Hoek's Corner
http://www.rocscience.com/hoek/Hoek.asp
Free downloads of Dr. Evert Hoek's Practical Rock Engineering (2007 ed.), a vital reference tool for engineers working in rock, a collection of Dr Hoek's published papers in PDF, and a 2D Stress Analysis for Underground Excavations - Examine^2D, a very fast two-dimensional indirect boundary element program for calculating stresses and displacements around underground and surface excavations in rock.

British Tunnelling Society (BTS)
http://www.britishtunnelling.org/

The Geological Society of London
http://www.geolsoc.org.uk

International Association for Engineering Geology and the Environment (IAEG)
http://www.iaeg.info/

International Society for Rock Mechanics (ISRM)
http://www.isrm.net/

International Tunnelling Association (ITA-AITES)
http://www.ita-aites.org/cms/

MiningLife and Miners Toolbox
http://www.mininglife.com/Miner/index.htm

Norwegian Tunnelling Society
http://www.tunnel.no

Tunnel Builder
http://www.tunnelbuilder.com/

Tunnelling and Underground Construction Society (Singapore) (TUCSS)
http://www.tucss.org.sg/