Acoustic evaluation of rock quality

107A mltter More experimental data is being collected, and more sophisticated processing techniques applied.

853374 Gravity profile and its role in positioning the edge of a twodimensional faulted structure having an arbitrary vertical

853369

variation of density

Measurements of earth attenuation from downimle and surface seismic recordings

Geophysics II49, N7, July 1984, P1097-1104

Ralkes, S A, White, R E

Geophys Prospect II32, N5, Oct 1984, P892-919 This paper considers, from a theoretical viewpoint, the attenuation ofcompresstonal waves from surface and downhole seismic recordings It attempts to remove or compensate for all sources oferror and finally concludes that there are too many uncertainties m attenuation determination over small depth intervals for it to be a useful diagnostic tool for identifying hthography

Paul, M K, Goodacre, A K It ~s shown analytically that the value of gravity at any point on the upward extension of the fault is constant, provided that there is no lateral variation of density Th~s result leads to a direct method of grawty interpretation to delineate the edge of a faulted structure The method has been theoretically verified and also apphed successfully to two sets of real data 853375

Acoustic jack to assess in situ rock behaviour 853370 Time-domain electromagnetic soundings at the Nevada Test Site, Nevada Fnschknecht, F C, Raab, P V

Geophysics V49, NT, July 1984, t)981-992 Short-offset TDEM mvest~gatlon was used w~th frequency domain electromagnetic and Shlumberger res~suwty methods to assess the smtabd~ty of the Yucca Mountain area, Nevada Test Site, for radioactive waste &sposal The work demonstrated that short offset TDEM was effective m th~s area, where lateral vanauons m reslsuv~ty made the apphcatlons of other geoelectncal methods difficult The mhomogeneous first layer gave little response in cases where deep layers affected TDEM results The TDEM method used is, however, not very sensitive to small lateral features, and care must be taken m interpreting results Short offset TDEM may not be the most suitable techmque under &fferent geological con&Uons 853371

Method of determining a preferred P-wave velocity profile in a borehole using surface explosions Wright, C, Huang, C

McElroy, J J, Koerner, R M, Lord, A E

lnt J Rock Mech Min Sci V22, N1, Feb 1985, P21-29 An overview of the technique that uses acoustic emission (AE) monltonng m conjunction with a borehole rock jack, which pressunzes the borehole walls and momtors both the induced deformation and the AE activity A description is given of the test eqmpment and procedure, the results of tests and their interpretauon and concludes with observations and recommendaUons for further studies

853376 Growth and development of microseismics applied to ground control and mine safety Leighton, F

Min Engng I"35, N8, Aug 1983, P1157-1162 The pnnclples and apphcatlons of mlcroselsmlc methods for warning and pre&ctlon of failures are discussed. Illustrated examples of single and multlchannel systems are described and problems m their usage hsted. 853377

Geophysics V49, NT, July 1984, P1041-1050

Role of seismic surveying in coal mining exploration

The crystal-cable well survey technique, using hydrophones suspended m deep boreholes and surface explosions, is examined mathematically An lterative method is used to determine relative time correction for the shots and a family of velocity-depth profiles is calculated for data windows of dlfferent lengths, using the method of summary values

Min Sci Technol V1, N4, Aug 1984, P253-267

853372

Synthetic full waveform acoustic logs in cased boreholes Tubman, K M, Cheng, C H, Toksoz, M N

Geophysics 1/49, N7, July 1984, P1051-1059 Synthetic mlcroseismograms are calculated for the case of a central fluid cyhnder surrounded by an arbltrary number of solid annuh The model used is general but the geometries considered are restricted to those of a cased hole, with steel, cement and formatlon surrounding the hquld 853373

Microgravimetric and gravity gradient techniques for detection of subsurface cavities Butler, D K

Geophysics V49, N7, Juh' 1984, P1084-1096 M~crogravlmetnc and gravity gradient techniques were applied to previously surveyed sites Mlcrogravimetry detected a shallow. complex, air-filled cavity system and denvauve techmques produced a residual grawty map and delineated complex subsurface structures A deeper, water-filled cavity was also detected, but shallow features tended to mask those at depth and so it was not possible to produce a 3D model of subsurface structure using this technique

Goossens, R F, Buchanan, D J High resolution surface selsm~c techniques, gwlng valuable mformation on geological structure, have been augmented by recently developed in-seam seismic methods, applied underground on the coal face itself Small faults ahead of the face, undetectable from the surface, can now be detected Seismic methods and dnihng data enable a 3-D geological model to be constructed. Illustrated examples demonstrate the value of seismic surveying in mine planning

853378 Acoustic evaluation of rock quality Quarry Manage Oct 1984, P665-667 CIRIA have carried out work to produce a portable instrument to charactense rocks m terms of an overall rock engmeenng quahty Preliminary work showed attenuation of seismic shock waves to be a useful m&cator of rock quality and spectral analysis was used to examine the relative attenuation of &fferent types of wave Evaluation of data collected at an open coal mine suggests that it should be posslble to develop predictor equations for incorporation into the designs of microprocessor based instruments for on-site use

P r e s e n t a t i o n and interpretation o f data

See also 853113, 853294