Teck Resources (TECK) and Anglo American said Tuesday they have struck a deal to combine the two companies in a merger of equals to form Anglo Teck.

Under the deal, Anglo American will issue 1.3301 ordinary shares in exchange for each outstanding Teck share, the companies said.

The Anglo American board also intends to declare a special dividend of $4.5 billion to be paid to its shareholders ahead of the deal's completion, subject to certain conditions, the companies said.

Once completed, Anglo American and Teck shareholders will own approximately 62.4% and 37.6%, respectively, of the new company. The merger is expected to close within 12 to 18 months.

The companies said the merger will be "highly attractive" to shareholders and "deliver significant, value-accretive growth."

The deal is expected to deliver annual pre-tax synergies of around $800 million by the end of the fourth year following completion, the companies said.

Anglo Teck will hold a portfolio that includes six copper assets, making it one of the world's largest copper producers, along with iron ore and zinc businesses, the companies said.

The new company will be headquartered in Vancouver, with corporate offices in London and Johannesburg, the companies said.

Shares of Teck Resources gained more than 8% in premarket activity.