NIAMEY, April 18 (Reuters) - Workers at Areva's Cominak uranium mine in northern Niger started a 48-hour strike on Thursday to demand the payment of a bonus payment, union leaders told Reuters, saying the company had understated profits last year.
"Work stopped on Thursday awaiting the resolution of our demands, principally the payment of a bonus of 600,000 CFA francs per worker on the 2012 financial results," said Inoua Neino, general-secretary of the National Union of Mine Workers of Niger (Syntramin).
He said the strike could be extended if workers' demands were not met. Areva is the largest shareholder in Cominak with a 34 percent stake, followed by the Niger state with 31 percent, Japan's OURD with 25 percent and Spain's Enusa with 10 percent.
Neither the government nor Areva in Niger had any comment.
The dispute comes as the French nuclear firm seeks to renegotiate its long-term contracts for its Cominak and Somair mines in the desert north of the landlocked West Africa state.
President Mahamadou Issoufou says Niger, one of the least developed countries in the world, has failed to reap appropriate benefits from decades of uranium mining.
"The conflict is due to the fact that Cominak has employed trickery," Neino said.
He said Cominak had made profits of 27 billion CFA francs last year, but the company had deducted 10 billion from this amount before calculating profit-related bonuses.
Output at the Somina uranium mine, controlled by China National Nuclear Corp (Sino-U), has also been suspended for the last month due to a strike by Nigerien workers demanding better pay. The mine, which started up in 2011, produces around 700 tonnes a year but is expected to reach 2,500 tonnes by 2015.
In February, Areva announced production of 4,500 tonnes of uranium in Niger in 2012, of which some 1,500 came from Cominak and a record 3,000 from Somair.
"This is the first time that workers have demonstrated about financial results of a uranium company," said Ali Idrissa, coordinator of transparency watchdog Rotab. "This is a good sign in the fight against opacity."
Areva recently announced that its giant Imouraren mine, which will double Niger's uranium production with a further 5,000 tonnes a year, has seen its start-up delayed until 2015, amid weak conditions in the uranium market and security concerns in northern Niger.