Ornamental Stone Cutting Processing and Sludge Production Evaluation with the Goal of Ending Waste

In the quarry sector, the reduction of landfill material may be obtained not only by finding a suitable recovery of the material as a by-product, but also by identifying the best available cutting technique to be used on the basis of the physical, chemical, and mechanical characteristics of the stones. The choice of the best cutting technique could lead to high efficiency and performance, high quality of the cut surfaces, and a very low environmental impact by reducing energy consumption, decreasing the concentration of heavy metals in the sludge, and producing less waste. In this context, an analysis of the procedures for cutting different types of ornamental stones into slabs together with the evaluation of sludge production for the different cutting methods has been carried out. Two types of analysis were carried out in parallel: evaluation of the stones workability and calculation of the amount of sludge produced in the three different cutting technologies and from the cutting of blocks. A comparison was carried out on the quality of the sludge produced, on type and quantity of metals present, taking into account the different cutting technologies. The performed tests were: chemical analysis, magnetic separation test, and SEM analysis of the metal fraction. The study could provide stone producers with a technological, scientific instrument to identify the best cutting techniques for the processing of their stones, in order to obtain a high-efficiency process, optimize the recovery process, increase the economic advantages, and evaluate the possible reuse of the sludge through a proactive waste management strategy.

Radiological Hazard Evaluation of Some Egyptian Magmatic Rocks Used as Ornamental Stone: Petrography and Natural Radioactivity

Magmatic rocks represent one of the most significant rocks due to their abundance, durability and appearance; they can be used as ornamental stones in the construction of dwellings. The current study is concerned with the detailed petrography and natural radioactivity of seven magmatic rocks. All are commercial granitic rocks and are identified as black Aswan, Nero Aswan, white Halayeb, Karnak, Verdi, red Hurghada and red Aswan. Their respective mineralogical compositions are classified as porpheritic granodiorite, granodiorite, tonalite, monzogranite, syenogranite, monzogranite and syenogranite. A total of nineteen samples were prepared from these seven rock types in order to assess their suitability as ornamental stones. Concentrations of 226Ra, 232Th and 40K radionuclides were measured using NaI (Tl) scintillation gamma-ray spectrometry. Among the studied magmatic rocks, white Halayeb had the lowest average values of 226Ra (15.7 Bq/kg), 232Th (4.71 Bq/kg) and 40K (~292 Bq/kg), all below the UNSCEAR reported average world values or recommended reference limits. In contrast, the other granitic rocks have higher values than the recommended limit. Except for the absorbed dose rate, other radiological hazard parameters including radium equivalent activity, annual effective dose equivalent, external, and internal hazard indices reflect that the White Halyeb rocks are favorable for use as ornamental stone in the construction of luxurious and high-demand residential buildings.

Artificial Thermal Decay: Influence of Mineralogy and Microstructure of Sandstone, Calcarenite and Marble

Within a major framework of studies around artificial weathering and its effects on different lithotypes, in this work we study the effects of thermal stresses after artificial thermal decay on different types of stones used in historical buildings: a sandstone, a calcarenite and a marble. The sandstone belongs to the so called “Macigno” Formation and mainly outcrops along the northern Apennine (North Western Tuscany) and it has been widely used around Tuscany for building purposes (e.g., in Florence, Lucca, Pisa, Pistoia, etc.); the analysed calcarenite (Gravina) comes from the surrounding of Matera Town and has been deeply used for the construction of the ancient buildings of the town itself; and the marble comes from the Carrara marble district (Northern Tuscany), a highly used stone throughout the centuries as ornamental stone. All these types of stone for their physical and mechanical properties, and aesthetic appearance, have been extensively used as both ornamental stones and as construction materials. To reproduce a plausible effect of natural thermal decay of the stones due to day-to-night and season-to-season fluctuations, we subjected the samples to artificial thermal decay. We carried out different thermal cycles on the samples by using a stove at 150°C and a muffle furnace at 300°C and 450°C. We analysed the physical and mechanical properties before and after each cycle to compare and evaluate the effects of thermal stresses on the stones. Among the different analyses: mass and volume measurements, water absorption tests, mercury intrusion porosimetry, thin-section observations and determination of chromatic alterations through image analysis and Munsell charts method. It was then possible to evaluate the influence of both mineralogy and microstructures on thermal decay of the studied stones (variations in fabric and modifications on physical and mechanical properties).

Industrial stones of the Northern Caucasus: (marble, decorative limestone)

На основании изучения геологических отчетов и публикаций охарактеризованы поделочные камни Северного Кавказа осадочного и метаморфогенного происхождения. Приведено краткое геологическое описание наиболее типичных месторождений мрамора и декоративного известняка. Рассмотрены возраст образования и цветовая палитра камней этого типа. Определены территории и геологические разрезы, благоприятные для их поисков Based Based on the study of geological reports and publications, the ornamental stones of the North Caucasus of sedimentary and metamorphogenic origin are characterized. A brief geological description of the most typical deposits of marble and decorative limestone is given. The age of formation and the color palette of stones of this type are considered. The territories and geological sections favorable for their search are determined

The Historic Centre of Urbino, UNESCO World Heritage (Marche Region, Italy): an Urban-Geological Itinerary Across the Building and Ornamental Stones

The local and extra-regional (national and transnational) stones mainly used as building and ornamental materials in the historic centre of Urbino (UNESCO World Heritage List) were unravelled through a detailed geological and petrographic study. The types of building stones used in the past for the development of an urban centre were mostly affected by the availability of suitable geomaterials in the surrounding areas. For this reason, the stones found in the historical buildings of Urbino generally come from the local sedimentary formations (mostly limestones) belonging to the Umbria–Marche–Romagna Succession Auct., which crops out in the Northern Marche Apennines. Only some ornamental highly prized stones used for monuments and decorations come from both extra-regional Italian areas (Alps, other sectors of the Northern Apennines) and foreign countries (France, Egypt). A brief description of the Northern Marche geology was also reported to exactly match the local provenance of the stones, so highlighting the relationship between the territory and the architecture of Urbino. Because of obvious conservation reasons, no samples were collected from buildings or monuments and only autoptic observations, together with a detailed historical and bibliographic research, were carried out to identify the different materials and the provenance areas. Besides the availability of the local sedimentary rocks, we emphasised how the choice of the building and ornamental stones could have been also influenced by the historic period and artistic style, aesthetic features, economic and social importance of the building and/or monument and the relationship to some distinguished personality (e.g., Pope Clemente XI). An open-air stone itinerary across significant places (10 stops and additional sites and monuments in the urban area) is finally proposed for the best fruition of the geological and cultural heritage of Urbino, also aimed at geotourism development.

Saint John Baptistery in Florence (Italy): Studies for Conservation of the External Marble Cladding

Saint John’s Baptistery in Florence (Italy), dating back to the XI century, represents one of the most outstanding historical buildings in the city, and has been under the UNESCO patronage as Cultural Heritage since 1982. In recent years, in the frame of a conservation project, detailed studies and mapping of all the tiles covering the Baptistery have been developed. Based on a laser-scan survey, a detailed wireframe model of all the external sides, reporting all the tiles and decor, has been developed. This model was implemented into a 2D-GIS, georeferenced in real scale and spatial position. An in situ survey of all the tiles, ashlars, inlays and columns, made in contradiction by experts in historical ornamental stones, allowed the recognition of several types of marble in place. All these marbles have been analyzed and characterized as geometric, geological and historical data, and the information implemented into a GIS for obtaining a spatial geodatabase representing a “box” to store all information achieved. All these data are manageable by web through smartphone, tablet and PC for querying or updating, thus representing an effective management tool for further conservation of such important historical cultural buildings.

Rock Emissivity Measurement for Infrared Thermography Engineering Geological Applications

Infrared thermography is a growing technology in the engineering geological field both for the remote survey of rock masses and as a laboratory tool for the non-destructive characterization of intact rock. In this latter case, its utility can be found either from a qualitative point of view, highlighting thermal contrasts on the rock surface, or from a quantitative point of view, involving the study of the surface temperature variations. Since the surface temperature of an object is proportional to its emissivity, the knowledge of this last value is crucial for the correct calibration of the instrument and for the achievement of reliable thermal outcomes. Although rock emissivity can be measured according to specific procedures, there is not always the time or possibility to carry out such measurements. Therefore, referring to reliable literature values is useful. In this frame, this paper aims at providing reference emissivity values belonging to 15 rock types among sedimentary, igneous and metamorphic categories, which underwent laboratory emissivity estimation by employing a high-sensitivity thermal camera. The results show that rocks can be defined as “emitters”, with emissivity generally ranging from 0.89 to 0.99. Such variability arises from both their intrinsic properties, such as the presence of pores and the different thermal behavior of minerals, and the surface conditions, such as polishing treatments for ornamental stones. The resulting emissivity values are reported and commented on herein for each different studied lithology, thus providing not only a reference dataset for practical use, but also laying the foundation for further scientific studies, also aimed at widening the rock aspects to investigate through IRT.

Destructive care

There is a growing awareness of the essential similarities between care and maintenance notions in more-than-human settings. Whereas the concept of care is increasingly extended towards non-living organisms, research on maintenance and repair still focuses mainly on technologies and infrastructures. This article extends the realm of maintenance theorizing towards humans' caretaking activities and discusses the concepts' parallels. It focuses on the case study of Veps ethnic minority in Karelia, Northwestern Russia. Since the 18th century, Veps have been extracting rare ornamental stones: gabbro-diabase and raspberry quartzite. The article demonstrates that Veps workers engage in close bodily and material interactions with the mining industry. Whereas many of them enter into affective relations with the stone, their attitudes towards their bodies and health become estranged and detached. The article introduces the concept of "destructive care" to analyze the process of the workers' growing alienation from their bodily needs. Through the Veps' example, the article demonstrates that the logics of care and maintenance become entangled in the realm of human – material co-existence.

Red Ereño and Cantera Gorria: Natural and Cultural Geoheritage (Basque Country, Spain)

<p>Construction and ornamental stones are important elements of cultural heritage and identity and shape the urban landscape of the territories (Pereira & Cárdenes Van den Eynde, 2019). These stones and their <strong>quarries</strong> are a part of <strong>geoheritage</strong> that is gaining interest in the tourism industry (Mateos <em>et al.</em>, 2011). <strong>Red Ereño</strong> is an urgonian limestone (Lower Cretaceous) with abundant rudist fossil shells, which white colours highlight on an intense red micritic matrix. This stone is exploited since Roman times in the north of the Iberian Peninsula (Basque Country, Spain). This lithology is found in many buildings, both heritage and common. Its uniqueness has contributed to its expansion worldwide and, it can be found in such emblematic places as the Colon Theatre in Buenos Aires (Argentina) or St Peter´s basilica in the Vatican (Italy) (Damas Mollá <em>et al</em>., 2021).</p><p>The main quarry related to Red Ereño is called <strong><em>Cantera Gorria </em></strong>(meaning Red Quarry) and is located inside the Urdaibai Biosphere Reserve (x: 529,659.29 m; y: 4,800,839.60 m; z: 15 m). It is included in the Geosites Inventory of the Basque Country (LIG nº 15), and is part of the historical heritage of the Biscay province. The last concessionaire of the quarry was <em>Marmolería Bilbaína </em>and it ceased its activity in 1968. At present the quarry is abandoned.  Nevertheless, on its exploitation fronts outstanding <strong>geologic features</strong> are recognised: <strong>stratigraphic</strong> (bioconstructions, facies changes), <strong>petrologic</strong> (diagenesis, mineralisations), <strong>tectonic</strong> (succession verticality, faults) or <strong>geomorphologic</strong> (karst). All of them make <em>Cantera Gorria</em> a point of reference for both <strong>research</strong> and <strong>teaching</strong> activities. Additionally, it is important to underline the richness related to the <strong>mining heritage</strong> itself. Numerous buildings from the mining activity are still preserved. Also noteworthy are the signs engraved on the rock showing the progress of exploitation in various stages, from manual to the use of helical steel wire.</p><p>In the case of Red Ereño and <em>Cantera Gorria </em>the <strong>symbiosis</strong> between <strong>geoheritage </strong>and <strong>cultural heritage</strong> is significant. This symbiosis, together with all the above mentioned characteristics of the quarry makes <em>Cantera Gorria</em> an interesting space for <strong>dissemination</strong> of geoheritage as well as for <strong>tourism</strong> (Damas Mollá, 2011).</p><p><strong>References</strong></p><ul><li>Damas Mollá, L. (2011): Las Calizas rojas de Ereño: facies, paleoambiente, mineralización y diagénesis. Patrimonio geológico-histórico de Bizkaia. PhD Thesis, University of the Basque Country.</li> <li>Damas Mollá L., Uriarte J.A., Zabaleta A., Aranburu A., García Garmilla F., Sagarna M, Bodego A., Clemente J.A., Morales T. & Antigüedad I. (2021). Red Ereño: an ornamental and construction limestone of international significance from Basque Country (northern Spain). Geoheritage 13:2. https://doi.org/10.1007/s12371-020-00529-5</li> <li>Mateos R.M, Durán, J.R & Robledo P.A. (2011). Marès Quarries on the Majorcan Coast (Spain) as Geological Heritage Sites. Geoheritage 3: 41-54. http://doi.org/10.1007/sl12371-010-0026-5</li> <li>Pereira D. & Cárdenes Van den Eynde V. (2019). Heritage Stones and Geoheritage. Geoheritage 11: 1-2. http://doi.org/10.1007/s12371-019-00350-9</li> </ul>