This report identifies tunnel locations, explores risks associated with tunnels, and presents tunnel closure alternatives. This was achieved by: ' Compiling site background information, such as geology, land use, and climate conditions ' Collecting information on location, extent, and current conditions of each tunnel by performing a field assessment survey, a geophysical investigation, and radiological assessment, and review of previous studies ' Categorizing the tunnels based on risk ' Proposing closure alternatives suitable for each tunnel category ' Providing cost estimates for typical tunnel closure using the proposed closure alternatives ' Proposing requirements for post-closure care The purpose of the report is to provide enough information so a tunnel closure design can be easily developed, if a decision is made to close a specific tunnel.