Cave mining: 16 years after Laubscher's 1994 paper ‘Cave mining – state of the art'

Abstract

This paper supplements a keynote address prepared for the 2010 Second International Symposium on Block and Sublevel Caving. The author gauges the cave mining industry's position (practice and theory) since the publication of what he considers a seminal paper on ‘Cave mining – state of the art’, hence ‘16 years after’. For clarity, this paper is not meant to be a critique or an endorsement of the cave mining design rules as presented by Laubscher's 1994 paper, as well as an endorsement of a selection of emerging and noteworthy cave mining design and optimisation approaches. The latter methodologies are expected to gain significance as cave mining enters into a new phase of large scale operations at greater depths which the author and others describe as super caves. In this next era of cave mining, improved knowledge and incorporation of the governing physics and fundamentals of the associated caving process or phenomena will become even more important for cave design and performance prediction and, therefore, reliability. The paper starts by providing a snap shot of contemporary caving designs (and practices), highlighting achievements made by the cave mining industry since the introduction of mechanised caving in primary ores. It concludes by listing the developments made in the last 16 years as well as the current and future challenges. The author concludes that contemporary designs and the number of design rules in Laubscher, while still remaining in use, may be reaching their limit when applied to large scale operations or super caves and they need to be supplemented by a number of the emerging techniques. The attributes which make super caves unique are presented. The opportunity is to continually improve and to test these emerging methods. Finally, it should be noted that the paper is written from the author's perspective as a mining research engineer and more recently (from 1997 to current) as the technical director of two international industry collaborative projects; the International Caving Study (ICS) and the Mass Mining Technology (MMT) projects. These projects focus on improving the understanding of the underpinning fundamentals associated with the caving of strong rock masses or primary rock (i.e. rock mass characterisation, caving mechanics including seismicity, preconditioning, gravity and disturbed flow, primary and secondary fragmentation and confined blasting), mainly at moderate depths and stress environments. The original intent of the ICS was to critique, improve and/or supplement a number of the design rules as presented in the Laubscher seminal paper, given the move towards caving of strong rocks or primary rocks. The MMT then put more emphasis on the study of caving fundamentals.