Geotechnical aspects of development over reclaimed former alluvial mining land and ponds in Malaysia

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SITE INVESTIGATIONS:GEOPHYSICS

vals to measure settlement, and the practicability of photogrammetric means. -from English summary

aim of finding a solution to the reclamation of slime filled mine ponds. -from Authors

Geophysical techniques Structural and geotechnical mapping 943179 Rock slope design in extremely tectonically deformed opencast coal sites C. P. Nathanail, in: The engineering geology of weak rock. Proc. conference, Leeds, 1990, ed J.C. Cripps & others, (Balkema; Engineering Geology Special Publication, 8), 1993, pp 415-421. The geotechnical behaviour of an extremely tectonically deformed rock mass is intermediate between those of intact material and individual discontinuities. Detailed engineering geological mapping, back analysis of existing slopes and rock mass classification both before and during excavation are essential in ensuring a safe and economic batter design. Subdivision of a site into structurally similar domains should be carried out in a consistent and objective way. Eigenvalue ratios can be used to verify this zonation. -Author

943180 Investigations for cooling tower foundations in Mercia mudstone at Rateliffe-on-Soar, Nottinghamshire R . L . Seedhouse & R. L. Sanders, in: The engineering geology of weak rock. Proc. conference, Leeds, 1990, ed J.C. Cripps & others, (Balkema; Engineering Geology Special Publication, 8), 1993, pp 465-471. Strengthening of two cooling towers at Ratcliffe-on-Soar Power Station, near Nottingham, required detailed ground investigation for assessment of existing foundations and design of foundation strengthening. Ground conditions comprised Mercia Mudstone, overlain by made ground. The ground investigation included percussion and rotary cored boreholes and in situ high pressure dilatometer testing to determine as reliably as possible the mechanical properties of the Mercia Mudstone. Extensive dynamic probing was also undertaken to determine the thickness of made ground and the extent of the existing foundations. Investigations revealed the degree of weathering and a site specific weathering classification was devised and engineeringpararneters were assessed for each weathering grade according to the percentage of clay infill and fresh mudstone. Two alternative foundation schemes were prepared using either mini-plies or burettes. -from Authors

943181 Geotechnical aspects of development over reclaimed former alluvial mining land and ponds in Malaysia E. B. Yeap, B. K. Tan & W. S. Chow, Journal of Southeast Asian Earth Sciences, 8(I-4), 1993, pp 573-586. Mining of tin placers in Quatemary alluvium is the main type of mining activity in Peninsular Malaysia carried out over the past 100 years. Worked out mines have left behind a landscape consisting of highly inhomogeneous tailing fiU and numerous large and medium size ponds often underlain by thick slurries of fine clay a n d silt on limestone bedrock. Rapid urbanization around the two main tin mining areas has led to the use of this previously mined land for residential, commercial and industrial purposes. Soft slime trapped during tailing deposition or during reclamation has caused numerous and often irreparable damage to houses built on former mining land. Characterization studies were undertaken on two ponds for their chemical, pnysical, mineralogical and engineering properties with the

943182 Rock mechanics in the 1990s: geophysical properties of rocks ed B. C. Haimson, International Journal of Rock Mechanics and Mining Sciences, 30(7), 1993, pp 751-808. These papers were originally presented at the 34th US Symposium on Rock Mechanics, June 1993. The 9 papers in this section include the following topics: compressional shear velocity in sedimentary rocks; shear wave attenuation; induced seismicity analysis; critical porosity; stress anisotropy effects; and acoustic emission analysis for site characterisation. -R.Gower

943183

Cavitation-induced seismic events caused by

small explosions in boreholes R. Fisher, I. M. Mason & C. C. Mosher, Geophysics, 58(11), 1993, pp 1565-1572. An electrolytically recharged sleeve exploder was fired at depths between 15.2 m and 51.8 m in a 200-ram diameter, steel-cased, water-filled shallow borehole in Hopkins County, Texas. Oxy-hydrogen explosive gas charges were varied between 30 and 170 kJ. Seismic traces revealed three distinct, delayed, anomalous arrivals. Two of these moved out nonlinearly with increasing charge. The anomalies appear to stem from the coUapse of cavities that are created by shock waves. The potentially destructive effects of implosion can be avoided by p l u g g i n g the borehole mouth before shooting in an uncased borehole. -from Authors 943184 Electrical response of two-phase soil: theory and applications

S. Thevanayagam, Journal of Geotechnical Engineering ASCE, 119(8), 1993, pp 1250-1275. A general frequency-domain solution for electrical response of two-phase dilute (high porosity) soil is presented. Tensorial character of the response in terms of dielectric constants as well as the resistivRies of the constituents is illustrated. For transversely isotropic soils a single measurement at 55" to the axis of symmetry can predict scalar parameters such as porosity of soils or conductivity and dielectric constant of particles. Under special cases the results reduce to some well-known relationships. Important characteristics of the dielectric formation factor are highlighted. Effects of particle concentrations on the electric response are introduced. The semitheoretical solutions taking into account the effects of particle concentrations do not deviate very much from the solution based on dilute particle arrangement. Beneficial effects of clay-water interaction of dielectric response are discussed. Applicability of the theory is examined using experimental data. -Author

943185 Application of spectral gamma-ray logging to low-level radioactive waste management studies at Port Hope, Ontario, Canada P. G. Killeen, K. A. Pflug, C. J. Mwenifumbo, R. L. Zelmer & B. A. McCallum, Nuclear Geophysics, 7(4), 1993, pp 501-514. The Geological Survey of Canada R&D logging system was used to make borehole geophysical measurements at the Port Hope landfill site for the Low-Level Radioactive Waste Management Office of Atomic Energy of Canada Limited. The objective was to assess the applicability of using borehole investigation methods to characterize lowlevel radioactive waste. Gamma-ray spectral logging was found to be a useful measurement for this application. A