BEIJING, July 26 -- China's coal producers faced greater inventories in the first half of the year as an economic slowdown and lingering oversupply continued to weigh down the sector, according to data from the National Development and Reform Commission (NDRC).

By the end of June, Chinese coal producers had 99 million tonnes of unsold coal, while the country's key thermal power plants, the primary consumer of coal, had 79.06 million tonnes of coal inventories able to meet demand for 23 days, the NDRC said Saturday in a statement.

Wang Xianzheng, president of China National Coal Association (CNCA), warned that the industry's situation could worsen due to a lingering oversupply in the current economic slowdown.

A CNCA investigation across the country showed more than 70 percent of the country's coal enterprises are operating at a loss and workers at over half of China's coal producers have had wage cuts or defaults.

In the January-June period, railway coal shipments reached 1.15 billion tonnes, up 0.7 percent from the previous year, according to the NDRC.

Customs data showed China's coal imports grew 0.9 percent year on year to reach 160 million tonnes in the first half of the year, while coal exports slumped 22.4 percent to 3.16 million tonnes.