Cheng-hua: Year 17, Month 10, Day 4
26 Oct 1481
The Ministry of Revenue made proposals on appropriate arrangements for grain transport and other matters memorialized on by grand coordinators: "...At the copper mines in Lu-nan Subprefecture in Yun-nan, it frequently occurs that evil persons steal, smelt and sell the copper. This assists Jiao-zhi in the manufacture of its weapons. It is requested that a despatch be sent to the local officials requiring that the mine be closed and that the annual copper tax be waived. Also, an Imperial proclamation should be publicly made known forbidding these activities and noting that offenders will be sent to misty and miasmic areas as soldiers..." The emperor said: "... People who privately trade Yun-nan copper beyond the the borders are to be punished with death and their family members are to be sent to miasmic areas as soldiers..."
Zhong-yang Yan-jiu yuan Ming Shi-lu, volume 48, page 3803/05