The elasticity is an important parameter for the evaluation of the mechanical behavior of a rock mass and a fundamental factor in the definition of the resistance characteristics, stability, and blastability in rock blasts, and it is an important parameter for the blastability equations like the Kuz–Ram method. This paper presents a comparison of the Uniaxial Compression Method (UCM) and the Impulse Excitation Technique (IET) in determining Young’s modulus. The IET is a static and nondestructive dynamic method of characterizing mechanical parameters of materials, while the UCM is a quasistatic and destructive method. We determined Young’s modulus of samples from nine basalt and diabase mines used as aggregates in the construction industry. Young’s modulus was determined by the acoustic response due to longitudinal oscillations caused by a mechanical impulse (IET) in the Sonelastic equipment and the stress-strain curve (UCM). Young’s modulus values showed high repeatability and agreed with those reported in the literature for the same material. The work shows that the solnelastic is an innovate equipment and elucidated advantages of IET in comparison to the UCM such as shorter execution time, greater safety, and a lower cost ranging from 11.5% to 22.5% of the UCM.

Electricity is one of the biggest expenses associated with underground mining and ventilation often accounts for 50% of the total electricity use. Ventilation on demand is not widely used in Brazil, but the Ipueira, Cuiaba, and Corrego do Sitio I mines reported savings of 26%, 30%, and 21%, respectively, following its application. Frequency inverters are used to control the rotation of the main fans during shift changes. The Cuiaba mine has a control room and fans are monitored online using wireless scattered sensors. Data from field studies were compared to other foreign mines. The results showed that the application of this technique, even in an experimental way, can reduce electricity consumption significantly. Despite the energy savings that can be achieved by providing air only when/where it is needed, the costs of automation, software, and infrastructure mean that it is not practical to apply this technique at a more advanced level.

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This article aims to review the issues to be considered in choosing primary access and transportation options for underground mines. The main accesses to underground orebodies are declines or vertical shafts. They serve both as a way to transport ore or waste, and move people, equipment or supplies. In underground mines, the ore transport option significantly affects the productivity and profitability of the company. Then, choice of access is a way to reduce costs and improve production. This study is primarily based on some case studies of Brazilian, South African, Australian and Turkish mines, among others. Literature review shows that the depth at which shaft hoisting becomes a more economically attractive alternative to decline truck haulage is changing from being previously 350 m to present 1000 m, depending on the mining country and cultural underground mine development. For some of them the depth of 1000 m would be the threshold for use of the access by decline. The main criteria in determining access are depth, rate of production and mine life. In South Africa, mines reach depths greater than 3000 m and shaft access is more common. In Australia there are mines that use a ramp (decline) to a depth greater than 1000 m. In Brazil, underground mines are still shallow (depth up to 800 m) and feature short mine life and, most of them have chosen access by decline. Results of this study corroborate the statement that decline is ideal for shallow mines and low production rates and that shaft is for deep mines, high production rate and long mine life.

As the deepening of an underground mine occurs, dynamic events (rockbursts) or high deformation ground conditions can occur. The Cuiabá underground gold mine (AngloGold Ashanti, Minas Gerais, Brazil) which is around 1300 m deep, started to experience some of these issues. High deformation associated with bulking and buckling was experienced in the main decline resulting in many rehabilitation stages. Aiming to better understand and reduce the impact of this behaviour, a damage mapping of the support and reinforcement were carried out in the Serrotinho decline. Field measurements of deformation were also undertaken. It was then possible to correlate the numerical modeling outputs with the observed damage and suggest design changes. Based on the observed mechanisms, as well as the reinforcement and support damage experienced in the decline, laboratory tests were necessary to adjust the rock bolt face plate capacity and redefine the most adequate rock bolt and surface support combination to guarantee the functionality of the whole support system.