- hace 21 horas
Two dams above the village of Stava in northern Italy collapse, causing an ensuing mudslide and flood down the Stava River valley that kills 268 people in the village below.
Categoría
📺
TVTranscripción
00:00Nestled in the beautiful Southern Alps of Italy lies the Stava Valley, the epitome of the unspoiled Alpine resort.
00:12Then, a terrifying tidal wave of mud surges down the valley at 90 km per hour, destroying everything in its
00:19path.
00:21268 people perish in just 209 seconds.
00:24Now, using advanced computer graphics, we reveal exactly what went wrong.
00:30Disasters don't just happen, they're a chain of critical events.
00:35Unravel the fateful decisions in those final seconds from disaster.
00:48Europe. Italy. Tessero.
00:52July the 19th, 1985.
00:58The peaceful village of Tessero lies in the Stava Valley.
01:02Its idyllic surroundings make it a popular holiday destination.
01:07Today, visitors and locals alike are out enjoying the sunshine.
01:1612.10pm.
01:18Umberto and Clemente de Florian are helping their father, Lucio, with his carpentry business.
01:24It was a typical summer's day.
01:27I was 15 years old and me and my brother were going to do some work for our family business,
01:32owned by my father.
01:38They load their van and head off up the Stava Valley road.
01:4612.15pm.
01:48Back in Tessero, Alma Tretel has arrived home from work and serves the lunch that her mother has prepared for
01:53the family.
01:55That day I came back.
01:57The table was laid. Everything was ready to eat.
02:0612.20pm.
02:0820-year-old Lucia Morandini is helping her father Mario in his sports shop.
02:16That day I thought that seeing as a new supplied stock had just arrived, I choose a present for my
02:21father because it was his birthday in a couple of days' time.
02:27It's a perfect day in the Southern Alps.
02:31But further up the mountain, there is something that makes the Stava Valley far from normal.
02:39Ever since the discovery of rich mineral deposits in the 16th century, Prestival Mountain has been mined.
02:49Local residents have lived a peaceful coexistence with the mining companies who worked the mountain for fluorite,
02:54a valuable chemical substance.
03:02Extracting fluorite from mountain rock produces large amounts of waste material in the form of sand and water.
03:08This waste is known in mining as tailings.
03:13It's also the name given to the massive dams where the tailings are filtered off and collected.
03:21There are two of these tailings dams in the Stava Valley, one built above the other.
03:3012.22pm.
03:32Umberto, Clemente and their father Lucio are driving up the road from Tessero straight towards the dams.
03:40I remember that my father was singing because the next day was the 25th anniversary of the Tessero Choir.
03:51In town, Alma Trettle and her family are all sitting around the kitchen table to eat.
03:57And in their sports shop, Lucio Morandini thinks she's found the perfect present for her father.
04:03We went to the storeroom. We opened the boxes and took out all the clothes.
04:07There was a nice tracksuit that I wanted him to try on.
04:14Over the years, the 30 meter high tailings dams have become part of the local scenery.
04:20Obscured by a dense pine forest, they're largely ignored by the townsfolk.
04:26We all knew the dams were there.
04:32But we never imagined there would be the slightest danger.
04:35But today, all that will change.
04:4512.22 and 55 seconds.
04:50Without warning, the dam bursts.
05:04At first, no one knows what it is.
05:08I saw the smoke on the horizon and I asked him, what's that?
05:14It really looked like a fire.
05:20At 12.23 and 25 seconds.
05:24230,000 liters of mud, sand and water from the two dams course down the valley.
05:30The town of Tessero is only three and a half kilometers away and directly in its path.
05:39We heard a huge noise. We thought it was roadworks.
05:44At 12.23 and 45 seconds, the colossal mudslide hurtles into the small hamlet of starboard, where more than 100
05:52hotel guests are sitting down to lunch.
05:54In one blow, they are all killed.
05:59Traveling at 90 kilometers per hour, the mudslide is now racing towards Umberto Clemente and Lucio de Florian.
06:10My father didn't waste a second.
06:14He said, get out quickly and get up the slope.
06:1912.24 and 45 seconds.
06:22The wave of mud continues on its path of destruction.
06:25Next in line, Tessero.
06:30It's lunchtime in the Italian mountain town of Tessero.
06:33A peaceful afternoon, but none of the 2,500 inhabitants have any idea that a massive mudslide is surging towards
06:41them.
06:44Just north of the town, it's already destroyed the van belonging to Clemente, Umberto and Lucio de Florian.
06:52At 12.25 p.m., the mudslide engulfs Tessero.
06:59Alma Tretel is at home having lunch with her four-year-old son Marco, Stefano, her husband, and her mother
07:05Maria.
07:06She hears a rumbling noise.
07:10I hadn't quite leaned over the balcony when I saw what was coming down the road.
07:20Seconds later, almost a quarter of a million litres of mud hit Alma's street, smashing 17 of its 25 houses
07:27to pieces.
07:32Further down the street, Lucio Morandini is working with her father in his sports shop.
07:38My father was trying on the tracksuit when we heard a huge noise.
07:44Out of curiosity, I said, I'll just go and have a look.
07:51The devastation continues as the mudslide follows the quickest route down the mountain.
07:56Entire buildings, streets, and forests are wiped out.
08:0112.25 and 44 seconds.
08:04The ancient bridge that has stood for 10 centuries is almost completely destroyed.
08:10Finally, 40 seconds later, it's over.
08:13The mud crashes into the valley floor, where at last it loses its momentum and flows into the river Avisio.
08:20The catastrophe lasts just three and a half minutes, but it leaves five kilometers of chaos in its wake.
08:28The beautiful Stava Valley has been reduced to a wasteland.
08:37Clemente de Florian narrowly escapes the mudslide by running uphill.
08:45I stopped and turned around.
08:47There was nothing left.
08:49Absolute silence.
08:51Not even a bird or a fly.
08:53Nothing.
08:54Nothing.
08:58Their van is totally wrecked, submerged in mud 50 meters from where they left it.
09:05Clemente frantically searches for his brother and father.
09:09I heard my brother's voice calling me, and I just saw his face sticking out of the mud.
09:20I couldn't move because I was completely covered in mud.
09:25Then I saw my brother and called out here.
09:30So I started to scrape some of the mud off him, and he immediately said, where's dad?
09:38Meanwhile, 100 meters away, local sculptor Giuseppe Mick sees the destruction from his workshop window
09:45and races to the scene.
09:47He's one of the first rescuers to get there.
09:51I saw a figure, a human figure lying, hugging a tree.
09:57When it spoke, I went closer.
10:00I recognized by the voice that it was Alma.
10:03Alma Trete.
10:07The force of the mudslide has catapulted Alma over her first floor balcony.
10:11Giuseppe finds her a full 300 meters from where her home used to be.
10:17I had no idea where I was.
10:19I could just feel grass below me, and I didn't know what was happening.
10:24Giuseppe and his friends fashion a makeshift stretcher out of Alma's jacket.
10:29They carry her to safer ground and awaiting ambulance.
10:35Lucia Morandini is completely buried in mud and the wreckage of what used to be her father's sports shop.
10:42Only a small gap in the debris allows her to breathe and stay alive.
10:46I was scared I would suffocate, or die of thirst, or hunger, a very slow death.
10:56And that I would prefer to end it quickly.
10:58But I couldn't even do that.
11:00I couldn't move at all.
11:06Luckily, people hear Lucia's cries for help and dig her out of the mud.
11:12She's rushed to an ambulance and taken to hospital.
11:201pm.
11:22Just half an hour after the accident, local firefighters, Alpine rescue and police are on the scene.
11:28In all, 7,000 rescuers take part in the recovery operation.
11:33A fleet of 19 helicopters and 26 ambulances are on standby, ready to ferry survivors to hospital.
11:41But they are hardly needed.
11:43Out of 281 missing, only 13 people are pulled out alive.
11:49Umberto de Florian, Lucia Morandini and Alma Tretel are three of those 13.
11:54While they are being treated in hospital for trauma and broken bones, rescuers are still searching through the rubble for
12:00their families.
12:02I kept asking after my son, my mother and my husband.
12:10But they wouldn't tell me anything.
12:1489 men, 120 women and 59 children perish in the mudslide.
12:19A total of 268 lives lost.
12:24Alma's husband Stefano, her mother Maria and her 4-year-old son Marco are amongst them.
12:30Lucia's father Mario and Umberto's father Lucio also perish.
12:35It's one of the worst dam bursts ever.
12:39After three weeks, the rescue operation is over.
12:43As the funerals begin, the town of Tessero is in shock.
12:47The whole of Italy feels a deep sense of loss.
12:50Not one, but two dams have burst.
12:54Finding out why is a national priority.
12:58What caused the two dams to break, unleashing 180,000 cubic meters of mud on the Starber Valley?
13:05Now we rewind the events of that fateful day and go deep into the investigation to reveal what really happened.
13:13Advanced computer simulation will take us where no camera can go.
13:18Into the heart of the disaster zone.
13:22On the day of the tragedy, the regional court launches an inquiry to determine the exact events leading up to
13:28the disaster.
13:30Professor Pietro Colombo, an expert on mudslides, heads the investigation team.
13:37Using their data, we can now piece together the chain of events to find out what really caused this terrible
13:43tragedy.
13:46Professor Colombo's immediate focus is on the two dams.
13:50What caused them to burst?
13:52Early claims are that the trigger was a natural phenomenon.
14:01Was one of the worst dam bursts ever caused by an earthquake?
14:06It was a deafening noise.
14:09I got out of my car.
14:11The ground was shaking.
14:12The car was shaking.
14:14It really seemed like there was an earthquake.
14:23Mudslide expert Professor Richard Chandler was consultant to the accident inquiry.
14:28The foothills of the Alps, where Starber is, are an earthquake area.
14:34One can speculate and one can also rely on evidence from a seismometer in a valley next door to the
14:44Starber Valley, which was in place to record possible earthquakes.
14:50There's a seismometer in nearby Cabalese.
14:54Investigators study the readings for the exact time that the dam burst.
14:5812.22pm.
15:07Amazingly, it shows a substantial tremor, followed by another large spike 30 seconds later.
15:14The investigation team think they're onto something.
15:16It looks like earthquake activity.
15:22So they carry out more detailed research.
15:26Other seismometers in the region barely register the tremor, if at all.
15:32This is highly unusual.
15:36It means the tremors were very localized.
15:39Too localized to be an earthquake.
15:41The dam burst couldn't have been caused by an earthquake.
15:47Investigators need a new lead.
15:49They know that the Southern Alps are an abundant source of minerals.
15:55The region is dotted with mines.
15:59The standard practice for exposing a new rock face is to blast it.
16:05Could a controlled explosion be what they see on the seismograph?
16:09Could that have caused the dams to rupture?
16:12Professor Giovanni Tosati was an expert witness at the Stava Valley disaster trial.
16:18There were discussions about the effects of explosions being carried out at nearby mines
16:24that could have been transmitted to the area and could have been the trigger of the collapse.
16:32To test this theory out, Chief Investigator Pietro Colombo tries something unique.
16:38He sets up controlled explosions in three mines within a 31 kilometer radius of Stava to see if such a
16:45blast could have been the culprit.
16:49Explosive experts detonate the dynamite.
17:02Analyzing the readings, the investigation team are baffled.
17:06The explosions barely register on the equipment.
17:10These seismographs look nothing like the one recorded on the day of the accident.
17:15Whatever caused the two Stava tailings dams to burst, it wasn't an explosion underground.
17:23So what did cause the two seismometer readings 30 seconds apart?
17:31Professor Colombo figures that they must have been caused by the dam burst itself.
17:39He deduces that the first shock is the upper dam collapsing.
17:48The contents of the upper dam pour into the lower dam.
17:51Under massive pressure from this huge load, the lower dam crumbles too.
17:57Mud, water and sand explode from the dam and smash into the valley wall opposite.
18:04Causing the second tremor on the seismograph.
18:13Investigators now know how the dams gave way.
18:16Their next task is to work out why.
18:20If external factors like an earthquake or an explosion were not the trigger, it must have been internal.
18:28Something inside one of the dams caused the collapse.
18:33And as the upper dam collapsed first, it becomes the new focus of the investigation.
18:41Tailings dams are widely used in the mining world.
18:50Fluorite production requires massive quantities of water.
18:54It makes up 95% of all waste products in the process.
19:02A huge machine called a hydrocyclone then separates the sand from the water.
19:12Sand builds up into the wall of the dam.
19:15The hydrocyclone pumps the water into the center of the dam, creating a reservoir.
19:23The safety of the structure relies on the outer wall of the dam, which, like a giant sand castle, remains
19:30dry and solid.
19:31And the liquid in the middle slowly drains out through massive pipes.
19:39Tailings dams are effectively self-building.
19:41The more waste, the bigger the wall of the dam.
19:51The two dams at Stava grew from ground level to over 25 meters high in two decades, dwarfing buildings around
19:59them.
20:03Although not unusual for tailings dams, with little else to go on, investigators decide to look into their design.
20:11The investigation finds that the mining company has kept detailed records of the upkeep of the two dams.
20:17They examine them and make a breakthrough.
20:24Six months before the disaster, the mining company suddenly has a problem.
20:33In January 1985, a small landslide occurred on the outer wall of the upper dam.
20:41This created a giant hole in the wall, a 20 meter gap, for water to leak out.
20:49It continued until March, when the mining company carries out an emergency repair.
20:56In May, they make further repairs and have to drain both upper and lower dams.
21:02The mining company only brings them back into operation on the 15th of July 1985, four days before the tragedy.
21:11The investigation team focuses heavily on the upper dam.
21:16Something strange must have been going on at least six months beforehand, causing it to disintegrate.
21:22But what?
21:24Professor Colombo realizes that the answer is all around him.
21:29It's everywhere.
21:32It's water.
21:35With the absence of any external forces, such as an earthquake or underground explosion,
21:40the only explanation for the collapse of the dam is through a weakening of the dam's wall,
21:45caused by the water inside it.
21:49The moment there is any significant amount of water in the face of the dam itself,
21:54then it would immediately become unstable and would collapse.
22:00One can do simple experiments on the beach with a bucket and spade and demonstrate when you add water
22:07how much less stable wet sand is than dry sand.
22:12This is the problem in this particular case.
22:14The small landslide and subsequent hole that appeared in the upper dam wall six months earlier is proof.
22:25Water from inside the reservoir saturated the outer wall, creating the 20-meter hole.
22:32Six months later, the whole wall gives way.
22:43Unleashing a wave of mud that kills 268 people.
22:48But the mystery is far from over.
22:52Investigators now know that water caused the dam burst, but how did it penetrate the outer wall?
23:01What was the final trigger for the dam burst?
23:07A dam burst in Italy has reached havoc.
23:10A quarter of a million liters of water and mud have coursed through the valley below it.
23:16268 people perish.
23:19Now, using advanced computer graphics based on accident reports, we go deep into the investigation to unravel the tragic chain
23:27of events.
23:29The dam burst is triggered when two tailings dams, huge reservoirs containing waste water from a mining process, collapse.
23:48The investigation team is now certain that the upper dam caved in like a sandcastle.
23:56But it's not supposed to work that way.
23:58A pipe should drain excess waste water before it reaches critical volume.
24:06Too much water pressure and the water is forced into the wall, causing it to crumble.
24:14Investigators assure that's what happened.
24:16But how?
24:19They start to examine why.
24:22They study the meteorological records for the 66 years before the accident.
24:26They make a fascinating discovery.
24:30Maximum rainfall in the Starver Valley occurs between May and August.
24:36Contributory factors to the rise of water would have been the tremendous thunderstorms that they typically get throughout the Alps
24:41in July and August.
24:44Then, investigators spot that for the Starver Valley, 1985 was one of the wettest years on record.
24:51Almost 22% more rain than normal fell.
24:57It's a good lead for Professor Pietro Colombo.
25:00He's sure that the record rainfall played a part in raising the volume of water.
25:08But he's not convinced it's the only contributing factor.
25:11He knows the dams must be designed to deal with something as foreseeable as heavy rain.
25:17He gets his team to look into other reasons for a dramatic rise in water levels.
25:25Suddenly, it all seems obvious.
25:37Every year, the neighboring ski resort of Latamar attracts thousands of skiers to its snow-capped mountains.
25:44The winter before the accident had been a particularly good one for skiing.
25:48A thick snow cover had been added to by regular snow showers.
25:53But at the end of the season, something happened that would go on to play a significant part in the
25:58disaster only a few months later.
26:04In the spring, in the Alps, the snow that fell during the winter melts, and melts relatively rapidly in the
26:11course of a few weeks.
26:14Investigators calculate that the water levels produced by the thaw that year were higher than average.
26:22Some of this meltwater would then flow down the valley through rivers, streams and underground springs
26:29into the tailings dams, raising the water level inside.
26:36This solves the pressure question.
26:42But Professor Colombo can't believe that increased rainfall and melting snow alone are responsible for such a catastrophic failure.
26:54The first time the upper dam sprang a leak was in January, before the rain and snow could have played
27:00a part.
27:05Investigators desperately need a new lead.
27:07They now concentrate on the heart of the accident, the wrecked dams themselves.
27:13The breach in the upper dam wall is clearly visible, but the lower dam and reservoir have been totally destroyed.
27:22Chief Investigator Pietro Colombo calls in heavy machinery to clear the site.
27:28The team begins the arduous task of sifting through the ruins of the dams in search of a clue.
27:35After searching through 360,000 tons of mud, silt and rubble in the remains of the upper dam, they find
27:43one.
27:45It's the drainage pipe, and it's broken.
27:51Now they're onto something.
27:53They take a closer look at the pipe.
27:56Crucially, it betrays signs of an earlier repair.
28:03A length of pipe was replaced.
28:07But over the years since the repair, the weight of mining waste or tailings placed on top of it have
28:15caused it to sag.
28:17Then, with the passage of the years, the tailings built up above this pipe, and the pipe could have pulled
28:23out of its end a joint,
28:25allowing water, which was draining the upper dam, to be discharged into the tailings at a location quite close to
28:33the outer face of the dam.
28:35Eventually, it would have been pulled free from its anchor points, leaving gaps and rendering the pipe useless.
28:44Now, instead of draining water away, it's actually leaking water back into the reservoir.
28:50Raising the pressure inside, and forcing more water to seep through the dam wall, weakening it more and more.
28:59But when did the leak from this pipe reach critical levels?
29:03Investigators realized that the emergency repairs that the mining company started just two months before the accident are to blame.
29:12To carry out the repairs, the mining company had to empty each reservoir.
29:16As the water was drained out, the pipe could have bent further out of shape, causing bigger gaps to appear.
29:25Then, three weeks before the dam burst, the reservoirs were refilled.
29:31Four days before, mining begins again.
29:36Waste tailings are pumped into the dam, but the broken pipe can't drain away excess water.
29:43And now, rainfall and meltwater are at peak levels.
29:47The pressure against the walls from these combined sources of water is too much for the dam to contain,
29:53and the water inside the reservoir forces its way out.
29:57It takes the path of least resistance, through the outer wall of the dam.
30:02Stable only when dry, this wall becomes saturated by the fluid seeping into it.
30:07The stability of the dams at Staba required that the water was kept away from the outer slope of the
30:14dam.
30:15If any water got anywhere near the outer slope of the dam, it was inherently going to collapse.
30:21Finally, something has to give.
30:24The wall of the upper dam collapses,
30:28releasing 360,000 tons of sand and water, which surges down the valley, destroying everything.
30:40But something still puzzles the investigators.
30:44They've rarely seen devastation on this scale.
30:47The violence is exceptional.
30:52268 people gone.
30:55Three hotels, six factories, 53 houses disappeared.
31:03This solitary tree is all that's left of a dense forest, ripped from the ground by the massive force.
31:13The devastation is total.
31:17Investigators are about to discover something very unusual about the mudslide.
31:27A catastrophic dam burst in the mountains of northern Italy releases a quarter of a million litres of mud and
31:33water into the valley below.
31:38As investigators pour over eyewitness testimonies, they begin to realise there's something very unusual about the destructive power of this
31:46mudslide.
31:51There were trees and soil flying through the air, even the roof of a house.
31:59You've been impossible to get out of the whale.
32:03The speed of a train or a lorry or something was devastation felt all the way down to the small
32:10town of Tesseroe.
32:14What is so unusual from the reports is the speed and violence of the mudslide.
32:19From the seismometer readings, investigators can calculate that the mudslide reached an astonishing 90 kilometres per hour.
32:25This is more like a tidal wave.
32:35Investigators study similar natural phenomena from around the world.
32:42This is actual footage of a mudslide in Russia.
32:47Although on a much smaller scale, it's behaving in a very similar way to the dam burst in the Stava
32:53Valley, with the speed of water, but the destructive force of mud.
33:00Studying records of dam bursts like this one gives the investigators the answer they're looking for.
33:05They believe they know why the Stava mudslide caused devastation on such a massive scale.
33:13But they have to travel back in time to be sure.
33:20Two hundred and ten seconds before disaster, the upper dam's outer wall saturates with water, but it's still solid.
33:28Another second and the dam breaks.
33:32The outer wall collapses and falls away with such power that it registers higher on the rickster scale than normal
33:38earth tremors in this region.
33:50This footage of a real earthquake in 1950s Japan shows what happens to the ground when a shockwave is so
33:57powerful that the solid earth acts just like a liquid.
34:01It's called liquefaction.
34:08Liquefaction occurs when water under high pressure enters a solid structure made up of grains like sand, forcing them apart.
34:16They become suspended in the water, making a very dense liquid, almost twice the density of water, but with all
34:23its fluid properties.
34:25It's exactly what happens when the upper dam collapses in Stava.
34:32As the outer shell disappeared down the slope, the tailings behind no longer had any support.
34:41And they become suspended in the water that surrounds them.
34:46You finish up with a high concentration of quite heavy particles suspended in the water.
34:52So it's like a double density material.
34:56And this liquefies, turns into a fluid and flows down the slope.
35:08Investigators now understand the critical chain of events that caused the catastrophe.
35:20209 seconds. The upper dam is turning to quicksand.
35:24The grains have lost their ability to stick together as a solid structure.
35:34198 seconds to go.
35:35This dense liquid suspension is now pouring out of the upper dam and into the lower dam, which is critically
35:41overloaded.
35:43For 19 seconds, the liquefied mud from both dams collects and grows.
35:58As the dams disintegrate, they throw up enormous clouds of dust high into the air.
36:05It looked like smoke to Umberto, Clemente and their father, Lucio.
36:11It really looked like a fire.
36:14179 seconds left.
36:16The lower dam reaches bursting point.
36:18It collapses, unleashing the liquefied tailings.
36:23159 seconds.
36:24The mud flow strikes the village of Stava, 800 meters away, destroying 24 houses and three hotels where over 100
36:33tourists are sitting down to lunch.
36:35They all perish.
36:3799 seconds to go.
36:40The mud wave hits the northern reaches of the town of Tessero.
36:45Umberto and Clemente are in their father's van, driving up the valley road.
36:50My father didn't waste a second.
36:54He said, get out quickly and get up the slope.
36:59Umberto and Clemente escape, but the wave, traveling at 90 kilometers per hour, kills their father, Lucio.
37:0779 seconds.
37:09The flow reaches the street where Alma Tretel lives and wipes out 17 homes.
37:17She hears the roar and goes to the balcony, where she sees the mudslide hurtling down the street.
37:27I didn't have time to say a word before the whole house fell away from under my feet.
37:35As the house collapses, Alma is hurled from the balcony and ends up 300 meters away.
37:4651 seconds to go.
37:48Lucio Morandini is in the storeroom of her father Mario's sports shop.
37:54She hears the rumble of the mudslide and opens the door.
37:59It seemed like a hurricane.
38:01There were trees and soil flying through the air.
38:03I was held back into the storeroom.
38:06I had no time to think.
38:11What feels like a hurricane to Lucio is the blast wave that precedes the mudslide all the way down the
38:17valley.
38:21Powerful enough to destroy buildings and uproot trees in its own right, it looks like a whitish cloud made up
38:27of fine sand from the tailings dams.
38:30An eyewitness in Tissero took this photo.
38:3740 seconds to go.
38:40The mudslide slams into the ancient bridge of Tissero.
38:45The wave of mud is so deep that some of it crashes over the 30 meter bridge.
38:55In just three and a half minutes, 230,000 cubic meters of mud, water and debris have laid waste to
39:03an area of almost 44 square kilometers.
39:09Tailings dams operate all over the world.
39:13Are thousands of people at risk?
39:18Is the disaster at Stava an isolated incident?
39:22Professor Colombo wants to find out.
39:25He turns to the maintenance records for the two tailings dams.
39:30His search yields shocking results.
39:38A mining dam has collapsed in the southern Italian Alps.
39:49Now investigators are scouring through maintenance records to find out if the company in charge has regularly monitored stability.
40:02In 1974, the municipality of Tissero ordered Fluormine, the company that owned the mine, to carry out inspections.
40:11Results of the tests show that the slope angle of the upper dam was exceptionally high, and its instability nearing
40:18danger levels.
40:23The engineer who carried out these tests was surprised that they had not collapsed earlier.
40:29This should have served as a warning.
40:33But nothing was done, the situation was covered up and work carried on as normal.
40:43This was ten years before the disaster.
40:49The findings prompt the investigation team to dig deeper.
40:53They discover a catalogue of errors.
40:56The soil is completely unsuitable to support the dams.
41:00The ground is too marshy to allow adequate drainage, an essential requirement for their stability.
41:06Without proper drainage, the walls can't dry out and become solid or stable.
41:14What's more, the foundations for the upper dam have been partially laid on the lower dam.
41:19It means the upper dam has been partly built on the wet mud of the lower dam, rather than solid
41:25ground.
41:26But most amazing of all was the inadequate repair of the broken pipe in the upper dam.
41:32With so many problems, the mining dams were an accident waiting to happen.
41:37It was built at the limit of its capacity to stand in a stable manner.
41:44It required only the slightest disturbance to this to cause it to collapse.
41:48There was no factor of safety, no leeway, no margin of error at all.
41:58And the slightest disturbance to all of this would have caused the collapse.
42:05And it's perhaps surprising that the structure didn't collapse a good deal sooner than it actually did.
42:12The investigation team's findings were compelling enough to seek a prosecution.
42:18In 1988, they went to trial.
42:24The Starver Valley disaster inquiry took seven years to complete.
42:28In the end, ten people, eight from the five companies that had run the mine since the building of the
42:33upper dam,
42:34and two members of the regional council in charge of mine safety were found guilty of culpable disaster and multiple
42:41manslaughter.
42:42They were all given prison sentences.
42:44The magistrate noted in his ruling that if one tenth of the money spent on the trial
42:49had been invested in the safety of the tailings dams, the accident would not have taken place.
42:57Vincenzo Campodel was manager of the mine when the accident occurred and received a three-year suspended sentence.
43:06We can all be said to have been at fault, right back up the line to myself,
43:11because we didn't carry out, I guess, the necessary and continuous inspections that we should have done.
43:23Today, Alma Trettle has to live with the loss of her four-year-old son Marco,
43:27her husband Stefano, and her mother Maria in the tragedy.
43:30She almost died herself, yet she no longer feels resentment towards the people responsible.
43:39I don't think it's up to me to judge these men.
43:42I'm not even going to start.
43:44I know I used to feel angry, because I thought,
43:48you had the duty to make safety checks and you didn't do them,
43:51otherwise this wouldn't have happened.
43:58But, you know, feeling resentment for the rest of your life towards these people,
44:02you just end up feeling bad yourself.
44:05So I said to God, I leave them to you, I leave them in your hands.
44:13After the disaster, Clemente de Florian took over his father's carpentry business.
44:19His brother Umberto, transformed by the events of the trial surrounding the disaster,
44:24decided to become a lawyer.
44:27After recovering in hospital, Lucia Morandini eventually took over her father's sports shop,
44:32and has since expanded the business, opening five new shops in neighbouring towns.
44:39She now has a nine-year-old son, Igor.
44:43Alma Trettle spent months in hospital recovering from multiple injuries.
44:48Rebuilding her life has taken a long time.
44:54I had lots of friends to help me, as well as my brothers and sisters who were very close to
44:59me.
45:03For five years it was really hard.
45:05But then I met my current husband and I got a bit of hope back into my life.
45:10And I saw a bigger light at the end of the tunnel than I was seeing before.
45:16Then we had two children.
45:19And now I'm happy about the life that I've been able to rebuild for myself.
45:29Seventeen years after the tragedy, Graziano Lucchi, who lost his parents,
45:34co-founded the Starver Foundation as a reminder of what happened on July the 19th, 1985.
45:43It's important for people to know what happened.
45:46We especially want people to know the causes.
45:48Who is responsible for this tragedy?
45:51Because only this knowledge would allow us to try to avoid other similar tragedies from happening elsewhere.
45:56Yeah.
46:03But the warnings have not been heeded.
46:07In the aftermath of the Starver trial, although the safety laws surrounding tailings dams were improved in Italy,
46:13elsewhere, lessons are still to be learned.
46:17Since 1985, there have been no fewer than 33 similar accidents worldwide,
46:23eight of these occurring in the United States.
46:27In Starver, the mine never reopened after the tragedy.
46:30But following extensive restoration, the valley has regained its former beauty.
46:36The tourists have come back.
46:37And the locals have helped each other to rebuild their community
46:41and return to a peaceful, idyllic way of life.
Comentarios