 By the end of the Qianlong era Yunnan's copper mines started depleting the production of cash coins was lowered by the end of the Qianlong era, and the copper content was debased once more.1794 all provincial mints were forced to close their doors, but subsequently reopened in 1796.In the Summer of 1759 the government of the Qing dynasty finished their conquest of Xinjiang, Xinjiang was divided into 3 circuits, the Northern Circuit, Eastern Circuit, and Southern Circuit.