It is the "BOO-CIOWAN" Mint meaning " Board of Revenue mint" (on left, squiggles) and Manchu mint (right symbol) meaning " Fountainhead of Currency". Yes it appears to be Chien-lung 1736-1796. If its about quarter size its a 1 Cash coin.
The ONLY reason I know this is because got a card of Ching Dynasty coins and then a sandwich bag of loose ones to identify and research, it was a blast, but...TMI and not a big interest for more!
