Yanaocha, one of Latin America's largest gold mines, produced 1.5 million ounces of gold in 2010, some 1.6 percent of the world's output.
The mine, partly owned by Peruvian precious metals miner Buenaventura
Shares of Buenaventura fell 2.5 percent to $40.70 and Newmont was down 0.5 percent at $66.51, while spot gold was off slightly at $1,667 an ounce.
The latest flare-up could test leftist President Ollanta Humala, who took office in July promising to calm debilitating conflicts between rural communities and companies that have threatened to delay some 200 mining and oil projects nationwide.
We've temporarily suspended work, the company said in a statement in which it called on local and national authorities to do what is necessary to clear the roadblock and maintain a climate of peace and legality in the region.
U.S.-based Newmont and Buenaventura are trying to move forward with a $4.8 billion project known as Minas Congas, which is essentially an expansion plan for Yanacocha. It would
be the largest investment ever in a Peruvian mine.
Yanacocha officials said protesters are trying to pressure the mine to sign a community relations pact that would give local communities 200 million soles ($72 million).
The mine said the eight pieces of burned heavy equipment were worth $2 million and owned by a contractor. It said bulldozers, excavators and a grader were vandalized.
($1 = 2.75 soles)
(Reporting by Teresa Cespedes;editing Sofina Mirza-Reid)