Peru’s government declared a 30-day state of emergency in the southern Andean province of Espinar yesterday after clashes between anti-mining protesters and police officers. The state of emergency suspends a number of civil liberties, including the right to freedom of assembly. It also grants local police officers responsibility over public order.

Protestors have been demonstrating against the Tinaya copper mine in Espinar, near Cuzco, since last week, blocking highway access to the mine and halting production. Violence escalated last weekend, resulting in the deaths of two civilian protestors and the injury of 46 police officers on Sunday. An additional 30 police officers were injured on Monday. Interior Minister Wilver Calle, who announced the deaths yesterday, did not explain how they occurred other than to say that police were forced to open fire in self-defense.

Protestors claim that operation of the Tinaya mine is polluting two local rivers and damaging the environment. They also say the mine has not contributed sufficiently to the local economy, and are demanding that the mine owner, Xtrata, increase the amount of royalties it provides the local government to 30 percent, from 3 percent. Xtrata, a Swiss-based company and the world’s fourth-largest copper producer, has denied the pollution allegations.

This is not the first time President Ollanta Humala has resorted to declaring a state of emergency to end anti-mining protests. Last December, his government issued a state of emergency in the northern province of Cajamarca in response to protests against the $4.8 billion Conga gold mining project. That project, owned largely by U.S.-based Newmont Mining Co., has been suspended pending further negotiations over the protection of highland water sources.