Application of the results of excavation response experiments at climax and the Colorado School of Mines to the development of an experiment for the underground research laboratory

Large-scale underground experiment programs to examine excavation response have been performed at the Climax facility in Nevada and at the Colorado School of Mines. These two programs provided fundamental information on the behavior of rock and the effects of excavation; on instrument performance and configuration; and on the relationship between test geometry and test behavior. This information is being considered in the development of a major excavation response experiment to be carried out in the Canadian Underground Research Laboratory. 11 refs., 3 figs

PRELIMINARY REPORT ON GEOPHYSICAL AND MECHANICAL BOREHOLE MEASUREMENTS AT STRIPA

Four different systems of borehole instrumentation have been employed thus far at an experimental site at Stripa, Sweden where a series of hydrological and thermo-mechanical experiments are being conducted to examine the suitability of granitic rock for the storage of radioactive waste materials. Asuite of seven logs--neutron, gamma-gamma, resistivity, gamma ray, sonic, caliper, and temperature--operated in a borehole of 380-m depth located eleven zones where the rock permeability is expected to be enhanced due to the presence of open fractures. The sonic waveform record proved especially useful in this regard. Borehole measurements were also acquired in a large number of boreholes from 5- to 14-m length located in experimental drifts some 340-m underground. Here several physical properties, including the porosity, density, sonic velocity, and borehole rugosity, are generally quite uniform, with the exception of a few local chloritic zones and a few minor fractures. However, in situ determinations of the mechanical modulus with the CSM cell indicate substantial variability, with some apparent fracture control. Uranium and thorium concentrations are quite high in the Stripa granite, with local fluctuations associated with mineralogical changes as revealed by the gamma-ray log. Adifferential resistance probe appears promising as a sensitive detector of fine fracturing. Across-hole ultrasonic system indicates variations of a few percent in compressional- and shear-wave velocities, reflecting the presence of fractures and changes in fracture characteristics as the rock is heated in a simulated storage test. The geophysical and mechanical data are being compared with the results from core and television logging, with hydrological test data on static pressure and injection permeability, and with displacements induced by thermal loading

An evaluation of some innovative fragmentation systems for oil shale

This report describes a large-scale underground mining method, large-hole stoping, using some innovative fragmentation systems (buffer blasting, continuous loading/hauling, and mechanical miners for development). This study includes a literature review and an experimental study of one of the key design factors--buffer blasting. The purpose of the buffer-blasting experiments is to examine the swell that is necessary to achieve satisfactory fragmentation results. The study also includes a technical and economic evaluation of the new mining method compared with conventional room and pillar mining. The purpose of this study is to examine innovative methods that exist today and may provide a more efficient mining system than that currently used. Note that this is a conceptual study, and that the mining for the two mine designs were compared using a daily production rate of 75,000 tones per day. This amount was chosen because it is the maximum amount possible for a rubber-tired room and pillar operation with only a one-shaft complex