JOHANNESBURG, July 24 (Reuters) - Tanzania has issued a notice demanding $190 billion in unpaid taxes, penalties and interest from Acacia Mining, the gold mining company said on Monday, adding it did not believe it owed the money.
"Acacia refutes each set of findings and re-iterates that it has fully declared all revenues," the company said.
Acacia shares in London closed down around 21 percent after hitting a 17-month low. The company's market value is less than 1 billion pounds ($1.3 billion), according to Reuters data.
Acacia is caught up in sweeping changes to Tanzania's mining industry spearheaded by President John Magufuli who believes the country is not getting its fair share of profits from the sector.
Following two rounds of audits of Acacia, government-appointed committees found the company had understated how much gold it was shipping and that it was operating illegally in the east African country.
Acacia, majority owned by Canada's Barrick Gold, has denied the allegations.
Tanzania introduced an export ban on concentrates for gold and copper ore in March. Tanzania and Barrick have agreed to start negotiations over the ban.
($1 = 0.7680 pounds) (Reporting by Zandi Shabalala; Editing by Mark Potter)