How can we rock mechanics and rock engineers contribute to the development of a better environment and better use of our finite and renewable resources? These were questions many of us asked ourselves before arriving to this Symposium and the wonderful city of Lisbon. After four days of intense program where we have been listening to keynote lectures, general reports of written contributions, presentations of individual papers, workshops, and lively discussions we are convinced that we have important safety and environmental issues to assess to the society. The general environmental issues have been i focus for quite some time now, but it is obvious that they start to enter more and more our specialisation. As we meet for the first time at an international symposium that is specially addressing the environmental and safety issues in rock mechanics we are in a stage of transition. We have been listening to contributions that can be looked upon as traditional rock mechanics but they fit in to the overall scope of the Symposium. The contributors are well aware of the environmental issues and they like to demonstrate how rock engineering contributes to the safety and environmental issues. The other group of contributions are those addressing new environmental issues to rock engineering. To illustrate this statement two examples from the written keynote lectures to the Symposium will be used. The paper by Hönisch about "Conclusions drawn from 100 constructed power caverns for future planning" gives design experience and design rules from constructed power caverns from various parts of the world. The compilation of data could have been presented at any rock engineering conference but Hönisch extracted the interesting data about safety and environmental issues and presented to us. As an example of a direct application of rock engineering to environmental issues I would like to refer to the study" Tunneling under an industrial waste landfill in Italy: Environmental controls and excavation procedure" by G. Barla and P. Jarre. The authors demonstrated the environmental impact and assessments to a rock engineering construction and the contribution illustrated the strong need for a better and deeper knowledge in rock chemistry as we start to tackle this kind of problems. The 1993 ISRM International Symposium on Safety and Environmental Issues in Rock Engineering consisted of four themes:
1. Modelling in Safety Evaluation
2. Influence of the Environment in Rock Engineering
3. Stability of Large Underground Structures
4. Contribution of Failures and Incidents to theProgress of Rock Engineering Modelling in Safety Evaluation To demonstrate to the public the long-time safety, stability and performance of rock engineering structures we need the tool of mathematical modelling. At the first theme of the Symposium only 4 contributions of totally 32 were dealing with modelling for safety evaluation. Seven contributions were addressing the important aspects of verification and validation of computer codes for rock engineering applications. In the field of verification and validation of numerical techniques and computer codes we can learn from the hydrologists and hydrogeologists.