China began Wednesday to build a railway over the Lop Nur, a former lake that is known as "the sea of death," in northwestern Xinjiang Uygur Autonomous Region.

Construction workers began building a 3-km railway bridge in Nanhu town of Hami City, the starting point of the 370-km railroad, sources with China Railway Group Co. Ltd., the prime contractor, said Thursday.

The railway project was launched by Xinjiang's regional government in June 2009, but civil construction was postponed for eight months to discuss technical details and raise funds, an executive with China Railway Group said on condition of anonymity.

The rail link would have a freight capacity of 33 million tonnes a year, he said.

The 3.28-billion yuan (470 million U.S. dollars) railway is co-sponsored by Ministry of Railways, the regional government of Xinjiang and a branch of the State Development and Investment Corporation (SDIC), a state-owned investment holding giant that has a potassium fertilizer base in the Lop Nur.

The Hami-Lop Nur railway will provide a faster route to transport Lop Nur's rich potassium salt, according to SDIC President Wang Huisheng.

The two places are linked by a highway that opened in 2006.

The railway, on completion in two years, would speed up exploitation of potassium salt, one of China's rarest resources used in fertilizer production, he said.

Lop Nur area has an estimated 500 million tonnes of reserves, valued at more than 500 billion yuan.

Without adequate exploitation of the potassium salt resources, China's total reserve is about 457 million tonnes, less than 3 percent of the world total. The country imports at least 4 million tonnes of potassium fertilizer every year.

At least 11 railways are under construction in Xinjiang. By 2020, the region's total rail mileage will top 10,000 kilometers.

The Lop Nur was the largest lake in northwestern China before it dried up in 1972 as a result of desertification and environmental degradation.

It once nurtured the civilization of Loulan (Kroraina) -- an ancient city that was one of the pivotal stops along the famous Silk Road, but mysteriously disappeared around the Third Century AD.

Due to its geology, geography and historical values, the Lop Nur has attracted the attention of scientists from home and abroad since the mid 19th century.

In 1980, Peng Jiamu, a noted Chinese scientist, went missing on his fourth expedition to the Lop Nur and was never found.