Joint analysis as an important tool for an optimizing block extraction of natural stones

Abstract

The steadily increasing demand on the natural stone market is accompanied by a predominantly poor economic balance in the extraction of the raw material "ornamental stone". Thus, the net production of raw blocks is far too low in relation to the resulting overburden, which is often the result of insufficient geoscientific input and evaluation of the deposit itself and the deposit-controlling factors. Under these conditions, the investigation pursued the goal of capturing an essential part of the geological conditions with the analytical observation of the fractures systems, in order to contribute to an optimized stone extraction. Only by critically derived constraints on the quarrying process based on the geological situation can the economic viability of natural stone deposits be maintained or increased in the long term, and this from an environmentally friendly point of view. Profitable dimensional stone production mainly depends on the number of extracted blocks. Compared to statistical approaches, the application of the 3D-BlockExpert computer code is based on modelling the block sizes on the discontinuity system such as fracture spacing and fracture orientation. The assessment of all joint and fracture systems provides a forward-looking approach for sustainable quarry management. It is essential to make the best possible use of high-quality material and to minimize the impact quarrying activities has on the natural landscape. Investigations were carried out in quarry areas with different lithologies in Germany and Spain, like sandstones, limestones, slate and granites. The block sizes, the irregularity of acute-angled blocks and the waste to block ratio controls the economic success by avoiding time- and cost-consuming procedures based on geoscientific considerations.