You've included marks near each of the most productive mines in the inner empire.

Until today the coalmine is one of the highly productive mines in Germany.

During the 1950s and 1960s it was the most productive mine in West Virginia.

Over its life, Bingham Canyon has proven to be one of the world's most productive mines.

Caradon Hill had the most productive mine in east Cornwall.

Not if there's a productive mine and an ideal flat for straight, wide business streets.

Amador's most famous and productive mine, the Keystone produced about $24 million in gold during 1853-1942.

Bagshaw's directory of 1848 calls the Bage* "the most productive mine in the District".

But productive mines, with 30-year life spans, no longer enlarge communities nor renew economic vitality here.

Three years later, the company added another shaft to the mine, named "G" shaft, which would become one of their most productive.