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|Stress has a significant effect on the stability of pillars. In order to get an accurate picture of pillar stability, one needs information not only on the primary Stress distribution but also on all the Subsequent Stress changes as time passes. Sonic methods are some of the fastest, most economical and least destructive means of stress prediction. The wave propagation velocity has long been applied to the investigation of the upper mantle and crust stress. Recently, it has also been applied to the prediction of rock bursts and to mine site investigations. Another parameter for investigating stresses in rocks is the attenuation coefficient. Attenuation has been observed to be more sensitive to stress changes than wave velocity; however, the measurement of attenuation is more difficult than that of wave velocity. In this paper, the mechanism of sonic attenuation in rock is reviewed. Both the velocity and the attenuation of sound waves in five different rock types under various stress fields were examined in the laboratory. It was found that for a specific rock type the relationship between the velocity ratio and stress, as well as that between the attenuation coefficient ratio and stress, can be expressed by simplified second order polynomial equations.Research showed the attenuation coefficient to be more sensitive to stress change than the velocity ratio. A field investigation method was proposed using a Schmidt hammer as a repeatable energy source. Initial trials appeared to show that monitoring by the wave attenuation method gave more repeatable data than monitoring wave velocity.|
Additional chapters/articles from the SME-ICGCM book Proceeding of the Fourth Conference on Ground Control in Mining (ICGCM)
|Truss Bolting On-Cycle in Jane Mine Lower Freeport Seam||Design Of A Roof Truss Bolting Plan For Bear Mine||Tension-Torque Relationship For Mechanical Anchored Roof Bol||A Novel System For Automatic Installation Of Cement Grouted||Load Transfer Mechanics In Fully-Grouted Roof Bolts||An Investigation Of Longwall Pillar Stress History||Impact Of Horizontal Load On Shield Supports||Interaction Between Roof And Support On Longwall Faces With||Roof Control With Polyurethane For Recovery Of Kitt Energy?s||First Caving And Its Effects--A Case Study||Staubbekampfung An Schildausbau In Bruchbaustreben (Combatin||Yield Pillar Applications--Impact On Strata Control And Coal||Constraint Is The Prime Variable In Pillar Strength||Massive Pillar Failure--Two Case Studies||Investigations Of Underground Coal Mine Bursts||Destressing Practice In Rockburst-Prone Ground||Statistical Characterization Of Coal-Mine Roof Failure: Sugg||Pillar Design - Continuous Miner Butt Section And Longwall D||Design Factors In Near-Seam Interaction||Remote Sensing For Roof Control And Mine Planning: An Overvi||Design, Construction And Performance Of A Single Pass Lining||Computer Modelling And In Situ Instrumentation Techniques: A||A Sonic Wave Attenuation Technique For Monitoring Of Stress||The Radio Imaging Method (RIM) -- A Means Of Detecting And I||Clay Veins: Their Physical Characteristics. Prediction, and||Evaluation of the Point Load Strength for Soft Rock Classifi||Ground Control Experiences in a High Horizontal Stress Field||Horizontal Stresses and Their Impact on Roof Stability at th||Ground Control Problem Associated with Longwall Mining of De||Geotechnical Aspects of Subsidence over Room and Pillar Mine||Proposed Criteria for Assessing Subsidence Damage to Surface||Surface Subsidence. in Longwall Mining--A Case Stud||An Integrated Approach to the Monitoring and Modeling of Gro|