The protesters, most of them Aymara Indians who say they are concerned about pollution, had lifted their blockade in the days before Peru’s election on Sunday to allow voters to reach polling stations.

But on Wednesday they started to retake control of highways with boulders to draw attention to their demands. Peru is a leading global exporter of copper, zinc, gold, silver and tin, with vast untapped resources in the Andes.

Humala, who is well-liked in the poor provinces, has said he will work to end social conflicts over natural resource projects that have plagued companies.

More than 200 rural towns in Peru have organized to stop the building of new mines, oil wells and hydroelectric dams that residents say will cause pollution or fail to bring them direct economic benefits.

Humala has promised to ensure social programs reach poor, isolated towns to try to spread the wealth from Peru’s resource boom to the one-third of the country mired in poverty.

“We are going to fundamentally focus on social programs,” Humala told Reuters on Tuesday.

The first round of protests in Puno drove down the share prices of Canadian mining companies such as Bear Creek and Rio Alto, although they were mostly flat on Wednesday.

Most companies in Puno are only exploring for minerals on concessions they have and have not started producing. The government has tried to calm protests by promising to turn a broad stretch of land in Puno into a nature reserve.

Rufino Machaca, a leader of the protests, said all concessions granted by the outgoing government of President Alan Garcia — which has lined up $40 billion in mining projects for the next decade — must be revoked.

Protesters also demand the Inambari hydroelectric project, which would be built by Brazilian companies, be canceled.