Fracture System and Rock-Mass Characterization by Borehole Camera Surveying: Application in Dimension Stone Investigations in Geologically Complex Structures

Ivica Pavičić,Ivo Galić,Ivan Dragičević,Mišo Kucelj

doi:10.3390/app11020764

Abstract

The successful exploration of dimension stone mainly depends on the quality, size, and shape of extractable blocks of dimension stone. The investigated area is in the Pelješac Peninsula (Croatia), in the External Dinarides orogeny, built from thick carbonate succession, characterized by relatively small deposits of high-quality dimension stone. These conditions demand challenging geological investigations in the “pre-quarry” phase to find optimal quarry location. The size and shape of dimension stone blocks are mainly controlled by fracture pattern systems. In the rugged, covered terrains, it is very hard to obtain a satisfactory amount of fracture data from the surface, so it is necessary to collect them from the underground. Borehole camera technology can visualize the inner part of the rock mass and measure the fracture characteristics. The main conclusions are as follows: (1) the digital borehole camera technology provides a quick, effective, and low-cost geological survey of fractured rock mass; (2) statistical fracture distribution parameters, P10, fracture spacing, Volumetric Joint Count (Jv) based on borehole wall survey can reflect the integrity of rock mass, providing a solid decision-making base for further investment plans and dimension stone excavation method.

Highlights

Dimension stone and crushed rocks are considered key natural resources that enable the sustainable functioning of the worldwide economy
In the research area in Pelješac Peninsula (Croatia), intensive geological research was conducted to define the potential of the location for dimension stone quarry
Challenged by the given task, a new methodology was proposed to survey fractures on drill hole walls by the borehole video camera and structural analysis of fracture sets that result in Volumetric Joint Count (Jv) estimation

Summary

Introduction

Dimension stone and crushed rocks are considered key natural resources that enable the sustainable functioning of the worldwide economy. Global demand for dimension stone, due to its aesthetic and petrophysical properties being used in the construction industry, including indoor and outdoor spaces, is related to the development of the economy [1]. A global increase in demand for dimension stone increased research activities worldwide, and in the Dinarides in Croatia and Bosnia and Herzegovina. The Dinarides are a fold-and-thrust orogenic belt that is geotectonically positioned along the NE margin of the Adriatic Sea. The Dinarides have great potential for dimension stone of sedimentary origin, but locations and the lateral extent of the potential areas are primarily controlled by regional tectonic settings. Since Dinarides are orogeny created by strong compressional tectonic forces, the rocks are often very faulted, folded, and fractured

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Conclusion