We hear many tales of goalscorers being in a rich vein where they hit the back of the net with almost monotonous regularity.

ohm Mother, help us, reward our labour, open to us the rich vein of flint that you hide deep in your body.

Polar literature is a rich vein for quarrying.

When the Press discover a rich vein they naturally exhaust it.

There's a rich vein of humour too.