"The sulphur-iron mine is located at the common boundary of Sichuan, Yunnan, and Guizhou province, with an area of 1774 square meters. The Yong Ning River originated from here, flowing northward 108 kilometers into the Yangtze River. The mine was established in 1950 and its products are mainly exported, with some concentrated uses within in the county. We found this place in the newspaper by accident; it's called Big Tree County. Many years ago, it was part of the forest along the Yangtze River. A sulphur-iron mine was discovered in the 1920s, which started large-scale sulphur smelting. Now the old way of sulphur smelting is ranking first in the country[sic]. On our second day there, in this remote valley in the southern part of Sichuan province with hundreds of thousands of people living there, we met a boy named Tan Cong. We then got to know his family, as well as a local school teacher, and some of the locals smelting the sulphur."