* Union says output down to about 30-40 pct
* Mine operator says has no figures on impact (Adds union head comments)
SANTIAGO, July 5 (Reuters) - Heavy snow and winds severely affected output at the world's No. 3 copper mine, Chile's Collahuasi, the head of its main union said Tuesday.
The mine operator said it had no figures on any impact, however.
Collahuasi union president Manuel Munoz said the snow storm had abated, but the mine was still operating with a small group of workers.
"Production under these conditions decreases considerably. We are now at about 30 to 40 percent of capacity," Munoz said.
Collahuasi mine spokeswoman Bernardita Fernandez said she had no figures on impact, and that the deposit operator was more worried about the well being of its workers at the moment.
She said the workers' shift will get back to normal once the weather permits.
Collahuasi saw output dwindle in the first quarter due to heavy rains that disrupted operations.
Unusually bad weather in Chile's arid north also hit first-quarter copper output from Collahuasi's joint owners Xstrata XTA.L and Anglo American (AAL.L).
Sand storms and heavy snow cut access to several towns in the country's northernmost region in one of the worst cold fronts seen in almost 20 years, authorities were quoted as saying in local media. (Reporting by Alonso Soto and Simon Gardner; Editing by John Picinich)