Research into the safety and efficiency of underground placer mining and frozen ground

Research into the safety and efficiency of underground placer mining and frozen ground

Huang, S.L.

Date: 1983-09

Publisher: University of Alaska Mineral Industry Research Laboratory

Type: Technical Report

Table of Contents: Abstract -- Acknowledgement -- Table of contents -- List of figures -- List of tables -- I. Introduction -- II. USA CREEL permafrost tunnel -- History -- Tunnel geology -- Silt -- Gravel -- Bedrock -- Ground ice -- III. Field instrumentation and monitoring -- Instrumentation -- Monitoring -- Air temperature -- Ground temperature -- Creep deformation -- Strata separation -- IV. Laboratory creep tests -- Theory -- Creep -- Strength -- Cold laboratory facility -- Specimen preparation -- Testing procedures and results -- V. Conclusions -- References -- Appendices.

Abstract:

Some of the underground excavation problems encountered in arctic and subarctic environments associated with thermal disturbance are excessive settlement of ground surface and pronounced displacement around openings. This study investigated the possible links between the significant settlement. Ground temperature was found to be the most influential. An empirical equation was developed for the USBM gravel room to predict the effect of temperature on creep of frozen gravel. Separation of the roof gravel and silt was observed as steady heating process increased the gravel temperature by one degree. The temperature dependent material constants were estimated from the laboratory testings. The factors affecting the creep characteristics were temperature and applied stress level. The primary creep behavior of frozen gravel loaded under 18% of unconfined compressive strength at 25° and 29° could be predicted empirically.

Show full item record