Underground infrastructure development. Underground facilities of special character. Types and uses of underground structures – selected case studies. Underground space development and future trends – advantages and disadvantages. Environmental importance of underground development. Modification of mining techniques for the development of underground installations. Design of underground structures using modified room-and-pillar mining method. Design of large underground rock caverns. Development strategies for mined spaces. Cost analysis of underground works. Cost-benefit assessment of underground facilities. Environmental valuation of underground space development.