EXPLORATIONS AT MYSTERIOUS LAGOON - BRAZIL - Bonito

EXPLORATIONS AT MYSTERIOUS LAGOON -
BRAZIL
Gilberto Menezes De Oliveira
“This time you did it,” I said to myself. You are going to stay stuck here till
you run out of air and it is going to take a long time before anybody will come
and recover your body! I was in a terrible situation: 96 meters deep on air,
inside a cave system never before dived, couldn’t see a thing, and my doubles
wedged in something so tight, I couldn’t move! It had all started the year
before…
I first went cave diving during a vacation in December l994. I had, for several
years, been reading about cave diving and found the activity fascinating, but
had not had the opportunity to go cave diving until then. I had studied the NSS
manual, Sheck Exley’s Blueprint For Survival and a few others. The book The
Darkness Beckons was a sort of Bible to me: it was the greatest book on
diving I had ever read. I would read it over and over again. All these
incredible explorations! I dreamed of one day doing it also. But I had no
formal training on cave diving. I did try to self teach me. I would often go to
Paraibuna Dam which is a place fairly close to where I live here in São Paulo.
There we have a lake formed by the dam in the early l970’s which has low
visibility, fairly cold water , lots of silt , trees to get entangled, but most
important it went very deep. It’s a perfect place to practice. Over the years I
practiced going deeper and deeper until I became quite comfortable diving 80
to 85 meters (275 feet) deep with run times of 3 to 4 hours. All on air. Of
course I had my share of problems during the learning process and on two
oxygen hits the dam nearly swallowed me. I was learning by survival. It is not
the best way to do it.
My first cave dive happened on December 1st, 1994 in a cave called “Gruta
do Mimoso” or Mimoso Cavern. Mimoso Cavern is situated in the Mimoso
Farm in Bonito county, in the state of Mato Grosso do Sul. It is located a
distance of about 1200 kilometers by road west of São Paulo. I got hooked
immediately. The cave was beautiful. Mimoso was once a dry cave that
eventually got filled with water so it has many cave formations like stalactites,
stalagmites, etc. Visibility was crystal clear, water warm and the passages
were big. All that I wasn’t used to. The cave did not extend very far and in
another 5 dives I already knew it very well. On these dives, we used basically
cavern dive equipment, diving on single tanks. It was when I met Roger which
was my dive guide on the Mimoso dives and we would start an important
friendship. I also met the owner of Mimoso Farm, a lady which would be very
important, Maria Aparecida, or as I would call her for short, Cida. Cida is a
very religious mother of two on her second marriage. Besides running the

Mimoso Farm with her husband, she also runs a lodging in her farm dedicated
to tourists that come to Bonito including divers.
Diving is rather new to the region around Bonito. By what I know diving
began there in the l980s in a cave called Gruta do Lago Azul (Blue Lake
Cavern). It is probably the most beautiful cave dive in Brazil. It,
unfortunately, is also the place of the first cave diving fatality in Brazil.
Unfortunately, also, it has been closed to diving for several years due to some
non-diving classroom biologist who thinks that in that only cave exists an
unique species of a shrimp like creature. We have found it in all other caves
we dived but she won’t hear us. Then I had heard about Bonito a few years
ago because of an accident one diver had diving deep on a lake there.
Reportedly the diver had gone to a depth of some 80 meters and run out of air
ascending without decompression. He got bent very badly, was taken to São
Paulo for recompression treatment and luckily recovered. Then I heard about
diving in Mimoso Cavern. Having the opportunity to go there, I went.
It didn’t take long for me to start asking Roger if there were other caves to
dive in the Bonito area. Roger explained that the potential in the area existed
for many more caves but exploration had to be done. A few others, already
discovered, existed though. There was a place known as Abismo Anhumas.
Roger took me there. Unfortunately you have to rappel a vertical distance of
66 meters (220 feet) which was out of the question for me. He told me of
Formoso Spring which had been dived by French divers a few years before
but unfortunately the land owner did not like divers on his land. Permission to
dive there would be very difficult. Then he told me about this lake that’s
supposed to have crystal clear water but unfortunately was very hard to get to
the site and worse it was a closed site to divers, by order of the landowner,
since an accident to a diver there, a few years before. Roger was talking about
the place the diver had had the decompression accident. The name of the
place: Lagoa Misteriosa or Mysterious Lagoon.
Insistence pays off. After talking a lot with Roger, Roger talking a lot with a
lot of people we were granted permission to make a dive in Mysterious
Lagoon. So in March l995 I was back to Bonito to make a couple of dives in
Mimoso Cavern and one in Mysterious Lagoon. We went with Claudio, the
owner of another farm in Bonito, who got the permission with Mr. Julio the
owner of the farm where Mysterious Lagoon is situated. The dirt road was
very long. Then at one point, already inside Mr. Julio’s farm, Claudio’s pick
up truck starts going through the middle of the pasture. At one point, we stop
as the vehicle can’t go any further because of the trees. Then we walk. And it
is hot also. Then we get to this rock path nearly vertical. And we follow it
down. And we are carrying our dive gear also. Just to get to the dive site was
an adventure. We weren’t tired though. We were excited we were going to
make the dive. When we got to the end of the rock path what we saw was an

oval lake some 60 meters by some 25 meters. The lake was situated at a
bottom of a depression on the land some 40 meters down with near vertical
walls all around with original vegetation. The dive was planned for Roger and
I to go first. I asked to everyone to be very cautious because this was a terrible
place to get into trouble and also because if we did everything right we
probably would be granted permission to return. The place had been closed
because of an accident. I would go first with the reel with Roger close behind.
The plan was to go no deeper than 40 meters (133 ft). We wore single OMS
121s with H valve and two regulators. This was something new to Roger who
was used to single 80s. Doubles were out of question due the logistics
involved. I remember Roger telling me over and over again how clear the
water was there because he had seen this video of the place. He insisted that
no lights were needed there. Roger didn’t take any. Stubborn as I am, I took 2
lights attached to my helmet and an extra on my pocket. The water was
terrible. Visibility had been greatly reduced due to rainfall. I started using one
of the lights of my helmet and handed the spare one to Roger. I had done the
initial tie off on a rock by the waters edge and we started following the bottom
which was covered with fine silt. We couldn’t see much. At 15 meters it
cleared and became vertical. We were in a sinkhole about 10 meters in
diameter. We kept descending with caution and halted at 40 meters looking
for a projection to tie the line. There was a good one a little deeper and so the
tie off was made at 42 meters. Having done what we had proposed, we started
ascending. We saw that it went deeper. After surfacing Roger took the others
for a short dive.
In April I returned with Roger for another dive in Mysterious Lagoon. This
time the water was crystal clear. Swimming at the surface we could see that
there were 2 sinkholes starting at about 12 to 15 meters deep, both about 10
meters in diameter. The water had this beautiful blue tone though the bottom
wasn’t very pretty as it is covered with brown silt and several logs and
branches fallen from above. We had made our first dive on the sinkhole next
to water entrance, Sinkhole A, so this time we decided to dive the other
sinkhole on the other side, Sinkhole B. At 17 meters there was a very
convenient horizontal log where I did the initial tie off and we continued
downwards. The sinkhole was basically vertical without any side tunnels that
we could find. We had planned not to go no deeper than 60 meters (200 ft). At
57 meters there was this tree branch on a ledge where I tied the line. We
looked around for a short time at this depth. We could see that it went deeper
but could not see were it ended. Swimming in the direction of Sinkhole A
there seemed to be a tunnel but we did not want to swim far from the line to
investigate and soon it was time to come up.
Suspecting that there could be a passage between both sinkholes I returned in
May during my vacation with Roger to try the connection. At this point we
were still diving on a single OMS 121 with H valves but now I carried an

extra Genesis 100 and dove with Superwings. We descended on Sinkhole B.
At the end of my line I noticed the tie off was not 57 but more closely to 59 to
60. I looped new line here and we started swimming in the direction of
Sinkhole A. We saw this big tunnel some 10 meters across with clarity far
away. I could see that there was a passage. We went a little deeper, to 68
meters (225 ft), and the tunnel ascended at an angle. Getting shallower I
started looking for my 42 meter (140 ft) tie off of Sinkhole A. And soon, there
it was! Joining the lines Roger and I shook hands and ascended.
Two days later Roger and I returned for another dive. The plans were to take
another look at Sinkhole B, possibly going a little deeper and, if everything
was alright, to make the sinkhole passage.
We descended Sinkhole B to the tying point at 60 meters and I looped new
line and started descending at an angle. I saw this boulder next to the still
vertical wall with the bottom of the boulder on a steeply inclined bottom. I
passed the line around the boulder and tied it. Depth 75 meters. Everything
alright, we started ascending and swimming in the direction of the passage.
Doing the sinkholes passage again we ascended. On all of these dives, we
were decompressing on dive computers, the old model Aladin Pro. We would
always over decompress what the computers indicated.
On the following days, I started diving Formoso Spring with Gilson, a young
local diver who acquired the necessary permission. But less than a week after
the last dive in Mysterious Lagoon, back I was this time with Gilson but
without Roger. Roger had work commitments as a dive guide in Mimoso
Cavern. I took Gilson to make the sinkholes passage but this time, on our way
up Sinkhole A, I decided to explore a side passage Roger and I had noticed on
the previous dives. The passage started at 34 meters (115 ft). There is a tree
branch at the beginning of the tunnel which is wide enough for one diver to
pass easily but not two. The bottom had fine brown silt and the tunnel
continued descending at an angle of about 30 degrees from horizontal. At 46
meters opened a small room with a small ledge but no bottom. I made a signal
to Gilson to wait for me here because we had not passed a line and I wanted to
take a look deeper. I started descending. I was in a crack about 2 meters wide
and a very irregular 10 to 20 meters long. The walls weren’t smooth but rather
rough and irregular with fine silt on the walls. This is consistant at Mysterious
Lagoon. At 60 meters I stopped my descent and could see way down what
seemed the end of the crack where there was a rock on the bottom. I ascend
worried about not having a line and the percolation from the air bubbles.
Luckily I could see Gilson’s light and we exited the tunnel without problem.
The next day I was back with Gilson. The plans were that we would pull a line
starting from the main line in Sinkhole A, and go inside the side tunnel.
Gilson would wait for me at the ledge at 46 meters while I descended. All

went well. As I descended I could see the rock at the bottom getting closer,
and could see also, that beside it, and a little deeper there was a restriction and
the cave would go on. I reached the bottom and proceeded to tie the line on
the rock. In the process the visibility turned to zero. Working by feel I wasn’t
getting a good loop around the rock. Eventually it stayed reasonable, but not
good, and not wanting to stay too long, I ascended. I had been at 82 meters
(275 ft).
The next day I decided to repeat the dive to check my tie-off at 82 meters. We
would also check a possible continuation at the ceiling of the small room at 46
meters that Gilson had noticed. The tie-off at 82 meters wasn’t bad but as a
safety measure I clipped a 1 Kg weight to the loop. In case the loop would
come loose from the rock the line would still hang vertical. I also checked the
restriction. Not too small, but with a tank on the back and another clipped
diagonally in the front, as I was doing, I wouldn’t pass. I could see that the
cave continued on the other side of the restriction. I also thought that to
negotiate a restriction at 82 meters on air would be a very dangerous move.
On the way back we checked the ceiling of the 46 meters room. We passed
line, starting at 46 meters by making a tee on the main line, to 35 meters. At
this point percolation was a big problem and the tunnel seemed to get tight.
Whenever I laid line I also would put direction arrows which I home made. I
would put quite a few. At the 46 meter room I put one of them indicating the
exit right after the tee we had just done. Coming up through the crack you
would notice a “T”, one line going up and another going to the right with the
arrow indicating the exit.
In June I came back and I decided to reach the bottom of Mysterious Lagoon.
Sinkhole A tapered off through the passage to Sinkhole B, not going any
deeper than about 60 meters. But Sinkhole B would go deeper. I expected it to
end shallower than 90 meters, a depth that I was used to diving in Paraibuna
Dam. Anyway, I knew things were going to start to get more dangerous. I
knew I had to start diving with proper equipment configuration and so I
decided to start diving with double tanks in the lagoon. By this time, we were
already getting used to the steep rock path we had to negotiate to get to the
water and a rope had been fixed along it, so going down with doubles in the
back was not too bad as we could now hold to something for balance. The
place had finally been opened to tourist divers. My equipment consisted of
double Genesis 120 on a Dive Rite back plate with Superwings. The primary
light was a mini Neutralite waist mounted with the MR-16 head helmet
mounted. On the helmet, I also wore 4 back up lights. I wore two of the old
model Aladin Pro dive computer on the left forearm along with the knife and
the Uwatec digital depth gauge on the right forearm. I carried also, clipped to
my left side an OMS 121 tank filled with air. Regulators were all Poseidon
Odins. Resting at the surface, I try to visualize my dive, a technique I tried to

learn reading materials by Tom Mount. Breathing from the stage tank, I
descended, not to quickly as I felt that this helped fight narcosis. Reaching 75
meters I looped new line to the tie off. Having done this, I changed to my
doubles, checked all gauges and descended. I glided at an angle of about 60
degrees from horizontal following the bottom but reasonably above it. The
passage was big. The direction was 90 degrees from the one that we use to
make the sinkholes connection. Below 80 meters you finally have a rock
ceiling above you. At 80 something, I see, just a few meters below me, a tree
branch sticking vertically from the slope bottom, a perfect tying point. I go to
it. I always wondered what the computers would indicate if I descended below
99.9 meters. Would it zero and start again or if it would continue without the
decimal point I check my depth on the computers: 5. something in one and 6.
something on the other. Here narcosis plays a little trick: instead of assuming I
was at 105 or 106 meters, I thought I was at 95/96 meters. Still I thought: I’m
deeper that I thought it would go. I also saw that the cave kept on going down.
I make the tie off, attach line arrow, take a quick look down and ascend. At 60
meters I meet Zé Roberto, an open water instructor from São Paulo who was
visiting Bonito and hearing about the dive I intended to make, volunteered as
a safety diver. We had planned to fix the 60 meter tying which needed
improvement. After fixing it we ascend for decompression. I then show him
the gauges so he would know how deep I had gone. At this point I see that the
digital depth gauge indicated 106 meters. At first I thought that it had
malfunctioned but later I realized what happened. Gilson approached to see if
everything was OK. During deco, Zé Roberto ran low on air (he was diving a
single 18 liter bottle). I shared my long hose. I was saving my safety diver!
The dive had gone so smoothly, I had felt so well, that I decided to return the
next day and repeat the dive, maybe even go a little deeper, just to see if it
hadn’t been a chance dive. The only thing that I changed were the double
tanks. This time I went with double OMS 121s. It seemed 121 would become
a magic number. I ended the previous dive with a lot of margin but, as Tom
Mount had written, “Nobody ever died because he had too much gas.” I also
took an SOS 150 meter (500 ft) helium depth gauge. I descend and at around
80 meters I change to my doubles. This time I pay attention to the computers
l00 meter (330 ft) depth change over. Reaching the tie off at 106 meters I feel
well and see another tree branch sticking to the slope bottom a perfect tying
point. This time though, I don’t assume that it is just a few meters deeper. I
loop new line around the existing tie off and start down. The passage was big,
the water would become clearer as I went deeper. The walls were dark and
gave a rather spooky feeling to the cave. The top of the tree branch was some
2 meters above the ground which continued sloping at a steep angle. I checked
the computers and the digital depth gauge: 121 meters. The SOS depth gauge
is remarkably accurate also. I’m deep, I thought. I checked air. I was good. In
an upright position and in perfect buoyancy control, I proceeded with the
tying. I looped the line twice around the top of the tree branch and let the reel

hang while I pulled my knife. My head was clear. I thought in clipping the
reel to my right chest D-ring before cutting the line so I wouldn’t loose the
reel by any chance. But then I thought that I wouldn’t want to be clipped to
the line in case I blacked out. I made the cut, put the knife back to its sheath,
clipped the reel to a D-ring and proceeded with the tying. Line arrow
indicating exit and a quick look. The water was extremely clear. The slope
went on maybe 10 meters (30 ft) more ending in a vertical wall. To the right
of when you descend (the direction back to Sinkhole A but below it) I could
see what appeared to be the end of the cave, where there were a cluster of
boulders and logs, some 30 meters deeper and 50 meters away. I ascend. At
50 meters I meet Gilson. I show him the gauges. The dive had gone so smooth
and I felt so well that I wrote in the slate with big letters: 121 METERS (400
ft) - IT WAS SO EASY! I decompressed by the computers, with margins,
without incident. I didn’t know then, but some future dives wouldn’t be so
easy.
In August I dove Sinkhole A once with Marcus Werneck from Rio de Janeiro
and Marcio Conte from São Paulo trying to survey the place. The survey was
terrible but we laughed a lot. (Gilberto loves to laugh! ed.)
In September I had vacations again and went back to continue the
explorations. I started diving with Roger again. I started to teach him how to
dive doubles. He began using my double Genesis 120 and twin wings on a
Dive Rite backplate, while I dived twin OMS 121s and superwings. By this
time I was already diving with the new model Aladin Pro dive computers. I
always dove with two, one read in meters the other in feet. On deep dives I
would also carry the digital depth gauge. On our first dive, we dropped down
Sinkhole B. I also wanted to test Roger’s condition on deep air dives. We
went to the 80 meter range. We noticed a passage on one of the walls and
investigated it with care. I was at 83 meters (275 ft) and Roger at 87. It was a
vertical crack narrow but tall. We went in just a few meters while I kept an
eye on Roger and the possibility of percolation. I soon made signal to Roger
to start back as we didn’t have a line and also didn’t want to stay too long at
the depth.
The next day I decided to push the restriction at 82 meters in the crack in the
side tunnel of Sinkhole A. I new it was dangerous but I believed I could do it.
I planned just to take a short look on the other side of the restriction. I planned
to carry a Genesis 100 as a stage bottle which I would clip at the tie off before
the restriction. This was going to be basically a solo dive so, as usual in these
cases, I wore the primary light head on my helmet. Roger would hang a little
shallower watching and to give me an assistance if necessary. The dive started
as planned. Reaching the tie off I unclipped the Genesis 100 bottle and looped
new line. This was enough to silt the area. Passing the restriction was simple.
No problem with just doubles on the back. I started going down at the

eginning but soon I started to taper off the descent. The water was very clear.
I had one wall to the left, another to the right, spaced about 8 meters apart.
Looking ahead I could not see where it ended, looking down I could not see
the bottom. I checked depth 90 something. 100… I was going further than I
had planned. But all was going well, I thought. My head was good, air
pressure was good, water is clear… So I went on a little further. I stopped
descending at 104 meters and started looking for a place to make the tying. I
could see some 20 meters ahead and a little shallower the only place that
seemed acceptable so I swam to it. It was 100 meters deep there. I pulled the
line, looped it around the projection and proceeded with the cut. In the process
visibility turned to zero as the wall was full of fine brown sediment. I started
working by feel. It was taking longer than I wanted and I started to feel weary.
As soon as I finished tying I started to head back feeling the line. I did not
waist time putting a direction arrow. But things were different now. I could
hardly see anything and I started to scrape myself on the walls. I had my right
arm extended above me holding on the line while I tried to progress. My
doubles were scraping and I couldn’t see where. Also, I was hardly getting
any shallower. At one point it got stuck but I was able to free myself quickly.
By now, the stress level was high. I wanted to get out of there fast because I
knew I was too deep for too long for an air dive. Then I really got stuck. My
doubles were wedged tight and I couldn’t move them. I checked my depth: 96
meters. At least this I could see. I didn’t bother to check my air as I thought it
would be an useless information. I would waste precious time doing so; I had
to get out. For a split second flashed in my mind an episode I read in The
Darkness Beckons when Mike Boon, gets stuck in a cave and tells himself
“This time you’ve really done it”. This time you did it, I said to myself. You
are going to stay stuck here until you run out of air and drown and it is going
to take a long time before anybody will come and recover your body. I also
thought that soon I would start feeling dizzy, and then, that would be the end.
But I was holding to the line and I knew that the line would get me out of
there if I could follow it. I tried twisting and turning to loosen the doubles but
I couldn’t. I did not want to let go of the line which I held with my right hand.
I was also afraid of breaking the line. I tried pushing myself down and
managed to get loose, stretching somewhat the line and managed to get free.
Soon the line became nearly vertical and I started to ascend. I started to hear
Roger’s breathing which was a wonderful sound. I passed the restriction
without problem even though visibility was bad. I quickly clipped the stage
bottle and made signal to Roger to come up. I then checked my air in the
doubles: 100 bars. A lot of air but less that I would like. During deco Roger
saw my computers and started to rave about the depth I had been. I signaled
“no” to him and wrote down on the slate what had happened. I hadn’t looked
back as I advanced with the line and when I got to the tying point and pulled
the line I had made the line get into line traps in the ceiling. I was lucky I
didn’t nark or tox. I started to think about what I was doing. I remembered

when I phoned Arnold Jackson a month or so before and told him I had laid
line to 400 feet on air: “Gilbert you have to use helium!”
As things were getting too dangerous on the crack we decided to concentrate
our dives on Sinkhole B. Two days later we were back. Roger wanted to go
deeper and I thought he could. We went to a depth of 96 meters where the line
goes over a log. We held there for some 3 minutes to have a good look and
ascended. On this dive we positioned a safety air bottle at the 60 meters tie off
(a Genesis 100).
Next day we went a little deeper: 104 meters. On this day we positioned
another 3 safety air bottles: 2 Genesis 80s at the log at 18 meters and one
aluminum 80 at 9 meters at the floor between Sinkholes A and B. I thought
that 104 meters was deep enough for Roger and he thought the same.
Next day I decided to dive solo with Roger as safety diver. I wanted to go
down the line to my tie off at 121 meters. When I reached the end of the line
my primary regulator started to make water. My reaction was to press the
power inflator button of the Superwings and come up. I did not think about
switching regulators. I later realized how narked I probably was. I had gone a
little deeper 124 meters and later found a small tweed breaking the seal of the
diaphragm of the Odin second stage.
Two days later I was back again. I had just bought an underwater camera and
wanted to take pictures of the place. Actually it was a camera and a camera
housing. The system was rated to 100 meters so I thought it would be good
enough for 121. Unfortunately the housing had problems and the flash
wouldn’t synchronize with the camera. Anyway the flash surely wouldn’t
resist the depth. I decided to work with what I had. I attached a mini
Neutralite to the bottom of the housing and focused an H-1 head for a medium
beam. Set all the rest of the camera in automatic and would hope for the best. I
wanted to get pictures of a dive following the line all the way to 121 meters. I
secured a lanyard to the housing which I clipped to my left chest D-ring. All
the rest of my equipment was as usual: twin OMS 121 on my back, stage
OMS 121 secured to my left, primary light helmet mounted. As I was busy
with the camera I decided to start from the surface breathing from my doubles.
I descended following the line and taking pictures. All went well. I reached
the end of the line at 121 meters and took a picture pointing to what seemed
the end of the cave. I decided to swim just a little in direction of what seemed
the end of the cave to get a better picture. It seemed safe because the room
where I was, was very big, the water clear, percolation impossible, surely it
was safe to get a little distance from the line. And that was it! The next thing I
remember I am holding to a line with my right hand, arm up. It is dark. I
check my depth: 100 meters. I check my air: 160 Bars. I couldn’t understand
how I had got in that situation. I was in a clear room; why is it so dark Well,

I have a lot of air, this line, it was me that put it and I know that it leads to
exit. I just have to remain calm and follow it. And that was it, again! The next
thing I remember I’m still holding to the line, the same way, I have this
feeling that I can’t go forward because it is tight, it is very dark, I can’t see
where I am. I check my air: 30 bars but when I inhale the needle drops to 20.
My head is fuzzy. I had this feeling that I have to remove gear to be able to
pass but I don’t know why. The regulator is breathing bad. I switch to my
secondary: it breathes just the same. I know I’m running out of time. I unclip
my camera. It falls. My regulator starts to freeflow. I know the air is very low.
I switch the button on the second stage to “minus” and the freeflow stops. I
know I have another one free-flowing dangling somewhere. I don’t care. I try
to unclip my stage bottle. The waist clip goes easy. The tank is heavy and
hangs from my left chest D-ring. My head is fuzzy and the breathing is getting
hard. I won’t take my hand from the line. With my left hand, I hold the snap
which is tied to the neck of the tank, open the trigger and try to remove it from
the D-ring. But the tank is heavy and as I pull up the snap, the D-ring follows
the movement and won’t come off. I say to myself: “não desiste, não desiste.”
(Don’t give up, don’t give up.) I try again. It doesn’t come off. It’s getting
harder to breathe. “Don’t give up.” I try again. It doesn’t come off. My head is
fuzzy. I try again. It doesn’t come off. “Don’t give up.” By the 5th or 6th time
that I try, it comes off. The stage bottle goes down and I come up. I start to
breathe a little better due to the pressure differential. I only have to make to 60
meters (200 ft) where I have the safety Genesis 100 bottle. I vaguely
remember checking my computers and had a run time of 30 minutes. They
beeped. I’m at 57 meters, hey where is the emergency bottle I pause for a
second. Should I go back to get it No, it might not be there. I go up. I’m
going up fast. It is very hard to breathe. Suddenly a bifurcation on the line and
an arrow pointing to the right! My head is still fuzzy. What the hell is going
on here This place looks familiar. I don’t know what is going on but I sure
know that arrow is one of mine and it points to the exit. I follow the line and
come out at Sinkhole A at 34 meters depth. I think on the air bottle at 9
meters. I think of just going up to the bottle. No, everything is going wrong
here. I will follow the line until it “Ts” with the main line and then go up. At
this point I realized I had this big pain in the chest and breathing was very,
very hard. I thought, at this point that I was bent real bad. It flashed in my
mind about suffering very much and ending in a wheelchair. I went up real
fast, the computers screamed! I got to the aluminum 80 bottle at 9meters,
opened it and started breathing from it. It breathed bad. While I did this, I
could see Roger decompressing in Sinkhole B at 12 or 15 meters looking
down, to my left, and the log, with the two Genesis 80s at 18 meters, to my
right. Should I go to Roger and request assistance or should I go the other
tanks Well, until I explain to Roger what’s going on… I swim to the log. In
record time I get one of the Genesis 80s and drop down holding to the line. I
knew I had to recompress. I was hoping to relieve my chest pain as I went
down but it wasn’t really improving. I pass 30 meters, I pass 40 meters, well,

I’m going to stop at 50. I stop at 50 meters. The pain was less but not much. I
inflate orally the superwings. I look at my computers: one reads maximum
depth 127 meters, the other 422 feet. Runtime was 30 something.
Decompression information was blanked on both. At least they didn’t beep
anymore. The digital depth gauge read maximum of 129 meters. What had
happened What am I going to do I stay for 3 or 4 minutes at 50 meters (165
ft) and start ascending very slowly: I can’t stay here forever. I remember to
close the valves in my doubles for water could go inside. I ascend one meter at
a time. Why doesn’t Roger come here to help me Suddenly I belch. And the
pain in the chest relieves. I’m very worried about my air supply. By the time I
reach 40 meters, I had belched several times and the chest pain is much better.
Deco information on the computers continued blanked. Then I realize: I can
move my legs and arms, I can think. There is still a chance. I remember
reading Bret Gillian: It ain’t over till it’s over! If I only knew what
decompression to follow and had enough air! Roger, why don’t you to come
over and help me
I continue ascending slowly worried about my gas supply. Suddenly at 32
meters I look at the computers and both were giving decompression
information: 6 minutes at 30 meters. I ascend to 30. Now my chances are
better. But if I have to spend 6 minutes at 30, imagine how long I’ll have stay
on the shallower stops! I don’t have enough air. Roger finally comes down to
me. (He later told me that he was looking down during deco seeing if I would
appear and thinking that I had died. When someone passed flashing down he
didn’t notice it was me. Anyway, it was a wise move not to go after me
immediately because I could have been in panic and jeopardized both lives.) I
write in the slate what was going on. I was much better then but explained that
I would need all the air available. I tell him to drive down to the city to get
more air. The 27 meter stop lasted for 7 minutes, and the 24 meter for 8
minutes. Roger still had to complete his decompression before surfacing. That
day, a few other divers had gone diving. Tourists and guides. All had about
half full aluminum 80s. All had already dived and sent the equipment up.
Roger made it all come back. Roger brought all the tanks to me. After some
time, I stopped belching and instead, I started to relieve air from the other side
of the digestive track. I got worried about having intestinal problems but felt
relieved that the pain in the chest had been, probably, because I had
swallowed a lot of air. During the long decompression that followed I
eventually realized what had happened. When I narked, I somehow got to the
line I had laid a few days before, beyond the restriction at 82 meters (270 ft).
Somehow I followed it until I got to the restriction. I don’t know how I knew I
had to remove the camera and stage bottle to pass. I was so narked that even
out of air I dumped a full tank. (Ironically the line that nearly killed me, saved
my life.) I ascended inside the crack, that’s why the emergency 60 meter
bottle wasn’t there. It was in Sinkhole B. I had accidentally made a deep
connection.

I remember saying to myself: if I escape this one I’ll write a letter to
UWATEC telling them they have the greatest dive computer in the world. The
9 meter (30ft) stop lasted 56 minutes, the 6 meter (20 ft) stop 70, and the 3
meter (10 ft) stop nearly 180 minutes. Hypothermia wasn’t a problem. The
water at Mysterious lagoon is 25 to 26 degrees Celsius and the thick Northern
Diver Semi Dry suit I was wearing was very warm. I barely felt any cold. The
total runtime of the dive was 429 minutes. Still having some 30 minutes to go
at the 3 meter stop, it was dark, and people started flashing lights to me. They
were trying to show me something but I couldn’t see. I thought: it is a snake
or an alligator. After what I’ve passed I’m not going to be afraid of anything. I
surfaced after the computers cleared. It was an alligator. I was very happy that
I hadn’t had DCS symptoms still in the water but now I didn’t know what
could happen. I felt good. I was put on free flow oxygen from an emergency
kit. That was all we had. I told everybody that I felt very embarrassed for
being such a foolish doing the dives that I was doing. But also I was very
happy to be alive. After half an hour we felt it was safe to climb the rock path
and go home. I even drove back to the city.
I had, over the time, made a good friendship with Cida the owner of Mimoso
Farm. We would always stay at her farm, and like a mother, would get
worried with us. When we got back to the city of Bonito we phoned the farm
to tell Cida that everything was OK and that we had just stayed a little longer
in the water playing with an alligator that had appeared (we lied). We didn’t
tell anybody the story for sometime because we didn’t want to make a big fuss
about it. Actually we were making a secret about all the deep dives because
we didn’t want to promote it. When people got to know about the 121 meter
dive, some divers started to come to dive deep there and have trouble. We
decided to stay a few more hours in the city to see if DCS symptoms
appeared. At least there was a hospital in the city. Later on I went to the farm.
The computers displayed a 68 hours desaturation time and 64 hours on ATN
mode. I didn’t write to UWATEC but in case UWATEC is reading this, hey
you guys, you’ve got the greatest dive computer in the world! I later
discovered that water had gone inside my doubles.
Cida is smart and got suspicious about what had happened. She later told me
that, that day when I left the farm to go diving, I forgot to tell her goodbye as
usual. She then started to have a bad feeling about me. Eventually the feeling
got so bad that she stopped what she was doing and went to this special place
she has by the woods for praying and prayed for me. She had a feeling I was
going to die. Eventually I told her what had happened. I now never leave the
farm, to go diving, if I don’t tell her goodbye and always ask if she has a bad
feeling.

Even though I had nearly died, I didn’t get a trauma or loose confidence in my
diving abilities. I had just become wiser. I knew then that would not make
extreme deep air dives anymore. Four days later, the computers had cleared
and we went back to recover the safety bottle we had left at 60 meters (200 ft).
The visibility had deteriorated due to rainfall. The diving season in the lagoon
was ending.
The accident strongly reassured me what I already knew: I had to get trained
in mixed gas diving. I was reading all I could about the subject and already
was diving on mix on the computer with the ProPlanner program but I only
would start doing it after formal training. My last formal diving lessons had
been in 1977 at age 16. Having no internationally recognized C-card I decided
to enroll in an Advanced Open Water Class in 1991 from a dive store in São
Paulo which taught PADI. It was a joke. I had to look outside of Brazil to seek
instruction in technical diving. The best place in the world is, of course,
Florida.
I was privileged. In late March 1996 the airplane lands in Miami International
Airport. I was going to be trained by the best: Tom Mount. He was fabulous! I
learned and I learned and I learned. He corrected me in many, many things.
He yelled at me underwater many, many times (correcting problems as they
occurred). Boy, can you hear him underwater! But I loved all of it. We dove at
Ginnie Springs, at Peacock, at Madison, at Eagles Nest, the wrecks out of Ft.
Lauderdale and Pompano. I also had the privilege of spending a week aboard
the Ocean Explorer on trip to the Bahamas Blue Holes with Tom. We did wall
dives and dove the blue holes. It was great! I also had the opportunity to meet
diving legends such as Jim Lockwood, Larry Green, John Zumrick. Of course,
Patti Mount was terrific also. And so were her dogs, Ninja and Zeus
(IANTD’s Mascot Rottweillers). After 5 weeks of intensive training, I went
back to Brazil with all the C-cards I could want: Trimix, Trimix Gas Blender,
Technical EANx, Advanced Deep Air, EANx Cave, and Advanced Cave
Diver.
By June, I finally had my modest mixing facilities working. Air Liquide was
supplying the Helium and Oxygen. On June 2, I made my first Trimix dive in
Brazil in Paraibuna Dam reaching a depth of 84 meters. It was probably the
first sport Trimix dive in Brazil. The following weekend I did another. I felt
ready to go back to Mysterious Lagoon.
I believed the cave should go to at least 150 meters deep so I planned a dive to
that depth. After many, many runs in the ProPlanner program, I settled with
the following profile for the 150 meter dive: 50 meters for 3 minutes on air, 90
meters for 2 min on Trimix 8/62, 110 meters for 1 minute on Trimix 8/62, 150
meters for 9 minutes on Trimix 8/62 (at this point runtime is 15 minutes), 90
meters for 1 minute on Trimix 14/33 and 70 meters for 1 minute on Trimix

14/33. Decompression was with air starting at 57 meters, Nitrox 32 at 36
meters, Nitrox 50 at 18 meters, Nitrox 75 at 9 meters and oxygen at 3 meters.
I used a safety factor of 25% and atmospheric pressure of 970 millibars. This
kept the CNS at 95%. I had contingency profiles for +2 and +4 minutes and
for 155, 160 and 165 meters.
The equipment was configured the following way: The double OMS 121s
were filled with Trimix 8/62 @ 250 bars; I carried with me as a stage bottle,
on my left side, one OMS 121 with Trimix 14/33 @ 250 bars. My primary
superwings bladder was filled from the stage bottle, the back-up inflator from
my doubles. I filled my Northern Diver dry suit from a 3 liter bottle filled with
air @ 230 bars which I attached to the right side of my doubles. Having read
about Sheck Exley’s tragic accident, I wanted to make sure I had a surplus of
gas to ascend, and thus I also decided on three independent sources of
buoyancy. The air travel gas for the first 3 minutes of the dive was breathed
from a 30 cu. ft. aluminum pony bottle which I clipped to the guide line at 50
meters. We had prepared a Deco/Descent line with a buoy (an inner tube)
where we staged the air bottle at 60 meters (Genesis 100), Nitrox 32 bottle at
39 meters (OMS 46), Nitrox 50 bottle at 21 meters (OMS 46) and Nitrox 75
bottle at 12 meters (OMS 85), (they were all staged one stop deeper than I
would need them so I would have time to sort out any problem with them).
The oxygen bottle (OMS 85) was positioned on the lake bank at 6 meters. We
also had an extra oxygen bottle (OMS 112) and Nitrox 80 bottle (OMS 112)
and several air bottles. I did not carry my Dive Rite light because I was afraid
of crushing the battery pack (I was waiting for the new ones) and so instead I
carried 5 lights helmet mounted (4 Uks and one Scubapro). I dove all 5 of
them on (as Sheck Exley used to do), and one spare in my dry suit pocket
(UK).
The descent was carried out just as planned but unfortunately visibility was
quite bad, lots of percolation, probably from the preparation of the deco line
by support divers just before my dive and tourist divers that had dived shortly
before we arrived. I couldn’t see much better than 5 or 6 meters. But it was
still diveable. I started following the deco line but at one point it crossed the
guide line so I started following the guide line which I knew would take me to
121 meters. At 50 meters I clipped the travel air bottle to the guide line and
kept going deeper at a speed no faster than 20 meters/minute, breathing from
my doubles. A couple of times during my descent I check to see that my backup
BC inflator is working. At 110 meters the Odin started vibrating on
inhalation but stopped after 3 breaths. At 121 meters I tied new line from my
primary reel and started swimming in the direction I thought the cave would
end. Visibility was bad here also but with helium I could see much clearer and
see that the cave wasn’t as big as I thought it was. I swam slowly with a
descent angle of about 30 degrees from horizontal. Even though I had planned
a bottom time of 15 minutes I wanted to begin my ascent with 13 minutes and

so wanted to begin my tie-off at 10 minutes. I kept going checking my depth
and time and gas pressure but could not see a good tie-off. Finally, I saw what
appeared as a reasonable point, I looped the line twice, made the cut and tied
off. I had tied to a projection on a vertical wall, right at the top of what
appears to be the entrance of a circular, horizontal tunnel about 5 meters wide.
It was pitch black and I could see no bottom. I was 151 meters (500 ft) deep as
measured on both my digital depth gauges. The SOS helium depth gauge was
reading way off the scale. At 13 minutes runtime I started up slowly attaching
line arrows to the line and taking a look around but visibility wasn’t helping.
At 102 meters, I sighted at the slope, some 2 meters from me, an aluminum 80
bottle which had been lost a couple of months before. It was light so I brought
it with me. At 90 meters I stopped to make the switch to Trimix 14/33 and
then resumed ascent and safety stop at 70 meters. Finally I could see the air
bottle hanging from the end of the deco line and the lights of Roger, one of
my support divers, a few meters above. I wanted to hand him the lost bottle
but he wouldn’t descend so I tied it to the deco line and picked up the air
bottle and ascended to 57 meters (190 ft) and started breathing from it. I check
my depth and found myself at 48 meters and light! I must have been narked
on the switch, I thought! I let go of the deco line, dump gas from the BC and
descend following the cave wall. I stop at 54 meters and decided to switch to
my first contingency deco (+2 bottom time) because of the ceiling violation.
This gave me a couple of minutes at 54 meters before resuming ascent. I start
searching for the deco line (the visibility was worse) but I could only find the
guide line so I ascend following it. At 42 meters I get worried for my next
deco bottle, I could not see the deco line and no support diver around, so I
started a search pattern with my safety reel. Shortly, Roger appears and points
me to the deco line and bottle. I let go of my safety reel and go for the other
line. I pick up the Nitrox 32 bottle and resume my ascent. The rest of deco
went on smoothly. What had happened (which luckily I hadn’t noticed) was
that a BC had been attached inflated to the deco line between the air and
Nitrox 32 bottles (to bear some of the weight from the deco line). When I
picked up the air bottle it pulled me up and later all the other deco bottles in a
big mess. I hadn’t seen the BC because I had switched descent lines on the
way down. Luckily the support divers cleared the mess before I arrived at the
Nitrox 32 stops.
All six lights survived and I used 145 bars of gas from my doubles. More than
I expected. Mistakes had happened. We had to improve the system.
In August we were back for one whole month of diving in the Bonito area.
This time we had all the helium and oxygen we could want which Air Liquide
delivered to Mimoso Farm for us. We explored Bee’s Hole spring and
Formoso Spring and then we started going to Mysterious Lagoon. On the first
day we dedicated to fixing the deco line. We used 2 inner tubes and two lines
for redundancy. We also had 2 deco tanks each, of 4 different sizes oxygen

service rated. We dedicated each size for one Nitrox mix to help avoid
confusion (besides regular procedures). On the OMS 46 we used Nitrox 32, on
the OMS 85 Nitrox 50, on the Dive Rite 95 Nitrox 75 and the OMS 112 pure
oxygen. These were the deco gases we had used on the 151 meter dive, we
were using on the spring dives and was working, so we decided to stick with it
(what works, works). We changed the placing of the bottles though. We
hanged the Nitrox 32 bottles from the deco line, the Nitrox 50 bottles we hung
from the log at 18 meters, the Nitrox 75 bottles stayed on the floor between
Sinkhole A and B, and the oxygen bottles on a log close to the entrance to the
water. Also, instead of dropping with an air pony bottle to 50 meters, I
dropped with the air deco tank to 60 meters. At this point I would clip it to the
line. We were also drinking fluids during deco. We would hydrate with
Gatorade and water, and drink high carbohydrate drinks such as Carb
Xcelerator and Mighty1.
The next day we returned. On this day I decided to take Matheus, a dive
buddy that was diving with me for the last several months, on his first Trimix
dive. The plan called to explore the tunnel Roger and I had began exploring
on an air dive, in Sinkhole B, in the 80 meter range. We prepared Trimix
10.5/50 for the dive. When we got to the depth range I looked around but
could not find the tunnel. We tested some spots, looked deeper but nothing.
We ascended. We had gone to 102 meters and Matheus told me he felt like
diving air to 20 meters.
Two days later was the turn for Roger to go Trimix. Roger was sure I had
missed the tunnel and said that he could find it. We used the same mixes and
deco profile. It’s funny how different things are with helium. Roger did not
find it. What we thought was a tunnel that had potential to go on was of little
importance when you see it with a clear head. Interesting to note that, on these
2 dives, when I made the switch back to air at 60 meters I clearly felt the
narcosis coming by means of lightheadedness. Unfortunately, after the dive,
when Roger was going up the rock path with his doubles on his back, he
ruptured his right calf muscle bad. You can see how good our decompression
model was (or I thought it was): after the dive we had to climb the rock path
with our doubles on the back, and we weren’t getting bent. We did rest before
doing so and breathed oxygen on the surface.
Two days later I returned to make a solo dive. The plan was to go all the way
down to 151 meters to check the tie off and have a good look around. The
water was much better and I received a light from Arnold Jackson, a Meteor 5,
which he told me was good to 1,000 feet (300 meters). It is a small light
perfect for these short dives which I had tested on the previous 2 dives and
had a very good beam. The profile had just a few changes from the other one:
I would go on air until 60 meters at 4 minutes runtime, switch to Trimix 8/62,
121 meters at 7 minutes runtime, 155 meters at 16 minutes, 90 meters switch

to Trimix 14/33 with 21 minutes, 75 meters with 23 minutes runtime (a one
minute safety stop). My first deco stop would be at 63 meters still on Trimix
14/33 and I would switch to air at 60 meters. All other switches like on the
other dive. Still computed using the ProPlanner with 25% safety factor.
During descent, at a depth of about 100/110 meters I felt a little narcosis
which went away as I went deeper. I could see much better this time. I got to
the end of the line and shined around the light. I dropped down a few meters
to have a better look (I went to 154 meters). I was in a vertical fissure, tall,
about 5 meters wide until the depth of 151 meters where I have the tie off.
Below this there is an overhang and the fissure widens another 3 meters.
Visibility was about 25 meters (80 ft). I would shine the light on the walls and
follow the beam down until I lost sight. The fissure was some 30 to 40 meters
long getting tight at both ends. I could see both ends from where I was, but
could see no bottom. The tie off seemed to be at about the middle of the place.
On the other dive, I had carried two pressure gauges for my doubles in case
one got stuck by the pressure. This time I thought it wouldn’t be necessary.
The needle got stuck at 210 bars.
Realizing the cave went deeper than I thought I decided to go back there and
plumb the depth leaving the line there as a future descent line. I tied a 2kg
weight to the end of a line in a reel (my favorite reel: an enclosed aluminum
frame Dive Rite explorer reel - also a favorite of Sheck’s) which contained
305 meters (1,000 ft) of line. I decided to increase my helium content to test a
mix I would use if I did a future deeper dive. I prepared Trimix 7/67 for my
doubles. All other gases were the same. I also wore a thicker drysuit
underwear which I would use on a possible deeper and consequently longer
dive. I also increased the safety factor on the Proplanner to 30%. I drilled a
hole on the lens of the pressure gauge that I was using and carried another one
of different model. Before reaching 100 meters (330 ft) the light head flooded.
After the dive I saw that the battery case had flooded also. But it still worked.
With more helium I felt even better at 151 meters. I proceeded dropping the
weight. I was working with the reel when I felt a heat wave around my
shoulders. I thought it could be the underwear I was using. It went away. I had
a knot at every 5 meters and one tape mark every 50.
Later at the surface I confirmed 70 meters (245 ft) of line. The cave goes to
220 meters (730 feet) at least.
I tied the line and ascended. When I was doing my 21 meter stop I realized I
had pain in my left shoulder. At first I thought I had just strained the shoulder
while changing deco tanks but soon I realized that it was DCS. I thought that
it could have something to do with the heat I felt on the bottom. I’m still not
sure what that heat was. I thought of what to do. Deco gas was not a problem.
I had 2 tanks of each deco mix with plenty of spare in each one. I decided to
ascend normally to 18 meters where I would change to Nitrox 50 and with

more oxygen maybe I would get better. I got better. By the time I was at 9
meters on Nitrox 75 I was fine. But when I ascended to 6 meters I instantly
felt the shoulder again, with the pain this time going all the way to the elbow.
The pain wasn’t much, it felt like a strained muscle. My deco at this stop was
on Nitrox 75 also. I remained at this depth and as time passed I would become
better. When my time was through I didn’t feel pain anymore. I then decided
to make my 3 meter (10 ft) oxygen stop at 6. And so I stayed the 88 minutes
on pure oxygen at 6 meters (20 ft). I didn’t even take air breaks. When the
time arrived I ascended very slowly to the surface at a rate of 1 meter per
minute. Reaching the surface I felt the left arm a little funny for a short while.
I continued to breathe oxygen for 30 minutes at the surface. Luckily this day,
Roger brought a sherpa to carry my doubles up the rock path. (Even with a
torn leg muscle Roger would come along to watch.) I’ll never forget how the
knees of the sherpa shook when he stood up wearing the doubles.
As I write this, I’m thinking about what I’m going to do to continue the
exploration. I have to change for the better a few things. The first thing will be
the decompression model.
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