BHP Billiton chairman Jac Nasser told shareholders at the AGM the company is "deeply sorry" to all the people affected by the Samarco mine tragedy in Brazil

A deadly mine waste spill that buried a village and contaminated a river basin two weeks ago is the worst environmental disaster in Brazilian history, the environment minister said Friday.

Izabella Teixeira estimated it would take 30 years to clean up the Doce basin in southeast Brazil, where the spill killed at least 12 people, left 280,000 without water and smothered thousands of fish, turtles and other animals.

The disaster struck on November 5, when a dam collapsed at the waste reservoirs of an iron ore mine owned by Samarco, a joint venture between the mining giants BHP Billiton of Australia and Vale of Brazil.

"It's clear what happened in the Doce River is the biggest environmental catastrophe in this country's history. We can't let it happen again anywhere," Teixeira told newspaper O Globo.

"Our current environmental laws are insufficient to deal with an accident of this magnitude."

A torrent of yellowish muck burst from the tailings pond, mostly destroying the nearby village of Bento Rodrigues and contaminating the water supply to more than 200 towns.

Twelve people are still missing.

The mud and mining waste have traveled across hundreds of kilometers of river in the states of Minas Gerais and Espirito Santo and is expected to reach the Atlantic Ocean on Friday or Saturday.

Brazilian President Dilma Rousseff has said the government holds all three mining firms—Samarco, Billiton and Vale—responsible for the disaster.

Izabella Teixeira estimates it will take 30 years to clean up the Doce basin in southeast Brazil

Samarco has already been hit with damages, fines and frozen funds totalling more than $400 million.

The clean-up could cost more than $1 billion, according to Deutsche Bank.

Renowned Brazilian documentary photographer Sebastiao Salgado, whose foundation has been active in efforts to protect the Doce River, toured the area and submitted a $27 billion clean-up proposal to the government.

"Everything died. Now the river is a sterile canal filled with mud," he told O Globo.

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© 2015 AFP