Chinalco has asked Guinea to let it take over the whole of the troubled Simandou iron-ore mine project, sources familiar with the matter say, as Beijing pursues a global strategy to secure key resources for its vast economy for decades to come. Mired in legal disputes, located in Guinea’s remote interior and being planned at a time of depressed world prices, the mine has nevertheless attracted intense interest from China, the world’s biggest producer and consumer of steel.