While effectively reducing overcapacity, China's coal industry is also making great achievement in clean, effective, and safe coal production capacity, according to a report released by China Coal Research Institute on Saturday.

The institute, which has been conducting annual survey in coal mines nationally since 2015, will release a report next year listing China's top 100 coal mines that have score the highest on a so-called scientific capacity index---an index that includes subindices on a coal mine's performance in clean, effective and safe production, through ratings in production safety, staff health, environmental protection, resource recycling and conservation, automation, and production efficiency.

In 2017, 502 coal mines nationwide participated in the survey, and had an average score of 79.08. These coal mines had a total production capacity of 1.19 billion tons, and accounted for 34.52 percent of national coal production in 2017.

Among them, 82.47 percent scored above 73, the passing score to be recognized for having "scientific capacity", according to the survey findings.

In 2015, only 105 coal mines took part in the survey. In 2016, the number was 406.

It is estimated that in 2017, China had about 2.19 billion tons of clean, effective and safe coal capacity, which amounted to two third of total coal capacity in the year, while in 2010, such capacity was estimated to be only of 1.08 billion tons and took up 33 percent of the total capacity, according to Wang Jinhua, president of China Coal Technology and Engineering Group, the parent company of China Coal Research Institute.

Among the 10 coal mines that scored the highest in 2017, seven belong to CHN Energy, including the top three. Two coal mines of Shaanxi Coal Chemical Industry Group Co, Ltd took the 4th and 9th spots, and a mine of Datong Coal Mine Group came at 10th.

The institute plans to cover more than 1000 coal mines in the 2018 survey, according to Wang.

At a press conference held on the release of the report, two titles of books on coal industry's revolution toward clean, effective and safe capacity were launched, as result of a research program on the issue led by Xie Heping, an academician of the Chinese Academy of Engineering.

"Chinese coal mines are increasingly aware of the importance of clean, effective, and safe coal production," said Xie.