Congo's government is bringing in outside experts to investigate the long-term impact of some $6.7 billion in contracts with Chinese companies that critics say could exploit the central African nation's mineral riches.

Congo's government has a 32 percent stake while China has 68 percent in the mining project called Sicomines. The Chinese companies are building roads, railways, hospitals and other infrastructure for a stake in mining.

Deputy general manager of Sicomines, Jean Nzenga Kongolo said the project now employs about 3,000 people, of whom 70 percent are Congolese.

World Bank representative Ahmadou Moustapha Ndiaye said the project is aligned with the right objectives. He and a U.N. official visited the site Saturday.

Civil society leader Jonas Tshiombela says a more thorough evaluation of the contract still must be done.