You are seeing more professionalism, particularly at the larger mines.

It can take decades for a large underground mine to move into the black.

They then used profits to buy larger more successful mines.

Enterprise is the largest mine on the island and accounted for 60% of the island's production in 2011.

At one time it was the largest hydraulic mine in California.

Mining at this large mine was started in 2011.

Kiruna was built because of the large mine, from 1898.

However, even federal court cases did little to break up already-established, large, commercial mines.

For experts, the survey may indicate the Roosevelt as the largest mine in the world.

It was, for a while, the largest mine in the county, producing 70 tons per day.