When T&TI selected ‘hand mining and the alternatives’ as a subject worthy of examining, we were aware of the issue of HAVS (Hand-Air Vibration Syndrome) associated with powered hand mining tools, but were perhaps unprepared for the fact that many attitudes on the subject were still firmly routed in the battles around the turn of the millennium between health and safety officials on one side and contractors on the other.
Our intention was to examine what improvements had been made in power hand tools, if any, and what mechanized methods could be adopted to carry out the same or similar work.
Bearing in mind the economics of modern tunnelling, hand mining is usually restricted to excavations of small dimensions, or to the enlargement of transport tunnels by small-scale, peripheral excavation. Any alternative to hand mining should be able to carry out such tasks with equal or improved efficiency as well as safety. However, we have also heard of at least one instance in mining in Africa when a drill jumbo used for a major development tunnel was dropped in favour of multiple air-leg compressed air drilling on the grounds that it was cheaper and gave fewer maintenance problems.
Due mainly to the location of work, HAVS is not the only heath and safety issue associated with hand mining; others include ventilation, working close to mobile machinery, heavy handling and noise, the last often being associated with vibration. Even mechanised tunnelling can have issues with whole body vibration through inadequate seating and other working positions.
Examination of the subject has revealed several anomalies in opinions including, surprisingly, whether HAVS is actually a problem in tunnelling. This is not helped by a lack of records specific to the industry, despite vibration-related health issues being a popular subject for researchers across industry and non-industrial activities. Also it is usually a requirement in health and safety law to monitor exposure to hazards, with recommendations to screen workers before, during and after exposure in much the same procedure as used for compressed-air working.
However the fact that HAVS is a hazard, i.e. a potential danger, is not generally in dispute, with evidence of long-term or intensive exposure causing damage to the hand and arm circulation and joints. This assertion is based on wide industrial use of powered hand tools, most having different vibration levels and modes of use. Most of the ‘horror’ pictures first displayed when HAVS became a concern in tunnelling are understood to be related to shipbuilding and boiler-making riveting. On the other hand there have been compensation cases proven on HAVS issues in related activities such as road-breaking and coal-mining. Some other industrial tools that could be hazardous, such as grinders, are also occasionally used in tunnelling.
Even those contractors forward-thinking enough to try alternative, mechanized means of small-scale excavation report difficulties in persuading miners to try alternatives to the power-tools with which they are familiar, such as the CP FL22 and Hauscherr ‘German jigger’. Some of this attitude stems from inadequate information on the different mode of operation of the latest equipment, but also, presumably, to ‘being happy in their work’.
Contractors also claim that the intermittent use of power hand-tools in tunnelling makes the industry some sort of special case. However, in the past there have been cases of virtually continuous use of power hand-tools, especially in manual pipe jacking. This allows contractors to also claim that there are no cases of HAVS, or ‘white finger’ due to tunnelling, at least not from working in soft ground. Again this is disputed by the health and safety authorities who say that intermittent use has been taken into consideration in the regulations.
Donald Lamont, former HM principal specialist inspector at the UK Health & Safety Executive comments, “I understand how this thinking comes about as the use of vibrating tools in tunnelling is now on an intermittent basis, however the limits are set out in the Control of Vibration at Work Regulations 2005. Further dose/response studies funded by the tunnelling industry would not be cost effective.”
Hopefully the series of articles in this review will throw some further light on the subject because, despite the great efforts of co-operation between various bodies in the tunnelling industry in producing guidelines, there are still great differences in actual practice and attitudes, and what is written down on paper.
Clearly there is still work to be done, in more ways than one, presumably there is money in it; so is it worth it? Give T&TI your opinions and experiences, and how you think the industry should reach a position on the subject that all are content with. Write a letter or email the editor on:
editor@tunnelsandtunnelling.com.
Raynaud’s Phenomenon, or ‘White Finger’ is the most recognisable symptom in HAVS patients
