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Crown pillars provide regional and local support by isolating the ground surface from underground mine workings. Topography above the underground mine may be a relatively flat ground surface or an open-pit structure. Depending on what lies above and design of the underground mine, the crown pillar behaviour will differ. In transitioning setups …
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To design an optimal crown pillar, a comprehensive investigation is necessary for each mine, focusing on the behaviour of the crown pillar regarding stress distribution, roof convergence, and yielding zones under the relaxation zone (Hosseini et al. Citation 2023). Geological and geo-mining conditions vary greatly between mines due …
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The pillar stability factor (PSF) is calculated in three different mining stages for a sublevel open stoping mining project located in northern Botswana. Several three-dimensional finite element models were developed by varying the stope span. Pillar strength was estimated using the Lunder and Pakalnis equation and pillar stress was obtained from the …
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Our Crown Pillar Scaled Span (Cs) value has been calculated and an area has been highlighted on the chart. It is calculated using the equation shown in the dialog. ... This would be acceptable in a mining block where surface risks can be mitigated perhaps by incorporating "continuous sophisticated monitoring" if critical surface ...
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Kumar et al. [7] conducted a numerical modelling study on sill and crown pillar stability using the finite element method. They determined the pillar thickness based on the extent of yielding within the pillar. ... It is shown that the sill pillar significantly reduces overbreak in the stope immediately above the sill pillar. As the mining ...
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The minimum thickness of crown pillar which will remain stable is a function of many parameters including the in-situ mechanical properties of the rock mass and the forces acting on the pillar. Crown pillar should be designed so that they remain stable for a predetermined period of time.
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Evaluation of the long-term surface stability of crown pillars overlying underground mines is an important component of mine closure planning. The definition of a crown pillar, as well as a brief discussion of the assessment of the probability and consequence of crown pillar failure are given in this paper. Techniques for stability assessment using mechanistic, …
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Crown-pillar risk assessment-planning aid for cost-effective mine closure remediation. ... Assessing crown stability Since in almost all situations where a crown pillar has been used in mining there are significant differences between the overall rock mass characteristics of the ore zone and those of the hanging-wall and footwall, it is …
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To tackle the technical challenges of medium-depth mining in sharply inclined medium-thickness ore bodies, the concept of an induced caving crown pillar was introduced, which led to the development of temporary crown pillar-induced caving technology. Building upon this foundation, a combined mining method of crown-pillar …
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A crown pillar is to be designed in the transition region from surface to underground operations. Crown pillar dimensioning effects the overall ore recovery in such small-scale ore bodies. Proper dimensioning has to ensure the stability of open pit mine slopes and underground mine structural units as underground mining progresses to …
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Pillar robbing is the method and technical process of ore pillar recovery based on the comprehensive consideration of various factors such as the ground pressure behavior law of the mine, pressure-bearing capacity of the pillar, output distribution of each stoping step, and economic benefit.
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The original development of the scaled span concept for evaluating crown pillar stability encompassed review of a database of over 200 case records, mainly comprising openings in relatively steep ore bodies. More recent updating has added a number of
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This paper reviews empirical methods to estimate crown pillar stability and their application in the breakthrough process in block cave mines, evidenced by a case study in Chuquicamata underground mine. Keywords: caving, crown pillar, subsidence, empirical method, breakthrough 1 Introduction
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A New Approach to Surface Crown Pillar Design T.G.CARTER Golder Associates, Toronto, Canada Abstract Crown Pillar Design for most hard rock mines has in ... classic Rules of Thumb for mining beneath crown pillars. Including empirical rules, three methods
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A steeply dipping orebody, having decreasing width with depth has been modeled considering horizontal cut and fill method of stoping at four different depth levels. The focus of the study is to identify and understand the behavior of crown and sill pillars in terms of varying stress and geo-mining conditions without reinforcement using finite …
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The geomechanical evaluation of crown pillar mining relied on numerical simulations supported by rock mass characterization, observations of ground reaction and geotechnical monitoring data. Multiple phases of numerical modeling have been completed for Santo Niño prior to, and during the crown pillar risk assessment. ...
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Although crown pillar stability in a mining context has been studied for more than 30 years, the design guidelines for surface crown pillars are still limited. This is particularly true for complex crown pillar cases involving overlying infrastructure; empirical and analytical design methods are inadequate to size crown pillar for the safety of ...
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The main parameters involved in the room-and-pillar mining method are the widths and heights of the pillars, height of the crown pillar, and overlap ratio of the pillars. These factors need to be considered to maintain the safety of the mine during development.
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