Implementation of a Fracture Modeling Strategy Based on Georadar Survey in a Large Area of Limestone Quarry Bench

Abstract

Rock mass fractures adversely affect the cutting of commercial-size blocks and cause rock material loss in ornamental stone quarries. In order to obtain a reliable evaluation and an optimized production of ornamental stone deposits, it is fundamental to detect fractures in a non-destructive manner identifying them through 3D deterministic modeling. In this study, a recently published fracture modeling strategy, based on Ground Penetrating Radar (GPR) survey was implemented on a large area of bench (27.0 m × 65.0 m) in a limestone quarry in Italy. The survey was done using a dual-frequency GPR system (250 MHz and 700 MHz). The objective of this work was to investigate the large-scale applicability of the mentioned fracture model for future consideration in quarrying optimization studies. Only the 700 MHz radargrams were considered for the fracture modeling, as they provided a higher resolution than the 250 MHz radargrams and a penetration depth of about 4.0 m. The bulk dielectric constant of the rock mass of the bench was estimated by averaging the velocities obtained from fitting the hyperbolic diffractions of fractures at different depths. The model showed that fractures from the same family set can have noticeable spatial variations. The results allowed us to roughly estimate the sizes of the blocks exploitable from the different rock layers of the quarry bench.

From Its Core to the Niche: Insights from GPR Applications

“…The detection of fractures of various scale, from millimetric up to a decametric scale, represents another topic widely researched with GPR, where its geometrical reconstruction capability has made it a valuable tool for characterizing mining sites and rock masses, improving quarries and extraction processes, and determining unstable rock slopes [241][242][243][244]. Another successful application of GPR within this domain is the determination of fracture openings and fillings [245][246][247], crucial for several environmental and engineering applications, including the accessibility of geothermal energy.…”

An Enhanced Data Processing Framework for Mapping Tree Root Systems Using Ground Penetrating Radar

“…The Opera Duo ground-coupled GPR system, manufactured by IDS GeoRadar (part of Hexagon) was employed for testing purposes [13,44]. The system includes two mono-static antennas of 700 and 250 MHz central frequency.…”

A 3D brute-force algorithm for the optimum cutting pattern of dimension stone quarries

“…BlockCutOpt was applied to a bench of limestone quarry where fractures were modeled deterministically in 3D based on Ground Penetrating Radar (GPR) survey. The site description and the fracture model are presented in detail in (Elkarmoty et al, 2018b). The final goal of applying BlockCutOpt software on this case study was to investigate the effect of fractures modeling as 3D surfaces on the production optimization results.…”

“…By personal communication with the quarry technical manager, the preferred block dimensions reported are 3.0 m length, 2.0 m width and the thickness of the block is limited to the thickness of the strata. In this case study, the surveyed bench had four strata (a, b, c, and d), as shown in (Elkarmoty et al, 2018b). Block-CutOpt was used to test the referred block size with its relevant thickness for each stratum in order to find the solutions for the maximum number of non-intersected blocks and the related optimum recovery.…”

“…The modeled fractures must be encoded in the Polygon File Format files (PLY) (Bourke, 2011). The results uncertainty may be minimized when using a 3D deterministic fracture model (Elkarmoty et al, 2018b(Elkarmoty et al, , 2017a. � No natural block identification algorithm is required and there are no restrictions on the number of fracture sets.…”