Original scientific paper
Monitoring to evaluate blasting quality and the prediction of fragmentation
Branko Božić
; Geotechnical Faculty, University of Zagreb, Varaždin, CROATIA
Abstract
Rock fragmentation is considered the most important aspect of production blasting because of its direct effects on the costs of drilling and blasting and on the economics of the subsequent operations of loading, hauling and crushing. Over the past three decades, significant progress has been made in the development of new technologies for blasting applications. These include the advancement of modern instrumentation for monitoring, increasingly sophisticated computer models for blast design and blast performance prediction and more versatile explosives and initiation systems. The first problem one faces when dealing with rock fragmentation by blasting is how to define it. The size distribution of a blasted bench could be accurately defined by screening, but this is not practical as it would be far too expensive (laborious and interrupts the production) and time consuming. Therefore, numerous methods for the estimation of the size distribution of rock fragments have been developed. Because rock fragmentation depends on many variables such as rock properties, site geology, in situ fracturing, moisture content and blasting parameters, there is no complete theoretical solution for the prediction of blast size distribution. However, useful empirical models are used to estimate the size distribution. The most commonly used is the KuzRam model, which is presented in the research report together with popular photoanalysis methods. Gold Size is a Windows based computer program to estimate the sizes of blast fragmentation size distributions. It can be concluded that by increasing the awareness and knowledge of the effects of rock fragmentation by blasting on the mining operations and the corresponding costs, the economics of an open pit can be improved. The authors have developed a blast fragmentation model “SB” which will take into account the compressive/shear mechanism of blast fragmentation, and will be able to predict the entire fragment distribution curve more accurately, irrespective of the mechanical properties of the rock matrix.
Keywords
monitoring, blasting quality, rock fragmentation
Hrčak ID:
318802
URI
Publication date:
12.12.2001.
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