UPDATE 1-Antofagasta copper output falls but keeps a lid on costs
* Changes to tax regime in Chile could impact the miner
* Weaker Chilean peso helps to keep costs down
* Company says on track to hit annual output target (Adds details on costs, background, comments)
By Silvia Antonioli
LONDON, April 30 (Reuters) - Chilean miner Antofagasta saw its copper production shrink in the first quarter due to scheduled plant maintenance and falling ore grades but a weaker Chilean peso helped it keep costs under control.
Like other copper producers, Antofagasta is grappling with falling ore grades and is trying to cut costs to protect margin as metals prices cool. A proposed tax regime change in Chile is also expected to weigh on its costs.
The London-listed miner produced 169,400 tonnes of copper in the first quarter, down 7.8 percent from a year earlier but broadly in line with analysts' expectations.
The fall was mainly due to scheduled plant maintenance at its Los Pelambres and Esperanza operations and declining copper grades but the company said it was on track to meet its full-year guidance.
Antofagasta, controlled by Chile's Luksic family, managed to keep its gross cash cost flat from the fourth quarter of last year at 183 cent per pound, helped by a weaker Chilean peso against the U.S. dollar. Most of its costs are priced in pesos while the copper it produces is sold in dollars or dollar equivalents. Continuación...