【導(dǎo)讀】ective. cient. aresultofmining[1].furnaceslag.a,CanningtonMine,BHPBilliton,.E-mailaddress:(N.Sivakugan).cementhasalimitede?ectongr

　　

【正文】 y measuring on the Richter scale.This figure has been adopted by the mining industry asthe minimum design strength fill for any fill mass. Thestrength of the paste satisfying the static stabilityrequirements are generally in excess of dynamic strengthrequirements.Barricades are designed as underground retainingwalls. The structural design and construction of thewalls may vary slightly to those designed for hydraulicTable 1Material properties for thickened tailings continuum [14]Material property Slurry ThickenedParticle size Coarse fraction only. No particlesless than 20 mm. Segregationduring transportation and orplacement is dependent only onthe coarse fractionSomefinesfrommoresegregateduringdependentPulp density (%) 60e72 70eFlow regimes/linevelocitiesCritical flow velocity. To maintainflow must have turbulent flow(velO2 m/s). If vel!2 m/ssettling occursCriticalmustIf velNewtonian flow NewtonianYield stress No minimum yield stress NoPreparation Cyclone CycloneSegregation in stope Yes/high Slight/partialDrainage from Stope Yes Partial/limitedFinal density Low Medium/hiSupernatant water High SomePost placement shrinkage High InsignificanRehabilitation Delayed ImmediatePermeability Medium/low Low1174 N. Sivakugan et al. / Journal of CleanerFLAC insimulatingthefillingoperationsinahydraulicfill and paste fill stopes, studying the developments ofstresses and drainage within the fill [19,21].The intention of this paper has not been to detail thefindings from these simulations but rather to highlightthe potential these modelling tools have to dramaticallyincrease the confidence with which stope predictionsmay be made, ultimately leading to optimised mineoperation and safety.tailings Pastefines included (typically !15%),content tends to modify behaviourslurry e . rheological characteristicssimilar to paste, however doeswhen bought to rest. Segregationtransportation and or placement isonly on the coarse fractionAdditional/most fines(typically 15% (min)O20 mm78e82flow velocity. To maintain flowhave turbulent flow (velO2 m/s).!2 m/s partial settling occursNo critical pipeline flowvelocity, . no settlingin pipeflow Laminar/plug flowyield stress Minimum yield Stressend elutriation Filter/centrifugeNoneNone/insignificantgh HighNonet InsignificantImmediateVery lowProduction 14 (2020) 1168e11757e35 mm/h.There is significant scatter in the uniaxial strengthand Young’s modulus of porous barricade bricksmeasured in the laboratory. Uniaxial strength decreasesby about 25% as a result of wetting the brick. Sincethese bricks are always subjected to wet conditionswithin the mine, the strength and Young’s modulusvalues of wet bricks should be used in the design ofTownsville: The Australian Institute of Mining and Metallurgy。2020. p. 161e5.[7] ASTM D 4254e91. Standard test method for minimum indexdensity and unit weight of soils and calculation of relative density.Annual book of ASTM standards. .: American Society ofTesting Materials。 1996.[8] ASTM D 4253e93. Test method for maximum index density andunit weight of soils using a vibratory table. Annual book ofASTM standards. .: American Society of Testing Materials。1175N. Sivakugan et al. / Journal of Cleaner Production 14 (2020) 1168e1175barricade walls.Paste fill contains at least 15% of grains finer than20 mm, and the e?ective grain size (D10) is in the order of5 mm. The 3e6% binder improves the strength and thusstability significantly. The large fine content within thepaste fill enables most of the water to be held to thesurface of the grains, and therefore drainage is not aconcern in paste backfilling.AcknowledgementsSeveral mines have contributed cash and inkindto the research discussed in this paper. Their supportis gratefully acknowledged. Senior Technical O?cersMr. Warren O’Donnell and Mr. Stuart Petersen assistedin most of the laboratory test work carried out on thebricks and hydraulic fills. Our regular discussions withMr. Richard Cowling of Cowling Associates were veryvaluable throughout our mining research.References[1] Grice T. Recent mine developments in Australia. In: Proceedingsof the 7th international symposium on mining with backfill(MINEFILL)。 2020. p. 351e7.[2] Bloss ML, Chen J. Drainage research at Mount Isa MinesLimited 1992e1997. In: Proceedings of Minefill ’98. Brisbane(Australia)。 1998. p. 111e6.[3] Herget G, De Korompay V. In situ drainage properties ofhydraulic backfills. Research and innovations, CIM specialvolume。 1978. p. 117e23.[4] Rankine KJ, Sivakugan N, Rankine KS. Laboratory tests formine fills and barricade bricks. In: Farquhar G, Kelsey P,Marsh J, Fellows D, editors. Proceedings of the 9th AustraliaNew Zealand conference on geomechanics. Auckland。 2020.p. 218e24.[5] Kuganathan K. Mine backfilling, backfill drainage and bulkheadconstruction e a safety first approach. Australia’s miningmonthly February, 2020。58e64.[6] Brady AC, Brown JA. Hydraulic fill at Osborne mine. In:Proceedings of 8th AUSIMM underground operators conference.1996.[9] Pettibone HC, Kealy CD. Engineering properties of mine tailings.Journal of Soil Mechanics and Foundations Division, ASCE1971。97(SM9):1207e25.[10] Clark IH. The properties of hydraulically placed backfill. In:Proceedings of backfill in South African mines. Johannesburg:SAIMM。 1988. p. 15e33.[11] Du?eld C, Gad E, Bamford W. Investigation into the structuralbehaviour of mine brick barricades. Institute of Engineers。March/April, 2020. p. 45e50.[12] Robinsky EI. Thickened discharge e a new approach to tailingsdisposal. Canadian Mining and Metallurgical Bulletin 1975。68:47e53.[13] Jewell RJ. Introduction. In: Jewell RJ, Fourie AB, Lord ER,editors. Paste and thickened tailings: a guide. Perth (Australia):