Xuan-de: Year 2, Month 6, Day 5
30 Jun 1427
The Yun-nan Regional Military Commission memorialized: "In the silver smelting administration offices established at Xin-xing and other mines, the mine workers were initially soldiers from Da-li and other guards. Later, many of the mine workers were taken for the expedition to Jiao-zhi and also to supplement losses in other guards. These mines are situated on the very distant border and defending them is difficult." It was thus ordered that the mines be abandoned.
Zhong-yang Yan-jiu yuan Ming Shi-lu, volume 17, page 741