The total gold reserve of Xiling gold mine in East China's Shandong province has risen to 580 metric tons after the recent discovery of nearly 200 tons of reserves in the mine, according to the Shandong Provincial Department of Natural Resources.

The discovery makes Xiling the largest single gold reserve mine in China, the department said last week.

Shandong Gold Group Co, the owner of Xiling gold mine, announced in 2017 that the company detected 382.58 tons of gold reserve in the Xiling mine.

Based on the price of gold in the Chinese market on Thursday, the gold reserve in Xiling mine represents a potential value of more than 200 billion yuan ($28.5 billion).

Xiling gold mine is located in the region between Laizhou and Zhaoyuan, the two coastal county-level cities of Yantai in Shandong province. The region is one of the largest gold production areas in China, with the gold reserves and output ranking first in the country, according to the China Gold Association (CGA).

North of the Xiling mine is the Sanshandao island area where a huge gold orebody was identified in 2016. The Sanshandao gold ore field is the first marine gold field discovered in China with a gold reserve of 470 tons.

"Xiling gold mine is a representative of deep prospecting projects. Gold reserve in the mine is mainly distributed at a depth of 1,000 meters to 2,500 meters, making Xiling the deepest gold mine discovered in China," said Feng Tao, vice-general manager of Shandong Gold Geological and Mineral Exploration Co Ltd.

Explorers drilled 180 boreholes into the mine with a total length of over 300,000 meters, among which the deepest reached 4,006 meters down into the ground.

The gold orebody at Xiling mine extends more than 2,050 meters and part of it has a thickness of 62.35 meters. The gold reserve has been detected to have an average gold grade of 4.26 grams per ton, Feng said.

"Xiling gold mine is expected to maintain production that has a daily process capacity of 10,000 tons of ore working for more than 30 years," he said.

Both gold consumption and investment demand for gold in the domestic market saw an increase during the first quarter. Gold consumption volume reached 291.58 tons in the first quarter, a 12.03 percent year-on-year growth, according to the CGA.

Sales of gold jewelry reached 189.61 tons in the first quarter, a year-on-year increase of 12.29 percent, while gold bars and coin sales totaled 83.87 tons, up 20.47 percent year-on-year.

Data from the People's Bank of China show that China has increased its gold reserves for six consecutive months, with the central bank's gold reserves reaching 66.76 million ounces by the end of April, an increase of 260,000 ounces compared to the end of March.