International Journal of Mining & Geo-Engineering
Volume:56 Issue: 1, Winter 2022

As one of the hazardous pollutants, ozone (O3), has significant adverse effects on urban dwellers' health. Predicting the concentration of ozone in the air can be used to control and prevent unpleasant effects. In this paper, an attempt was made to find out two empirical relationships incorporating multiple linear regression (MLR) and gene expression programming (GEP) to predict the ozone concentration in the vicinity of Zrenjanin, Serbia. For this purpose, 1564 data sets were collected, each containing 18 input parameters such as concentrations of air pollutants (SO2, CO, H2S, NO, NO2, NOx, PM10, benzene, toluene, m- and p-xylene, o-xylene, ethylbenzene) and meteorological conditions (wind direction, wind speed, air pressure, air temperature, solar radiation, and relative humidity (RH)). In contrast, the output parameter was ozone concentrate. The correlation coefficient and root mean squared error for the MLR were 0.61 and 21.28, respectively, while the values for the GEP were 0.85 and 13.52, respectively. Also, to evaluate these two methods' validity, a feed-forward artificial neural network (ANN) with an 18-10-5-1 structure has been used to predict the ozone concentration. The correlation coefficient and root mean squared error for the ANN were 0.78 and 16.07, respectively. Comparisons of these parameters revealed that the proposed model based on the GEP is more reliable and more reasonable for predicting the ozone concentrate. Also, the sensitivity analysis of the input parameters indicated that the air temperature has the most significant influence on ozone concentration variations.

The non-linear Generalized Hoek-Brown (GHB) failure criterion for rock mass is widely accepted and has been applied in a large number of open pits slope designs. This paper proposes new equations for estimating the maximum confining stress from the (GHB) parameters and geometrical properties of the slope in the case where the strength ratio is critical (SR)_crit=(σ_ci/γH)_crit and the factor of safety (FOS)=1. This maximum confining stress can be used to calculate the global equivalent Mohr-Coulomb (MC) parameters. It was found that, compared to the calculation with the limit analysis method (LAM), the discrepancies do not exceed 5% and remain in the most cases less than 1%. Hence, the estimation of the (FOS) is much more improved, because the comparison of the literature’s results with the (LAM) leaded to a difference up to 21%. For any value of (FOS≠1), an iterative method has been proposed to evaluate (SR)_crit. The comparison between the results driven from this method and those of (LAM) showed a good agreement, which proves its accuracy. A case study has been conducted in an open pit located in Sudan to evaluate the discrepancy of the (FOS) provided by different methods using limit equilibrium method (LEM) with Rocscience Slide software and using the (LAM) given in the form of charts.

The infrastructures of Sungun copper mine are located inside the ultimate extraction limits where blasting operation is carried out in their proximity. In such cases, investigating blast-induced phenomena is at most important to reduce their adverse impacts on the mine and surrounding environments. The main objective of this study is to analyze and improve the most critical adverse outcomes of over 100 cases of blasting in different zones of Sungun mine to make it feasible from an operational viewpoint. Hence, the blasting operation and its adverse outcomes recorded in the mine were first studied. Moreover, the important factors that resulted in blast-induced phenomena were investigated. These investigations were in the form of observation, acquisition, and complete field studies at the site. Then, the technical problems and weaknesses of the blasting operation resulted in undesirable outcomes and their negative impacts on the mine and surrounding environment were extracted and analyzed using checklists, specification forms, and recorded observations. Given the results of the qualitative and quantitative analysis of operation based on a trial blasting strategy, an improved blasting scheme was discussed to enhance the current conditions and reduce the undesirable outcomes down to the permissible limits. The present study could provide a practical framework to identify, analyze, and reduce the critical adverse blast-induced phenomena in metallic open-pit mines.

Prediction of powder factor is a major activity while preparing drilling and blasting operation, as the total production cost depends on it. It is a major input parameter in blast design as it influences the efficiency of subsequent operations in mining. Generally, effective parameters that influence powder factor can be divided into three, namely, rock mass, geometric and explosive parameters. In this study, the rock mass properties and geometric parameters were studied based on the ratio of the mass of explosive and blast design. The main objective of this study is the application of rock engineering system (RES) to calculate the powder factor index (Pfi) based on predominant rock mass properties and geometric parameters. This approach was applied to a database of twenty-four blast sites comprising of rock mass rating, blastability index, porosity, specific gravity, uniaxial compressive strength, the burden, the ratio of space to the burden, the ratio of drilled-hole depth to burden, drilled-hole diameter and the ratio of the burden to drill-hole diameter. The relationship between these parameters and how each of them influence powder factor was studied and used to predict powder factor index. The result shows that rock mass rating, blastability index, porosity, specific gravity, uniaxial compressive strength and drilled-hole diameter affect powder factor. It also shows that Pfi is a robust technique for generating an improved line of fit and predicting more dependable and accurate valuation of powder factor with the coefficient of determination (R2) of 0.86, and root mean square error (RMSE) of 0.023 when compared with the traditional multivariable regression method.

In this research, support vector machine (SVM) as a supervised classification method has been used to explore the relationship between the geochemical anomaly and the surface alterations quantitatively in the Tanurcheh mineralization area. The Tanurcheh area has been located in the Khorasan Razavi province, Iran. This area has been considered as a high potential region for Cu and Au mineralization. The different mineralization processes of Au and Cu have unclearly been intertwined in this area and have created extreme surface alterations.Determination of the major origin of mineralization that has created strong alterations in this area is an important issue that can be addressed using a new proposed scenario. The relationship between the geochemical distribution map and the alteration zone was mathematically calculated using the proposed approach and then the geochemical anomaly map was predicted based on the alteration zones as an innovative achievement.In this paper, the Au and Cu geochemical data were divided into three classes, namely background, regional anomaly and local anomaly using the probability plot method. Two threshold values for Cu (70 and 300 PPM) and Au (0.13 and 0.4 PPM) were obtained by the probability plot method. Then the SVM was utilized to classify the geochemical samples using the ASTER images based on these obtained thresholds. The ASTER 14-band images were used as features in this classification. Using this novel scenario, the relationships between the Au and Cu mineralization processes with the intensity of alterations were determined and therefore the origin of these alteration zones was clarified. The SVM classification indices of correct classification rate (CCR) and confusion matrix demonstrate the main origin of alterations is related to the Cu mineralization process in this area. The CCR indices obtained based on the Au and Cu thresholds are 0.66 and 0.85 respectively. It demonstrates the intensity of alterations has more been affected by the Cu mineralization process and there is a relatively good relationship between the alteration zone and the Cu geochemical distribution map. Finally, the geochemical anomaly and background maps were properly predicted using the SVM and the ASTER bands. This paper shows the new application of SVM as a powerful tool for the interpretation of geochemical anomaly and the intensity of alteration.

Thickener is a major and convenient applied equipment for tailings dewatering in mineral processing plants. Past investigations have shown that feed slurry dilution can improve flocculation efficiency by affecting both floc size and density. Advantages of thickener feed dilution method include reduced flocculent consumption, increased settling flux, and enhanced bed/sediment compressibility. Gol-E-Gohar iron complex is one of the largest iron concentrate producer in Iran and is located in Kerman. Gol-E-Gohar thickeners Performance was monitored through daily inspections. High flocculent consumption and turbidity of recycled water were major thickeners problems. Inspections showed that high solid content of thickeners feed was the major issue. Diluting pump method was used to decrease solid content of the thickeners feed. Also the reduction of used flocculent dosage happened by 45 % via Flocculent preparation improvement .the number of Flocculent distribution points was increased from 4 point to 9 .for enhancing flocculent solubility, water with less total dissolved solids was used for Flocculent preparation. The modifications resulted the a very clear thickener overflow water (turbidity less than250 ppm) and flocculent consumption was decreased from 114 g/t (gram per thickener feed tailings ) to 43 g/t, in other words there was a 45% decrease in flocculent consumption.

Stabilization of excavations and retaining walls are important issues in geotechnical field. Use of new and novel methods in excavation sites, and providing safe condition for the final aim of project is one of the challenging matters in this regard. Excavation in sandy soils, due to lack of enough cohesion for its stability, face serious problems. In order to solve this problem, using special techniques to improve the stability is very important subject. Geosynthetics (i.e. geotextile, geogrid, and geocell) are among the new techniques, which could enhance the stability and performance of sandy soils. In this research, 3D finite different analysis performed to investigate unreinforced and reinforced excavations using geotextile, geogrid, and geocell elements and their comparison. Results indicated that in the case of using geotextile, geogrid, and geocell the critical depth of excavation increased up to 3.125, 2.75, and 2.25 times of unreinforced excavation, respectively.

This work assessed the curve fitting ability of Rosin-Rammler and Swebrec functions and the comparison of their fitting parameters with rock strength properties. The work aimed to show if there exist a relationship between the function’s distribution parameters and rock strength properties. The rock strengths properties were determined in accordance with International Society of Rock Mechanics standards. The two functions were used to reproduce sieving curves of different rocks fragmented on a laboratory scale using electric detonators. The Swebrec function reproduces the sieving curves better than Rosin-Rammler. The Rosin-Rammler curve fitting performs creditably with well fragmented rocks of poor grading or uniformly sorted fragments. The Rosin-Rammler curve fitted better to Class II rocks than the Class I rocks. The Rosin-Rammler parameters are shown to be interdependent while only factor ‘a’ and exponent ‘c’ parameters of Swebrec function are mutually dependent. The undulating exponent ‘b’ of Swebrec is related to the uniformity index, ‘n’ and characteristic size, ‘Xc’ of Rosin-Rammler. By comparison, the parameters of the two functions show correlations with rock strength properties (BTS, UCS, E and v). The uniformity index, ‘n’ is related to rock properties included in this study while the Swebrec ‘c’ parameters did not show any relationship with rock properties. The ‘Xc’ parameter of Rosin-Rammler is related to UCS, E and v. The ‘a’ and ‘b’ parameters of Swebrec function are related to BTS, UCS and v and BTS UCS and E respectively. In all cases the correlation coefficients are greater than 0.6 and can be fitted by power form function.

Underground conduits or utility pipelines are buried at shallow depths in trenches with the help of flowable fills. These pipes are subjected to deformations and damage due to application of dynamic traffic loads or heavy static loads from the vehicles. This study presents the results of a pipe model installed in geocell reinforced and unreinforced sand. A PVC pipe of 110 mm diameter and 1.4 mm wall thickness was installed in a rigid tank to simulate buried pipe. Different types of instrumentation such as earth pressure cell and vibration meter were used to measure the vertical transmitted pressure and displacement amplitude on the pipe crown, respectively. Different factors that affect the performance of pipes installed in sand bedding and backfill were investigated. The factors included state of compaction of bedding and backfill, magnitude of the applied surface dynamic pressure, and the load frequency. The results of this study were presented in terms of the vertical transmitted pressure on the crown of the pipe, surface soil settlement, the displacement amplitude of the pipe crown. It was concluded that the performance of the buried pipe depends on the state of compaction of sand bedding and backfill. When the relative density of the sand increases from 30% to 60%, the vertical pressure on the pipe crown, surface settlement, and the amplitude of displacement, decrease by about 30 %, 40 % and 15 %, respectively. When the relative density of the soil increases from 30% to 60%, more than 40% reduction was recorded in the surface settlement for unreinforced model while this reduction is about 25% for model reinforced with geocell.

One of the crucial stages in the operation of quarry exploitation is the selection of an appropriate mining method because the lack of attention to this issue may bring about many problems in the process of mining, leading to extra charges incurred to the mine owner or the possible drop in the quality or quantity of the mine product. The adoption of the appropriate method of quarry mining, given the various interacting factors involved, requires a multi-criteria decision-making method. This paper makes use of the hybrid AHP-ELECTRE model to examine the conventional quarry mining methods including Diamond Wire Sawing, Blasting, Feathers and Wedge as well as the expansive agents such as KATROCK and FRACT.AG in the granite quarry of Gazik located in the South Khorassan Province, taking into consideration various factors such as the gross profit increase, safety, quality, decrease of adverse environmental effects, wastage and the reduction of mining time. In this model, the items weights were applied by the AHP method, and the items were assessed through non-rank comparisons so that, finally, the Diamond Sawing Blasting was chosen as the most appropriate method of Gazik granite quarry mining based on the ELECTRE model. Such studies can aid in managing the mining costs to decrease, which can lead to the profitability of the quarries.

Increasing demand for the application of mechanical excavation techniques in various civil and mining projects has increased the importance of ground abrasive properties and its mechanized excavatability. The accurate prognosis of cutting tools lifetime has crucial importance in the planning of mechanized tunneling projects. Moreover, the precise estimation of the required cutter number for excavating the determined length of a given section in a specific geotechnical condition is one of the main tasks of the project consultants. The main objective of these estimations is to assess the needed time and cost of cutter replacements in the phase of feasibility studies and to plan a proper maintenance schedule. The LCPC testing procedure is one of the simplest and most common soil abrasivity assessment methods. The purpose of the presented study is to investigate the steel – soil interaction during the LCPC abrasion test. The consumed energy of LCPC tests on different abrasive samples was measured. Based on the recorded energy values, a new parameter of wear specific energy of the LCPC test (WSEL) was introduced. The obtained WSEL values showed meaningful correlations with the sample grains size and the sample average hardness. Moreover, the results revealed that the high LCPC abrasion coefficient (LAC) values are relevant to the high consumed energy levels recorded during the tests.

Bearing capacity plays a significant role in evaluating the safety of the foundations rest on the slope. Many solutions have been proposed to assess the ultimate bearing capacity of foundation adjacent to the slope, however, the available analytical and empirical methods are associated with some shortcomings in view of slope material properties and geometry. Also, numerical methods suffer from the rigorous computational effort, and the accuracy of the outcome depends on the mesh and boundary effect. Therefore, a new analysis is employed in this research work that is able to consider all the effective parameters on the evaluation of ultimate bearing capacity. The results are compared with the existing numerical one in the literature and show good agreements. Also, in order to facilitate the use of the proposed method a Mathematica package code has been proposed to help the researcher to evaluate the bearing capacity of a shallow foundation rests on the slope.