Loss of corporate memory in a fast-changing industry with high staff turnover remains a serious problem, says Geoffrey Walton.
Thank you for the articles on the Aberfan Disaster. There was much to agree with in both articles, but also more that could have been said. The beneficial impact in terms of improvements in professional practice has not been as widespread internationally as it should have been starting with the collapse of a colliery refuse dam at Middle Fork, Buffalo Creek in West Virginia in 1972 when 125 people were killed and over 1,000 injured. As outlined in the excellent Engineering Group Memorial Lecture on 18 October, similar coal and mine waste tip failures continue to occur internationally.
They also continue to occur in Britain a recent significant failure of discards tip taking place in February 2013 at Hatfield Colliery. In the Ansel Dunham Memorial Lecture ‘Aberfan and After’ given at this September’s Extractive Industry Geology Conference at Birmingham University, Dr Alan Cobb explained how the Hatfield Colliery tip failure disrupted and closed a 4 track main railway line. A disaster was averted by Network Rail’s safety system working properly when the tip failed along a 260m length of tip flank and moved up to 70m beyond the toe of the tip.
There had been no accurate survey of the tip, no design, no stability analysis and the latest tip report was more than 6 months out of date. So much for failing private sector safety systems – thank goodness it was not Rail Track! Those who advise or are employed in geotechnics by the surface mining and quarrying sector in Great Britain now work with the Quarries Regulations 1999 which are more demanding and explicit in their requirements than those of the 1971 Regulations. However, even with continuous and on-going monitoring and investigations, some problems still occur.
Alan Cobb also outlined in his talk the precursor events in and near Aberfan and especially the three flow slides that were identified as having taken place previously. Two of these took place at Aberfan as noted in your Tipping Point article namely at Tips 4 and 7 in November 1944 and November 1963, but were not recognised as such and the first occurred near Abercynon in December 1939. This latter flow slide which travelled down the eastern side of the Taff Vale, further down-stream, crossed the main road, a canal, a railway and the River Taff which it slightly diverted. No-one was killed and the then owners Powell Duffryn prepared a detailed report which set out future tipping arrangements to avoid such problems. The war and nationalisation intervened and although the report was still ‘in the system’ no one paid attention.
This represented then, in 1966, and remains to this day a problem of ‘corporate memory’. It is particularly a problem with an industry that changes rapidly with closures, take-overs and the like, especially if they are failing financially. More often than not senior management on the geotechnical side are ‘retired’ or given a part time consultancy role, when they may be the only repository of knowledge of past events. It behoves the Engineering Group of GSL and other professional interest groups such as the IMMM and the EIG to publish key information on these and other things that go wrong, for future use. So often this is frustrated by companies and lawyers seeking to hide or delay matters being made public – often using litigation or gagging measures to prevent employees, consultants and others from publishing precautionary advice.
One may seek to criticise the Aberfan Tribunal’s work by today’s standards, but it blamed and severely criticised the NCB, it was technically sound, relevant and moreover it was made public promptly. No one should underestimate the valuable scientific work done by Prof Alan Bishop of the Department of Civil Engineering at Imperial College in assessing the causes of instability for the Tribunal. The Engineering Group and the Society should also be proud of the work done subsequently by Dr Roy Taylor of the engineering geology section of the Department of Geology at Durham University (who was active in the Group) on the engineering properties of colliery discards.
In spite of the horrors for those involved in the disaster, the event changed the lives of many geo-professionals, often beneficially and certainly of those living and working near these structures across the country. We should be grateful to those who investigated the causes and controls of slope instability following the disaster. Perhaps we should more actively seek to thwart those who aim to prevent the spread of enlightenment in geotechnics and other areas of geoscience practice.
Geoffrey Walton