Chinese geologists have found more uranium deposits at China's largest uranium mine, Xinhua learned on Thursday. Geological exploration around the western areas of the Daying uranium mine, located in Erdos City in north China's Inner Mongolia Autonomous Region, started early this year and lasted six months, said Cheng Liwei, director of the China Central Geological Survey Fund Management Center.

The belt of uranium at the Daying mine is now thought to be 20 kilometers longer than originally estimated, making the mine the 14th largest in the world, said Cheng.

"Compared with a preliminary survey in 2012, this new discovery represents a uranium deposit increase of about 60 percent," Cheng said, without disclosing the estimated size of the deposit.

Exploration staff have reached a drilling depth of about 15,000 meters around the western areas of the Daying mine. The exploration project is supported by investments totaling 24.6 million yuan (4 million U.S. dollars), the Management Center said in a statement on its website.

The Land and Resources Ministry announced in September 2012 that a large leaching sandstone-type uranium deposit was discovered in Daying, along with a large coal mine, with estimated reserves of 51 billion tonnes.

The discovery is significant for boosting domestic uranium supplies and ensuring energy sources for developing nuclear power, the ministry said in 2012.

Uranium is the only commercially available fuel source for nuclear power plants. When used in the civilian sector to fuel nuclear power plants, one kilogram of uranium-235 can theoretically produce as much energy as 3,000 tonnes of coal.

According to the World Nuclear Association, nuclear energy is used to generate around 11 percent of the world's electricity.

China began developing its nuclear power industry in the late 1980s to help ease an energy bottleneck, optimize energy structure and achieve cleaner growth.

By the end of 2013, 17 nuclear plants were in operation, with a total capacity of nearly 15 gigawatts (GW). China aims to raise its installed nuclear power capacity to 40 GW by 2015, according to a government white paper on energy released in October 2012.

As China constructs and puts into operation more nuclear power units, its demand for uranium is set to soar. Currently, it relies heavily on imported uranium to fuel existing nuclear plants.

Without a breakthrough in domestic uranium supply, China will have to rely more heavily on imported uranium as more nuclear power plants go into operation.

Li Ziying, head of the Beijing Research Institute of Uranium Geology under China's largest atomic energy developer CNNC, said China lags behind developed countries in nuclear energy use.

A sufficient domestic uranium supply is of strategic importance to the sustainable development of China's nuclear energy, Li said.