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As soon as possible after the injured had been treated, an investigation was begun.

Sections of rope, approximately 6 feet long, were taken as follows :—

from the dead coils on the drum;

from the drum side of the fracture;

from the capel side of the fracture.

These were submitted to the Safety in Mines Research Establishment at Sheffield for examination.

The full report of this examination is given in Appendix II.

Cause of the Wear

By studying the Safety in Mines Research Establishment report it is obvious that the wear had been caused by the rope rubbing against obstructions. The haulage engine was situated in intake air and the trains were in the main return; therefore the ropes had to pass through apertures in the air lock walls. To reduce the inevitable air leakage to a minimum these apertures were as small as possible, but the angling of the ropes and the vibration in them caused them to rub against the side. This effect might have been reduced by making the rope angle on to the drum from a fixed pulley on the intake side of the air lock.

Many carrying rollers were missing and others were in such a poor state that they would not revolve, so the rope was rubbing on the stationary rollers or the sleepers. Several wooden and steel sleepers were completely sawn through. At one point, where there was a sharp change of gradient, the roof girders were being sawn through. At one time a roller had been installed there but must have been damaged and had not been replaced.

Corrosion had been caused by the damp to wet conditions of the roadway and, although some attempt had been made to drain the track, the absence of rollers allowed the rope to come in contact with the corrosive water on the floor. Lack of suitable rope dressing enabled the corrosion to continue unabated.

Rope Examination

It is difficult to understand why action had not been taken weeks sooner, because in May 240 feet were cut off and in July 300 feet were removed; thus it must have been obvious that excessive wear was taking place on that length of rope next to the set.

It is perhaps not so easy to judge the amount of wear by eye when there is nothing with which comparison may be made, but in this case the inbye train rope, which had been in use nine months, ran parallel to and about 3 feet from the outbye train rope.

The usual signs of rope deterioration, namely :—

(a) the looseness of all outer wires, as shown by the ropeman's hammer test;

(b) the extreme looseness of some outer wires, enabling light to be seen between those wires and the rope;

(c) the fact that each extremely loose wire could be examined on all sides of the wire, and thus the serious reduction in the section of the wire could be noted;

(d) the fact that several outer wires had been broken before the accident and that protruding broken ends of those wires had become wrenched off in subsequent service;

should have been obvious to all persons who had any responsibility for the examination of ropes.

The complete absence of protective rope dressing was a contributing factor to the severe corrosion.

 

A copy of this report was kindly donated by
West Cumbria Mines Research.