It’s safe to say most people would rather not have a gravel mine in their back yard. They’re noisy and dusty. And large trucks create traffic jams as they drive in and out of the pit. We may not like gravel mines, but experts say we need them. The country’s infrastructure is crumbling - and it will take trillions of dollars and a lot of sand and gravel to fix it. That will likely lead to more conflicts with residents.