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FCC Construction managed the construction for the two new head frames on this $1.7 billion potash mine expansion.
The foundation for the production shaft head frame was done inside
a secant pile wall, due to an anticipated inflow of water at a rate of
600 gallons per hour. The wall was constructed of 3’-0” diameter
concrete caissons, drilled and socketed into bedrock, and overlapping
each other to create a retaining and water cutoff wall. The excavation
was then done inside the wall. As the excavation continued down,
equipment (including excavators!) had to be lowered into and lifted out
by cranes.
Both head frames have 60 feet deep foundations. The excavations,
including both common excavation and rock blasting and removal,
required moving in excess of 55,000 cubic yards of material. Both
foundations required placement of 10,000+ cubic yards of concrete. All
concrete pours were mass concrete pours, the largest at 2100 cubic
yards, started at 5am and lasted well into the evening.
The head frame construction utilized the slip form concrete method.
This process consists of placing concrete in a form that is continually
rising. The first head frame, at a height of 300 feet, was completed in
just 14 days and required approximately 6500 cubic yards of concrete.
The work deck, that is part of the rising form, had in excess of 50 men
working on it at all times. They continually placed concrete, installed
rebar, installed forms for pockets in the walls, finished the walls
(inside and outside), checked the levels of the deck, etc. In addition
to the main wall, an elevator structure was constructed up the outside
of the head frame for access, along with a staged stair tower. The
tower will also encompass steel framed floors (some with concrete
decks) and mechanical and electrical services. |
Customer: Cementation Canada
Project: Construction of two new head frames (Service Shaft and Production Shaft) at Penobsquis Potash Mine owned by Potash Corporation of Saskatchewan (PotashCorp) - the world's largest fertilizer company..
Location: Penobsquis, NB
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