Detroit Project Office Stone Supply. The US Army Corps of Engineers, Detroit Project Office (DPO) requires the supply and delivery of stone for one of its structures. The intent of this work is for th... Detroit Project Office Stone Supply. The US Army Corps of Engineers, Detroit Project Office (DPO) requires the supply and delivery of stone for one of its structures. The intent of this work is for the Contractor to supply and deliver the specific items laid in within the attached PWS.