Rudarsko-geološko-naftni zbornik

Prediction of blast-induced flyrock by using neural-imperialist competitive method (Case Study: Sungun Copper Mine)

2024-07-28T08:25:24+02:00

This research focuses on conducting studies that predict the distance of blast-induced flyrock, which is an undesirable environmental phenomenon in open-pit mines. While there are experimental methods available for predicting blast-induced flyrock, the complex process of assessing the distance of flyrock has reduced the efficiency of these approaches. This study employs artificial intelligence methods and statistical techniques to forecast the flyrock distance in the Sungun copper mine. Thus, an Artificial Neural Network (ANN-MLP) and a new hybrid model of Artificial Neural Network (ANN) optimized by the Imperialist Competitive Algorithm (ICA), known as (ICA-ANN), are used to predict the flyrock distance, considering crucial parameters such as the number of holes, hole spacing, burden, total charge, specific drilling, charge per hole and specific charge. The results showed that the Artificial Neural Network, with RMSE, MAE, and R² error values of 9.31 m, 7.10 m, and 0.81, respectively, was able to predict the flyrock distance well compared to the measured data in the test phase. However, the implementation of the imperialist competitive algorithm optimizer in the neural network enhanced the prediction of the flyrock distance, yielding RMSE, MAE, and R² values of 5.66 m, 4.60 m, and 0.89, respectively. Finally, by performing sensitivity analysis on the input parameters of the flyrock distance, it was determined that the amount of explosive consumption and the number of holes have the greatest impact on the blast-induced flyrock distance.

Iron ore allocation model to feedstock concentrate plants from multiple sources to multiple destinations considering the uncertainty of grade, in iron ore mines: a case study in Sangan mine, Iran

2024-08-25T21:06:10+02:00

Operations research is a science that is used in various fields. This science is a set of quantitative techniques that help managers make decisions using scientific methods. This science is related to many axial decision-making issues of managers. For this reason, it is also called the science of management. This science is widely used in industries and mines. One of the most appropriate methods for solving research problems in operations is using linear programming in mining projects. This study was conducted in the Sangan iron ore mine in Iran. In this article, by using linear programming modeling and solving the transportation problem, the allocation of iron ore to feedstock concentrate plants from multiple sources to multiple destinations has been done considering the uncertainty of the grade. This paper is in the field of studying and identifying the quantitative and qualitative amount of extractable iron ore reserves in the mines, and on the other hand, the needs of concentrate plants concerning their feedstock supply by considering the uncertainty of iron ore grade in mines and deciding on their proper allocation. Mineral modeling and estimation of the amount of extractable minerals have been done using the block model. Uncertainty of iron ore grade in the block model is investigated using the sequential Gaussian simulation method. The amount of mining capacity and its sequence is planned considering the type of iron ore used in the plans during 5-year periods. In this article, the modeling of the problem has been done by considering the existing limitations in mines, such as the amount of supply, grade of iron ore, iron oxide and sulfur. On the other hand, the limitations in plants, such as demand, type and grade of iron ore, iron oxide and sulfur are considered in the modeling. In the end, the amount of iron ore tonnage sent from each mine to each plant during 5 years is presented by solving the problem.

Investigating the role of human factors in the risk assessment of underground coal mines

2024-08-26T08:09:06+02:00

Underground coal mines are always faced with their own specific uncertainties. These uncertainties lead to safety risks and ultimately result in chaos and safety disturbances. Human factors are among the uncertainties that play a vital role in various industries, including underground coal mining. For instance, they affect safety, production processes, machinery maintenance, and productivity. Risk management is one of the primary methods for improving safety in underground coal mines. Risk management is a process that helps identify, assess, and mitigate risks and uncertainties. Its main goal is to protect resources, enhance safety, and increase efficiency through informed decision-making. This article examines the role of human factors in risk assessment of coal mines; it first classifies human factors and then uses the Fuzzy Technique for Order of Preference by Similarity to Ideal Solution (Fuzzy-TOPSIS) method for pairwise comparison to evaluate the risks of underground coal mines. The TOPSIS method is a multi-criteria decision-making technique that operates based on the distance of options from the best and worst solutions. This method ranks the options based on specific criteria and assists in selecting the optimal option. The results of the study on human factors indicated that carelessness, negligence, and distraction had the greatest impact on the risk assessment of underground coal mines, with a similarity index of 0.6516, while the level of education had the least impact with a similarity index of 0.2871.

Quantification of hydraulic characteristics of swelling material

2024-08-21T13:33:41+02:00

This paper presents a laboratory and numerical study to determine three hydraulic characteristic curves of a swelling material (soil or rock) in which montmorillonite is the predominant type of mineral. The first, the soil-water characteristic curve, represents the relationship between suction and moisture content that needs to be defined to solve the water flow problem and the accompanying change in the volume of the swelling unsaturated porous medium. The second curve presents hydraulic conductivity as a function of saturation or suction. The third curve represents the relationship between the volume change and the moisture content of the swelling material. These curves are crucial for understanding water flow and volume changes in swelling materials, with this study focusing on wetting regime behaviour. The aim of this research was to establish reliable methods for the definition of the hydraulic properties of the swelling material and to verify a proposed swelling model. While the swelling material shows significant hysteresis between the drying and wetting regimes, the hydraulic conductivity function shows little or no hysteresis between drying and wetting paths at equal moisture contents (coefficients).

Deep Ground Penetrating Radar Imaging for the purpose of exploring ore and geological structures in the Calamine Mine, Central Iran

2024-07-04T13:17:29+02:00

This study aimed to identify mineralized zones within a sedimentary structure, including its discontinuities such as layer boundaries, and faults. The Loza-N model Deep Ground Penetrating Radar (DGPR) system with a 25 MHz antenna was employed to achieve a target depth of up to 200 meters. The investigation was conducted on mine terraces, berms, and the flat northern part of the Mehdiabad calamine mine located in Yazd, Iran. A total of 23 profiles were surveyed. Data acquisition for some profiles involved parallel transects, while others utilized a series approach where the transmitter and receiver antennas were progressively moved along the ground surface. The processed radargrams from selected profiles were compared amongst themselves and with borehole data collected along the same profiles. The geological structure was successfully visualized using two different software programs. Krot software effectively distinguished all limestone units and their zonation. By combining the GPR data with borehole results, it was possible to identify potential ore mineral zones within the marly units. Based on the DGPR traces at borehole locations, high-grade ore minerals in the marly limestone exhibited positive phase and amplitude values, represented by intermediate to maximum color hues. Conversely, light green and light gray limestone containing iron oxide and calcite veins displayed negative phase and amplitude values, with negative zero to intermediate color hues. Dark green limestone showed the most negative phase and amplitude values, reflected by the maximum negative color hues. Finally, light red limestone, likely containing low-grade ore, presented positive but minimal phase and amplitude values, visualized by positive minimum color hues.

Natural phytomelioration processes on rock dumps of abandoned coal mines (Ukraine)

2024-07-02T12:04:09+02:00

Mining is accompanied by direct irreversible changes in the biosphere. Analysing the results of recent studies on the anthropogenic hazard of coal mine tailings and the peculiarities of tailings reclamation and phytoremediation on a global scale, it necessitates the investigation of the ecological state and natural phytoremediation of the Nadiya mine tailings in the Lviv-Volyn coal basin. The stages of succession processes on the rock dump surface have been determined. The phytomeliorative efficiency coefficient has been calculated for all periods of the phytomeliorative process on the rock dump surface. The total area of the studied site is 280 m². Based on the calculations of changes in the dynamics of the phytomeliorative efficiency coefficients at different stages of the phytomeliorative process (K_FM=0.155-4.485), it is expedient to conduct reclamation and phytomeliorative operations on the rock dump surface. The coal mining industry causes a significant technogenic burden on the environment, affects human health and transforms living conditions regardless of the place or country of extraction. Waste heaps are the most dangerous factors of environmental degradation. Studies of the impact of coal mine waste heaps on the human body and biota are conducted in almost all industrialised countries as well as countries where mineral mines are operated.

Beneficiation of Ferruginous Manganese Ore of Um Bogma Locality, Sinai: Comparison Between Conventional Reduction Roasting Techniques and Microwave Technology

2024-06-12T13:52:24+02:00

The increasing demand for high-grade manganese ores in various industries has led to a growing necessity to enhance the quality of lower-grade manganese ores with time. A representative manganese ore was collected from Um Bogma, Sinai, Egypt, and subjected to various characterization methods including X-ray diffraction (XRD), X-ray fluorescence (XRF) and ore microscopy. XRF analysis revealed a low Mn/Fe ratio of 2.81 (as elements), indicating a low ore grade. For suitability in Mn alloy production at the Sinai Manganese Company (SMC) plant in Abu Zenimah, southeast of Sinai, Egypt, this ratio should ideally exceed 5. Additionally, XRD and ore microscopy identified the mineralogical composition of the ore as pyrolusite, hematite, and manganite, with manganese patches embedded in a ferruginous groundmass at the textural scale. Three different reduction roasting techniques were evaluated, involving conventional heating in a furnace utilizing either CO – CO₂ or charcoal as reducing agents, alongside reduction roasting with charcoal utilizing microwave technology. Following each technique, magnetic separation was employed, resulting in the production of high-grade manganese concentrates exhibiting high Mn/Fe ratios ranging from 19.8 to 27.45 and substantial Mn recovery rates ranging from 93.86% to 96.76%.

The Performance of Bivariate Statistical Models in Landslide Susceptibility Mapping (Case Study: Cisangkuy Sub-Watershed, Bandung, Indonesia)

2024-06-28T21:07:18+02:00

Landslide occurrences are common in hilly and mountainous areas, especially in tropical countries with high rainfall and intensive weathering. Landslide susceptibility mapping (LSM) is an initial effort to mitigate landslide hazards. This research conducted a comparative study of four LSM maps, namely frequency ratio (FR), information value model (IVM), weight of evidence (WoE), and Shannon entropy (SE), for the Cisangkuy Sub-watershed, West Java. Those models determine the relationship between the landslide density and the causative factors. The model utilized 76 landslide pixels and 15 causative factors. 70% of the landslides were used as training data, and the remaining was used for validation. The 15 factors were selected from 27 causative factors. The highly correlated causative factors were removed to address multicollinearity. In addition, only causal factors related to landslide data are involved in the modelling. The receiver operating characteristics (ROC) curve and the landslide density index (LDI) method were used for model validation. All models indicate appropriate prediction rates for FR, IVM, WoE, and SE, which are 0.770, 0.790, 0.793, and 0.788, respectively. Based on the LDI analysis, the LDI values did not increase gradually from very low to very high susceptibility classes for each LSM map. However, the maps are still favorable because the classes that are most susceptible in all models have the highest LDI. The performance of the models may be influenced by the number of classes and classification methods used to categorize each continuous parameter, as well as the small quantity of landslide inventory data.

New Dasycladal algae from the Anisian (Middle Triassic) of Lika (Croatia)

2024-08-01T14:11:29+02:00

Two new species of dasycladal algae are described from the Anisian limestones of the Lika region in Croatia. Griphoporella? speleoluka n. sp. is characterized by very small cylindrical thallus and vesiculiform laterals arranged in close whorls. In consecutive whorls, laterals are positioned one above the other. It differs from other species by smaller dimensions and the arrangement of the laterals. Palaeodasycladus primus n. sp. has cylindrical thallus with whorls of inclined laterals up to the third order. Primary laterals are not completely calcified, producing so-called intusannulation. Trichoform or tubular secondary laterals bear bundles of thin, probably trichoform, tertiary laterals. Both of the new species have been found within typical Anisian microfossil assemblage.

An Update to the Geology of Sebuku Island, South Kalimantan, Indonesia: Constraints From Petrological Studies

2024-07-16T07:40:43+02:00

Sebuku Island is located at the southeastern tip of Kalimantan Island and has geological similarities with the Bobaris-Meratus complex in distribution pattern and stratigraphic sequence. The pattern of straightness of geological structures between the two, both folds and faults, is generally directed from northeast-southwest to northwest-southeast. The previous geological research on Sebuku Island focused on the distribution of ultramafic rocks, which are speculated to contain iron, particularly from laterite soils. This research aims to determine the rock units in the study area to update the geological map of Sebuku Island, especially in the Sei Pinang and Halaban areas.

The research method consists of fieldwork, laboratory analyses, and data analyses. The geological fieldwork collected 34 samples from detailed mapping on outcrops, trenching, and drilling. Geological structure observations were carried out on fresh outcrops and measured 57 structural geological elements from 6 locations. Petrographic analysis of 34 samples was carried out with the aim of determining rock type and mineralogical composition. Stereographic analysis of geological structure measurement data was used to define the general direction and type of geological structures in the investigated outcrops. The geological map is constructed on the basic topographic map in the scale 1:50,000 using MapInfo Pro v17.0.5.

Based on petrographic observations and detailed field observations, especially in North Damar, from surface outcrops and drill core observations from Madang, the following results are revealed. In the geology of North Damar, in particular, and Sebuku Island, in general, the lithology can be described as an ultramafic rock unit (lherzolite, harzburgite, and dunite), pyroclastic rock unit (crystallo-lithoclastic tuff and crystalloclastic tuff), limestone unit, dike rock unit (microgabbro and diorite), sandstone unit, and alluvial deposit.

Almost 60% of Sebuku Island outcrops belong to the ultramafic rock units, which are tectonically covered by crystalline lithic tuff and crystalline tuff and volcaniclastic rock units with interbedded limestone, unconformably covered by sandstone units, alluvial deposits, and swamp deposits. Microgabbro and diorite were observed from the drill core and were not exposed to the surface. Hydrothermal mineralization is indicated by quartz veins cross-cutting the pyroclastic rock group observed in drill cores. This research shows a more detailed geological description of the study area compared to previous research and regional geological map.

Use of the Groundwater Quality Index, Multivariate statistics and Hydrogeochemistry for Groundwater Assessment in the Malabar Volcanic Area, Indonesia

2024-06-26T14:53:27+02:00

The South Bandung basin has had significant population growth in the last ten years, particularly in the regions that border West Java. Consequently, there was an increase in the demand for groundwater, an essential resource for numerous uses. On the other hand, human activities have given impact significantly on the change of groundwater quality in the Bandung basin, the Malabar volcanic area. In the Bandung basin, the Malabar volcanic area has become an important location for urban water supply recharge. Within the current investigation 27 water samples were collected during the dry and wet seasons. The purpose of this study was to analyze the seasonal variability of parameters using different approaches. The comprehensive methods involving the application of multivariate statistics, geographical modelling, and the groundwater quality index. The spatiotemporal variability showed that the dilution effect of precipitation during the rainy season contributed to the significant seasonal variations. The hydrogeochemical facies was determined as Ca-Cl, CaMg-Cl, CaMg-HCO₃, and NaK-HCO₃. The Ground Water Quality Index (GWQI) analysis indicated that physicochemical factors influence water quality classifications from unsuitable to excellent. According to the conceptual model, the upstream area has excellent GWQI; however, the downstream area has decreased GWQI due to anthropogenic influence and the dissolution process. The results suggest that NH₄⁺-N, Fe²⁺, and Mn²⁺ have significant impact on GWQI. The novelties of this research include sensitivity analysis of each parameter to GWQI while conceptual model differentiates its findings from previous research. This conceptual model can be applied in various geographic environments to determine groundwater quality and its distribution regarding seasonal and land use changes.

Shallow subsurface structures and Quaternary deformations on the easternmost Matano fault, Indonesia, revealed by electrical resistivity tomography

2024-06-26T14:41:00+02:00

In active fault studies, electrical resistivity tomography (ERT) with wide electrode spacing (10 m) and fewer than 60 electrodes is typically utilized. However, this configuration limits the ability of ERT to resolve detailed geological information, such as fault geometry and motion, small-scale offset, and thickness of Quaternary layers. High-resolution electrical resistivity tomography (ERT) with narrow electrode spacing (1.5‒5 m) and 112 electrodes offers an opportunity to uncover finer geological information. This study combines ERT measurements with geological data from trenches and field observations to investigate the subsurface structures and Quaternary deformation on the easternmost Matano fault. On ERT sections, the easternmost Matano fault is characterized by deformed resistivity layers and resistivity contrasts. The subsurface fault structures dip steeply and indicate reverse and normal motions for the vertical component, with the displacement related to the Quaternary faulting ranging from 3 to 26 m. Notably, fault structures on ERT sections are not necessarily expressed by geomorphic features, suggesting obscured tectonic features. This study demonstrates the reliability of high-resolution electrical resistivity tomography (ERT) in unveiling geological information, such as fault location and geometry, fault vertical motions, buried fault structures, small-scale vertical offsets, stratigraphy, and Quaternary sediment thickness, which are essential for seismic hazard assessment.