LIMA (Reuters) - A jailed opponent of Newmont Mining Corp's proposed $5 billion Conga mine was headed for re-election in Peru's Cajamarca region, provisional results and a pollster's quick count showed on Monday.
A second term as Cajamarca's president for Gregorio Santos will fuel doubts about the Conga mine getting off the ground.
With almost two-thirds of all ballots counted, Santos won 43.7 percent of the vote, the National Office of Electoral Processes (ONPE) said, well above the 30 percent required to avoid a November runoff.
His closest rival, Osias Ramirez, trailed with 22.2 percent, ONPE said.
Cajamarca's fiery leftist leader has spent the past three months in prison after a judge ordered him jailed until August 2015 pending a corruption trial.
Santos has denied wrongdoing and said his imprisonment was designed to ease the way for Newmont's gold and copper project. Peruvian law allows detained citizens to be elected to office, but not if they have been convicted and sentenced to prison.
"To be honest, we expected him to win ... but not with this proportion of the vote," said Olmedo Auris, vice president of Santos' party. "It is a clear message from the people of Cajamarca that they do not want Conga."
Santos spearheaded protests in 2011 that turned violent and forced Newmont to shelve the project. Five protesters were killed in clashes with police in 2012.
Newmont declined to comment on the election. Yanacocha, Newmont's subsidiary in Peru, said it would not issue statements before a final result was confirmed.
Ipsos showed Santos winning with 45.6 percent of votes after a quick count of all ballots. It said its quick count has a margin of error of three percentage points.
Santos' candidate for regional vice president, Hilario Porfirio Medina, who will govern Cajamarca while Santos is behind bars, has pledged to maintain efforts to block the Conga project.
Newmont said last year it would re-evaluate the future of the proposed mine in 2015 after Peru's nationwide local and regional elections, held on Sunday.
Peru's electoral body is expected to announce final results later on Monday.
Conga was expected to help offset dwindling gold output from Newmont's aging Yanacocha gold mine, also in Cajamarca. Denver-based Newmont holds a 51.35 percent in the Conga project, Buenaventura has 43.65 percent and the International Finance Corp [IFK.UL] holds 5 percent.
The project's opponents, especially peasants who farm in Cajamarca's highlands, worry the mine will pollute and drain local water supplies.
Newmont has said it would not work on the mine until water reservoirs for community use are built first.
Anglo American Plc, Rio Tinto and Lumina Copper all operate exploration projects in Cajamarca, but have not been targeted by Santos or anti-Conga protesters.
Financial markets appeared unphased by the partial vote count, with Newmont's share price up 1 percent at midday.
Reporting by Mitra Taj, Marco Aquino and Patricia Velez; editing by Richard Lough, G Crosse and Dan Grebler