Long-Term Slope Stability of Abandoned Mine Lake—Numerical Modelling and Risk Assessment

Almost all post exploitation open pit mines in the world are shaped as a final reservoir intended to be filled with water. In Europe, the creation of water lakes is the most common way of reclaiming post open pit mines. The safety and the security of mine lakes is one of the priorities of mine regions. One of the main hazards identified is the slope stability of lake banks. To develop a reliability methodology for assessing the long-term stability of flooded open pit mines, a large-scale numerical model of the lake was carried out and was applied on Lake Most, which is one of the largest mining lakes in Europe (Czech Republic). The large-scale numerical model was built, based on the site observations, large scale LiDAR data and geotechnical data. The results highlighted the reliability of the methodology to combine the geometric model with the geological model to create a large-scale numerical model, and to identify local and potentially instable zones.

Infomapa da mineração: Cartografias e convergências temáticas

O Infomapa da Mineração: Cartografias e convergências temáticas é um esforço de sistematização de temas relevantes que compõem a questão mineral brasileira. O objetivo deste material é popularizar alguns ele­mentos que constituem a geografia da mineração no país e ampliar o debate público a partir de uma linguagem acessível que possibilite uma visão de conjunto sobre as dinâmicas da atividade mineral no Brasil. O material está dividido em quatro seções. A primeira seção apresenta a evolução dos processos minerários em todo território nacional em quatro recortes temporais. A segunda seção mostra a distri­buição das barragens de mineração segundo o dano potencial associado. A terceira seção traz a distribui­ção das minas ativas a céu aberto e as localidades com garimpo ilegal. E a quarta seção representa a densidade de conflitos no campo envolvendo a mineração. Palavras-chave: Mineração; cartografia; Brasil; conflitos. Abstract The Mining Infomap: cartographies and thematic convergences is an effort to systematize relevant subjects that make up the Brazilian mineral issue. The aim of this material is to popularize some elements that constitute the geography of mining in the country, and to broaden the public debate based on an accessible language that allows an overall view of the dynamics of mineral activity in Brazil. The material is divided into four sections. The first section presents the evolution of mining processes throughout the country in four time periods. The second section shows the distribution of mining dams according to their associated potential damage. The third section shows the distribution of active open-pit mines and the locations of illegal mining. And the fourth section represents the density of conflicts in the countryside involving mining. Keywords: Mining; cartography; Brazil; conflicts. Infomapa de la minería: Cartografías y convergencias temáticas Resumen El Infomapa de la Minería: cartografías y convergencias temáticas es un esfuerzo por sistematizar temas relevantes que componen el tema mineral brasileño. El objetivo de este material es popularizar algunos elementos que constituyen la geografía de la minería en el país y ampliar el debate público a partir de un lenguaje accesible que permita una visión global de la dinámica de la actividad minera en Brasil. El material se divide en cuatro secciones. La primera sección presenta la evolución de los procesos mineros en todo el territorio nacional en cuatro períodos de tiempo. La segunda sección muestra la distribución de las presas mineras según el daño potencial asociado. La tercera sección presenta la distribución de minas a cielo abierto activas y los lugares con minería ilegal. Y la cuarta sección representa la densidad de los conflictos rurales relacionados con la minería. Palabras clave: Minería; cartografía; Brasil; conflictos.

Exploring the Relation between Seismic Coefficient and Rock Properties Through Field Measurements and Empirical Model for Evaluating the Effect of Blast-Induced Ground Vibration in Open- Pit Mines: A Case Study at the Thuong Tan III Quarry (Vietnam)

Blasting is one of the most effective methods for fragmenting rock in quarries. Nevertheless, itsadverse effects are significant, especially blast-induced ground vibration. Field measurement andempirical equations are simple methods to determine and estimate the intensity of blast-induced groundvibration. However, we cannot evaluate the effects of blast-induced ground vibration on the surroundingenvironment based on these outcomes. Therefore, this study explores the relation between seismiccoefficient and rock properties through field measurements and an empirical model for evaluating theeffect of blast-induced ground vibration in open-pit mines. Accordingly, the seismic coefficient (K) isconsidered the main objective in this study. Firstly, it was determined based on the rock properties.Subsequently, an empirical model for estimating blast-induced ground vibration was developed based onfield measurements. This empirical equation was then expanded to determine K to check whether itmatches the determined K by the rock properties. Finally, it was used as the threshold to determine themaximum explosive charged per delay to ensure the safety of the surrounding environment from blastinducedground vibration. For this aim, the Thuong Tan III quarry (in Binh Duong province, Vietnam)was selected as a case study. Fifth-teen blasting events with a total of 75 blast-induced ground vibrationvalues were recorded and collected. An empirical equation for estimating blast-induced ground vibrationwas then developed based on the collected dataset, and K was determined in the range of 539 to 713 forthe Thuong Tan III quarry. Based on the measured blast-induced ground vibrations, developed empiricalmodel, and K values, the Phase 2 software was applied to simulate the effects of blast-induced groundvibration on the stability of slopes as one of the impacts on the surrounding environment. From thesimulation results, we can determine the maximum explosive charged per delay for each type of rock toensure the stability of the slope.

Applying Artificial Pillar to Replace the Coal Pillar Protecting Roadway to Increase Production Efficiency and Sustainable Development in the Vietnamese Coal Industry

Vietnam's domestic coal production is growing fast and is expected to reach 68.9 million tonsin 2030, nearly 1.5 times higher than today. Open-pit mines will gradually reduce production and close,and underground mining coal output will increase progressively year by year and take a leading role.Besides the investment in new mines to achieve these goals, it is necessary to maximize the coal reserveexploited annually of existing underground mine projects, which its coal reserve in pillars protectingroadways currently accounts for 12−15%. The further exploitation of this coal reserve will decrease thecosts of preparation of underground mines and granting mining rights and depreciation of infrastructureassets. Moreover, it will help reduce the loss of non-renewable resources and contributing to thesustainable development of Vietnam’s coal industry.