《明史·列传·卷一百九十三》
遣官收税从二十四年开始，此后说开矿的人争相奔走于朝廷，每次皇上都立即命令宦官随来人前往，以致天下处处都有矿监。
其遣官自二十四年始，其后言矿者争走阙下，帝即命中官与其人偕往，天下在在有之。
Starting from the twenty-fourth year, officials were sent to collect tax. Afterward, those who wanted to open mines sought after the court. Each time, the emperor immediately ordered the eunuchs to follow these people. Consequently, there were mine supervisors everywhere in the empire.