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Backfill support in deep level tabular mining — predicted performance at great depth
291A
Shotcrete See also." 905415 905293 Shotcreting innovations in the Shing Mun tunnels Bergfors, A; Coates, R; Ostqord, S Tunn Tunalg V22, N4, April 1990, P41-44
The Shing Mun tunnels, Hong Kong, run through granite rock whose stability is dictated by the state of jointing. Excavation was by drill and blast with top heading and bench. Primary support was shotcrete and rock bolts. A flexible contract was specified whereby different types of concrete, including steel fibre reinforcement, could be used as ground conditions dictated, without affecting apportionment of risk. This produced benefits to both client and contractor. 905294 Sealing tunnels constructed in single shell shotcrete Schreyer, J Proc International Congress on Tunnels and Water, Madrid, 15-18 June 1988 VI, P317-320. Publ Rotterdam: A A Balkema, 1988
Improvement of the watertightness of shotcrete to allow single shell tunnel linings has been studied. Initial laboratory tests examined the spraying quality of reinforcement, spraying technique and use of wet or dry mixes, and installation ofjointing strips. Results were applied to single shell lining of a 100m long experimental tunnel, but waterproofing achieved was not sufficient for very wet tunnels or aggressive groundwater. Further developments were made using sprayed resin or resin modified concrete layers in the lining.
Direct rock support methods
905297 Hydraulic stowing - a solution for subsidence due to underground mining in the USA Sinha, K W Rock Mechanics as a Guide for g~icient Utifization of Natural Resources: Proc 30th U.S. Symposium, Morgantown, 19-22 June 1989 P827-834. Publ Rotterdam: A A Balkema, 1989
Recovery from deep mines in the USA is often only 50% in order to minimise surface subsidence. In other countries extraction of almost 100% is achieved using hydraulic backfilling to support the entire void left by mining. River sand obtained nearby and mixed with coal ~vaste is a suitable fill for US pits. Sand gathering and stowing equipment is described. Sites in Illinois within 50 miles of the Mississippi, which is dredged on a regular basis, where this approach is feasible are mapped. 905298
Backfill support in deep level tabular mining - predicted performance at great depth Stacey, T R; Kirsten, H A D Proc International Symposium on Rock at Great Depth, Pau, 28-31 August 1989 V2, 1'589-593. Publ Rotterdam: A A Balkema, 1989
Hydraulically placed uncemented deslimed tailings are widely used as support in deep South African gold mines. Multiple step and single step analyses are used to predict closure and pressure in the backfill behind the face for a stope in a jointed rock mass. Single step analysis is seen to be adequate, particularly for purposes of comparison. Modelling suggests that the soft backfill can be used at depth 5000m, considerably deeper than current mining levels.
Grouting See: 905513
See also: 905488, 905500 905295 Effect of foundation damage on the performance of stabilizing pillars Ozbay, M U; Ryder, J A J S Aft lnst Min Metall V90, N2, Feb 1990, P29-35
Reinforced earth
An Energy Release Rate-based method for assessment of performance of stabilising pillars in deep gold mines is presented, which takes into account effects of fracturing of pillar foundations under high stress. Damage in the foundations of underdesigned pillars can result in ERR up to 30% greater than for unfractured foundations. Even in this case, ERR is significantly lower than when alternative stabilising measures such as stiff backfill or backfill ribs are used.
905299 Strength of fabric reinforced sand under axisymmetric loading Chandrasekaran, B; Broms, B B; Wong, K S Geotext Geomem V8, N4, 1989, P293-310
905296 Study of the application of T-H support systems in coal mine gate roadways in the UK Baxter, N G; Watson, T P; Whittaker, B N Min Sei Teclmoi VIO, N2, March 1990, P167-176
Constituents and principles of operation of the T-H yielding arch are outlined, with particular examination of the clamping system, which is seen to be a crucial component. Load deformation characteristics of T-H yielding and rigid H-section arches are compared. Results of an underground comparison at the Coventry colliery are discussed. Recommendations are made for the further application of yielding T-H arches.
See also: 905047, 905318, 905328, 905366, 905379, 905385, 905406,
Strength of fabric reinforced soils is governed by the friction mobilized along the fabric-soil interface. Effects of confining pressure on frictional resistance and fabric tension have been examined for cylindrical specimens reinforced with horizontal textile layers. Spacing, initial applied confining pressure, and fabric strength and stiffness are all important. A simple formula is developed to relate force in the fabric to increased strength. Good correlation was found with test results. 9O53O0 Earth reinforcement for foundations - east and west Fukuoka, M Geotext Geomem V9. NI, 1990, P3-9
A brief overview of soil reinforcement using natural materials or steel wire or nets before the advent of geosynthetics is first presented. Development and initial applications of geotextiles and geonets in contruction projects are described together
© 1990 Pergamon Press plc. Reproduction not permitted RMMS 27 5--K
Shotcrete See also." 905415 905293 Shotcreting innovations in the Shing Mun tunnels Bergfors, A; Coates, R; Ostqord, S Tunn Tunalg V22, N4, April 1990, P41-44
The Shing Mun tunnels, Hong Kong, run through granite rock whose stability is dictated by the state of jointing. Excavation was by drill and blast with top heading and bench. Primary support was shotcrete and rock bolts. A flexible contract was specified whereby different types of concrete, including steel fibre reinforcement, could be used as ground conditions dictated, without affecting apportionment of risk. This produced benefits to both client and contractor. 905294 Sealing tunnels constructed in single shell shotcrete Schreyer, J Proc International Congress on Tunnels and Water, Madrid, 15-18 June 1988 VI, P317-320. Publ Rotterdam: A A Balkema, 1988
Improvement of the watertightness of shotcrete to allow single shell tunnel linings has been studied. Initial laboratory tests examined the spraying quality of reinforcement, spraying technique and use of wet or dry mixes, and installation ofjointing strips. Results were applied to single shell lining of a 100m long experimental tunnel, but waterproofing achieved was not sufficient for very wet tunnels or aggressive groundwater. Further developments were made using sprayed resin or resin modified concrete layers in the lining.
Direct rock support methods
905297 Hydraulic stowing - a solution for subsidence due to underground mining in the USA Sinha, K W Rock Mechanics as a Guide for g~icient Utifization of Natural Resources: Proc 30th U.S. Symposium, Morgantown, 19-22 June 1989 P827-834. Publ Rotterdam: A A Balkema, 1989
Recovery from deep mines in the USA is often only 50% in order to minimise surface subsidence. In other countries extraction of almost 100% is achieved using hydraulic backfilling to support the entire void left by mining. River sand obtained nearby and mixed with coal ~vaste is a suitable fill for US pits. Sand gathering and stowing equipment is described. Sites in Illinois within 50 miles of the Mississippi, which is dredged on a regular basis, where this approach is feasible are mapped. 905298
Backfill support in deep level tabular mining - predicted performance at great depth Stacey, T R; Kirsten, H A D Proc International Symposium on Rock at Great Depth, Pau, 28-31 August 1989 V2, 1'589-593. Publ Rotterdam: A A Balkema, 1989
Hydraulically placed uncemented deslimed tailings are widely used as support in deep South African gold mines. Multiple step and single step analyses are used to predict closure and pressure in the backfill behind the face for a stope in a jointed rock mass. Single step analysis is seen to be adequate, particularly for purposes of comparison. Modelling suggests that the soft backfill can be used at depth 5000m, considerably deeper than current mining levels.
Grouting See: 905513
See also: 905488, 905500 905295 Effect of foundation damage on the performance of stabilizing pillars Ozbay, M U; Ryder, J A J S Aft lnst Min Metall V90, N2, Feb 1990, P29-35
Reinforced earth
An Energy Release Rate-based method for assessment of performance of stabilising pillars in deep gold mines is presented, which takes into account effects of fracturing of pillar foundations under high stress. Damage in the foundations of underdesigned pillars can result in ERR up to 30% greater than for unfractured foundations. Even in this case, ERR is significantly lower than when alternative stabilising measures such as stiff backfill or backfill ribs are used.
905299 Strength of fabric reinforced sand under axisymmetric loading Chandrasekaran, B; Broms, B B; Wong, K S Geotext Geomem V8, N4, 1989, P293-310
905296 Study of the application of T-H support systems in coal mine gate roadways in the UK Baxter, N G; Watson, T P; Whittaker, B N Min Sei Teclmoi VIO, N2, March 1990, P167-176
Constituents and principles of operation of the T-H yielding arch are outlined, with particular examination of the clamping system, which is seen to be a crucial component. Load deformation characteristics of T-H yielding and rigid H-section arches are compared. Results of an underground comparison at the Coventry colliery are discussed. Recommendations are made for the further application of yielding T-H arches.
See also: 905047, 905318, 905328, 905366, 905379, 905385, 905406,
Strength of fabric reinforced soils is governed by the friction mobilized along the fabric-soil interface. Effects of confining pressure on frictional resistance and fabric tension have been examined for cylindrical specimens reinforced with horizontal textile layers. Spacing, initial applied confining pressure, and fabric strength and stiffness are all important. A simple formula is developed to relate force in the fabric to increased strength. Good correlation was found with test results. 9O53O0 Earth reinforcement for foundations - east and west Fukuoka, M Geotext Geomem V9. NI, 1990, P3-9
A brief overview of soil reinforcement using natural materials or steel wire or nets before the advent of geosynthetics is first presented. Development and initial applications of geotextiles and geonets in contruction projects are described together
© 1990 Pergamon Press plc. Reproduction not permitted RMMS 27 5--K