Each cavern was in a rocky area, near metal mines.

This award is given to the metal mine which has the lowest accident frequency in the country.

This award is given to the metal mine with the best safety record for the previous year.

The agency estimated last year that the cost of cleaning up metal mines could reach $54 billion.

No national standards exist for how to close down the nation's 140 or so open-pit metal mines, most of which are in the West.

Many different types of minimum metal mines have been produced in various countries over the years.

By 1944 the situation had improved and production of metal mines resumed.

In the 19th and early 20th centuries, many metal mines used stamp mills to process ore-bearing rock.

Both general and detailed surveys on the soil pollution status of 936 deserted metal mines across the country have been executed since 1992.

To get this resources he/she has to upgrade or build a metal mine.