The U.S. Geological Survey (USGS) said total copper output from the United States slipped by 6 percent following the April landslide at Kennecott Copper’s Bingham Canyon Mine near Salt Lake City, UT. Meanwhile, the USGS reported that domestic zinc output increased by 5 percent.

The April 10, 2013, rock slide at Kennecott Utah Copper’s Bingham Canyon Mine caused average U.S. daily copper mine production to decrease by 6 percent in April, compared to March, the USGS said.

“Downstream, smelter and refinery production were unaffected owing to sufficient concentrate and anode inventories, the U.S. average daily smelter production remained unchanged in April and average daily electrolytic refinery production increasing by 9 percent,” the agency noted.
U.S. mines yielded 90.7 kt (100,000 st) of copper in April, down from 97.2 kt (107,000 st) in April 2012, as well as a combined total of 391kt (431,000 st) from January through April of this year.

Arizona led the U.S. in mined copper output with total production of 255 kt (281,000 st) for the first four months of the year, the USGS noted.
U.S. smelters produced 172 kt (189,000 st) of copper from January through April of this year.

In its analysis, the USGS observed, “Although imports of refined copper decreased significantly from the high monthly levels experienced during the preceding five months, copper continued to flow into commodity exchange warehouses. The combined COMEX and London Metal Exchange Ltd. stocks held in the U.S. warehouses increased by 17.7 kt (19,500 st) (7 percent) in April and by 98.4 kt (108,000 st) (54 percent) since yearend 2012.”

Meanwhile, the USGS reported that domestic mine production of zinc in April was 63.2 kt (69,600 st). Average daily mine production was 2.1 kt (2,300 st), up 17 percent from March and 5 percent more than in April 2012.

For the first four months of this year, U.S. total combined mined zinc production was 237 kt (261,000 st) while 75.7 kt (83,400 st) of zinc was smelted domestically.