Colossus Centre Mall, located in Vaughan, Ontario, is a diverse and unique shopping complex that sprawls over 16 acres of land near the Hwy 407 and Hwy 400 interchange. It features a clearly defined hierarchy of internal streets servicing over 60 famous brand name retail outlets. In 2013, Cole Engineering was retained by RioCan Management Inc. to complete a detailed Subsurface Utility Engineering study, and to assist with design considerations for alterations and additions to the mall. Cole Engineering designated all underground facilities, including utility structure inspections, over much of the existing south end of the facility and captured all data with differential GPS measurements. These findings were plotted to ASCE 30-02 guidelines. The timely delivery of these data provided the owners, architects and design engineers with an accurate understanding of the existing underground utility network, and to permit go-forward consideration of design impact to existing underground facilities.