(Adds details, context) CONAKRY, March 11 (Reuters) - Guinea's...

(Adds details, context)

CONAKRY, March 11 (Reuters) - Guinea's ruling junta has ordered the cessation of all activities at the massive Simandou iron ore deposit owned by Rio Tinto and a Chinese-backed consortium, saying it was seeking clarification on how Guinea's interests will be preserved.

Simandou, in Guinea's remote south-eastern corner, is the largest known deposit of its kind, holding more than 2 billion tonnes of high-grade ore.

In a statement read on national television late on Thursday, Guinea's interim government said interim president Mamady Doumbouya, who took power in a military coup in September, had not seen progress towards developing the long-stalled project.

"He therefore ordered the cessation of all activity on the ground pending the answers to questions posed to various actors and the clarification of the modus operandi by which the interests of Guinea will be preserved," said government spokesman Ousmane Gaoual Diallo.

Rio Tinto RIO.L (RIO) owns a 45.05% stake in Blocks 3 and 4 of Simandou. Aluminium Corp of China (Chinalco) holds 39.95% and Guinea's government 15%.

Blocks 1 and 2 are controlled by a Chinese-backed consortium, which is developing the mine and associated infrastructure through a company called Winning Consortium Simandou (WCS).

Rio Tinto, WCS and Chinalco did not immediately respond to requests for comment.