摘要
In the original publication,there were few amendments to be made:In Abstract,"4,844,500 tons"should be changed into"4.4845 million tons".The ordinate unit of Fig.1"million tons"should be changed into"billion tons".In Introduction Section,"China’s total coal production increased from 2.57 million tons in 2006 to 3.52 million tons in 2017."should be changed into"China’s total coal production increased from 2.57 billion tons in 2006 to 3.52 billion tons in 2017."
