A worker checks a shipment of copper inside the plant at the copper refinery of Codelco Ventanas in Ventanas city, about 100 miles northwest of Santiago, April 2012. Reuters / Eliseo Fernandez

Chile, the world's top copper producer, said Tuesday it expects to produce 5.53 million metric tons of the red metal in 2013, down from its previous forecast of 5.58 million tons, which was announced in April.

Chilean authorities attributed the lower estimate to two factors, delays at the Caserones mine managed by Japan's JX Holdings and lower forecasts for output from the Spence and Esperanza deposits. These factors combine with Chile's aging mines and labor unrest to curb output.

The price of copper, a barometer for the health of the global economy, has fallen about 15 percent this year. Its price on the Comex has fallen from nearly $3.80 per metric ton in February 2013 to $3.05 on Tuesday -- a 19 percent drop in slightly more than four months.

The government's copper commission, known as Cochilco, also cut its average copper price forecast to $3.27 per pound compared to the previous level of $3.57 per pound as a result of a slowdown in purchasing activity from the world's top metals consumer, China.

The price cut is also influenced by the prospect of the U.S. Federal Reserve winding down its economic stimulus program -- and thus potentially trimming U.S. economic activity, including demand for copper -- as well as a projected copper surplus in the coming years.