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Abstract

Proper values of physical and mechanical properties and their homogeneity are one of major requirements deciding about technological suitability of the rocks quarried to manufacturing aggregates. These properties depend on the natural features of a rock, its mineral composition, texture and structure. The characteristic of aggregates and the technical requirements they must meet are normalized in adequate standards that describe the procedures of conducting particular determinations and the methods of interpreting their results. In the basaltoids (usually called basalts) of selected deposits of Lower Silesia that represent different intrusive forms, five textural varieties have been distinguished: aphanitic, aphanitic-porphyritic, porphyritic-aphanitic, porphyritic-nodular and nodular-porphyritic. The petrography and essential physical and mechanical properties of these varieties have been described in Tables 1 and 2, respectively. The highest technical parameters have the aphanitic and aphanitic-porphyritic rock varieties. They result mainly from the textures of these rocks and their insignificant weathering, and to a lesser degree from their mineral composition. The resistance to wear (micro-Deval) and the resistance to fragmentation (Los Angeles) of the aggregates that represent the grain fraction 10-14 mm of the five varieties of basaltoids and the rock composites were determined according to the standards PN-EN 12620: 2008 and PN-EN 13043: 2004. Of the aggregates produced from the five major varieties, only those made of the nodular-porphyritic basaltoids have the properties of lower categories, whereas the remaining four are the materials of very high quality. Additionally, it has been shown that by combining various basaltoid types it is possible to produce composite aggregates with the variable qualities belonging to the categories LA and MDE (Tab. 3). The effect of rock petrography on the differentiation of the parameters of aggregates depending on the grain fraction of the products (Fig. 1, Tab. 4) is the lowest in the case of the aggregates produced from the homogenous and not weathered rock. In contrast, the range of variability of the parameters is higher if the starting material to produce aggregates is composed of several textural varieties and shows signs of weathering as well. The possibility of delineation of the areas occupied in the deposit by basaltoids with specific textural varieties creates the conditions of determining the rock zones, from which the aggregates of the predicted quality may be produced. This quality may be controlled and partly changed to the user needs by producing aggregates from the specially prepared rock mixtures (i.e. the charge to crushers) with specified proportions of the basaltoid varieties.

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Authors and Affiliations

Marek Rembiś
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Abstract

Artykuł podejmuje problem analizy rozpowszechnienia szczególnej techniki barokowej stosowanej w projektowaniu fasad budynków monumentalnych na Dolnym Śląsku. Po raz pierwszy metodę tę wykorzystał w swych rzymskich aranżacjach Francesco Borromini. Dlatego nazwa tej techniki pojawia się najczęściej w literaturze pod włoskim określeniem parete ondulata. Ten sposób formowania fasad rozpowszechnił się szybko krajach europejskich, gdzie przyjmowały się formy nieklasycznego baroku, w tym na Dolnym Śląsku. Metoda elewacji wklęsło-wypukłej dawała bowiem duże możliwości w kreowaniu przyciągającej uwagę architektury i umożliwiała wyszukaną aranżację wnętrz urbanistycznych o silnym oddziaływaniu na odbiorcę. Metoda parete ondulata nie została przyswojona w lokalnej architekturze śląskiej. Większość budowli, które prezentują tę formę powstała na podstawie projektów Kiliana Ignaca Dientzenhofera. Poza tym metoda w zredukowanej formie została też zastosowana w kilku przypadkach przez architektów austriackich działających na Śląsku (J. B. Peintner, Ch. Hackner). W ciasnych wnętrzach urbanistycznych technika parete ondulata umożliwiała silniejsze oddziaływanie. Jednak na Śląsku wykorzystano ją tylko w pałacowych fasadach pierzei ulicznych we Wrocławiu – pałac Hatzfeldów i Uniwersytet Wrocławski oraz drobnych formach stosowanych w architekturze w latach 1715–1740, np. w portalach. Pomimo to, tych kilka dzieł architektury monumentalnej wzniesionych na Dolnym Śląsku z użyciem omawianej techniki prezentuje się jako dzieła wybitne w skali ogólnoeuropejskiej o indywidualnych, lokalnych cechach. Ze względu na twórców, wykazują również powinowactwo z kręgiem austriackim i czeskim.
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Authors and Affiliations

Bogna Ludwig
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Abstract

Chromium ore is treated as an important strategic raw material. It is used by many branches of the industry. The most important applications are metallurgical, refractory and chemical. Unfortunately, no chromium ore deposits have been found in Poland until now, with the exception of two chromium ore sites described in the Lower Silesia region. These concentrations are formed by chromitite, which is rock consisting mainly of chromian spinel. They are localized within so called Sudetic Ophiolite rocks along the edge of the Góry Sowie Massif. They form typical podiform deposits, which are characterized by the high Al content of the rock. The first locality, near Tąpadła village (the Gogołów-Jordanów Massif), is better known. The ore was exploited here at the turn of the19th century and at the beginning of the 20th century. According to the literature, 3500 tons of the ore was obtained - all the resources at this location. The second locality, situated at the Braszowice-Brzeźnica Massif, was never studied and described properly, falling into obscurity since the 19th century. During the field work at the Braszowice-Brzeźnica Massif, the author has found numerous chromium ore fragments among the debris. The rising prices of chromium on the world's markets suggest that it is reasonable to study the ore quality and overall resource potential of this deposit. The preliminary studies have shown that chromitities from Braszowice are typical ores of the podiform variety, the majority texturally massive and nodular. The chemical analyses of the primary chromianspinels grains revealed that they could be treated as refractory chromite (38% wt. of Cr2O3, lower than 30% wt. of Al2O3, and Cr/Fe ratio about 3:1). However, the metamorphic processes modified the primary chemical composition of the studied ore. They caused enrichment in Fe and Cr, and a decrease in Al in comparison to the primary ore. Moreover, the whole rock chemical analyses revealed that the content of the main elements is insufficient to use the ore without enrichment processes. Furthermore, the size and number of the potential ore bodies are presumably small. Consequently, both the chemical composition and the resources of the chromium ores from the Braszowice–Brzeźnica Massif are insufficient to allow for profitable exploitation, despite the high price of chromium.

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Authors and Affiliations

Katarzyna Delura

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