On determining the parameters of face blocks during mining operations with backhoes

The backhoe hydraulic shovels (backhoes) have been widely used in open-pit mining operations in the Kuznetsk coal basin since the early 2000s. Now their number is growing every year, both because new operations begin on new sites, and because of the backhoe advantages. However, up to now parameters of their operation, more particularly the parameters of the face blocks, are often taken according to the actual data, i.e. based on the accumulated experience of the mining companies, and are not calculated using the approved scientifically validated methods. In the given article the authors give some preconditions for creation of a uniform methodology to calculate parameters of the face blocks depending on mining-geological and miningtechnical conditions. It is noted that the manufacturers of excavation equipment quote the data corresponding to the maximum possible parameters of the equipment operation, in particular the height of the excavated layer, as a result of which it is rather difficult to apply this in practice. Preliminary conclusions about the need to take into account the diversity of the above conditions and their interrelation with the parameters of a particular model of the excavation and loading equipment have been made.

The Environmental Activism of a Filipino Catholic Faith Community: Re-Imagining Ecological Care for the Flourishing of All

Extensive open-pit mining activities in the Philippines since the 1970s up to the present confront the meaning of the “Church of the Poor”, a description that the Catholic Church in the Philippines uses to visualize its prophetic mission. Alongside mining, many more environmentally destructive industries are present in the poorest areas in the country, even though the Philippines is disaster-prone and one of the world’s most vulnerable countries to the devastating effects of the climate crisis. The environmental degradation has prompted many Filipino Catholic organizations and communities to act together through various campaigns to address the problem. The article examines a case of a faith-based community that rose to the challenge to address various environmental issues their community was and continues to experience. The community’s environmental activism presents a viable model for a re-imagined ecological care towards the “flourishing of all” as a response to Pamela McCarroll’s call to action to continue conversations on the many ways practical theology can move beyond anthropocentrism while focusing on social justice.

Determination of the Area of Energy-efficient Working Equipment Position and Effective Digging Radius of Hydraulic Excavators in Open-pit Mining

Since the end of the last century, a significant number of hydraulic excavators have arrived on Russian quarries. Most of these excavators are equipped with backhoe operating equipment. The widespread use of such excavators in open-pit mining proves their exceptional efficiency. However, at the same time there is no clear understanding of the conditions under which a hydraulic excavator will be most effective: a theory of the face block of hydraulic shovels has not yet been developed. The available scientific studies are limited to determining the rational height of the excavation layer for efficient operation. If to take the quality of preparation of rock mass and the scheme of its loading into dump trucks as external parameters, i.e. not depending on the features of excavator design, then the position of its working equipment relative to the rock block has a decisive influence on operation of the hydraulic drive and fuel consumption. This is due to the changing value of digging force at various points of the bucket teeth position in the range of their possible positions at constant power of the hydraulic drive. Thus, application of optimal position of hydraulic excavator working equipment elements (bucket, arm, and boom) relative to the rotary platform and the rock massive during the digging cycle allows both to reduce fuel consumption and to increase the digging force. The application of the developed methodology is promising in terms of improving the energy efficiency of both individual excavation and loading units and the enterprise as a whole.

Asbestos rehabilitation project as a model of landscape sustainability

Greece was one of the biggest producers of asbestos in the world as well as a consumer. It took advantage of the asbestos rich Zidani mine, in the region of Western Macedonia in Greece. However, due to serious health problems caused by inhaling asbestos, it was banned in 1979 and the mine closed in March 2000. Rehabilitation management of the abandoned asbestos mining area, the depositions in the open - pit mining area and the tailings remnants was necessary in order to avoid health and environmental problems in the wider area The detailed soil protection and rehabilitation project of the degraded mining area was implemented taking all necessary and appropriate safety and health measures according to the requirements of the relevant E.U and National legislation, so that accidents would be prevented. Results show that the rehabilitation, soil protection and enhancement of the area help the ecosystems to be sustainable, ecologically and socially acceptable

Determination of non-hazardous areas in terms of seismic effect for the use of explosives in the open pit in safe conditions

In addition to the technical and economic advantages of blasting rocks from open-pit mining, this method of extraction can produce effects with a direct impact in the area near the open pit. Blasting works generates effects such as seismic waves that cause vibrations, rock throws, noise and toxic gases. When their intensity and scope are not systematically evaluated and analysed, blasting works can cause serious consequences for people, civil / industrial buildings, the environment, thus affecting the health of the population and the stability / integrity of the buildings / slopes in the vicinity of the mining operations. The paper presents design / determination methods of areas where explosives may / may not be used in conditions of maximum safety in terms of seismic intensity, thus protecting the population and the civil / industrial objectives in the area of the mining work. The obtained results are extracted from a research study carried out for the opening in operation of a new mining deposit, having as reference calculations and theoretical interpretations related to the conditions established for the development of the blasting works.

Stochastic Final Pit Limits: An Efficient Frontier Analysis under Geological Uncertainty in the Open-Pit Mining Industry

In the context of planning the exploitation of an open-pit mine, the final pit limit problem consists of finding the volume to be extracted so that it maximizes the total profit of exploitation subject to overall slope angles to keep pit walls stable. To address this problem, the ore deposit is discretized as a block model, and efficient algorithms are used to find the optimal final pit. However, this methodology assumes a deterministic scenario, i.e., it does not consider that information, such as ore grades, is subject to several sources of uncertainty. This paper presents a model based on stochastic programming, seeking a balance between conflicting objectives: on the one hand, it maximizes the expected value of the open-pit mining business and simultaneously minimizes the risk of losses, measured as conditional value at risk, associated with the uncertainty in the estimation of the mineral content found in the deposit, which is characterized by a set of conditional simulations. This allows generating a set of optimal solutions in the expected return vs. risk space, forming the Pareto front or efficient frontier of final pit alternatives under geological uncertainty. In addition, some criteria are proposed that can be used by the decision maker of the mining company to choose which final pit best fits the return/risk trade off according to its objectives. This methodology was applied on a real case study, making a comparison with other proposals in the literature. The results show that our proposal better manages the relationship in controlling the risk of suffering economic losses without renouncing high expected profit.

Artificial Neural Network Optimized by Modified Particle Swarm Optimization for Predicting Peak Particle Velocity Induced by Blasting Operations in Open Pit Mines

Blasting is an indispensable part of the open pit mining operations. It plays a vital role inpreparing the rock mass for subsequent operations, such as loading/unloading, transporting, crushing, anddumping. However, adverse effects, especially blast-induced ground vibrations, are considered one of themost dangerous problems. In this study, artificial intelligence was supposed to predict the intensity ofblast-induced ground vibration, which is represented by the peak particle velocity (PPV). Accordingly, anartificial neural network was designed to predict PPV at the Coc Sau open pit coal mine with 137 blastingevents were collected. Aiming to optimize the ANN model, the modified version of the particle swarmoptimization (MPSO) algorithm was applied to optimize the ANN model for predicting PPV, called theMPSO-ANN model. For the comparison purposes, two forms of empirical equations, namely UnitedStates Bureau of Mining (USBM) and U Langefors - Kihlstrom, were also developed to predict PPV andcompared with the proposed MPSO-ANN model. The results showed that the proposed MPSO-ANNmodel provided a better performance with a mean absolute error (MAE) of 1.217, root-mean-squared error(RMSE) of 1.456, and coefficient of determination (R2) of 0.956. Meanwhile, the empirical models onlyprovided poorer performances with an MAE of 1.830 and 2.012, RMSE of 2.268 and 2.464, and R2 of0.874 and 0.852 for the USBM and U Langefors – Kihlstrom empirical models, respectively.

Analysis of Occupational Accidents in the Spanish Mining Sector in the Period 2009–2018

Occupational accidents in the Spanish mining industry have been substantially reduced over the last decades. However, the incidence rate shows higher values than other leading mining countries. In this regard, the research carried out reveals the factors influencing the high incidence rates of the Spanish mining sector, based on three scenarios: underground mining (UG), quarries and open pit mining (OP) and mineral processing plants (PP). The three most common types of accident for each scenario have been determined, considering the accidents in Spain between 2009 and 2018. The analysis also includes the main deviations, and physical activities that the injured worker was carrying out at the time of the accident. Besides, a model to predict the number of accidents based on the lost working days is also presented together with the incidence and severity risk index adjusted by the number of employees and their worked hours, respectively, in each scenario. These finding can be relevant to define the most effective measures and policies to reduce the number of accidents in the mining sector.

Optimization study of blasting operations in Roşia Poieni open pit mine, Romania

Purpose. Drilling-blasting technology is one of the simplest and most often used techniques in open pit mining. This allows the excavation of a large volume of rock and useful mineral substance. The operation of blasting using the energy of explosives plays an important role in open pit exploitation, being also the key element of the blasting process through which a corresponding granulometry is obtained. This operation is a part of a series of interdependent operations, in the sense that each operation determines a certain result that will be an important element for the next operation that takes place in the working face. Consequently, the blasting operation with explosives should not be considered as an independent act. A global approach to the entire production technological process including blasting is required. Methods. In the optimization study, the basic method consisted in the analysis of the blasting operations performed at the drilling diameter of 250 mm (blasting technology used in Roşia Poieni open pit mining) and simulation of the excavation of the same rock volume, with the optimization of the explosive charge distribution at two other drilling diameters: 200 and 150 mm. Findings. The main problems when shooting 250 mm dia holes are caused by the length of the tamping in the mineralized rock that leads to the appearance of blocks with dimensions which are maximum allowed in the crusher tank (1.2-1.3 m). That is why discontinuous loads with intermediate tamping are used – the method that successfully limits their number. In order to obtain a granulometry corresponding to the primary crushing operation, which will allow to decrease the crushing costs, it is necessary to use smaller drilling diameters, but with productivity high enough to ensure the optimal development of the extraction process. Originality. Based on the performed study, it is recommended to use the discontinuous load, preserving the total length of the explosive charge. In the zones where the rocks have a Protodiakonov coefficient f > 6.5, it is recommended to apply an appropriate drilling diameter (150-200 mm) and use the intermediate tamping at 2-3 m length to limit the upper stemming area to a maximum of 7 m (to limit or eliminate the occurrence of oversized blocks). Practical implications. The research results will enhance the geometric and safety factors of the operation, limiting the explosion effect on the massif and the environment and reducing the total costs of the cutting operation. The cost of explosives and initiating materials can be reduced by using a smaller quantity of explosive gels in a dry environment (12-18 kg/hole), the difference in the explosive charge length being completed with AM 1.