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Considering the applicability of Kuz-Ram model, which has been used extensively for predicting rock fragmentation size distribution by blasting, to domestic open-pit limestone mine, a total of 21 blasting tests have been executed at an open-pit limestone mine in eastern Gangwon of South Korea. A comparative analysis of field measured value and Kuz-Ram predicted value showed that there are a considerable amount of error in the predicted values regardless of application of various correction parameters for rock factor and uniformity factor; up to 56.45% in mean fragmentation size and 37.52% in uniformity index. Also the problem of applying different correction parameters has been derived even though a similar blasting pattern has been adopted for a same blasting bench. The authors therefore suggest that Kuz-Ram model needs to be modified for a proper application to domestic open-pit limestone mine.

The Linear Cutting Machine (LCM) test is known to be a reliable method for designing disc cutters by estimating the penetration performance of a Tunnel Boring Machine (TBM). The LCM test is a laboratory test that uses large-scale rock blocks to estimate the real-scale load on disc cutter; the LCM test offers many advantages, but the costs of preparing the rock samples and performing the laboratory test are too high. In addition, the test results from jointed rock blocks are rarely trustworthy because of the difficulty of performing the LCM test with this type of rock sample. To compensate for the failings of the laboratory test, many studies have been conducted to develop a suitable numerical model. However, few studies have investigated the mechanism of rock fragmentation as a function of the joint spacing and the joint direction. This paper presents the results of a Discrete Element Analysis (DEA) of the cutting power exerted on a TBM disc cutter at various joint dip angles, dip directions and spacings. The results show that the cutting power must be increased when the disc cutter advances in a direction opposite to the joint dip. The numerical analysis also shows that the cutting power of a disc cutter increases as the joint dip angle decreases and the joint spacing decreases. Comparing the relationship between the cutting power of the disc cutter and the distribution pattern of the rock joints with the LCM test results can be used to increase the reliability of TBM performance predictions.

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The LCM (Linear Cutting Machine) test is one of the most powerful and reliable methods for designing the disc cutter and for predicting the TBM (Tunnel Boring Machine) performance. It has an advantage to predict the actual load on disc cutter from the laboratory test on the real-size large rock samples, however, it also has a disadvantage to transport and/or prepare the large rock samples and to need an extra cost for experiment. In order to overcome this problem, lots of numerical studies have been performed. In this study, the PFC3D (Particle Flow Code in 3 Dimension) has been adopted for numerical analysis on optimum cutter spacing and failure aspects of Busan Tuff. The optimum cutting condition with  ratio of 16 and minimum specific energy of 14   was derived from numerical analyses. The cutter spacing for Busan Tuff had the good agreements with those of LCM test and numerical analysis by finite element method.