A fork light moves aluminium ingots at the aluminium processing plant at the Saudi Mining Company, (Maaden AB ) mineral industry complex in Ras Al-Khair, Saudi Arabia on Wednesday, Nov. 23, 2016.

Saudi Arabian Mining Co., commonly known as Maaden, has raised $1.25 billion from its debut Islamic bond sale as the company looks to fund a huge expansion program over the next five years.

Maaden attracted over $10 billion in offers from investors for the sukuk, which was split between $750 million maturing in 2030 and $500 million maturing in 2035.

“The market appetite for investing in Saudi Arabia, in mining, and in Maaden specifically, is strong, and a sign of the untapped potential seen in the kingdom,” Maaden Chief Executive Officer Bob Wilt said in an interview. Around half of the demand came from US investors with the rest split between Europe, Asia and the Middle East, he said.

The company is tapping fixed income investors as it embarks on a more than $12 billion investment drive through to the end of the decade that includes major expansions of its gold, phosphate and aluminum businesses. It’s also ramping up efforts to explore for more copper in the kingdom.

Maaden’s board will make a final decision on new investments in gold and phosphate production around the middle of this year, Wilt said.

Maaden is unlikely to tap bond markets again soon but may do so in future to raise further funds for growth projects, he added.

Maaden, majority owned by the kingdom’s sovereign wealth fund, is one of the key entities behind the country’s push to make mining a so-called third pillar of the Saudi economy along with oil and petrochemicals, as part of Crown Prince Mohammed Bin Salman’s economic master-plan.

Maaden announced in January it was working on creating a joint venture with state-controlled oil giant Saudi Aramco for the exploration and mining of energy transition metals in the country.