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STANDARD OF MATERIALS USED IN MINE HAULAGE TRACKS

Recommendations of the Technical Committee on Mines Standards in respect of Material for use on Mine Haulage Tracks (Cir 58/1966)

Sleepers and rail fastenings - The length of the sleepers should not be less than the gauge plus 60 cm subject to a minimum of 1.5 m. Where locomotives heavier than 05
tonnes are in use the sleeper section should be not less than 20 cm to 12 cm. Wooden sleepers should be not less than 15 cm wide and 10 cm thick.
According to available information, the average life of treated timber is 7 to 17 years, depending on mine conditions, compared to 2 to 5 years for untreated timber.
Length of dog spikes should be at least one (01) cm less than the thickness of sleeper. Steel sleepers of suitable sections can be used in conjunction with wooden sleepers, or
steel sleepers alone can be used, depending on availability.
Concrete sleepers have not proved satisfactory for mine use due to their tendency to break under load. Pre-stressed construction gives better qualities but adds to the cost. When
concrete sleepers are used, the rail should be laid on a chair plate, and between this chair plate and the sleepers is placed a felt or rubber pad (one ply of old conveyor belting is
quite suitable).
Sleepers should be spaced at 90 cms. Rail joints should be free, with two sleepers for supporting the end rail placed not more than 30 cm apart.
Ballast - Ballast provides an elastic bed for the track, distributes the applied load over a larger area and holds the sleepers in place. Selected mine rocks and/or fused boiler clinker are very suitable as ballast as the mass will bind well together when laid down and yet
remain porous to allow drainage and so maintain an elastic road bed. The material size should, as far as possible, be plus one (01) cm minus 6 cm.
In locomotive and main haulage tracks, a layer of coarser ballast should be laid under the sleeper, and finer material used between the sleepers. In order to stabilise the track, ballast
bed should be wider than sleeper length, by about 30 cm on either end.
Lighter ballasting may be used in hand-tramming lines.