Development status of coal mining in China

As a controllable active resource in China, coal mining is facing the transition from output to quality. Based on the total mining production and average capacity, the current situation and level of coal mining at three scales of mine, city and province is analyzed, data support for the layout of sustainable mining development and the optimization of output is provided. The results show that China's coal is mainly mined by underground mining, accounting for 87%, with an average production capacity of 0.93 million tons. Open-pit mining accounts for 13%, with an average production capacity of 5.73 million tons. So the average production capacity of open pit and underground workers is 1.045 million tons, with 1,181 coal mines capacity lower than 0.3 million tons, accounting for 35% of the total coal mines, contributing only 4% to their output. They are distributed in about 48 cities in 6 provinces, seriously restricting the green coal mining. The coal industry should speed up the reduction of small coal mines in key provinces and cities, eliminate outdated production capacity in the central region, increase the speed and proportion of coal resources moving westward, and promote high-quality development of coal mining.

However, there are 1,181 mines with an annual output of less than 0.3 million tons (1,176 Wells and 5 open pits), accounting for 35% of the total number of coal mines and only 4% of the total output, showing a serious imbalance between quantity and output. In order to advance the national three-year action plan for the special rectification of work safety, in the next three years, small coal mines with an annual output of less than 0.3 million tons will be disposed of by category and more efforts will be made to eliminate and close them. By 2022, the proportion of large coal mines in China will reach more than 70%. At the same time, by further improving the level of mechanization, information, automation and intelligence of coal mines, the number of intelligent working faces for coal mining and mining has reached 1,000 from 280 at present, and the production capacity of this part of coal mines will account for 1 billion to 1.5 billion tons. At the same time, the proportion of national coal mine safety production standardization at the first and second levels will also reach over 70% [2] .
In order to discuss the status and level of coal mining in China in detail, this paper analyzes coal mining from three dimensions: mine, city and province, which provides data support for the proactive strategic layout of coal resources in China.

Mining type
China is the largest coal mining country and is turning to high-quality development. Due to national conditions and geographical differences, coal mining is dominated by underground mines, accounting for  coal output of 0.9 million tons or less that do not meet the standards of industrial policy, safety, environmental protection, resources and quality [3] .

Open-pit mining
It is worth noting that Guizhou and Henan are great provinces of coal producing, and their mining level is lower than the national level, so outdated coal mines should be eliminated as quickly as possible. In April, 2020, Guizhou province released 254 legally produced coal mine production capacity, totaling 135 million tons, as of March 31, 2020 [4] . In 2020, Henan province will eliminate coal overcapacity, close and withdraw six coal mines, and promote high-quality development of coal mining [5] .

Output and production capacity of open-pit coal mine
China I n n e r X i n j i a n g S h a n x i Y u n n a n L i a o n i n g H e i l o n g j i a n g Q i n g h a i N i n g x i a G u a n g X  Fig.8 Coal production capacity of provinces [6] It can be seen that in the past six years, only in 2017 and 2018, the national average thermal coal price was within a reasonable range, while in the other four years, the price was relatively low, mainly due to the oversupply of coal production. Due to geographical and regional economic development differences, 3) China will transition from a major country to a powerful country in coal mining, and from output to quality. China should accelerate the strategic shift of coal in the west region, optimize the central region, and promote coal to become a sustainable resource that can be adjusted proactively.