Question
I've lived in my home for over a year with a partial brick and wrought iron fence facing a highway.  Recently a red dirt mine was opened close to my home and now have dump trucks going past all day long.  The noise is almost unbearable.  We planted 12 foot arborvitae trees behind the fence to help with noise reduction. I want to erect an effective fence now between the trees and the other fence.  I need suggestions on the type of fence to install.

Answer
The best fence would be solid wood with overlapping edges as tall as you are allowed. Cover with vines or plant infront and behind it for more buffering.
Plus you might consider approaching them to pay for it or your local zoning board to complain that a buffer should have been required (if one wasn't).
Sorry about your situation.
Best of luck,
Sean Murphy