Journal of Mining and Environement
Volume:14 Issue: 2, Spring 2023

Rock blast production rate (BPR) is one of the most crucial factors in the evaluation of mine project's performance. In order to improve the production of a limestone mine, the blast design parameters and image analysis results are used in this work to evaluate the BPR. Additionally, the effect of rock strength on BPR is determined using the blast result collected. In order to model BPR prediction using artificial neural networks (ANNs) and multivariate prediction techniques, a total of 219 datasets with 8 blasting influential parameters from limestone mine blasting in India are collected. To obtain a high-accuracy model, a new training process called the permutation important-based Bayesian (PI-BANN) training approach is proposed in this work. The developed models are validated with new 20 blast rounds, and evaluated with two model performance indices. The validation result shows that the two model results agree well with the BPR practical records. Additionally, compared to the MVR model, the proposed PI-BANN model in this work provides a more accurate result. Based on the controllable parameters, the two models can be used to predict BPR in a variety of rock excavation techniques. The study result reveals that rock strength variation affects both the blast outcome (BPR) and the quantity of explosives used in each blast round.

The highway contributes significantly to human existence by providing safe, dependable, and cost-effective services that are environmentally friendly and promote economic progress. Highway projects need extensive planning to prevent work revisions, save time and cost, and increase job efficiency. Without a doubt, Highway transportation system must be constantly updated to keep up with technology breakthroughs, environmental change, and rising client needs. Incorporating Remote Sensing (RS) and Geographic Information Systems (GISs) has the potential to go beyond the limitations of RS, which typically collects information about the earth and its peripheries from space, and does not alter, analyze, calculate, query or display geographic engineering maps. Over the last few decades, the fusion of RS and GIS has shown promise, and the researchers are employing it in different stages of the Highway Planning and Development Process (HPDP) such as optimal route analysis, geometric design, operation and management, traffic modeling, accident analysis, and environmental impact analysis (noise pollutions, air pollutions). This paper gives an overall review of the use of RS and GIS on HPDP at various stages of their lifecycles.

The northwestern margin of the Red Sea is developed as several rift-related fault blocks. These fault blocks comprise two mega tectono-stratigrahicsuccessions; the Pre-riftsuccessioncould be sub-divided intothe Precambrian Basement rocks and theUpperCretaceous-Lower Eocenedeposits,whilst the Syn-rift sequence includesthe Oligocene to Quaternary deposits. Lithologic differentiation of these rock units being encountered in thestudied area is accomplishedutilizing different remote sensing imagery enhancement techniques of the OLI data (Landsat-8) aided with field verification. Spectral signature analysis of different rock units, false-color composite, band-ratio, principle component analysis, minimum noise fraction, and independent component analysis are powerful tools in discrimination of the main rock units.The maximum likelihood distance supervised classificationtechnique is a robust tool in the identification of the contact between the different rock units. Radiometrically terrain corrected (RTC) DEM data extracted from PALSAR with a spatial resolution of 12.5m is utilized for the construction of a 3D perspective view image of the studied area. The present study offers a unique method for lithologic discrimination of main rock unitsutilizing OLI images, and introduces an enhanced high-resolution structural map of the studied area aided with field verification.

Granular pile anchor is a new technique that is commonly used to improve the pull-out resistance of expansive soil like soft clay, loose sand, and black cotton soil. Using the Abaqus software, this work presents a numerical investigation to estimate the pull-out capacity of granular pile anchor in soft clay. By applying a specified displacement of 10% of D (pile diameter) on the granular pile anchor, the effects of length, diameter, angle of inclination (α), and number of GPA at varying spacing values on uplift capacity is examined. Additionally, L/D ratios of both individual and group piles are examined using various variables. The study uses expansive soil and GPA of unit weight 17 kN/m3 and 22 kN/m3, poisson’s ratio of 0.4 and 0.3, modulus of elasticity 4 MPa, and 11 MPa, respectively, for the estimation of uplift capacity. The cohesion value for the expansive clay is 25 kPa, and the angle of shearing resistance for GPA is 36˚. According to the numerical study, both for a single pile and for piles placed in a group, with increases in pile length and diameter, the granular pile anchor's pull-out capability improves. For a pile placed in group the value of the pull-out capacity shows optimum result when spacing (S) is 2.5D. Additionally, the uplift capacity of the granular pile anchor increases with an increase in angle inclination (α) from 0˚ to 10˚, and then decreases from 10˚ to 15˚. The efficiency of GPA is examined, which assists in the choice of the different granular pile anchor parameters.

Today, energy produced from coal is economical compared to other sources but it faces a very serious waste problem. However, these wastes are evaluated by using them as mineral additives in cement, which leads to lower cement costs, saving resources, producing environmentally friendly cement, reducing CO2 gas, and producing high-strength cement. In this work, the pozzolanic properties of different types of fly ash (Afşin Elbistan C type and Çayırhan F type) are investigated. The fly ashes used in the study are first subjected to the milling process (10, 20, 30, 45, and 60 minutes), and then the 28 and 90-day pozzolanic activity index tests of the milled and unmilled ashes are performed. The results obtained show that the 28-day pozzolanic activity value of the ashes subjected to 20-, 30-, 45-, and 60-minute milling times are higher than the value specified in the standard, compared to the unmilled and 10 min milled fly ash. In addition, for all fly ash samples, the 90-day pozzolanic activity index results show that while the pozzolanic activity index value of Çayırhan (ÇYH) fly ash is higher than the standard value, that of Afşin Elbistan (AE) fly ash is lower than standard. The outcomes of the present study show that the mechanical properties of the fly ash are generated by the burning of coal increase after milling process, and thus can be used as a mineral additive. With the effect of grinding, both fly ash increase the pozzolanic activity. The results are determined with the experimental results obtained.

This paper discusses the applications of industrial waste like waste foundry sand (10%, 20%, 30%, and 40%) and calcium carbide residue (3%, 6%, 9%, and 12%) blended with polypropylene fibre (0.25%, 0.50%, 0.75%, and 1%) for soil stabilization. The purpose of this study is to develop a composite of clayey soil mixed with different additives, so it can be used for improving the geotechnical properties of the clayey soil. Multiple tests are conducted including differential free swell, Atterberg's limits test, compaction tests, unconfined compression test (UCS), and California-bearing ratio test (CBR) on clay soil individually and in different combinations and proportions with additive mixed with each other. The optimum percentage for the additives is found by performing differential free swell index and Atterberg limits test. The results demonstrate that the inclusion of additives in the clayey soil decreases the differential free swell and plasticity index of the composite but raises the composite UCS and CBR values. The maximum increase in the UCS and CBR values is obtained for optimum combination of C:PP:WFS:CC::76.25:0.75:20:3. Based on the CBR values, the thickness of flexible pavement is designed using the IITPAVE software. The results of the software analysis show a reduction in the pavement thickness for various values of commercial vehicles per day (1000, 2000, and 5000) for all combinations. The maximum reduction in layer thickness and construction costs is noticed for C:PP:WFS:CC:76.25:0.75:20:3. To further examine the improvement in the geotechnical properties of soil, calcium carbide residue, and waste foundry sand can be blended with nano-additives for potential uses.

The Precambrian rock assemblages of Umm Tawat area in the North Eastern Desert of Egypt have a distinctive ENE-trending exposure of Hammamat sediments (HS) between the Gebel Gattar granitic pluton and the volcanoclastic succession of Gebel El Dokhan. The present work applies the Landsat-8 data and image processing techniques such as spectral signature, principal component analysis, decorrelation stretch, and band ratios to map the various Precambrian rock units and the lithofacies of the HS and their geological contacts. The recognized mappable units of this assemblage are fully identified by their spectral signature, field verification, lineament analysis, and petrographic description. The resultant high-resolution lithological map based on the maximum likelihood algorithm demonstrates ten fully discriminated mappable units of younger granitoid and HS lithofacies units besides the Dokhan volcanics and metagabro-diorite rock units. The identified five HS lithofacies units are brownish gray conglomerate and sandstone HSf1, a green conglomerate with dominant volcanic fragments HSf2, fine-grained sediments of graywacke and silty-mudstone HSf3, interbedded conglomerates and siltstone with uranium enrichments related to the intrusive contact HSf4, and thermally metamorphosed pelitic sediments HSf5. Remote sensing techniques have been applied for the first time to reveal detailed facies variation of the Hammamat sediments of Umm Tawat. Finally, the results aforementioned above are imported to the Arc GIS database to update the geologic map with precise rock unit boundaries.

The rocks in the studied area are prone to deterioration and failure due to frequent exposure to extreme temperature variations and loading conditions. In the context of rock engineering reliability assessment, understanding the energy conversion process in rocks is critical. Therefore, this research work aims to assess the energy characteristics and failure modes of pink and white-black granite subjected to uniaxial compression loading at various temperatures. Samples of pink and white-black granite are heated to a range of temperatures (0 °C, 200 °C, 400 °C, 600 °C, 900 °C, and 1100 °C), and their failure modes and energy characteristics including total energy, elastic energy, and dissipated energy are studied by testing preheated samples under uniaxial compression. The results show that the dissipation energy coefficient initially rises rapidly, and then falls back to its minimum value at the failure stage. The micro-structures of granite rock directly affect its elastic and dissipation energy. Axial splitting failure mode is observed in most of the damaged granite specimens. After heating granite to 600 °C, the effect of temperature on the failure mode becomes apparent.

Himachal Pradesh state is located in seismically active western Himalayas (India) and its seven districts are in seismic zone V and other in zone IV as per the seismic code of India. Ninety% area of Hamirpur district, the studied area, lies in zone V. Peak ground acceleration (PGA) is one of the most important seismic response parameters in structural seismic design, largely influenced by the sub-soil and input seismic motion characteristics. In the present work, the primary objective is to identify the areas in the district that are prone to amplification of peak ground acceleration and can be delineated for infrastructural planning. Peak ground acceleration is one of the most important parameters used in seismic design of the structures. It is estimated using the computer programme ProShake, wherein the soil parameters from 181 borehole profiles up to 30 m depth and software in-built standard earthquake input motions of magnitude 6.9, 7.0, and 7.2 used as the input parameters. The output peak ground acceleration range from 0.24 g to 0.72 g at the ground surface and from 0.21 g to 0.54 g at a depth of 10 m. There is an attenuation of peak ground acceleration at 30 m depth. The estimation of peak ground acceleration will play an important role in delineating the starta having higher peak ground acceleration amplification. This information can be effectively used for planning of important infrastructure projects like hospitals, educational institutions, and commercial establishments in an economical way in the studied area.

Land surface temperature (LST) is one of the most important geological features of any area in the present times. During the study, the information regarding the land surface temperature is calculated using the Arc-GIS software. The LANDSAT 8 (2022) and LANDSAT 4-5 (2001 and 2011) satellite images are used for the calculation of LST. From the LST maps of years 2001 and 2011, a significant rise is noticed; this is due to the rapid increment in the population of the said area. A gradual increment in the LST is present between the second period of 2011-2022. A connection between the LST and the specific humidity has also been drawn in this aspect. The specific humidity in the region has seen a significant increment in the concerned time period. Overall, it is observed that the LST of the area has increased rapidly from the -12 ˚C minimum temperature in 2001 to 27 ˚C in 2022; this is because of the human activity in the area, which has ultimately catered towards the degradation of the climatic condition and environment like LST.

High-level vibrations caused by blasting operations in open-pit mining can exert adverse effects such as destruction of surrounding surface structures. Therefore, it is essential to identify the factors effective in mitigating the damaging effects of ground vibration in open-pit mines, and monitor them. This study investigates the effects of some of the most important blast design parameters in a row of blast holes. According to the advantages of numerical methods, the 3D discrete element method is employed for this purpose. The Peak Particle Velocity (PPV) values are measured along the central hole at the distances of one meter. The results obtained demonstrate that an increase in the blast damage factor and inter-hole delay time results in higher PPV values. However, the increased delay time has no remarkable effect on reducing the development of the blast damage zone. On the other hand, as the decoupling increases, the PPV values diminish, leading to substantial reductions in the ground vibration and rock mass damage. It is also observed that the elimination of sub-drilling does not significantly reduce ground vibrations. The analysis of the results obtained from the numerical modeling show that the discontinuities of the rock mass act as a filter, which could decrease the wave energy by more than 90%. Moreover, it is found that the direction of the discontinuities also affects the emission of waves caused by the blast. The PPV values are reduced, and the damaged zone is less developed if the discontinuities are opposite of the slope surface.

One of the significant negative factors involved in exploiting granite stones as ornamental stones is the presence of heterogeneous fractures within the rock mass. Joints can either be destructive or beneficial in the production granite piles and building stone mines depending on their characteristics. This work focuses on evaluating the joints in the Divchal mine area of Kelardasht, north Iran. To get to that point, the main faults are surveyed from the aerial photograph, geological and tectonic maps, and field observations. According to this implementation, a density map of faults is provided for the entire studied area. The characteristics of the main joints including the length, slope, number, and orientation are collected in the mine area. The volumetric percentage of joints ( ) and joint set spacing ( ) parameters are computed at specific stations to identify suitable locations for granite extraction. The findings of this work suggest that the lower the value of  (  < 10), the larger the blocks can be extracted. On the other hand, at the high  values, the width of the extraction block increases. These conditions are typically found in locations far from the main faults where the density of joints is low, and as a result, the distance between joints is higher. The values  > 60 indicate a crushed rock mass, and are typically observed in clay-free shear zones. It is recommended that the opening of the working face be avoided in situations near the main faults due to the fragmentation of rocks and denser joint spacing.

This work aims to investigate the effect of water saturation on cutting forces and chipping efficiency by performing a series of small-scale linear cutting tests with a chisel pick on twelve low- and medium-strength rock samples. The peak and mean cutting force acting on the chisel pick are measured and recorded under dry and saturated cutting conditions by the strain sensors that are embedded in the dynamometer. Also the amplitude of cutting force fluctuations in dry and saturated cutting conditions is compared by the standard deviation measurement of cutting force data, and its relationship with the size of cutting fragments is investigated. The results obtained show that the peak cutting force is reduced in saturated conditions compared to dry conditions. The mean cutting force in the synthetic sample cutting test is unchanged or in some cases increase, while in the natural samples it decreases. The relative increase in the mean cutting force in synthetic rock specimens is due to the paste state of fine materials produced from saturated cutting and chisel pick clogging. A strong correlation is found between the standard deviation of cutting force data and the average size of rock debris, indicating that the standard deviation of cutting force data is a useful measure for evaluating the chipping efficiency. The present study's findings reveal that to have an efficient excavation system in field operations, it is necessary to consider the presence of water and saturated conditions in designing the cutting machine's operating parameters and predicting the performance of mechanical excavators.

The presence of pores and cracks in porous and fractured rocks is mostly accompanied by fluid flow. Poroelasticity can be used for the accurate modeling of many rock structures in the petroleum industry. The approach of the stress to the value of the fracture stress and the effect of pore pressure on the deformation of rock are among the effects of fluid on the mechanical behavior of the medium. Due to the deformation-diffusion property of porous media, governing equations, strain-displacement, and stress-strain relationships can be changed to each other. In this study, constitutive equations and relationships necessary to investigate the behavior and reaction of rock in a porous environment are stated. Independent and time-dependent differential equations for an impulse and point fluid source are used to obtain the fundamental solutions. Influence functions are obtained by using the shape functions in the formulation of the fundamental solutions and integrating them. To check the validity and correctness of provided formulation, several examples are mentioned. In the first two examples, numerical application and analytical solution are used at different times and in undrained and drained conditions. In times 0 (undrained response of medium) and 4500 seconds (drained response of medium), there is good coordination and agreement between the numerical and analytical results. In the third example, using the numerical application, a crack propagation path in the wellbore wall is obtained, which is naturally in the direction of maximum horizontal stress.

This work presents the hollow center cracked disc (HCCD) test and the cracked straight through Brazilian disc (CSTBD) test of oil well cement sheath using the experimental test and Particle Flow Code in two-dimensions (PFC2D) in order to determine mode I fracture toughness of cement sheath. The tensile strength of cement sheath is 1.2 MPa. The cement sheath model is calibrated by outputs of the experimental test. Secondly, the numerical HCCD model and CSTBD model with diameter of 100 mm are prepared. The notch lengths are 10 mm, 20 mm, 30 mm, and 40 mm. The tests are performed by the loading rate of 0.018 mm/s. When the notch length in CSTBD is 40 mm, the external work is decreased 48%, related to the maximum external work of model with notch length of 10 mm (0.225 KN*mm decreased to 0.116 KN*mm). When the notch length in HCCD is 30 mm, the external work is decreased 33%, related to the maximum external work of model with notch length of 10 mm (0.06 KN*mm decreased to 0.04 KN*mm). The fracture energy is largely related to the joint length. The fracture energy is decreased by increasing the notch length. In constant to the notch length, the fracture energy of the CSTBD model is more than the HCCD model. Mode I fracture toughness is constant by increasing the notch length. The HCCD test and the CSTBD test yield a similar fracture toughness due to a similar tensile stress distribution on failure surface. The experimental outputs are in accordance to the numerical results.

Resource estimation and determining the grade distribution is one of the most important stages in planning and designing the open-pit and underground mines. In this work, a new mythology is used for resource estimation of the Angouran underground mine based on the optimized integration of the indicator kriging (IK), simple kriging (SK), and inverse distance weighted (IDW) methods. For this purpose, waste blocks are first removed from the block model using the IK method. Then the amount of mineral resource is estimated using the SK and IDW methods. Indeed, variograms are developed to estimate the grade of zinc minerals in the three used methods. Variograms analysis in three directions prove that the studied resource is anisotropic. Also the validation results confirm that the correlation coefficients between the measured and estimated zinc values by the SK and IDW methods equal to 0.76 and 0.75, respectively. Knowing this satisfactory result, a 3D model of the resource is prepared using the IK method, in which the ore and waste sections of the Angouran underground mine are separated definitely. According to the above methodology, the calculated resource of the Angouran underground mine using the SK method is achieved 1373962.5 tons with an average grade of 30.11%, whereas the estimated amount of this resource is attained 1349325 tons with an average grade of 31.88% using the IDW approach. The verification results show that the suggested methodology based on the optimized integration of the IK, SK, and IDW methods can be successfully applied for resource modeling and grade estimating of the Angouran underground mine.

This work investigates the effect of adding micro-silica as a pozzolan and a replacement for part of concrete cement when placing concrete in an acidic environment. Two types of ordinary concrete and concrete-containing micro-silica are constructed. The specimens are subjected to 0, 1, 5, and 10 cycles for two hours inside two types of acidic water containing sulfuric and nitric acid with pH = 3 and normal water with pH = 7. Mechanical properties including Brazilian tensile strength and uniaxial compressive strength, and physical properties including effective porosity, water absorption, and the longitudinal wave velocity of specimens are determined after the mentioned number of cycles. Thr results show that by decreasing the pH and increasing the number of cycles, the effective porosity and water absorption increase, and the velocity of longitudinal waves, Brazilian tensile strength, and uniaxial compressive strength of concrete decrease. Replacing 10% of micro-silica as a part of concrete cement has boosted the durability of concrete in corrosive conditions containing sulfuric and nitric acid more than ordinary concrete.

Implementing maintenance protocols for industrial machinery is essential since a well-thought-out plan may support and improve machinery dependability, production quality, and safety precautions. Implementing a maintenance plan that considers the equipment's actual functional behavior and the effects of failures will be easier and more practical. Engineers must consider environmental conditions when studying in hostile environments such as mine. The major goal of this study is to create a mining equipment maintenance program that is as effective as possible while incorporating risk and performance indicators and taking environmental factors into account. The study uses the “reliability-centered maintenance” method, which combines the reliability operating index and risk. The Cox model also includes the risk factors associated with environmental conditions in the reliability analysis. The proposed approach was implemented in a 5-758 Komatsu dump-truck case study at the Sungun copper mine in Iran. The reliability-centered maintenance approach is implemented for dump-truck in three scenarios based on risk factors: 1- baseline, 2- First semi-annual, cheap maintenance, and 3- second semi-annual, expensive maintenance. All failure modes are low-risk, making corrective maintenance appropriate. In Scenario 1, electrical-electrical, electrical-start, mechanical, and pneumatic-related failures are low-risk, making corrective maintenance suitable. In Scenario 2, corrective maintenance is recommended for pneumatic-related failure. In Scenario 3, the fuel-related failure has a high criticality number and failure intensity, indicating a high-risk situation. Time-based preventive maintenance is the most appropriate strategy for this scenario.

Back-break is one of the adverse effects of blasting, which results in unstable mine walls, high duration, falling machinery, and inappropriate fragmentation. Thus, the economic benefits of the mine are reduced, and safety is severely affected. Back-break can be influenced by various parameters such as rock mass properties, blast geometry, and explosive properties. Therefore, during the blasting process, back-break must be accurately predicted, and other production activities must be done to prevent and reduce its adverse effects. In this regard, a hybrid model of extreme gradient boosting (XGB) is proposed for predicting back-break using gray wolf optimization (GWO) and particle swarm optimization (PSO). Additionally, validation of the hybrid model is conducted using XGBoost, gene expression programming (GEP), random forest (RF), linear multiple regression (LMR), and non-linear multiple regression (NLMR) methods. For this purpose, the data obtained from 90 blasting operations in the Chadormalu iron ore mine are collected by considering the parameters of the blast pattern design. According to the results obtained, the performance and accuracy level of hybrid models including GWO-XGB (R2 = 99, RMSE = 0.01, MAE = 0.001, VAF = 0.99, a-20 = 0.98), and PSO-XGB (99, 0.01, 0.001, 0.99, 0.98) are better than the XGBoost (97, 0.185, 0.132, 0.98, 95), GEP (96, 0.233, 0.186, 0.967, 0.935), RF (97, 0.210, 0.156, 0.97, 0.94), LMR (96, 0.235, 0.181, 0.964, 0.92), and NLMR (96, 0.229, 0.177, 0.968, 0.93) models. Notably, the GWO-XGB hybrid model has superior overall performance as compared to the PSO-XGB model. Based on the sensitivity analysis results, hole depth and stemming are the essential effective parameters for back-break.

Due to the challenge of finding identical rock samples with varying grain sizes, investigating the impact of texture on rock material has been given less attention. However, macroscopic properties such as compressive strength, tensile strength, and modulus of elasticity can indicate microscopic properties like intergranular resistance properties influence rock fracture toughness. In this work, both the experimental and numerical methods are used to examine the effect of grain size on the mechanical properties of sandstone. Uniaxial compressive strength and indirect tensile tests are conducted on sandstone samples with varying grain sizes, and the particle flow code software is used to model the impact of grain dimensions on intergranular properties. Flat joint model is applied for numerical modeling in the particle flow code© software. The aim of this work is to validate the numerical model by peak strength failure and stress-strain curves to determine the effect of grain size on the mechanical behavior. The results show that increasing grain size significantly decrease compressive strength, tensile strength, and modulus of elasticity. The impact of the change in grain size is more significant on compressive strength than on the other two properties. The correlation coefficient for tensile strength and grain size is R2 = 0.57, while for modulus of elasticity and grain size, it is R2 = 0.79. The PFC software helps calibrate intergranular properties, and investigate the effect of changing grain size on these properties. Overall, this study offers valuable insights into the relationship between the grain size and the mechanical properties of sandstone, which can be useful in various engineering applications, especially in petroleum geo-mechanics.