141A

883300 Complex slope failure in a highly weathered reck mass Irfan, T Y; Koirala, N; Tang, K Y Proe 6tk intematioul Conferemce on Rock MeelmMes, Montreal, JO Amg-lO Sept 1957 V1, 1'397-402. Pubi Rotterdam: A A Balkema, 1987

A 37m high cut slope in highly weathered rock underlying a colluvial mantle has shown continuous instability. A detailed monitoring and mapping programme was begun in 1983 fol- lowing large scale shearing. The weathering pattern, disconti- nuity pattern, hydrogeological conditions, groundwater table and mode and mechanism of failure are described, using detailed diagrams. The case history shows that detailed knowl- edge of stress history and weathering effects are necessary for slope design.

883301 Evaluation of hearing capacity of foundation ground and stability of long slope for weathered granite Ishikawa, K; Miyajima, K; Yamada, K; Yamagata, M Proc 6tk lntermai~al Confereoce on Rock Meelwauics, Montreal, 30 Amg-lO Sept 1957 V1, P403-406. Publ Rotterdam: A A Balkema, 1987

Finite element analysis (FEM) is used to evaluate the bearing capacity and deformation characteristics of a weathered gran- ite. Results correlate with field values. The stability of a 70m high cut slope in granite is studied using elastic FEM which shows that the slope as a whole is stable,although there may be local instability in the fissure zone and loosened zone in the slope surface.

8833O2 Stability of the Flysch coastal slopes of the Adriatic Sea in the marie and eebmle eonditioas Jasarevic, I; Jurak, V Proc 6tk International Conference on Rock Meclumies, Montreal, 30 Ang-lO Sept 1957 VI, P411-418. Publ Rotterdam: A A Balkema, 1987

Stability of natural and artificial slopes in an area of Eocene Clastic Complex (fiysch) is analysed. The flyseh has a low per- meability. Ground water seeps down the plane between the flysch and the overlying material, which is a potential sliding plane. Grain size classification, triaxial and shear strength measured in the laboratory, and supplemented by in situ test data from borehole logging, SPT tests and shear strength of large blocks, were used to analyse slope stability. It is sug- gested that the model of an 'endless' long slope based on extended sliding planes is applicable. Natural slopes are found to be stable under static and seismic conditions, whilst artifi- cial slopes may be unstable due to, eg, irregular drainage or incorrect load distribution.

8g&103 Application of rock reinforcement and artificial support in mrface mines Martin, D C Proc 6th l n t e r ~ Conferc~we on Rock Meelmalcs, Montreal, JO Amg-lO Sept 1957 VI, P437-443. Pub/ Rotterdam: A A Balkema, 1987

Rock reinforcement and artificial support using rock anchors, rock bolts or dowels are becoming increasingly attractive as a viable technology for development of open pit mines. Both localised support and systematic pattern support can be used for significant reductions in mining costs through improved safety and increased slope angles. Considerations in installing artificial support in surface mines are discussed and case stud- ies are presented. Auth.

883304 Flexarsl backllag of haul rock - a poteatial fa l lm mode ia Ugh rock slopm: Nilsen, B Proc 6tl~ lstmmdmal Comfermce on Rock Meekmics, Momreal, fro Amg-lO Sept 1957 VI, 1'457-461. Publ Rotterdam: A A Balkema, 1987

Most methods to analyse rock buckling consider axial stress in 1 direction only. This is an oversimplification as tectonic stress may lead to a horizontal axial stress greater than the axial stress in the direction of dip. A stability analysis programme is outlined to study the probability of flexural stress in 2 perpen- dicular directions, based on a general method to analyse elas- tic, flexural buckling of rectangular plates. The application of the method to the Ortfjell mine, Norway, indicates a certain combination of geology, stress conditions and rock character must exist for fiexural buckling of hard rock to occur.

8833O$ Geetechaleal investigation of the s o / w a i l , Mt Whaleback pit - a case study - hew geetedhmlegy can pay its way MacFarlane, G A; Parker, R J; Swindells, C F Proc Large Open Pit M b ~ Comfert~e, Newmtm, October 1986 1'245-256. Publ Parkville: AuslMM, 1986

The study for the design of the south wall of the Mt Whale- back open pit iron ore mine, Western Australia, is presented. A comprehensive geological, hydrological, and geotechnical investigation was part of the study. Although the site investi- gation was expensive, it was economically justified when the increased recovery and minimum failure risk achieved by optimising slope design and reinforcement are taken into account.

883306 Smooth batters, fewer berms and eresion control: the keys to steeper slopes at Beegainvak McMahon, B K; Lye, G N Proc Large Opera Pit Mialmg Comfereoce, Newton, October 1956 P267-270. Publ Parkville: AuslMM, 1986

Rock mechanics investigations at the Paguna pit suggested that some major slopes would be stable at angles in excess of 50 deg if near-surface instabilities were controlled. Excavation of final batters at angles of 55-60m deg is now being attempted, with berms at 45-60m centres. A trial wall with berms at 90m centres is planned. Shotcreting of weak zones and crest reinforcement with dowels and anchors prevent against erosion and toppling of crests. These slopes are 10deg stceper than those excavated by blast and shovel methods.

8833O7 Current mate of the art of # t design and lmfformame Dight, P M; Windsor, C Proc Large Open Pit Mial~ CMfera~, N e ~ , October 1986 1'285-293. Publ ParkviUe: AuMMM, 1986

A review of pit design procedures and performance is presented. The investigation included pit slopes, haul roads, waste dumps and tailings dams. Eighteen mines with varia- tions in commodity, size, age, and expected life span were cov- ered. Design is presently based largely on experience and observation, rather than engineering design and analysis. Improvements may be possible by rigorously applying geomechanics principles. However, current procedures for col- lecting, analysing and presenting data must be simplified to be usable by existing staff before widespread use of sound geotechnical principles for pit design is common.

© 1988 Pergamon Press plc. Reproduction not permitted