Residents in the northern city of Cajamarca planned a mass protest Thursday to vent their anger over a new mine they say will harm agriculture and livestock by relocating water supplies.

The protest against the $4.8 billion Conga Project, run by US-based Newmont Mining Corporation, threatens to become violent as protesters plan to block roads and close down businesses.

People in the region "categorically" reject the project, said Wilfredo Saavedra, head of the Cajamarca Environmental Defense Front, a coalition of groups that will participate in the strike.

Cajamarca, known as the city where the last Inca emperor filled a room with gold to pay ransom for his release from Spanish conquistadores, is located in the Andes 870 kilometers (550 miles) north-east of Lima.

Newmont already runs Yanacocha, South America's largest gold mine, located some 70 kilometers (40 miles) north of Cajamarca.

The conflict exemplifies the problems that President Ollanta Humala faces in trying to balance the needs of the people who elected him -- mainly the country's poor and working class -- with the demands of the mining industry, the engine of Peru's economic growth in the past years.

At the heart of the conflict is access to water: the Conga Project involves moving the water from four lakes located high in the mountains into reservoirs the company would build.

Locals however say the reservoirs do not adequately replace the lakes, which also provides ground water for agriculture and for raising livestock.

"President Humala has let us down by affirming that it is possible to find a balance between water and mining -- that is impossible," Saavedra told AFP. He urged the president to live up to his campaign promise to "defend Cajamarca" against the abuses of the mining companies.

Humala, a leftist nationalist former army major who took office in July, "has been abducted by the country's powerful groups," said the president of the Cajamarca region, Gregorio Santos.

The Congra Project environmental impact study was approved under the previous president, Alan Garcia. The company says it meets all international environmental safeguards.

Mining in Peru generated last year some $15 billion, and this year mining exports are expected to be above $25.5 billion, according to government figures.

Friction between mining operations and local residents however has also increased.

Some 30 people were wounded on November 10 in clashes with police in the south-eastern province of Apurimac as locals tried to stop area mining. Locals and police have also clashed in Ancash province over mining resources, and Garcia was forced to cancel a major Canadian mining project in the southern province of Puno before leaving office due to massive protests.