The Globe and Mail reports in its Tuesday edition that Acacia Mining is halting underground work at its flagship Tanzanian gold mine and cutting its production guidance. A Reuters dispatch to The Globe says that shares in the FTSE 250 company plummeted 9 per cent to 188 pence Monday. Acacia, majority owned by Barrick Gold, said it would have to scale back operations at Bulyanhulu mine and cut staff as it coped with a government ban on exports of unprocessed ore, imposed in March to encourage the construction of a local smelter. The ban had left a buildup of ore and cut revenue as the firm met taxes and other bills, Acacia said in a statement, adding that "ordinary course operations at Bulyanhulu [are] unsustainable." Annual production is expected to be 100,000 ounces lower than the bottom of the previous guidance range of 850,000 to 900,000 ounces. Acacia has been caught up in sweeping changes to Tanzania's mining industry spearheaded by President John Magufuli, who in July handed Acacia a $190-billion tax bill, equivalent to four times the East African country's annual gross domestic product. The company said did not need additional financial resources or financial assistance from Barrick.