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Koepe Winding at Grängesberg In my 1951 student report on the Grängesberg iron ore mine in central Sweden, where the winding engines were mounted in a large room on top of the concrete headframes, I described to Koepe winders. The rectangular 16m x 3m Central Shaft had seven compartments, four for skips, two for cages and one for pipes, cables and a ladder-way. Skip winding was from the 360 metre level, cage winding had recently been extended to serve the 410 metre level. Two skips hoisted magnetite ore, two skips a "mixed" magnetite/hematite ore. My description of the winders reads as follows: "Both skip winders were originally of the drum type. During the summer holiday, when winding was not in progress, one of the winders was converted to the Koepe system by adapting the existing drum. The old grooved drum covering was stripped off and a central groove built up centrally around the drum, made of aluminium and wooden blocks arranged alternately, with which a negligible amount of slip is obtained. This Koepe hoist, for the magnetite skips, was fitted with a 72mm diameter hoist rope running at a maximum speed of 16 metres per second. A flat balance rope is used. The hoist rope is of Lang's lay. The skip winders are designed for a maximum working depth of 1,000 metres and work on the Ward-Leonard system. The Koepe skip winder is a 24 pole motor [manufactured] by ASEA, directly coupled to the drum. Running at 44 revs/min it consumes 2,900 kW at 1,400 volts. The mixed ore skips winder still operates as a drum hoist, though the change-over to Koepe winding is to be made at the next opportunity, as Koepe winding is considered to be faster and more efficient......." There is much more in the report about the Grängesberg mine as it was in 1951 - the above is about half a page worth of text extracted from a 99 page hand-written document - but that is the bit on Koepe winding! Tony Brewis