Introduction: L.L K. Daemen: Background; Sealing Requirements - Rules and Regulations; Current Practice; Recent Borehole Sealing Research - An Introductory Overview; Sealing of Shafts, Tunnels, Mine Adits, Portals and Drifts; Book Summary; The Future. LABORATORY PERFORMANCE OF CEMENT BOREHOLE SEALS, D.L. South and K. Fuenkajorn: Conceptual Approach; experimental Apparatus; Experimental Procedures; Analysis; Summary of Test Results; Design implications; Acknowledgements. STRENGTH PARAMETERS OF CEMENT BOREHOLE SEALS IN ROCK, H. Akgun: Introduction - Push-Out Test Experimental Procedure; Push-Out Test Mechanical Interactions; Finite Element Analysis and Discussion; Push-Out Test Results and Discussion; Conclusions and Recommendations. DYNAMIC LOADING IMPACT ON CEMENT BOREHOLE SEALS, G.S. Adisoma: Experimental Methods; Flow Test Results; Dye Injection Test Results; Dynamic Loading Test Results; Design Considerations. PERFORMANCE AND DESIGN OF BENTONITE AND BENTONITE/CRUSHED ROCK SEALS, S. Ouyang and J.J.K.Daemen: Materials; Permeability Tests and Results; Piping and Flow of Bentonite; Prediction of Bentonite Permeability; Conclusions and Recommendations. IN-SITU PERFORMANCE OF CLAY-BASED BARRIER, Kjartanson, N.A. Chandler and A.W.L. Wan: The Canadian Nuclear Fuel Waste Management Program; Evaluation of Buffer Physical Performance; In-Situ Experiments; Buffer/Container Experiment; Isothermal Test. PERFORMANCE TESTS OF CEMENT BOREHOLE SEALS: PROCEDURE AND ANALYSES, W.B. Greer: Proposed Test Scheme; Seal Tests. IN-SITU HYDRAULIC PERFORMANCE OF CEMENT BOREHOLE SEALS, W.B. and D.R. Crouthamel: Preliminary Survey for Seal Installation; Seal Test at Oracle Ridge Mine; Discussion of Testing at Oracle Ridge Mine; Seal Testing at Superior, Arizona; Recommendations for Testing In-Situ Borehole Seals. SEALING BORFHOLES IN ROCK SALT, J.C. Stormont and R.E. Finley: General Practice in Sealing Boreholes in Rock Salt; Rock Salt Properties Relevant to Borehole Sealing; Materials for Sealing Boreholes in Rock Salt; Seal System Performance; Design Considerations. DESIGN OF UNDERGROUND PLUGS , F.A. Aulud: Types of Plugs; Factors to. be Considered in Design of Plugs; Design Calculations; Construction Aspects; Plug Sealing and Resistance to Leakage; Case Studies; Conclusions and Recommendations. DESIGN OF BOREHOLE SEAL PROCESS CRITERIA AND CONSIDERATIONS, K. Fuenkajorn and J.J.K.Daemen: Applications, Objectives and Requirements: Considerations of Site Characteristics; General Design Criteria; Material Selection and Placement Methods. SODIUM BENTONITE AS A BOREHOLE SEALANT, J.E. Papp: Geographic Origin; Geologic Origin; Structure of Sodium Bentonite; Properties of Sodium Bentonite; Bentonite as Borehole Sealants; Bentonite as an Annular Sealant; Types of Bentonite Sealants; Placement of Bentonite; Case History Featuring High Solids Bentonite Grout.