The dredge at Martin Marietta Materials' New Harvey Sand near Des Moines, Iowa is moved in after the overburden is removed and the pond forms. The operation uses a chain dredge that looks like a chain saw with a vacuum cleaner attached to it. The big blade rotates and knocks the material loose so it’s not packed tight. Then, the big nozzle vacuums it up, and sends it through a 12-inch poly pipeline to the processing plant.