Peru's Humala to shuffle cabinet to calm protests

(Adds tweet from Valdes)

LIMA, July 23 (Reuters) - Peruvian President Ollanta Humala will shuffle his cabinet later on Monday, the prime minister and two government sources said, as he seeks to calm a wave of violent anti-mining protests.

Prime Minister Oscar Valdes, a former army officer, said via twitter he was stepping down in a widely expected move. He led a crackdown this month on protesters opposed to Newmont Mining's ${esc.dollar}5 billion Conga project in the northern region of Cajamarca that killed five people.

Two government sources said the president would likely pick Justice Minister Juan Jimenez, a human rights lawyer, to be the next prime minister.

"Dear friends, I wanted to share with you the end of my turn as the head of the Cabinet, thanking you for your support and constructive criticism," Valdes tweeted.

Peru's constitution requires all ministers to offer their resignations whenever a prime minister quits, though Humala will probably reappoint Finance Minister Luis Miguel Castilla, a favorite of investors.

Besides Valdes, Interior Minister Wilver Calle is expected to be replaced, one of the sources said.

Promoting Jimenez, who served as vice justice minister in the government that led Peru's transition to democracy in 2000, may help Humala overcome criticism that his government developed a militant, authoritarian streak under Valdes.

Prominent members of Congress have called for Valdes to step down and say the government should emphasize mediation instead of force to solve environmental disputes.

However, a Jimenez-led Cabinet may not pacify regional government leaders who have led anti-mining protests and say Humala has turned his back on the rural poor who largely voted for him.

Jimenez backed Humala's decision to suspend civil liberties in Cajamarca, where human rights groups have sharply criticized the government's use of force and drift to the right.

Humala has sought to push ahead with more than ${esc.dollar}50 billion in planned mining investments in one of Latin America's fastest-growing economies, but has faced stiff resistance from poor rural communities left behind by a decade-long boom.

Peruvian leaders often shuffle their Cabinets on July 28, Peruvian Independence Day, which also will mark the anniversary of Humala's first year in office. Humala's approval rating fell to a fresh low of 40 percent this month, according to an Ipsos poll. (Reporting By Patricia Velez and Marco Aquino; Writing by Terry Wade; Editing by David Brunnstrom and Philip Barbara)