A comprehensive review of ore pass records, from ten Quebec underground mines, indicated some of the limitations of available design tools to predict the occurrence of ore pass interlocking hang-ups in metal mines. The Distinct Element Method was used to perform a series of numerical experiments in order to investigate the influence of ore pass geometry, rock fragments shape and size distribution on material flow in an ore pass. Guidelines have been developed to help limit the occurrence of interlocking hang-ups in an ore pass. The proposed guidelines were evaluated with respect to field observations.

Ein kompletter Bericht der Erzrollezeichnungen, von 10 Quebec unterirdischen Gruben, hat einige der Beschrankungen der vorhandenen Designwerkzeuge angezeigt, um das Auftreten Erzrolle der blockierenhang-ups in den Metallgruben genau vorauszusagen. Eine Reihe numerische Experimente mit der eindeutigen Element-Methode, wurden aufgenommen, um den Einfluss von Erzrollegeometrie, Partikelform nachzuforschen und Felsenkorngrößenverteilungen auf Materialfluss in ein Erz ueberschreiten. Dieses hat zu die Entwicklung der Richtlinien gefuehrt deren Implementierung das Auftreten der blockierenhang-ups in eine Erzrolle begrenzen sollte. Die vorgeschlagenen Richtlinien wurden in Bezug auf Labor- und Feldbeobachtungen ausgewertet.

Une revue de la performance actuelle des cheminees à minerai dans 10 mines souterraines du Quebec a indique les limites des outils de conception servant à dimensionner les cheminees pour minimiser le nombre d'accrochages par enchevêtrement rocheux. Des series de modelisations numeriques, utilisant la methode des elements distincts, ont ete realisees afin d'evaluer l'influence de la geometrie des cheminees, de la forme des fragments rocheux et de la distribution granulometrique sur l'ecoulement du materiel dans les cheminees. Cet exercice a permis de developper des lignes directrices pour le dimensionnement des cheminees afin de limiter l'occurrence d'accrochage par enchevêtrement rocheux. Les lignes directrices proposees ont ete evaluees en fonction des observations effectuees sur le terrain.


The profitability of mining operations is strongly influenced by the performance of their material handling systems. In underground mines ore pass and waste systems provide a low cost method for the gravity transport of material though large vertical distances. Ore pass related problems can result in the disruption of ore production with important economic consequences. Comprehensive reviews of ore pass related problems have been undertaken by Lessard and Hadjigeorgiou (2003), Hagan and Acheampong (1999), Stacey and Swart (1997), Emmerich (1992) and Ferguson (1991).

This paper addresses problems associated with disruption of material flow above the chute in an ore pass. Subsequent efforts to restore flow are often hindered by lack of suitable access. Furthermore, traditional hang-up release methods, result in production slow downs. Another concern is worker safety, as documented by accident reports during efforts to restore material flow in ore passes. There is also evidence that repeated efforts to unblock ore pass using explosives can result in wall degradation. This may result in costly rehabilitation or, in severe cases, the abandoning of an ore pass.

There is ample empirical evidence that gravity flow of fragmented rock is influenced by material properties and the size and shape of the ore pass.

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