State-owned Saudi Arabian Mining Co (Maaden) plans to raise 9.25 billion riyals ($2.47 billion) in July in the Middle East's biggest mining IPO, valuing the firm at $4.9 billion, the Saudi bourse regulator said.

Maaden is a partner in an aluminium venture with Rio Tinto Alcan. Last April, Maaden agreed with Canada's Alcan -- before it was taken over by Rio Tinto -- to develop what would be one of the world's largest aluminium projects at a cost of $7 billion. That includes a smelter, an alumina refinery and a power station.

Maaden will offer Saudi institutional and individual investors 462.5 million of stock -- equivalent to 50 percent of its share capital -- at 20 riyals each, Saudi bourse regulator Capital Market Authority (CMA) said on the stock exchange website.

The sale starts July 5 and ends July 14, it said.

The other 50 percent will be held by the Public Investment Fund (PIF), according to a cabinet statement in March.

Only Saudi investors will be able to buy the stock, with individual investors guaranteed a minimum 25 shares each, the CMA said.

Maaden chief executive officer Abdullah Dabbagh told Reuters in February that the company plans to offer 40 percent of its capital in an IPO and another 10 percent to two Saudi state pension funds.

The share sale, on which JPMorgan Chase & Co was advising, was initially planned for last year, and put at between $1.9 billion and $2.5 billion.

Maaden, which generates most of its revenue from gold production, is developing projects -- including phosphate mining -- worth about 44 billion riyals, as the world's largest oil exporter seeks to diversify its economy from energy.

The phosphate venture with state-controlled Saudi Basic Industries Corp will cost about 17 billion riyals.

The CMA also approved two other IPOs -- Astra Industrial Group and Methanol Chemicals Company (Chemanol). Astra will sell 22.24 million shares representing 30 percent of its capital, starting July 26 and closing Aug. 4 and Chemanol will sell 60.3 million shares representing 50 percent of its capital over Aug. 11-20, the CMA said.

The pricing of these two sales will be fixed after the completion of a book-building process, it added. - Reuters