Bulkhead pressures due to cemented hydraulic mine backfills

Mitchell, R.J.; Smith, J. D.; Libby, D.J.

doi:10.1016/0148-9062(76)90757-9

Cited by 3 publications

(6 citation statements)

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“…Throughout the 1970s and 1980s, as underground mining activity increased and stopes became larger, the lack of field or numerical data on bulkhead pressures generally forced mines to over-design barricades; an expensive operational consideration that was required in the absence of any barricade pressure data. An example of such over design gave rise to a barricade that consisted of a 1 m thick heavily reinforced concrete bulkhead with interior drain pipes (Mitchell and Smith 1979;Mitchell et al 1975). The design strength of this barricade exceeded the measured horizontal pressures; for example in this instance, the primitive timber fill fences designed for a working pressure of 100 kN/m 2 were found to be sufficient according to their historical success.…”

Section: Underground Barricade Historymentioning

confidence: 95%

Materials properties of barricade bricks for mining applications

2007

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Barricade bricks are fundamental to the safe operation of a mining site. Past failures have lead to loss of life and reduced mine efficiency or even shut down. The fundamental material property that determines the operational characteristics of barricade bricks is their permeability, which must be tailored to suit the operational environment of the mine. The ability of the barricade to control the hydraulic pressure within a stope application is crucial for safety and economic returns. In the current work practical barricade bricks were tested for permeability. As well, the strength and modulus of bricks were measured after being soaked in water for either 7 or 90 days so that a measure of their engineering functionality could be determined. The primary conclusions of this work are as follows. There was substantial deviation in permeability between bricks; however, the average permeability of the barricade bricks was several orders of magnitude larger than the values obtained for the hydraulic fill. This difference indicates that modelling efforts can assume that the barricade does not contribute to the pore pressure development within the fill. Hence the drainage of the system is not related to the permeability of these bricks provided that the barricades are built from the bricks in such a way that the construction or future migration of fines from the fill does not impede the drainage performance.

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Section: Underground Barricade Historymentioning

confidence: 95%

Materials properties of barricade bricks for mining applications

2007

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“…Underestimation of friction angle will result in underestimation of the arching effect in hydraulic fills and hence the overall stability of the material (Mitchell et al, 1975). Due to limited access and safety issues, it is often difficult to carry out in situ tests within the stopes.…”

Section: Friction Angles Of Hydraulic Fillsmentioning

confidence: 96%

“…In other words, the sample prepared by the above sedimentation process will give a good representation of the in situ hydraulic fill. Mitchell et al (1975) determined the permeability of cemented hydraulic fill using 152 mm diameter and 305 mm high samples prepared in the laboratory. They found that the drainage characteristics in the mine stope agreed with the predictions based on the permeability values measured in the laboratory.…”

Section: Test Proceduresmentioning

confidence: 99%

Emplaced Geotechnical Characteristics of Hydraulic Fills in a Number of Australian Mines

2006

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Hydraulic fills used in Australian mines have similar grain size distributions whilst having quite different specific gravity values, typically in the range of 2.7-4.4. When produced and distributed in slurry at 65-75% by solid content, they settle to produce fills with similar geotechnical characteristics. The fills under investigation have been found to settle, in the laboratory, to a dry density of about 0.56 · specific gravity, a saturation water content of about 17-34%, and a porosity of 37-49%. A quick estimate of the optimum water content that gives the minimum porosity may be obtained by locating the intersection of the saturation curve and minimum porosity line, which may simply be done on a water content vs. porosity plot. However, transportability of the slurry requires it to be mixed at water content substantially greater than the optimum water content. As the tailings settle out of suspension, they settle to relative density of 50-80%. This paper shows that the current empirical relationships relating relative density and N-value to friction angle for sands will significantly underestimate the friction angle of the hydraulic fills. Based on limited experimental data, a unique relationship between relative density and friction angle is proposed for hydraulic fills placed in some Australian mines.

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“…Relating Rankine Theory to backfill design was previously proposed by Mitchell et al [2], Revell and Sainsbury [12], Marcinyshyn et al [13] and Dehn et al [14]. Rankine Theory relates the horizontal pressure to the vertical pressure based on a coefficient which determines whether the soil is active, passive or at rest [11].…”

Section: Loading Mechanics Of the Pastementioning

confidence: 99%

“…Previous barricade studies have focused on timber barricades [1], concrete barricades [2,16] and brick barricades [3]. Previous studies have addressed the loading mechanics of hydraulic fill [1,4], however until recently the performance of barricades under paste loading has not been studied.…”

Section: Introductionmentioning

confidence: 99%

Composite paste barricade performance at Goldcorp Inc. Red Lake Mine, Ontario, Canada

Hughes

Pakalnis

Hitch

et al. 2010

International Journal of Mining, Reclamation and Environment

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Appropriate strength barricades and fill fences are a necessary component of underhand cut and fill mining operations and stoping operations in general. These important structures are subject to a number of stresses and strains as a result of the deposition and curing of the backfill material. Parametric monitoring of fill fences gives the engineer the required data to predict not only the behaviour of the paste backfill as it is being deposited, but also the ability to predict the deformation and eventual failure of the barricade. A study was undertaken to determine the performance of the paste barricades at Goldcorp Inc.'s Red Lake Mine using real time instrumentation to monitor the stresses, strains and deformation of paste and paste barricades during placement. The barricades at the mine are a standardised barricade comprised of 10 cm of shotcrete applied to a rebar skeleton spaced nominally 60 cm apart. In total, eight fill barricades were instrumented to determine the behaviour of the paste during the loading. Complementing the eight barricade tests, an instrumented destructive test was carried out to determine the ultimate capacity of the composite barricade. It was determined that the paste backfill behaves as a Rankine-like soil in the initial stages of placement with an average coefficient of lateral earth pressure, K a , of 0.56. The destructive test determined that the yielding stress of a paste barricade is approximately 100 kPa. The results of the investigation have resulted in operational changes in the placement of paste at the mine.

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Bulkhead pressures due to cemented hydraulic mine backfills

Cited by 3 publications

References 0 publications

Materials properties of barricade bricks for mining applications

Materials properties of barricade bricks for mining applications

Emplaced Geotechnical Characteristics of Hydraulic Fills in a Number of Australian Mines

Composite paste barricade performance at Goldcorp Inc. Red Lake Mine, Ontario, Canada

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