As early as 2006, the China Coal Miner Pneumoconiosis Treatment Foundation reported that pneumoconiosis [1] patients in China accounted for 50% of the total pneumoconiosis patients around the world. Out of all the Chinese pneumoconiosis patients, 50% of them were coal workers.
Four years later, on September 30, 2010, China News Service (CNS) reported that "according to incomplete statistics, cases of pneumoconiosis in the coal industry account for about 50% of the total number of those in China with pneumoconiosis." The statement was made by Zhao Tiechui, Deputy Director of China’s State Administration of Work Safety.
[1] A person with pneumoconiosis has damage to the lungs, caused by years of exposure to some type of dust, such as coal, silica or asbestos. There is no cure.
Source: China Coal Miner Pneumoconiosis Treatment Foundation, 2006
http://www.cfbjjh.org.cn/mtbd.asp
China News Service (CNS), September 30, 2010
http://www.chinanews.com.cn/gn/2010/09-30/2566948.shtml