China's coal prices have fallen sharply this year, as a slowing economy has reduced industrial demand and coal supplies have continued to grow, an official said Thursday.

Thermal coal prices at China's benchmark Qinhuangdao port fell to 635 yuan ($100.79) per metric ton in early October, down from 800 yuan per ton at the start of the year.

Wu Yin, deputy director of the National Energy Administration, said at an industry meeting that the country's economic slowdown, especially in energy-intensive industries, has greatly reduced domestic demand for coal. Related reading: Slowing economy weighs on China's coal sector

China's economy expanded at 7.6 percent in the second quarter, the slowest pace in more than three years, as exports and real estate investment sagged.

China produced 2.57 billion tons of coal in the first eight months of the year, up 4.4 percent year-on-year. Coal consumption rose 1.4 percent from the previous year to 2.71 billion tons, down from the 10.1-percent growth seen in the same period last year.

Inventories at major thermal power plants stood at 90.32 million tons at the end of September, enough for 29 days of use, according to Wu.

Countries like Australia and the United States have increased coal shipments to China due to faltering demand in Europe, creating more pressure for domestic stocks.

Wu predicted that China may continue to see supply growth exceed demand for a period of time. China imported 185 million tons of coal in the first eight months, up 46.3 percent year-on-year, according to customs data.