A design philosophy for surface crown pillars of hard rock mines

Abstract Surface crown pillars, acting to safely protect underground workers and operations from surface elements, are recognized, herein, as distinct from conventional deeper underground pillars. Moreover, because of the variation in mining and geological conditions that exist from mine site to mine site, each case is viewed as unique. A review of numerous case studies and existing literature indicates that there is little general information or systematic problem-solving approach associated with them.
A design process, not unlike that of other engineering disciplines, is presented to correct these deficiencies. As part of its purpose, it will inform operators of the key elements required for design and will address the problems of these appendages. The design, while taking into consideration possible surface crown pillar settings and inherent characteristics, is founded on a step-by-step procedure starting with site investigations through to monitoring or pillar recovery. The process is flexible, in that it incorporates decision making and changes in mining strategy. The purpose of each step is explained and each step is extensively described in terms of the required equipment and methods for field work, analysis and support measures. Analytical formulae and studies from several fields directly applicable to surface crown pillars are also given. Recommendations for future research studies are presented.
Keywords: Rock mechanics, Surface crown pillars, Canadian mines, Design philosophy, Design process, Geotechnical investigations, Mining strategy, Design methods, Mining activity, Monitoring, Back analysis, Pillar recovery, Design evaluation.
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Summary: The February 18, 1987, Federal Budget contains a proposed amendment which would simplify somewhat the "successor corporation" rules in the Income Tax Act. Despite this amendment, though, the important successor rules will continue to be relatively complex.
Publication: CIM Bulletin
Author(s): ROBERT B. PARSONS
Issue: 903
Volume: 80
Year: 1987
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Summary: An approach to the in situ testing of mine backfills is outlined. It has been developed to provide a measure of the effective strength and stiffness of such materials after placement in stapes. This paper is based upon recent field studies undertaken at five Quebec mines. Details of the selected instrumentation, supporting equipment and testing procedures are reviewed. The mechanical behaviour of the backfills is reported and related to their physical properties. This approach represents an...
Publication: CIM Bulletin
Author(s): MALCOLM SCOBLE, LUCIANO PICIACCHIA, JEAN-MARC ROBERT
Keywords: Rock mechanics, Underground mining, Backfills, Stopes, In situ testing, Mine design, Quality control.
Issue: 903
Volume: 80
Year: 1987
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Summary: This paper describes the objectives and design parameters for the operation of a computerized In-The-Hole (I.T.H.) Drill. The principal objective is to add computer control to an Inco GO-60 I.T.H. (CMS-CD-90) drill in order to drill holes with greater accuracy. The computer provides control of the angle of the hole by maintaining the orientation of the drill head, and optimizes the straightness of the hole by maintaining a constant force on the drill bit.
The second objective is to provide...
Publication: CIM Bulletin
Author(s): J. KELLY, R. ENGLAND
Keywords: Drill design, Computer controlled drilling, Rod handling, I.T.H. drill rig, GO-60 drill.
Issue: 903
Volume: 80
Year: 1987
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Summary: This paper describes the objectives and design parameters for the operation of a computerized In-The-Hole (I.T.H.) Drill.
The principal objective is to add computer control to an Inco GO-60 I.T.H. (CMS-CD-90) drill in order to drill holes with greater accuracy. The computer provides control of the angle of the hole by maintaining the orientation of the drill head, and optimizes the straightness of the hole by maintaining a constant force on the drill bit.
The second objective is to provide...
Publication: CIM Bulletin
Author(s): J. KELLY, R. ENGLAND
Keywords: Drill design, Computer controlled drilling, Rod handling, I.T.H. drill rig, GO-60 drill.
Issue: 903
Volume: 80
Year: 1987
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Summary: Analysis of gold placer data from gold placers throughout the world suggests that gold grades and volumes cannot be used to distinguish between most types of gold placers. Only the alluvial plain and fan placers are significantly different among the types of gold placers considered. Gold grades and volumes change when working gold placers go from small-volume methods to large-volume methods. The small-volume methods are either of the surface or subsurface (drift mining) type. The odds that a...
Publication: CIM Bulletin
Author(s): J.D. BLISS, G.J. ORRIS, W.D. MENZIE
Keywords: Gold placer deposits, Simulation, Gold recovery, Grade-volume models, Grade estimation.
Issue: 903
Volume: 80
Year: 1987
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Summary: Centrifuge modelling of earth structures is a well-proven technique for evaluating the performance of prototype structures using physical models. The applications of this technique have increased dramatically during the last decade such that even the modelling of dynamic responses in structures has been accomplished.
This paper presents the first model test results used to design a mine backfill. The models were tested using aim radius 30 g-tonne geotechnical centrifuge which was constructed...
Publication: CIM Bulletin
Author(s): R.J. MITCHELL, J.D. SMITH
Keywords: Rock Mechanics, Centrifuges, Modelling, Backfill design, Mine backfill, Stability, Subsidence.
Issue: 903
Volume: 80
Year: 1987
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Summary: For the last three decades, the application of network planning has provided a basis for a formal and general approach to the discipline of project management. For fixed activity duration, a very simple algorithm commonly known as critical path method (CPM), gives the length of time required for the total project as well as indicates the activities which are vital to the completion of a project. Project Evaluation Review Techniques (PERT) on the other hand, generalize the above approach to...
Publication: CIM Bulletin
Author(s): SUKUMAR BANDOPADHYAY, ARUNAPURAM SUNDARARAJAN
Keywords: Simulation, Longwall development, Project management, Modelling.
Issue: 903
Volume: 80
Year: 1987
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Summary: Sulphuric acid treated with hydrogen peroxide to destroy organic contaminants could conceivably show increased cor-rosivity toward carbon steel shipping and storage vessels, caused by the persistence of a peroxide residual. This paper describes work performed to determine the effect of 0-200 ppm hydrogen peroxide on the corrosion of carbon steel by 93% and 98% sulphuric acid at room temperature (23 °C) and 50°C.
Steel electrodes were exposed to acid containing several peroxide levels...
Publication: CIM Bulletin
Author(s): C.M. DAVIDSON, D.J. DREXLER
Keywords: Hydrogen peroxide, Carbon steel, Corrosion , Contaminants.
Issue: 903
Volume: 80
Year: 1987
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