The world's biggest iron-ore miner plunges after suspending its dividend following dam breach that left at least 52 dead and more than 300 missing (VALE)

A dam at one of Vale 's mines in Brumadinho, Brazil, gave way Friday, leaving scores of people dead and hundreds missing.
It was the second incident at a Vale dam since 2015.
Vale shares opened down 20% in Brazil. American depository receipts were set to open down close to 10%.
Watch Vale trade live .

Shares of Vale , the world's biggest iron-ore producer, plunged 20% early Monday in Brazil as the company's board of directors suspended its dividend after a breach at one of its dams left scores of people dead and hundreds missing.

On Friday, the company said one of the dams at its Feijo mine in Brumadinho, Brazil, gave way , leading to the deaths of at least 52 people. More than 300 others are missing. It was the second deadly incident for Vale since 2015, when dams ruptured at an iron-ore mine jointly owned by BHP Billiton, killing 19.

Monday's plunge had shares trading below 45 Brazilian reals for the first time since April. On Friday, the American depository receipts, traded in the US, fell as much as 13.5% on the news. They were set to open down close to 9% Monday morning, near $12.40 apiece.

In a note sent out to clients on Monday, a team of RBC Capital Markets analysts led by Tyler Broda cut their price target to $11 from $13.66, saying, "It is certainly too early to quantify any financial impact (as the company rightly focuses its efforts on assistance) but we fear the potential liabilities for a disaster so similar to the one in 2015 will likely be heightened."

Vale is set to report its fourth-quarter results on February 13, with analysts surveyed by Bloomberg expecting adjusted earnings of $1.94 per ADR on revenue of $37.5 billion.