BRUCE REID / COURTESY OF H.B.M.S.
AATS of South Africa provided an innovative shaft steel design. This is the first such installation in North America. The 777 mine project manager Pat Smyth described the mine construction project.
The shaft steel set buntons, which support the steel guides for the production skip, are cantilevered. The steel, supplied by Mine Steel Fabricators of North Bay, Ont., is attached to the side of the shaft in only four places using the standard North American concrete insert technique. The 6-m spacing between sets and the flexibility that is provided by the cantilever guide attachment system, provides for smooth conveyance travel. The flexibility in the system makes for less wear and tear than with rigid closer-spaced steel set systems. As well, huck bolts (cold mechanical rivets) are used instead of welding for all steel work, to increase the durability of the steel frame. The shaft steel is galvanized to prevent corrosion.
"This design allows us to go with 6-m steel set spacing (1 m more than normal), and provides a smoother ride for skipping and less maintenance because of the huck bolts," says Smyth.