Sino-Zimbabwe Ltd. of China fired workers at its Marange diamond fields operation in Zimbabwe because the mine isn’t economically viable, the Herald reported, citing Gift Chimanikire, the deputy mines minister, and unidentified workers.

Sino-Zimbabwe entered into a joint venture to dig for gems with the state-owned Zimbabwe Mining and Development Corp. on March 11, the Harare-based newspaper said.

Mbada Mining Ltd., Marange Mineral Resources Ltd., Pure Diamonds Ltd. and Anjin Mining also mine for diamonds at the field, the Herald said. Mbada Mining and Marange Resources export gems from Marange, it said. The Herald didn’t say how many workers were employed by Sino-Zimbabwe.