Monitoring equipment for mining induced stresses at Niobec Mine

Abstract The need for monitoring the effect of changes in ground stresses due to mining in hard rock has existed for many years. The Mining Research Laboratories of CANMET, EMR have developed a new tool which monitors with high precision the radial deformation in boreholes. The result is the Mining Research Laboratories strain monitoring system (MSMS) which uses the highly stable and very sensitive vibrating wire principle to monitor deformations in relatively large boreholes, e.g. 76 mm to 153 mm diameter.
The vibrating wire is strung across a relatively large proving ring and operates at a frequency between 600 to 1800 Hz. The read-out system is based on continuous vibration.
The ring is installed with a hydraulic tool and brought into contact with the surrounding rock through precisely machined and guided wedges. The resolution of the system is in the neighbourhood of 4 x l(r4 mm/Hz. The data collection can be carried out with a portable read-out unit and provisions are available for automatic data collection. Stresses may be calculated from strain readings.
The system was tested in cooperation with the Centre de recherches minerales at the Niobec Mine in Quebec for the purpose of monitoring the effects of drill drift development and slope mining on surrounding ground stresses.After access was available to the site, 153 mm diameter holes were drilled for the determination of in situ ground stresses. These holes were then used to install the strain monitoring system. The effect of drill drift development and production blasling in slopes C-203-13 and C-203-15 on ground stress distribution could be observed clearly.
The horizontal relaxation in the core of a pillar which occurred during mining, of adjacent rooms was between 0.082 mm to 0.111 mm. Calculations of stresses from these deformations indicate that the rock material is still in an elastic condition.
Roctest of Montreal has obtained a license on the manufacturing and distribution rights. A patent has been registered and CANMET will assist in installation oftheMRL strain monitoring system and the interpretation of records.
Keywords: Rock mechanics, Monitoring equipment, Equipment, Instrumentation
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Summary: This paper introduces a new approach for the design of rib pillars. The approach involves an empirical method for pillar design and a discussion of the pillar stability used for open stope mining methods.
The empirical method predicts the degree of stability of rib pillars. Pillar load is estimated using two and three dimensional numerical modelling. Rock strength and the shape effect of pillars are used to account for pillar strength. The method has been calibrated with case histories from...
Publication: CIM Bulletin
Author(s): Y. Potvin, M. Hudyma, H.D.S. Miller
Keywords: Rock mechanics, Pillar design, Open stope mining
Issue: 927
Volume: 82
Year: 1989
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Summary: The influence of annealing of galvanized steel (galvannealing) on its corrosion kinetics in a saturated solution of Ca (OH)2 has been studied by means of the polarization resistance method.
Galvannealing heat treatment was carried out at 450°C and 550°C for varying times. Annealing at 450°C for 24 hr or at 550°C for 5 hr showed the highest corrosion potential (Ecorr) = - 400 m V/SCE as well as, the lowest corrosion current density (icorr = 3 mA.cm-2, while Ecorr and icorr...
Publication: CIM Bulletin
Author(s): M.I. Abbas, M.S. Ahmed, M.A. Shahin
Keywords: Metallurgy, Corrosion, Steel, Gavanized steel, Galvannealling heat treatments
Issue: 927
Volume: 82
Year: 1989
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Summary: A kinematically admissible velocity field is applied to study the arching phenomenon in a cohesionless granular backfill placed between two rough vertical inflexible walls. The study is different from the previous works which are almost entirely based on statically admissible stress fields. It is shown that the development of arches is strongly influenced by the previous loading history of the backfill which controls the nature of the constitutive laws that govern the mode of stress deformati...
Publication: CIM Bulletin
Author(s): H.B. Poprooshasb, F.P. Hassani
Keywords: Rock mechanics, Arching phenomena, Backfill, Underground mining
Issue: 927
Volume: 82
Year: 1989
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Summary: Unanticipated low recovery or extraction of gggoldfrom heap teachable ore can often be attributed to phenomena such as non-uniform percolation (channelling) of solution through heaps, excessively slow percolation rates due to densification of ore during stacking on the pads and parasitic or competing reactions of the cyanide solution with undesirable elements or geochemical "impurities" in the ore. The nature and causes of these phenomena are discussed in this paper, and it is...
Publication: CIM Bulletin
Author(s): R.F. LOPES, P.L LEHOUX
Keywords: Mineral processing, Extraction, , Gold, Leaching, Heap leaching, Ore preparation, Agglomeration
Issue: 927
Volume: 82
Year: 1989
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Summary: With the growth of large scale surface mining operations, waste disposal and stability of waste dumps pose a challenging problem to engineers. Vibrations due to blasting operations proximal to these dumps further complicates dump design. Many dumps which are statically stable may become unstable due to the effects of blasting vibrations.
A joint project between CANMET and Smoky River Coal Ltd. has been initiated to study the dynamic stability of waste dumps. The study involves development of...
Publication: CIM Bulletin
Author(s): B. Stuckert, J. Balfour, D. Fawcett, P. Sheehan, B. (Manas) Das
Keywords: Rock mechanics, Waste dumps, Surface mining, Blasting, Slope stability
Issue: 927
Volume: 82
Year: 1989
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Summary: The practical determination of optimum stope geometry has, until recently, been an art relying primarily on experience at a given operation. Due to the complex and variable nature of rock masses in situ, slopes are often designed either very conservatively, resulting in excess development, or nonconservative resulting in excessive dilution and, in some cases, in loss of ore reserves.
The Geomechanics group of the Mining Technology Division, Centre de Recherche Noranda, uses a combination...
Publication: CIM Bulletin
Author(s): W.F. Bawden, G. Sauriol, D. Milne, P. Germain
Keywords: Rock mechanics, Stope design, numerical-modelling, Empirial design, Mine design, Slope stability
Issue: 927
Volume: 82
Year: 1989
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