The two photos immediately above are of "Operation Up and Over". This was an impressive engineering feat in which the dredge would be moved, intact, from the Hogarth pit to the South Roberts pit. The engineers carefully considered all the possible ways they could move the dredges (between 800 and 1000 tons): wheels, skids, rollers were discussed. They finally decided that the dredges, stripped of their superstructures and reduced in weight by several hundred tons, could be moved on crawler tracks. A road from the Hogarth to the Roberts pit was prepared. There were 8% grades to climb and one sharp corner to negotiate. Six large bulldozers were used to pull the dredges up out of the Hogarth and over the hump to the Roberts mine. An intricate system of wire ropes and blocks had been devised to provide the motive force and, when the move finally started, in bitter cold weather, progress was almost imperceptible at first, measured in feet per day. However, the hundreds of hours of planning that went into this operation paid off, as the move went off without a hitch. Hour after hour, the dredges, first the "Steep Rock" and then the "Marmion" inched their way over the route, eventually arriving at the Roberts pit where the tracks were removed and the dredges once again went to work.
Dredging was completed in 1962. By successful experimentation with unorthodox excavating methods and the practical application of huge dredging equipment, they were able to excavate large quantities of lake bottom silts to expose the iron ores of the Steep Rock Range. |
