Victims of the Mariana Dam collapse speak out as the London trial begins

“The last words I heard him say were, 'Did you know you're the best mother in the world?'”

Gelvana Rodrigues' son, Thiago, was seven years old when toxic mud flowed into their home and killed him.

He was one of 19 people who died on November 5, 2015 after the collapse of the Mariana Dam in Minas Gerais, Brazil.

It is considered the worst environmental disaster ever in Brazil.

The dam was owned by Samarco, a joint venture between mining giants Vale and BHP.

It was used to store waste from iron ore mining. When it burst, tens of millions of cubic meters of toxic waste and sludge were released.

The mud swept through communities, destroying the homes of hundreds of people and poisoning the river.

Gelvana was at work when the disaster occurred while her son stayed at home with his grandmother.

After hearing the news, she ran back and found that “everything was destroyed.”

“I didn’t eat or sleep for three days, I just wanted to find my son,” she said.

After seven days, she learned that rescuers had found Thiago's body.

“My life ended that day because I lived for him.”

Gelvana is one of 620,000 people taking BHP to court in the UK over the disaster.

A civil trial starting October 21 in London will decide whether the Anglo-Australian company is responsible.

The plaintiffs' lawyers successfully argued that the trial should take place in London because BHP's headquarters were “located in the United Kingdom at the time of the dam collapse.”

If BHP loses this case, a second step will be to determine who is entitled to further compensation payments and to what extent.

A separate trial is currently taking place in the Netherlands against Samarco's second parent company, the Brazilian mining group Vale, with around 70,000 plaintiffs.

Both companies have agreed that if either of them is found liable for damages, they will share the costs.

Marcos Muniz, known as Marquinhos, moved to one of the affected towns – Bento Rodrigues – in 1969, when he was six years old, to the same house where his father was born. Later, as an adult, he built his own house on another piece of land his father had purchased there.

Marquinhos worked for Samarco for almost 30 years before retiring. He had livestock, pigs and orange trees that he wanted to take care of in retirement.

“I never thought this could happen,” he said. “If I had known that this would happen in the future and that the place and community I grew up in would be destroyed, I would definitely have stopped working there.”

Bento Rodrigues now resembles a ghost town. The houses are in ruins and are still covered in thick mud. Marquinhos' house was washed into the nearby lake and only the very tip of it is visible.

BHP and Vale have created an organization called the Renova Foundation, whose mission is to compensate victims.

She offered them either cash compensation or a house in a new town called Novo Bento, which the foundation built to replace that town.

The Renova Foundation says it has paid out over $7.7 billion (£5.9 billion) in repairs and compensation to more than 445,000 people to date, with around 50% of this paid directly to those affected.

However, the companies say that does not mean they will take responsibility for the disaster.

The community had a say in the construction of the town and the design of its new houses.

Marquinhos has been offered a house there, but he fears his way of life and community will be lost in this modern city.

The new city is still being built. It's up in the hills rather than down by a lake and has a more modern, urban feel.

Darliza das Graças moved there a year ago. She owned a small bar in the “old” Bento Rodrigues and now runs a restaurant.

“Life here is wonderful, it’s good. But at the beginning it was very difficult, there were only a few residents,” she said.

“Now they come, it’s much better.”

More than 100 people have been relocated there so far, but nine years later there are still some who have not yet moved in because their house is not yet finished or because they have decided not to.

While Darliza is happy here, she says she preferred her old life because “the community was more united there.” Not everyone from their old community has decided to live here.

BHP and Vale deny liability claims in their entirety, arguing that the UK's legal actions are “unnecessary as they duplicate issues already covered by the existing and ongoing work of the Renova Foundation and other legal proceedings in Brazil.”

All companies involved say they remain “committed” to repairing the damage caused. BHP and Vale have made a new offer to the Brazilian government, expected to be signed on Friday, to pay more than 170 billion reais ($45 billion) in compensation.

Samarco added that the Renova Foundation has compensated 18 of the 19 families of the deceased victims and continues to contact families and lawyers in cases that remain unresolved.

Fernanda Lavarello, head of corporate affairs at BHP Brasil, said: “What happened in 2015 was a tragedy. We're sorry about what happened. Since then, BHP has never left the country and is doing everything it can to improve the environment and the lives of these families.”

“Some processes are taking longer than expected because it is quite complex, but for the families who quickly decided to have their homes built here, their homes are ready and they have already moved in.”

The UK legal battle against BHP began in 2018 when residents and some local businesses and authorities decided to seek what their lawyers describe as “fair and full compensation” for the harm suffered.

The plaintiffs' lawyers – Pogust Goodhead – argue that BHP was liable because Samarco “was a legal entity for iron ore production and BHP had operational control over the company and its decisions.” This means that BHP knew or should have known when key decisions were made that led to the collapse of the dam.”

If they win, they reckon compensation could reach $44bn (£34bn) in one of the world's largest collective environmental lawsuits.

For some, like Marquinhos, it's about receiving higher compensation than before so he can afford to rebuild his life in a location of his choice.

For some, no amount of money can make up for the loss.

“Nothing can bring back a life,” says Gelvana about her son Thiago. “There is no money in the world that can buy a life. I just want justice so that no mother sits here in the same place as me.”