Saudi Arabian Mining Company (Maaden) has invited companies to bid on an estimated $1bn contract to construct a new ammonia plant in Ras al-Khair, according to sources familiar with the project.

The plant will have the capacity to produce 3,300 tonnes a day (t/d) of ammonia, which is largely used in the production of fertilisers.

Contractors have been invited to submit engineering, procurement and construction (EPC) bids by 29 May. About 10 companies and consortiums are thought to be prequalified to bid.

In July 2013 Maaden awarded a $825m EPC contract to South Korea’s Daelim to construct at 1.1 million tonne-a-year (t/y) ammonia plant at Ras al-Khair as part of its Waad al-Shamal fertilisers megaproject.

Maaden uses phosphates mined in the north of the kingdom to producer fertilisers at Ras al-Khair on the Gulf coast of the kingdom, where they are exported to international markets.

Maaden has a variety of mining and chemicals operations in Saudi Arabia, including gold, phosphate, aluminium, magnesia, low-grade bauxite and industrial minerals.

The company announced in its annual earnings call in January that it plans to build a third phosphate complex at a costs of SR24bn ($6.4bn) by 2024.