Optymalizacja kosztów wydobycia ścianowego z prowadzeniem stropu na zawał, przy wybieraniu warstwami poziomymi

To increase the economic and technical performances of the Jiu Valley hard coal mines, the top coal caving, in horizontal slices, mining methods (Bourbaki methods) were introduced, adapted to the local geo-mining conditions. This mining was successfully experimented by using classical technology, using the individual supports and coal blasting. In the future, it is planned to adopt the mechanized technology, with frame supports and shearers. The mechanized longwall faces with top coal caving mining, in horizontal slices, of coal seam no. 3 could be efficient only if the sizes of the top coal height and the panel length determine a minimum cost of production. Therefore, the goal of this paper is the optimization of these parameters, from a technical and economic point of view, taking into account the general model of the cost function, at the panel level. For that, it was necessary to make a certain sequence of analysis involving: technological unit establishment, purpose function and optimizing model. Thus, there attaining to the mathematical model of the unit cost, after determination of all the individual calculation articles, regarding the preparatory workings, coal face equipments, materials, energy, workforce, etc. Because of the complexity of the obtained technical and economic model, to determine the optimum sizes of the panel length and top coal height, it was necessary to archive a sensitivity analysis of the unit cost function to the main parameters implied into this mathematical model.W celu podniesienia wydajności i opłacalności wydobycia, w kopalniach węgla kamiennego w Dolinie Jiu wprowadzono metodę wybierania warstwami poziomymi, z prowadzeniem stropu na zawał (metoda Bourbaki), przystosowaną do panujących w terenie warunków geologicznych i górniczych. Wydobycie prowadzono z powodzeniem przy użyciu tradycyjnych technologii: prac strzałowych i systemu podpór. W przyszłości planuje się zastosowanie wybierania zmechanizowanego, z wykorzystaniem systemu obudów oraz wrębiarek. Wybieranie ścianowe warstwami poziomymi w prowadzeniem stropu na zawał w przypadku pokładu nr 3 będzie efektywne jedynie wtedy, gdy odpowiednio dobrane zostaną wysokość węgla stropowego i długość pola wybierania, tak by zapewnić minimalne koszty wydobycia. Celem niniejszego opracowania jest optymalizacja tych parametrów, z uwzględnieniem aspektów technicznych i ekonomicznych, z wykorzystaniem ogólnego modelu funkcji kosztu dla danego poziomu pola wybierania. W tym celu przeprowadzono wieloetapową analizę, obejmującą określenie parametrów jednostkowych, funkcji celu oraz modelu optymalizacyjnego. Matematyczny model funkcji kosztu opracowano po uwzględnieniu niezbędnych do procedury obliczeniowej aspektów: prac przygotowawczych, analizy sprzętu używanego w rejonie przodka, materiały, energii, siły roboczej. Z uwagi na złożoność otrzymanego modelu technologicznego i ekonomicznego, aby obliczyć optymalny wymiar pola wybierania i wysokość węgla stropowego, niezbędne było przeprowadzenie analizy wrażliwości funkcji kosztu jednostkowego na zmiany podstawowych parametrów modelu

Representações sociais de saúde bucal entre mães no meio rural de Itaúna (MG), 2002 A social representation study of oral health among mothers in rural areas, Itaúna (MG), 2002

Análise das representações sociais sobre o processo saúde-doença bucal entre 29 mães de escolares residentes no meio rural de Itaúna, em 2002. As entrevistas semi-estruturadas foram transcritas e a análise de conteúdo foi desenvolvida. A análise mostra que as representações sociais sobre saúde-doença estão vinculadas à alimentação e utilização de serviços médicos. Em relação ao processo saúde-doença bucal, identifica-se um discurso associado às normas odontológicas de higiene e dieta. A cárie dentária é vista como uma experiência inevitável, mas a perda dentária, não. Apesar de as condições materiais de vida no meio rural dificultarem a adoção de práticas consideradas favoráveis à saúde bucal, essas mulheres são cobradas em relação ao trabalho de cuidar dos filhos. Essa vivência contraditória causa sentimentos negativos (culpa) e, como conseqüência, queda na qualidade de vida nessa população. Na realidade de vida das entrevistadas, verifica-se que, apesar de as mesmas apresentarem informações sobre o cuidado bucal e desejarem "cuidar dos filhos direito", uma complexa rede de fatores sociais, econômicos, culturais etc., não favorece a promoção de saúde. O planejamento das ações de saúde bucal coletiva deveria levar em consideração não somente dados epidemiológicos quantitativos, mas também as representações sociais sobre saúde bucal.<br>The study evaluated social representation on oral health-illness process between 29 scholarship's mothers in rural areas from Itaúna, in 2002. Semi-structured interviews were transcripted and content analysis was developed. The results have showed that social representation of health-illness was associated with food intake and medical service utilization. Discourse on oral health-illness process was related to dental hygiene and diet rules. Dental caries were an inevitable experience, but tooth loss was not. Despite material conditions of life in rural area have not enabled favorable oral health practices, these mothers were considered responsible for their children oral health care. This contradicted life has caused negative feelings (as guilty) and, consequently, bad quality of life. Respondents have had information about oral home care and they desired to "take care of children well". However, a complex net of social, economic and cultural factors has not favored health promotion. Planning public oral health actions should take in account not only quantitative epidemiological data but social representation of oral health