Production at the Tara zinc mine in Co Meath will be disrupted for about six weeks after a grinding mill broke down, mining and smelting firm Boliden said yesterday.

The disruption will cut production by about 40 per cent for the time it takes to repair the motor, the Swedish company said yesterday. It will also reduce overall operating profit by 40 million crowns, or about 10 per cent of the company's annual operating profit.

"This is quite a serious issue for us," said Ulf Soderstrom, Boliden's senior vice-president of group communications. "In terms of the effect on the profit, it's quite big."

Boliden, which has mining and smelting facilities in Sweden, Finland, Norway and Ireland, said that, while the breakdown was a circumstance outside its control, it would mean the company was unable to complete some of its contracted deliveries, including some of those to its own smelters.

It is possible the breakdown may therefore also result in a temporary decline in metal production at Boliden's own zinc smelters during June and July, the company said.

The Tara mine has an annual production capacity of about 400,000 tonnes of zinc concentrate and approximately 50,000 tonnes of lead concentrate.

Zinc is used as a coating to help other metals last longer, as well as in batteries and the construction of buildings.

Boliden in April reported first-quarter pretax profit of 353 million crowns, an increase on the year-earlier quarter, but below market forecasts, as the firm was hit by higher costs for input goods, currency swings and lower grades in two of its mines, including the Tara mine.

Boliden bought Tara along with other mining and smelting assets from Finnish company Outokumpu in 2003.