Installation of Shaft Bottom Steel Prior to Shaft Sinking


Dwayne Ziebarth, WSP Canda Inc.

Normal sequence of operations to develop a new underground mine is: construct and outfit headframe for shaft sinking, sink shaft, construct and outfit shaft sump, develop shaft station and shaft bottom steel.  In an effort to reduce the overall project schedule, an innovative plan was developed to install service shaft steel below station level prior to the completion of the shaft sinking effort.  To better evaluate the construction of this substantial steel tower, a preliminary constructability evaluation was conducted, including the best method of supporting the main tower; from the bottom, middle or top of the tower.  The design criteria and plan involved: Develop access from existing service shaft, 25 km underground. Use of materials to maximize strength while minimizing corrosion exposure Estimating the location of the shaft centerline Over excavating the station and shaft below station to allow future shaft steel repositioning Designing the tower steel for modular installation Incorporate commissioning considerations, such as suspension of the cheese weights during steel installation Provision for covered stair access to shaft bottom Enclosed shaft envelope with open panels to allow visibility and ventilation The design approach was innovative and this paper will describe the design principles and challenges encountered while providing insight into the solutions developed and implemented; especially the modular construction and installation methodology.
Keywords: shaft, steel, innovation, modular construction,