbon tanks with us.

And as a final act of arrogance, we tried to put a

climb directly over the top of the sump.

So the conclusion of this story will leave you hanging,

so to speak.

So where is all this is going?

Why do all these people spend enormous amounts of their

private effort and money and time and risk their lives at

to do this?

Well, it's largely because we're looking at something

that's going to happen.

It's going to be an event.

It's going to be like is the US or the Russians going to be

the first on the Moon?

Once it's happened, that's it, it's history, it's gone.

Right now, the deepest cave in the world is

sitting out there waiting.

There's a of couple people who think they have it.

They quite likely do have it.

Either the Russians or the US team probably are on to it,

and Cheve, in the eyes of the American conglomerate team, is

the place where it's going to happen, and it probably will

not be anywhere else in the world than Southern Mexico in

our opinion.

We may be surprised.

But this is the way things have been going starting as

early as 1700, how deep people have been underground.

Currently, this is a little bit out of date.

The Russians hit 2,140 as of January last year.

Otherwise, the map is pretty much the same.

Cheve is down there at number nine.

You'll notice, however, that there's not a whole lot of

difference between the top 10 in terms of vertical distance.

If we were to find a 400 meter shaft at the end of Cheve, for

example, we would surpass all that in one afternoon.

I mean it's just a matter of taking a 200 meter rope down

there and another 200 meter rope.

Throw them, connect them together, rig them,

and down you go.

But you know, it's always more arduous than that.

This is giving you an idea as late as 1980, you could count

the number of 1,000 meter caves just the way you would

the number of 8,000 meter peaks.

So it was a very serious thing.

Since then the technology has changed.

It's become a more popular sport.

I want to close with one last PowerPoint slide here and then

show you two other images.

These are not all the same.

When you say the deepest cave in the world at 2,140 is

sitting in Chechnya right now with the Russian team standing

on top, was that as difficult as what's going on at Sistema

Cheve, for example.

If you look over here, Krubera, which is the place

that was explored by the Russians, there's a great

article in National Geographic, May of last year

if anybody wants to read about what the

Russians have been doing.

Great guys, good work.

But on the scale of things, you can see that what's going

on down in Southern Mexico absolutely dwarfs everything

that's going on over there.

The distances are enormous, what you're

dealing with over here.

Krubera, you can pretty much be at the bottom of Krubera in

two days and that's it.

And it's not going to go any deeper because the springs are

at a level approximately 30 to 40 meters below that, and it's

a very difficult piece of terrain in terms of strata

that they'd have to get through to go that deep.

So what I want to show you now, just in closing, this is

the vertical view now.

This is Cueva Cheve.

This is J2 out to what we did this year.

There's another cave, Charco, and there's the resurgence.

So you can kind of get an idea now, we're inside the

mountain, and all these things are generally trending down in

this direction.

Ultimately, they're going to hit this area in here.

And because you can see that they're getting close to it

already and there's a long distance here, what that means

is there's going to be a lot of diving in that section

right there.

Not a very pleasant prospect, but it's waiting out there in

the looms, which means we're going to have to invent better

diving gear.

Fortuitously, that is in the wind right now.

We are working with a company to develop the Marc 6

re-breather.

It's going to be about the size of a briefcase.

Give you three hours under water at depths down to 60

meters, and that'll be out by January next year.

Our team will start training with it for a 2008 push on the

second sump in J2 down there.

Now, from a logistics standpoint, this

is that topo map.

What we've added now is this new piece of information here.

Here is the work that's taken place over the last three

years at J2.

Three months in the field this year--

added this little tiny green line.

Now you start to get an appreciation for the scale of

this kind of thing.

I know a couple of really good people who have done

high-altitude mountaineering work, and I always ask them

what's it like, like Ed Viesturs, for example, we were

having a conversation one time, and I said, you know

what, when you go do Everest or K2 or something like that,

what is the thing that really impresses you most. And he

says, you know, it's when you get to base camp and you look

up and you go holy smokes, this thing is huge, enormous,

just bigger than anything you could possibly imagine by

looking at a picture.

Well, that's kind of how you start to feel after you go to

a place like this and you say, oh man, that was a really

tough expedition.

We were down there for three months, we beat ourselves all

over the place.

That's what we added.

This is another thing.

The difference between exploration and

adventure is one word.

Data.

If you don't bring data back, you haven't done anything.

You had an adventure, you've have a thrill, you've had some

kind of a tourist trip or whatever.

And some people, you really don't see that much in the

deep caving world, but it's starting to happen in the

mountaineering world with people going to Everest in

particular, and you see the results of that with what

happened, for example, in 1996.

But any event, all of this stuff in here in between is

the giant unknown.

How are you going to beat the Russians if you

can't get into that?

Well, this is the logistics map that

we're projecting down.

Each one of those little red circles represents a projected

underground camp, one day travel time underground based

on our knowledge of what's been going on in the system.

We're expecting that there's a major fault that takes it all

down to Mano curving Northeast and then finally Northwest.

But just to give you an idea, if you want to get to the

resurgence from some place like J2, which is currently

the only open system that's down there, you're looking at

11 days one way travel time to get to the bottom.

11 days back out.

That's 22 days just to go down there and say hi.

And then you normally will spend anywhere from 7 days to

two weeks doing actual exploration.

So we're looking at times of 35 days roughly when we

finally pull this off.

And God knows when that's going to be.

The 2008 expedition is targeting right here, and if

we're really lucky, we may get to 7D or 7U on that project.

So that's where the world of very deep exploration

endeavors is standing today.

We could give you similar discussions over some of the

other caves in Europe, but this is the kind of technology

that's out there.

This is what people are doing.

Yeah.

AUDIENCE: How quickly, if at all, does the underground

terrain change?

Like you'd say one year you'd come back and suddenly one of

the caves has collapsed?

Is that common or not?

BILL STONE: Almost not at all.

We used to say that those are Hollywood theatrics to inject

collapses into movies and things like that.

If anybody had the bad karma of going and seeing that movie

The Cave last year, they had an underwater collapse that

traps this steam beyond it.

But in fact, I know of at least two or three cases where

that has happened.

And it's usually been in places where it was a virgin

exploration, nobody had ever been there before, the rocks

were just precisely balanced at the wrong angles.

It's quite common, for example, to go through

unexplored territory and step on a rock the size of a truck

and have it just move like that.

Go back and forth.

It's really scary the first time it happens to you, but

you realize oh, that's not going

anywhere, it's just balanced.

But every once in a while, you have to

think about those things.

One of the things that we do is when you have a team of 40

to 50, you come prepared for what we'd refer to as

self-rescue.

So we have tools in there for dealing with that if we do

have a collapse.

Highly unlikely.

I've never had to deal with one in 53 expeditions.

But we have had to deal with a lot of other stuff, including

fatalities, broken bones, all kinds of stuff like that.

Yeah.

AUDIENCE: What are you guys bringing down there for food,

like nutrition?

BILL STONE: We changed that dramatically.

We used to all freeze-dried, and then we went to the

extreme of taking the freeze-dried, running through

a salad shooter and compressing it with a jack

into a four-liter Nalgene bottle so that you'd get the

absolute, most dry food into the smallest possible place.

What's happened in the last two years is that we said you

know, this stuff really sucks, and it would be better to have

something that is dense and dry.

So we've gone to doing things like a high carbo routine.

So for example, rice.

We've gone back to whole grain rice.

I wouldn't have predicted this 20 years ago.

We've done that.

We go to ground-dried meat.

For anybody who's traveled to Mexico, there's a very popular

breakfast that's called machacado.

You can get machacado dry in Mexico at Sam's Club.

So this year we bought an eight-ton truck worth of food

from Sam's Club and Suriano and a few other places in

Oaxaca City, and we didn't buy a spec of freeze-dried food,

and everybody actually liked it.

It was pretty good.

It was heavier, a little bit heavier, but everybody were on

a higher calorie diet than we've had in the past. We're

running about 8,000 calories a day, by the way,

if anybody's wondering.

If on tour with the Tour de France.

AUDIENCE: Talking about logistics, you say you

unstring the ropes.

You take the pins out of the rocks.

Do you carry everything?

Everything back?

BILL STONE: No.

It depends on where you're working.

This is considered an active exploration project.

So the things that will survive year to year, a

stainless spot, for example, will stay at camp three, camp

two, camp one.

The ropes, if they can, will be pulled up to a location

that is outside of the zone if the water arrives.

You can tell on the wall how far the water's going to rise.

And you pull your ropes out of the main shaft.

You coil them up and you hang them.

Staged them is the term that's used.

And frequently we can just reuse them year after year.

It saves on the order of two weeks of a restocking effort.

When you're totally done with a place, if you're absolutely,

absolutely certain that it's done, you clean it.

Everything comes out.

AUDIENCE: But at the end of the two weeks, you carry out

your debris and your waste and all that.

BILL STONE: All the debris comes out, all the waste, all

the used/spent trash.

Anything like that all comes out.

Frequently, if the sleeping bags and things like that that

are down there is utilities--

we use common sleeping bags.

People don't carry personal bags.

So you go from camp to camp to camp.

If they're wet or something like that and you're not going

to dry them down here, you'll bring those out.

OK.

If anybody has any other questions you can hit me

afterwards.

The Description of Journey Towards The Center Of The Earth