Abstract: An Excavation System is disclosed in which fragmented excavated material is entrained in a gas and pneumatically conveyed to a desirably remote site for separation of such material from such gas. Energy is supplied to a motor to operate a gas pump to induce high velocity gas flow through a long vacuum conduit. At a vacuum intake end such flow entrains such material and conveys such material into and through such conduit to one or more separators communicating serially with the flow path for separating and collecting the excavant, then such gas is discharged into the atmosphere. At least one separator includes a high-efficiency cyclone chamber for maintaining a gas vortex for high-efficiency centrifugal separation with minimal flow-resistance.