Adilson Curi

Otimização econômica de explotações a céu aberto

The determination of the final pit limits of any mining project is one of the most important challenges in a mining project. Such limits need to be defined at the beginning of the mine planning and should be reconsidered, again and routinely, during all the useful life of a mine. One of the purposes of the open pit mine exhaustion plan is the determination of the optimal final pit, based on an economic model subject to technical restrictions and aimed to maximize the net present value. LERCHS e GROSSMANN (1965) published the first specific algorithm related to the theme. This algorithm has been accepted as standard in comparison to other equivalent algorithms which have been proposed, because it solves the corresponding problem, according to the graph theory, of the minimum cut and maximum flow. Other final pit optimization algorithms are presented in this study too. The authors developed an academic program for pit optimization and the principles of this program are presented in this article.

Perspectives for use of hydraulic fracturing in oil and gas production

Hydraulic fracturing emerges currently, all over the world, as one of the more strategic techniques used by companies in the oil exploitation sector. This technique is characterized by its high productivity and profit in relation to conven tional methods of hydrocarbon exploitation. However, in many countries, as is the case of Brazil, there are several divergences considering the employment of this methodology. Many renowned researchers attest that there are several irreversible environmental impacts generated by the use of this methodology. Among the main environmental impacts are the risk of groundwater level contamination, the risk of surface subsidence, and the risk of the environment contamination with fluids used in the process of the oil and gas extraction.

Las Zeolitas y su Aplicación en la Descontaminación de Efluentes Mineros

En este articulo se presenta la genesis, la estructura y la clasificacion de las zeolitas naturales. Se describen las propiedades mas relevantes de las mismas, tales como porosidad, adsorcion e intercambio ionico. Se revisan los usos de las zeolitas naturales en el tratamiento de efluentes conteniendo metales pesados segun la literatura vigente. Dichos usos estan enfocados hacia el tratamiento de efluentes minero-metalurgicos y la contaminacion por mercurio en actividades mineras informales. El estudio muestra que las zeolitas naturales son eficientes en la remocion de metales pesados en efluentes minero metalurgicos, pueden ser producidas y beneficiadas a bajo costo, y pueden ser usadas tambien para la adsorcion de vapores de mercurio en hornos de copelas quemadores de amalgama.

Avaliação econômica do minério remanescente nos taludes da cava final da Mina de Alegria

Esse trabalho apresenta uma estimativa do beneficio que pode ser auferido atraves da recuperacao do minerio remanescente nos taludes da cava final de uma mina a ceu aberto atraves da aplicacao de uma metodologia de lavra baseada no metodo de corte e enchimento. Para exemplificar o uso da metodologia proposta, foi adotado o caso das minas de minerio de ferro de Alegria de propriedade da Samarco Mineracao S.A. A viabilidade economica da recuperacao do minerio remanescente em taludes de cavas exauridas de minas a ceu aberto envolve recursos que estarao diretamente ligadas ao valor de mercado do produto e ao custo operacional para sua recuperacao. Na fase de exaustao de uma mina, tradicionalmente, considerada como de desembolso de capital, a geracao de receitas adicionais e bem-vinda, pois implica ganhos economicos nao previstos na fase de fechamento de minas e ate em minas ja paralisadas, acrescendo-se tambem um ganho ambiental devido a nao construcao de pilhas de esteril.

A dependência da arrecadação do município de Ouro Preto do setor mineral

The promotion of the mining industry can be an opportunity for the local government to improve revenue, allowing for more possibilities to provide public services of quality to the population; it is a financial source for local development. Knowledge of the dependency level of the local revenue derived from mining activities is necessary for mining-based municipalities. Monitoring of reserve levels and ore production is a way to get prepared for the temporality of the mineral industry and the fluctuation of the commodities market. Thus, it is indispensable that public policies be provided to diversify the local economy and to elaborate a tax policy consistent with the characteristics of the local mineral economics. This study analyzes the situation of the mining revenue dependency of the Ouro Preto municipality as compared with other municipalities and then introduces perspectives for debate.

Realização de projeto de lavra de mina subterrânea com utilização de aplicativos específicos

Underground mine planning is an important element for achieving project realization in the current highly competitive scenario. This is due to the peculiarities of the underground mines, where it is difficult to obtain profound knowledge about the body and location of the underground excavations. Computer applicationsspatially visualize the ore body with its geological sections and mineral formation contours. This visual is in 3D that facilitates the allocation of major mine development services. Although such resources are available, their mining applications are generally developed for open pit mining methods, and is still incipient for underground mine-development methodologies. With the use of applications for mine development and planning, and the similarity of existing mines, it was possible to prepare the infrastructure project for a specific underground mine, and a 3D view of its underground openings. It was also possible to develop a methodology for drawing the galleries described. This paper deals with the selection of mining methods for a major simulated mineral deposit and describes breakthroughs of underground mine development design using a commercial mining application.

Efeito da rugosidade recortada polida no escoamento em modelo de passagem de minério

The main objective of this paper is to analyze the behavior of bulk material fl ow in rough-surface ore passes. A physical model of an ore pass in reduced scale has been used to observe the effect of the roughness on the fl ow. The insertion of wooden plates on the internal walls of the model was carried out in order to simulate the slickensided stepped roughness. This model of roughness has been selected from the standards adopted internationally by the ISRM due to its similarity with the actual roughness found in ore passes built using explosives. The tests showed that the slickensided stepped roughness causes a signifi cant decrease of the fl ow rate when compared to the tests carried out with smooth walls. The tests’ results also indicated the occurrence of mechanical arches, funnel fl ow and turbulent fl ow.