China's coal production continued to ease in the first half of this year on flat domestic demand amid the economic slowdown.

The crude coal output increased 8.7 percent year-on-year to 1.36 billion tons in the first six months, but 6.1 percentage points lower than the same period a year ago, data released by the National Development and Reform Commission (NDRC) has shown.

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The industry reaped a revenue of 67.8 billion yuan ($9.93 billion)?through Jan-May, up 4.2 percent year-on-year, but the growth rate was almost half of the figure for the first two months.

The coal inventory at the northern China's Qinghuangdao port, a major Chinese port, was 6.47 million tons at the end of June, up 730,000 tons from the beginning of the year.

The thermal coal reserve remained at normal level, with 33.08 million tonnes in storage, up 11.34 million tonnes year-on-year, according to the NDRC data.

But there are also signs that the demand is gradually recovering as customs figure has shown China's net coal import was 36.60 million tons in the first half, which is in contrast with a net export of 3.94 million tons a year earlier.