Search

The paper presents the evaluation of quarrying operations as specified by the Eco-Label standards for hard coverings, while it develops the work done by (Elkarmoty et al., 2020a). The economic and environmental optimization of the quarry activities were analysed taking in to account several parameters: production costs, obtainable revenues, waste production, dust and CO2 emissions, water and energy consumption, and the Eco-Label ‘natural resource’ criteria for hard coverings. For the dust and CO2 emissions, water and energy consumption, the research presents a comparison between a chain saw cutter machine and a diamond wire cutter machine. The research’s objective is to evaluate the optimal sustainable engineering and optimization practice in terms of economy and the environment by means of block dimensions and block cutting machinery choices. The research was implemented in a case study of limestone quarry bench in Italy. The highest obtainable recovery ratio was detected as 53%, while the obtainable revenues were found in correlation with the recovery ratio, decreasing with increasing block surface area. However, the lowest production costs were obtained for the block dimension that reflected the lowest recovery ratio, hence, highest waste volume. The dust emissions, energy consumption and carbon footprint of the block cutting operations of the quarry were lower when the diamond wire cutter was used, compared to the chain saw cutter, respectively. For the block cutting of the bench, using blocks with lower surface area were found to have higher recovery ratios than the threshold value which Eco-Label natural resources criteria indicates. The excellence level of the Eco-Label criteria can be obtained in the presented case study only by one block dimension. Each criterion was evaluated in order to find the best practice for the quarry in terms of environment, economy and sustainability.

Ornamental stones are natural building materials, extracted from quarries, which need to be cut and processed sustainably. Natural discontinuities adversely affect the sawing/cutting of blocks into commercial-size slabs. This work presents a 3D optimization algorithm for the sawing/cutting of ornamental stone blocks. The developed algorithm is based on 3D modeling of discontinuities as data input. The algorithm search for the intersection between a 3D cutting grid formed of a determined size of slabs and the model of discontinuities leading to calculate the recovery ratio considering several cutting orientations and displacements of the 3D cutting grid. The algorithm was coded in a program named SlabCutOpt that allows speed problem solving. SlabCutOpt was implemented on a real case study of a commercial-size limestone block extracted from a quarry in Italy. A number of 37 different commercial-sizes of slabs forming 37 cutting grids were tested to investigate the optimum results in geo-environmental direction (recovery ratio) and economic direction (revenue). The findings revealed that a certain slab size gave the optimum recovery ratio, whilst another slab size provided the optimum revenue.

This paper presents a 3D algorithm for finding the optimum cutting direction in ornamental stone quarries aiming at maximizing the recovery ratio of blocks through tackling the fracture problem that causes material and economic loses. The presented algorithm is based on 3D deterministic fracture modeling or mapping data and considers new parameters: i) displacement of the cutting grid; (ii) material lost by quarrying; (iii) irregularity of the tested area; (iv) and subdivision of large quarrying area. The algorithm searches for the optimum cutting direction and displacement of the cutting grid that maximizes the number of non-fractured blocks. The algorithm was coded in a software package named BlockCutOpt. This paper presents BlockCutOpt results applied in two case studies of different characteristics. The first case study was a limestone bench where fractures were modeled deterministically using Ground Penetrating Radar (GPR) survey. The second case study was in a very large area of granite deposit where the regional fractures were mapped using the aerial photogrammetry method (literature data). BlockCutOpt was found a fast tool for finding the optimum cutting pattern in the presented case studies. The results showed that the optimum cutting direction of blocks can vertically (within different strata) and horizontally (within very large scale area) vary, giving geometric information about the cutting grid design that optimizes the number of non-fractured blocks.

The awareness of the impact of high temperatures on rock properties is essential to the design of deep geotechnical applications. The purpose of this research is to assess the influence of heating and cooling treatments on the physical and mechanical properties of Egyptian granodiorite as a degrading factor. The samples were heated to various temperatures (200, 400, 600, and 800 °C) and then cooled at different rates, either slowly cooled in the oven and air or quickly cooled in water. The porosity, water absorption, P-wave velocity, tensile strength, failure mode, and associated microstructural alterations due to thermal effect have been studied. The study revealed that the granodiorite has a slight drop in tensile strength, up to 400 °C, for slow cooling routes and that most of the physical attributes are comparable to natural rock. Despite this, granodiorite thermal deterioration is substantially higher for quick cooling than for slow cooling. Between 400:600 °C is ‘the transitional stage’, where the physical and mechanical characteristics degraded exponentially for all cooling pathways. Independent of the cooling method, the granodiorite showed a ductile failure mode associated with reduced peak tensile strengths. Additionally, the microstructure altered from predominantly intergranular cracking to more trans-granular cracking at 600 °C. The integrity of the granodiorite structure was compromised at 800 °C, the physical parameters deteriorated, and the rock tensile strength was negligible. In this research, the temperatures of 400, 600, and 800 °C were remarked to be typical of three divergent phases of granodiorite mechanical and physical properties evolution. Furthermore, 400 °C could be considered as the threshold limit for Egyptian granodiorite physical and mechanical properties for typical thermal underground applications.

Il georadar o GPR (Ground Penetrating Radar) può essere utilizzato per rilevare la presenza di fratture nei depositi di rocce ornamentali con delle limitazioni in termini di profondità di penetrazione e risoluzione dei risultati. Il GPR è stato scelto in questo lavoro di ricerca per l’utilizzo in cava in quanto è in grado di fornire un’immagine del sottosuolo, attraverso l’ammasso roccioso sia in 2D che in 3D. Ciò consente di definire lo stato reale di fratturazione che, a sua volta, permette una modellazione dei fenomeni di frattura secondo un approccio deterministico 3D. Questo si rivela utile per la valutazione dei giacimenti lapidei e necessario per l’ottimizzazione della produzione e la minimizzazione degli scarti. Il GPR potrebbe essere utilizzato non solo a livello di bancata in cava, ma anche per l’analisi dei blocchi. Di conseguenza, l’ottimizzazione della produzione può avvenire in modo sostenibile per entrambe le applicazioni.

The exploitation potential of shallow geothermal energy is usually defined in terms of site-specific ground thermal characteristics. While true, this assumption limits the complexity of the analysis, since feasibility studies involve many other components that must be taken into account when calculating the effective market viability of a geothermal technology or the economic value of a shallow geothermal project. In addition, the results of a feasibility study are not simply the sum of the various factors since some components may be conflicting while others will be of a qualitative nature only. Different approaches are therefore needed to evaluate the suitability of an area for shallow geothermal installation. This paper introduces a new GIS platform-based multicriteria decision analysis method aimed at comparing as many different shallow geothermal relevant factors as possible. Using the Analytic Hierarchic Process Tool, a geolocalized Suitability Index was obtained for a specific technological case: the integrated technologies developed within the GEOTeCH Project. A suitability map for the technologies in question was drawn up for Europe.

Discontinuities can be hidden or out-cropping with variable aperture sizes in rock media. Obtaining deterministic geo-spatial features of discontinuities inside quarried ornamental stone blocks is a decision-making tool for the post processing phase of cutting slabs. In a case study of a limestone block, discontinuities were detected by the Ground Penetrating Radar (GPR) through a high frequency antenna (700 MHz) and deterministically modeled in three dimensions following the method presented in Elkarmoty et al. (2017). The use of the 700 MHz GPR antenna in this kind of rock allowed to detect tiny-size apertures of discontinuities. The results showed that it is possible to detect and model not only the outcropping discontinuities, but also the hidden ones. Hidden three-dimensional voids or defects were detected and modeled as well. The resulting model was visualized in different orientations, using a 3D data visualization software package, for a better perception of the results.

none 5 no The paper examines methods of assessing the critical fractures and quality of an ornamental stone deposit. Fracture status was evaluated by an in-situ Ground Penetrating Radar (GPR) test. The resulting 3D GPR model allowed exploration of the extension, shape, and orientation of the detected fractures surfaces. It also identified a rock stratum with a noticeably lower load of critical fractures compared to the other strata. Physico-mechanical properties were investigated by laboratory tests allowing classification of the deposit into quality categories, which provided a promising correlation with the GPR survey results. mixed Elkarmoty, Mohamed; Colla, Camilla; Gabrielli, Elena; Bonduà, Stefano; Bruno, Roberto Elkarmoty, Mohamed; Colla, Camilla; Gabrielli, Elena; Bonduà, Stefano; Bruno, Roberto

none 5 no Rock mass fractures adversely affect the production of ornamental stone quarries. Fractures cause natural rock blocks which threaten extracting the required commercial block size of ornamental stones. An accurate subsurface detection and modeling of fractures is required for pre-exploitation evaluation and planning. This paper introduces a new three-dimensional deterministic fractures modeling approach using Ground Penetrating Radar (GPR) as a data acquisition tool. A case study was performed in a fractured bench of a sandstone quarry in Firenzuola, Italy, using a 400 MHz GPR antenna. To accurately detect fractures at true depth, an in-situ calibration based on knowing the depth of a subsurface reflector, as a reference, allowed to estimate a bulk dielectric constant of the rock mass in the time of data acquisition. A data interpretation tracing technique was developed to model fractures as 3D surfaces in two forms, either irregular or planes. The modeled fractures were visualized through a multiplatform visualization software package (ParaView). A comparison between the orientations of the fractures measured through the traditional manual survey and the orientations of the modeled fractures is presented as a possible geologic validation for the detection and interpretation of fractures. For the objective of pre-exploitation evaluation, a distribution analysis study of fractures allowed to obtain an evaluation-based fracture index for the bench of the case study. mixed Elkarmoty, Mohamed; Colla, Camilla; Gabrielli, Elena; Bonduà, Stefano; Bruno, Roberto Elkarmoty, Mohamed; Colla, Camilla; Gabrielli, Elena; Bonduà, Stefano; Bruno, Roberto

The document is an extended abstract presented at "GeoENV 2016", the 11th International Conference on Geostatistics for Environmental Application Conference, 6-8 July 2016, Lisbon, Portugal.