A Brazilian Tensile Strength (BTS) laboratory test for meta-andesite was modeled using a Finite/Discrete Element Method (FDEM or FEM-DEM). These hybrid methodologies allow modeling the transition from continuous to discontinuous that happens on mechanical tests of rock samples. This article presents the calibration and the simulation of BTS tests using some parameters previously calibrated on UCS modeling of the same material. Irazu, a two-dimensional software developed by Geomechanica, was used to simulate the tests based on the tensile strength and the fracture pattern. The model shows that, in BTS test simulation, the mode II (shear) happens mainly on the rock-platen contact. The mode I (traction) rules the fractures on the BTS test as observed in laboratory tests. The model represents, with great fidelity, the results obtained in the physical test.

Finite/discrete element methods (FDEM) are hybrid numerical models that use algorithms to analyze the transition from continuous to discontinuous. This type of formulation allows modeling physical laboratory tests with greater proximity to reality. This article proposes to simulate the average behavior of a uniaxial compression test campaign. The tests were modeled and calibrated based on the strength and the fracture pattern using Geomechanica Inc. Irazu two-dimensional software. The simulated results were analyzed by the mean standard deviation of approximately 3000 elements in the middle third of the model, the same region where the clip gages are located in the physical test. The obtained results show that FDEM can replicate the laboratory test with great similarity.

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The important role of ventilation in underground mines is to ensure safety and adequate environmental conditions in all accessible areas of a mine. This research aims to develop low-cost solutions for monitoring ventilation parameters in underground mines using the Internet of Things (IoT). A comparison between standard measuring equipment and a new low-cost wearable monitoring device prototype was performed, and the variables measured in an underground mine were pressure, temperature, and relative humidity. The results in all surveys indicate that the wearable monitoring device prototype can properly be used for continuous monitoring of the underground environment. The standard measurement devices for underground mines should continuously be used by mining companies as requested by local legislation. The low-cost wearable monitoring device developed should be viewed as a redundant measurement device for operators’ safety. The constant innovations in technology can support mining operators in anticipating problems, improving productivity, ensuring safety, and meeting standards at low investments.

RESUMO: O algoritmo híbrido de elementos fintos e discretos (FDEM) permite analizar a transição do comportamento mecânico continuo para o descontinuo. Tatone e Grasselli (2015) propõem a utilização de uma campanha de ensaios mecânicos em rochas como: Determinação da Resistência à Compressão Uniaxial (R.C.U), Determinação da Resistência à Compressão Diamaetral e ensaios de Determinação da Resistência à compressão triaxial para a calibração de rochas. A calibração é realizada simulando os ensaios de laboratório utilizando como objetivo a sua resistência máxima e o seu padrão de fraturamento. O software utiliza um algortimo em Python para obter a tensão de ruptura baseado na reação dos pratos de aplicação de força em um corpo de prova. A proposta deste artigo é investigar o comportamento mecânico da amostra em seu terço médio, onde são medidas as deformações nos ensaios laboratoriais. Avaliando o desvio padrão médio das tensões e deformações principais em conjunto com o número de elementos utilizados para esta avaliação. Os resultados apresentam convergência para numeros de elementos maiores que 3000 elementos.

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