NAIROBI (Reuters) – Acacia Mining’s “very existence” has been jeopardised by accusations of wrongdoing levelled against it by the Tanzanian government, chief executive Brad Gordon said in an internal memo seen by Reuters.

In the memo, Gordon denied accusations of tax evasion and forging documents to avoid paying taxes. He also said the firm operated through locally registered subsidiaries, contrary to a government accusation it had been operating illegally.

Acacia has been caught up in President John Magufuli’s campaign to reform the mining industry, a key source of foreign exchange for the East African country. The sector accounts for 4 percent of Tanzania’s gross domestic product.

(Reporting by David Lewis; Writing by Duncan Miriri; Editing by Ed Cropley)