Tanzania's President fired the mining minister and the chief of the state-run mineral audit agency on Wednesday.
This was after receiving a report into whether mining companies were under-declaring the value of their exports.
President John Magufuli's decision, announced in a speech, signals an escalation of tensions between the government and the industry, which has denied engaging in tax evasion. Mining accounts for about four per cent of Tanzania's gross domestic product.
In January, Magufuli sacked the head of the state-run electricity company after the firm put up tariffs.
Tanzania's energy regulator had approved a power tariff hike of 8.53 per cent by the Tanzania Electric Supply Company, less than half of what the utility said it needed to stem losses.
Hours before the announcement of Mramba's dismissal the president rescinded the price increase.
More on this: Magufuli sacks energy firm boss over tariff hike