The International Society of Rock Mechanics has been in existence for almost 25 years and the South African National Group has been a member for much of that time. It is believed that an increased knowledge of the activities and objectives of individual National Groups could further the understanding and community of interest that the parent society seeks to promote. With this purpose in mind, the size and structure of rock mechanics practice in South Africa is briefly reviewed. This gives an indication of the main problems in hard- and soft-rock mining and in surface and sub-surface civil engineering and the emphasis and approach which is adopted in theae areas.
La Societe Internationale de Mecanique des Roches existe depuis presque 25 ans et le Groupe National sud-africain en est un membre pendant beaucoup de ces annees. On croit qu'une connaissance augmentee des activites et des objectifs de chaque groupe national pourrait augmenter l'entendement et la solidarite d'interêts que la societe paternelle quête d'avancer. Ayant cet Objectif en vue, on examine en bref la dimension et la structure de mecanique des roches en Afrique du Sud. Cette communication donne une indication des problèmes principaux en exploitations minières des roches dures et fragiles et en genie civil de surface et souterrain et l'insistance et la methode que l'on adopte dans css domaines.
Die ‘Internationsl Society of Rock Mechanics’ besteht seit nahezu 25 Jahren, und die ‘South African National Group’ ist seit geraumer Zeit Mitglied. Es besteht die Meinung, dass ein besseres Wissen um die Arbeit und die Ziele der einzelnen ‘National Groups’ Verstandnis und gemeinsame Interessen, wie sie von der Muttergesellschaft angestrebt wird, fördern könnte. Im Hinblick hierauf werden Umfang und Struktur angewandter Felsmschanik in Suedafrika kurz betrachtet. Daraus ergibt sich ein Umriss der Hauptprobleme beim Abbau harten und weichen Gesteins, und im Hoch- und Tiefbau, sowie der Zweckbetonung und der Zielrichtung, die auf diesen Gebieten verfolgt werden.
The profession of rock mechanics is a relatively small, specialized community which has perhaps a disproportionate responsibility for the safety and the welfare of the society in which it functions. Its Working environment is the earth's crust which can be both hostile and unforgiving of error. Tectonic processes from time to time cause the largest natural disasters. However, inadequate understanding of even its more quiet moods can result in design errors which may lead to incidents causing major loss of life. This great responsibility requires that the profession should draw closer together in the search for improved understanding. International congresses are expressly intended to provide opportunities for the sharing of knowledge and the strengthening of bonds of professional friendship. It is with the hope of encouraging this process that the South African National Group on Rock Mechanics (SANGORM) presents the following description of its structure and a brief outline of the areas of interest of the main groups which make up its membership.
At the time of writing, the total individual membership of SANGORM was 333, in addition to which there are three institutional bodies who are supporting members of the ISRM. South Africa is a country rich in mineral resources with an economy which is, to a large extent dependent on their exploitation. Gold is the largest single contributor with much of the production coming from deep mines with many rock mechanics-related problems. Consequently it is perhaps not surprising that two-thirds of the membership of SANGORM are directly involved with mining. The great majority of these (80 %) are based on the Gold Mines while most of the remainder are from the Coal Mining Industry. Civil Engineers and Engineering Geologists represent the next largest group, together making up 22 % of the total membership; while the remaining 12 % includes people from universities, research organizations and other geotechnical activities. Figure 1 analyses the mining-related membership of SANGORM, together with information on the revenue derived from the various mining activities.
The total annual SA gold production of 610 metric tons comes from some 30 mines which together process 106 million metric tons of ore, hoisted from mining depths of as much as 3 500 m. On occasions however, rockmass instabilities can lead to rockbursts; the sudden and violent collapse of part of this fractured rock or closure of the excavations. These rockbursts, together with simple gravity-driven falls of ground, are responsible for a large proportion of the accidents occurring in the mining environment. The occurrence of rockbursts is perhaps the most pressing problem at this time. To alleviate this hazard, improvements are being made to methods of mining, to the design of excavations and their layouts and to methods of supporting the fractured rock. Furthermore, fundamental research is being carried out to obtain a better understanding of the causes of unstable rock behaviour.