Radon is a chemically inert noble radioactive gas found in several radioactive decay chains. In underground mines, especially those that contain or have contained ores associated with uranium-bearing minerals, workers might be exposed to high levels of radon and its decay products (RDP). This work aims to investigate whether the exposure of workers to radon gas and its progeny has been evaluated in Brazilian non-uranium and non-thorium underground mines. Any such results and control measures undertaken or recommended to maintain concentrations under Brazilian occupational exposure limits (OELs) are documented. The methodology we adopted consists of three main phases. The first was an extensive bibliographical survey of the concentration levels of radon and RDP, as well as the radiation dose estimates, considering measurements made heretofore by various Brazilian researchers and exhibiting original measurement work undertaken by the one of the authors (mine O). In the second phase, the values obtained were compared with OELs. In the third phase, any control measures undertaken in mines with high exposure of workers to radon and its progeny were verified, and the adopted controls were determined. Radon concentration data obtained from 52 campaigns in 40 underground mines were analyzed. The results show that assessment of the exposure of workers to radon and its progeny was undertaken in many mines at least once, and that radon levels in 62.5% of the mines, when visited for the first time, were below the Brazilian OELs. As expected, the main control measure adopted or recommended was improvement of the ventilation system.
Mining plays an important role in Brazilian exports. On the other hand, large urban centers like São Paulo, with approximately 21 million inhabitants, also demand an increasing domestic consumption of natural resources, such as construction aggregate. There are many quarries located in the surroundings of urban centers in Brazil, competing with the growth of urbanized areas. Such proximity leads to a series of conflicts involving quarries and surrounding communities, where the increase in noise levels is highlighted. Operations in quarries, in general, are intermittent. Noisier equipment, such as drilling rigs and primary crushers, operates only a few hours during the day, while other operations, such as screening and secondary and tertiary crushing, are more constant. This paper presents a study carried out in a quarry located near São Paulo, where in addition to conventional short term noise measurements at surrounding receptors, one noise monitoring station was installed, allowing to identify the noisiest moments during the quarry operating time. Through data transmitted by wireless technology, it was possible to follow the noise variations emitted from mining activities in real time and observe the noisiest events that were recorded for events that exceeded the established standards. A mobile application associated to this monitoring station facilitated the quarry's manager and employees to access immediately the monitoring information. Therefore, by using this system, it was possible to evaluate the effectiveness of noise reduction measures already taken and indicate what steps still need to be held.
Este é um artigo publicado em acesso aberto (Open Access) sob a licença Creative Commons Attribution, que permite uso, distribuição e reprodução em qualquer meio, sem restrições desde que o trabalho original seja corretamente citado. a ResumoNa mineração subterrânea a ventilação é um fator crítico. Uma ventilação inadequada ou insuficiente compromete a saúde e a segurança dos trabalhadores, principalmente nas minas de carvão que precisam lidar normalmente com gases inflamáveis e poeira explosiva. Esse trabalho tem como objetivo analisar o sistema de ventilação atual de uma carbonífera no sul do Brasil, através da medição da velocidade, cálculo da vazão de ar em suas galerias e simulação via modelagem em um software de ventilação. Foi feita uma visita para a realização dos trabalhos de medição e o levantamento das características essenciais para a construção do modelo. Os resultados dos parâmetros medidos e simulados permitem concluir que é possível utilizar o modelo e adotar a metodologia proposta com uma precisão satisfatória. Conclui-se também que a empresa atende às exigências regulatórias devido ao acompanhamento periódico e manutenção de uma vazão superior à necessária. Ainda assim, poderia haver benefícios com uma modelagem do circuito de ventilação que pudesse otimizá-lo, segundo a evolução da lavra. Contudo, para isso, recomendam-se mais pontos de amostragem, assim como a determinação da perda de carga entre trechos. Palavras-chave: Ventilação de mina; Qualidade do ar de mina; Simulação de ventilação.
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