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This study focuses on evaluating the influence of the energy accumulation hole diameter on bi-directional cumulative tension blasting. Firstly, the penetration depth of bi-directional cumulative tension blasting is determined, followed by an analysis of the corresponding fracture mechanics behavior. Secondly, the Smooth Particle Hydrodynamics (SPH) method is used for numerical analysis of the bi-directional cumulative tension blasting process, and the Johnson- Holmquist constitutive model is then employed to examine the dynamic process during tensile blasting-induced cracking. This analysis provides insights into damage development, particle distribution, stress distribution, and crack propagation in the rock at different opening diameters. The findings reveal that, except for the 2 mm case, bi-directional cumulative tension blasting effectively produces directional cracks aligned with the energy accumulation direction. For hole diameters between 4-8 mm, linear through cracks form in the energy accumulation direction. However, a 2 mm diameter opening only generates short shear cracks around the blast hole. With energy accumulation hole diameters ranging from 10-14 mm, the crack propagation depth is insufficient for complete penetration, despite the presence of linear cracks in the energy accumulation direction. When diameter exceeds 14 mm, symmetrical airfoil cracks appear in non-concentrated energy directions, with larger diameters resulting in shorter crack propagation lengths. During the directional cracking process for hole diameters of 4-8 mm, explosive particles facilitate crack expansion in width and length through the action of a "gas wedge." Onsite blasting tests confirm the excellent directional pre-splitting effect of bidirectional cumulative tension blasting. [ABSTRACT FROM AUTHOR]

The evaluation of blasting vibrations primarily hinges on two physical quantities: velocity and acceleration. A significant challenge arises when attempting to reference the two types of vibration data in relation to one another, such as different types of seismometers, noise, etc., necessitating a method for their equivalent transformation. To address this, a transformation method is discussed in detail with a case study, and equations for the ratio (Ra) of the particle peak velocity (PPV) to the particle peak acceleration (PPA) are proposed. The findings are twofold: (1) The conventional data conversion processes often suffer from low accuracy due to the presence of trend terms and noise in the signal. To mitigate this, the built-in MATLAB function is used for trend term elimination, complemented by a combined approach that integrates CEEMDAN with WD/WDP for noise reduction. These significantly enhance the accuracy of the transformation. (2) This analysis reveals a positive power function correlation between Ra and the propagation distance of the blast vibrations, contrasted by a negative correlation with the maximum charge per delay. Intriguingly, the Ra values observed in pre-splitting blasting operations are consistently lower than those in bench blasting. The established Ra equations offer a rapid, direct method for assessing the transformation between the PPV and PPA, providing valuable insights for the optimization of blasting design. [ABSTRACT FROM AUTHOR]

The research on blasting damage of medium has important engineering significance, wherein one of the main factors affecting the blasting effect of the medium is the free boundary of the medium. In this article, the blasting damage of media with one free boundary is studied and the damage evaluation based on fractal theory is carried out. Firstly, an experimental device is designed to simulate the state of the medium's one free boundary. The distance between blasthole and the free boundary is the only variable considered in the experimental investigation. The fractal theory is used to analyze the fractal damage of the medium caused by the explosion, and MATLAB is used to extract three characteristic parameters (damage depth, damage width, and damage zone) of the binary image after the explosion. Finally, LS-DYNA is used to build a 2D plane strain model with the same size and boundary conditions, which simulates the damage evolution process of medium under a single free boundary blasting pattern. The fractal theory is then used to evaluate the fractal damage observed in the numerical simulation results. The experimental results and numerical simulation results of blasting fractal damage of one free boundary medium are in good agreement. The blasting fractal damage grows initially and subsequently decreases as the distance between the blasthole and the free boundary increases. Thus, the distance between blasthole and free boundary affects the efficiency of blasting energy destroying medium and the blasting failure pattern. [ABSTRACT FROM AUTHOR]

The dominant hazard in the Polish copper ore mining industry (LGCD mines—Legnica–Glogow Copper District) is the occurrence of mining tremors and rockbursts. One of the effective active methods of preventing this threat is torpedo blasting, which results in disturbing the structure of roof rocks. A change in the integrity of a roof, especially in the tremor-generating layer or in the contact between stiff rock layers, reduces the possibility of an elastic energy concentration and may also be a kind of stress concentrator, provoking the destruction of rocks. This article presents original solutions for determining the areas of rock mass within a mining area where it is advisable to conduct torpedo blasting, and the experience of blasting in the Rudna copper mine in the LGCD is described. The first part of this article presents the results and experiences of using torpedo blasting prevention in the LGCD mine conditions in the Rudna mine. Assuming that due to the stress of the rocks, torpedo blasting brings the greatest benefits in the areas of elastic energy concentration, the second part of this article presents the results of numerical modeling, on the basis of which the zones of elastic energy concentration in the form of total, shear and volume deformation were determined in the vicinity of mining activities for typical geological and mining conditions in the LGCD. The importance of methods for the verification of the proposed solutions based on the analysis of seismic activity and geophysical mechanisms of events' foci and seismo-acoustic emissions was also emphasized. The numerical simulations performed and conclusions from in situ observations allowed the formulation of general principles for the selection of torpedo blasting parameters. [ABSTRACT FROM AUTHOR]

The research on the attenuation law of blasting vibration has become the foundation and precondition of the effective control of blasting vibration damage. Aiming at the characteristics of low frequency, low velocity, and strong amplitude of the R wave, an improved wave component separation method based on R wave suppression is proposed. Combined with the measured vibration signals of a field test, the attenuation parameters of different types of waves in the propagation process of blasting seismic waves are studied. The analysis results show that, in the process of blasting seismic wave propagation, the attenuation parameters of different types of waves are significantly different. With an increase in propagation distance, the proportion of the different types of waves will also change. The study of attenuation law with only coupled particle peak vibration velocity often showed high discreteness. The fitting correlation coefficient and prediction accuracy of peak vibration velocity without distinguishing wave modes are lower than those induced by the P wave or R wave alone, which should be attributed to the conversion of dominant wave modes in blasting vibration at different distances. [ABSTRACT FROM AUTHOR]

It is very important to predict the blasting fragmentation size of fractured rock mass. Based on the geological conditions of practical engineering rock mass, a plane analysis model of bench blasting in layered rock mass considering microcrack structure was established. And the distribution law of stress in the bench blasting of layered rock mass with different occurrence and layer thickness is analyzed by using the CDEM numerical simulation method. Combined with the theory of rock fracture mechanics and relevant test results, this paper quantitatively studied the change laws of the angle for the cracks to propagate, speed and crack initiation length at different particle points in bench blasting and realized the time history analysis of the crack development and rock fragmentation in bench blasting. And then, this paper derived the quantitative relationship between the post-expansion cranny ratio and the blasting fragmentation from a theoretical point of view, and proposed the prediction method of the median fragmentation in bench blasting of layered rock mass. Combined with the bench blasting productive test of Changjiu (Shenshan) limestone mine, the largest sand aggregate production mine in the world, the correctness of the theoretical results is verified. The test results demonstrate that in a vertically inclined rock bench, the degree of rock fragmentation intensifies in the horizontal direction, and the overall fragmentation effect can be optimized by adjusting the blasting hole spacing; the blasting fragmentation prediction method proposed in the paper can accurately predict the median fragmentation of layered rock, which provides a novel method for predicting the effects of bench blasting. Highlights: The prediction method for the median fragmentation of layered bench rock mass blasting is obtained The quantitative relationship between the post-expansion cranny ratio and the median fragmentation of bench blasting is theoretically derived The distribution law of microcracks in bench rock mass is simulated by discrete fracture network model. The internal force distribution characteristics are analyzed by continuous medium discrete element method The propagation law and rock breaking process of microcracks and layered cracks in bench blasting are studied At the same time, the correctness of the prediction method is verified by the field test and production of Changjiu (Shenshan) limestone mine [ABSTRACT FROM AUTHOR]

Drilling and blasting method used for excavation causes damage to surrounding rock mass, and frequent blasting often leads to cumulative damage effects. Thus, understanding the distribution of Blast-Induced Damage (BID) zone is critical to assess the slope stability of open-pit mines. Herein, this study aims to investigate the cumulative damage effects and safety control criteria on the final wall of the open-pit slope under blasting. The cumulative damage zone was defined using a continuous damage model coupled with tensile damage and Drucker–Prager yield criteria embedded in the finite difference method. The simulation results were validated against field data collected from the Wushan open-pit mine in Inner Mongolia, China. The results demonstrate that the cumulative damage of the final wall exhibited a non-linear decreasing trend from the bench face to the interior of the slope, successfully reproducing the spatial distribution of the BID obtained from the in situ test, and revealing that the maximum cumulative damage depth occurred at the slope crest. Additionally, a safety control criterion for the critical damage zone of open-pit final slope was proposed based on the investigation of the effects of dynamic loading rate and stemming length on excessive overbreak. The results highlight how important it is to account for cumulative damage effects when assessing the final slope stability of an open pit and optimizing the mining design. Highlights: The cumulative damage effects on the final wall of the open-pit under blasting are investigated. A model coupled with tensile damage and Drucker-Prager yield criteria is established and incorporated into finite difference method to simulate the blast-induced damage zone. The subsurface damage depth is obtained using the digital drilling images technology. The dynamic loading rate and stemming length could significantly affect the excessive overbreak along the crest. [ABSTRACT FROM AUTHOR]

Shotcrete has been widely used in the support of tunnels and mine roadways, but frequent blasting disturbances can easily cause it to spall from rock surfaces. In previous laboratory tests, it has been shown that thin spray-on liner (TSL) has shown significant potential as an alternative to traditional shotcrete support, but these studies were mainly conducted under static conditions, and doubts remain among many scholars and mine managers regarding the practical application of TSL in the field. The aim of this study is to compare the support effects of TSL and shotcrete under blasting loads and verify the support performance of this new type of skin support material. Through 21 in situ blasting tests, the installation process, support effects, and benefits of the two support methods were analyzed. The results show that compared to shotcrete, TSL provides a better construction environment and lower cost. Under far-field blasting, the downward displacement of the roadway roof supported by TSL is smaller than that of shotcrete, and the wave velocity decrease rate of TSL does not exceed 10% (indicating that the TSL has not been damaged). Under near-field blasting, TSL provides a smaller destruction area than shotcrete. TSL can effectively restrict the movement of the roadway roof, and the damage degree is much lower than that of shotcrete. The tests in this study were only conducted in intact hard rock roadway at a depth of − 520 m. Further research is needed to investigate the support effects of TSL in roadways with different stress environments and the quality of rock masses. Highlights: Through 21 in situ blasting experiments, the support effects of TSL and shotcrete in hard rock roadways within an underground mine under the influence of blasting loads were validated and compared. A variety of methods, including displacement monitoring, ultrasonic tests, strength tests, and dynamic data tests, were employed to compare the support effectiveness of TSL and shotcrete. Compared to shotcrete, TSL provides a better construction environment and lower cost. Furthermore, the TSL incurs less damage and exhibits a smaller destruction area under blasting loads. In this study, the on-site conditions suitable for TSL application were evaluated, and the reasons for TSL blast-induced damage resistance were analyzed. [ABSTRACT FROM AUTHOR]

In drilling and blasting, initiation modes determine the propagation direction of detonation wave, which affects the distribution of blast vibration field. In this study, the near-field distribution characteristics of peak particle velocity (PPV) induced by different initiation modes were obtained based on the solution model of the Heelan equivalent elements. The influence law of the initiation mode on the transmission of explosion energy was determined. Through onsite single-hole blasting experiments, the PPV resulting from different initiation modes, such as top initiation, bottom initiation, midpoint initiation, and two-point initiation, were compared and analyzed. The influence of the initiation mode on the transmission of explosion energy was also discussed. The results revealed that the PPV are positively proportional to the blasting load amplitude and the charge length, but inversely proportional to the duration and rising time of the blasting load. The PPV induced by the different initiation modes has the following relationship: bottom initiation > midpoint initiation > two-point initiation > top initiation. The effect of initiation mode on PPV gradually decreased with increasing distance from the blasting centre. [ABSTRACT FROM AUTHOR]

Underwater drilling and blasting techniques have been developed to overcome the challenges posed by various subaquatic operations, including marine construction, oil and gas exploration, and underwater mining, demolition, dredging and excavation, seismic surveys and marine research. The drilling operation is followed by underwater blasting, which involves the creation of boreholes in submerged surfaces, such as sea beds or riverbeds. Specialized drilling equipment is utilized, which can operate in aquatic environments. To ensure efficient and reliable performance, the drilling equipment is designed to withstand the pressures and corrosive nature of seawater. Once the desired depth is reached, underwater blasting is utilized to break the rock or seabed. The primary objective of blasting is to loosen the substrate and create a cavity for subsequent operations. Safety is a crucial factor in underwater drilling and blasting operations. To safeguard personnel involved and prevent accidents during drilling and blasting activities, strict safety measures are implemented. In addition to human safety, precautions are taken to minimize the environmental impacts of underwater drilling and blasting, including measures to prevent pollution, protect marine life, and preserve the underwater ecosystem. In this article, the core elements of underwater drilling and blasting operations are outlined. Despite notable progress in this domain, the paper highlights the enduring constraints and obstacles, underscoring the need for continued investigation and understanding. [ABSTRACT FROM AUTHOR]

Blasting presplitting is an effective method for preventing rock bursts in thick hard roofs. In this study, two adjacent working faces in the No. 10 mining area of the Jining No. 2 coal mine were considered as case studies, and the conditions of the working face and the construction parameters for roof blasting presplitting were introduced. The microseismic characteristics of the 2 working faces during the mining period were analyzed, and 10 indices for evaluating the microseismic characteristics of the working faces were proposed. Accordingly, the influence of blasting presplitting on the microseismic characteristics of the surrounding rock was evaluated. The results showed that the frequency of microseismic events changed with the mining stage of the working face. After the roof of the 103down03 working face was presplit, the average energy of microseismic events, maximum energy of microseismic events, and proportion of high-energy events all decreased significantly. The average height of the source decreased from 31.08 m above the coal seam to 8.78 m, and the average strike location of the source decreased from 102 to 32 m in front of the working face. After presplitting, the roof gradually changed from large-scale and high-energy fractures to small-scale and low-energy fractures. After blasting presplitting, the energy accumulated in the roof was released through the collapse of the roof in the goaf, which improved the burst risk in the coal and roadway in front of the working face, thus ensuring the safety of underground construction personnel and equipment. [ABSTRACT FROM AUTHOR]

With the application of electronic detonators, delayed blasting is considered a very effective method to improve rock fragmentation, and this technique is widely used in practical engineering. Therefore, it is necessary to study the rock-breaking mechanism of double-hole delayed blasting. In this paper, based on the finite difference method, the influence of double-hole delayed blasting on the reservoir permeability was quantitatively analyzed by adopting the adjacent hole spacing, delay time, and decoupling coefficient (K) as variables and the permeability increment as an evaluation index. Based on the parameters studied in this paper, it was found that the effect of the delay time on the reservoir permeability depends on the hole spacing. When the hole spacing is less than 20ra (ra is the borehole radius), a reasonable delay time could significantly increase the reservoir permeability, but when the hole spacing is greater than 20ra, the delay time does not affect reservoir permeability enhancement. The decoupling coefficient could control the attenuation speed of shock wave energy. For K = 2, energy attenuation occurred the slowest, and the reservoir permeability increase effect was the best. Based on site-scale numerical simulations, the mechanism of stress superposition between boreholes was revealed, and the position of stress superposition was controlled by adjusting the delay time to break hard reservoir rock so that the cracks between two holes were connected, i.e., accurate reservoir reconstruction was achieved. This work provides a certain guiding basis for actual engineering applications. [ABSTRACT FROM AUTHOR]

Accurately estimated quarry blast equivalents can be compared with the quantity of initiated explosives to detect misfires or undetonated explosive remnants, thereby ensuring safe mining operations. Seismic waves are commonly used to estimate the equivalent; however, the ability of permanent seismic networks to detect low-magnitude events is limited. Therefore, we conducted experiments in the Minglongshan–Shangyao fault segment of the Tan–Lu fault zone in the Chuzhou area of Anhui Province in China, deploying six shallow-borehole short-period seismometers at a burial depth of 1 m for continuous monitoring for 20 days. Forty-two earthquakes were detected using a convolutional neural network, and the detected earthquakes were processed based on the source location, frequency spectrum analysis, time of occurrence, equivalent, and magnitude statistics. Through comparison, we found that one of the earthquakes was the M3.1 Suqian earthquake on March 19, 2022. Unlike this natural earthquake, the remaining 41 earthquakes have not been reported by any seismic network. The source location is concentrated, the frequency spectrum is simple, and the time of occurrence is concentrated in the daytime. Based on these results and the widespread quarries in this area, we speculate that these 41 earthquakes were caused by artificial blasting. Through seismic array monitoring, the precise locations of quarry blasts can be determined. Furthermore, the seismic wave energy-blast equivalent algorithm can be used to accurately estimate the quarry blast equivalent. [ABSTRACT FROM AUTHOR]

To study the effects of the initiation position on the damage and fracture characteristics of linear-charge blasting, blasting model experiments were conducted in this study using computed tomography scanning and three-dimensional reconstruction methods. The fractal damage theory was used to quantify the crack distribution and damage degree of sandstone specimens after blasting. The results showed that regardless of an inverse or top initiation, due to compression deformation and sliding frictional resistance, the plugging medium of the borehole is effective. The energy of the explosive gas near the top of the borehole is consumed. This affects the effective crushing of rocks near the top of the borehole, where the extent of damage to Sections I and II is less than that of Sections III and IV. In addition, the analysis revealed that under conditions of top initiation, the reflected tensile damage of the rock at the free face of the top of the borehole and the compression deformation of the plug and friction consume more blasting energy, resulting in lower blasting energy efficiency for top initiation. As a result, the overall damage degree of the specimens in the top-initiation group was significantly smaller than that in the inverse-initiation group. Under conditions of inverse initiation, the blasting energy efficiency is greater, causing the specimen to experience greater damage. Therefore, in the engineering practice of rock tunnel cut blasting, to utilize blasting energy effectively and enhance the effects of rock fragmentation, using the inverse-initiation method is recommended. In addition, in three-dimensional (3D) rock blasting, the bottom of the borehole has obvious end effects under the conditions of inverse initiation, and the crack distribution at the bottom of the borehole is trumpet-shaped. The occurrence of an end effect in the 3D linear-charge blasting model experiment is related to the initiation position and the blocking condition. [ABSTRACT FROM AUTHOR]

In rock blasting for mining production, stress waves play a major role in rock fracturing, along with explosive gases. Better energy distribution improves fragmentation and safety, lowers production costs, increases productivity, and controls ore losses and dilution. Blast outcomes vary significantly depending on the choice of the explosive and the properties of the rock mass encountered. This study analyzes the effects of rock mass and explosive properties on blast outcomes via numerical simulation using data from the case study, and later validates the simulation results from the field blast fragmentation. The findings suggest that, for a given set of rock properties, the choice of explosive has a major influence on the resulting fragmentation. Strong explosives (high VOD and detonation pressure) favor large fracture extents in hard rocks, while weaker explosives offer a better distribution of explosive energy and fractures. The presence of rock structures such as rock contacts and joints influences the propagation of stress waves and fractures depending on the structures' material properties, the intensity and orientations, and the direction and strength of the stress wave. When the stress wave encounters a contact depending on its direction, it is enhanced when traveling from soft to hard and attenuates in the opposite direction. The ability of the stress wave to cause fracturing on the opposite side of the contact depends on the intensity of the transmitted wave and the strength of the rock. Transmitted wave intensity is a function of the strength of the incident wave and the impedance difference between the interface materials. The presence of joints in the rock mass affects the propagation of the stress wave, mainly depending on the infill material properties and the angle at which the stress wave approaches the joint. Less compressible, higher stiffness joints transmit more energy. More energy is also transmitted in the areas where the stress wave hits the joint perpendicularly. Joints parallel to the free face offer additional fracturing on the opposite side of the joint. Other parameters, such as the joint width, continuity, fracture frequency, and the distance from the charge, enhance the effects. To achieve effective fragmentation, the blast design should mitigate the effect of variability in the rock mass via explosive selection and pattern design to ensure adequate energy distribution within the limits of geometric design. [ABSTRACT FROM AUTHOR]

To investigate the effect of stemming length on the blasting of cylindrical rock samples, a three-dimensional zone-divided model of cylindrical rock samples undergoing single-hole charging was established through numerical simulation methods. A comparative analysis was conducted on the damage, displacement, and crack propagation of the stemming and rock by changing the stemming lengths. The simulation results were consistent with the observed crack propagation and damage during the blasting process of the cylindrical rock samples in the laboratory, validating the effectiveness of the blasting model in simulating the rock blasting process. Within a stemming length that constitutes 23.7% of the borehole length, an increase in stemming length considerably suppresses the extent of stemming expulsion from the borehole and the unit inhibition effect diminishes beyond this range. As stemming length increases from 7.9% to 39.5% of the borehole length, the complexity of surface crack networks gradually decreases while crack width significantly increases. The highest damage value, reaching 0.75, occurs in the middle region of the rock pillar at a stemming length of 23.7% of the borehole length. In the upper region of the rock pillar, the damage shows a concave change with the stemming length, with a difference of 0.054 3. Among the five stemming lengths, the largest difference in damage is observed in the middle region of the rock pillar, with a value of 0.067 9. The impact of the damage in the lower region of the rock pillar is relatively small, with a variation amplitude of 0.009 9. The reasonable selection of stemming length offers a new approach to achieving precise regional blasting and improving blasting effectiveness. [ABSTRACT FROM AUTHOR]

To investigating the influence of faulting on blast vibration wave propagation in an underground metal mine in Yunnan, the measuring points are arranged in the north and middle part of 3736 and the south and middle part of 3736 respectively. Using as a research object the actual blast vibration data collected from an underground metal mine in Yunnan, based on the wavelet packet transform, the HHT algorithm, and the STFT algorithm, the attenuation law of the blast vibration wave is investigated. The results show that the instantaneous energy amplitude of the vibration wave of a subsurface metal mine in Yunnan reaches 10X10-4 dB before the fault and 1. 5X10-4 dB after the fault, and the instantaneous amplitude of the energy attenuates by as much as 85%. This fault will perturb the energy distribution of the vibration wave to some degree and retard the rapid rise of the vibration energy. After the vibration wave passes through the fault, the low-frequency energy attenuates by 60%,the high frequency energy by 71%, the total energy power by 77%, the high frequency energy by 18%, the low frequency energy by 17%, and the overall energy power by 15%. Once the blast vibration wave has passed through the defect, a large amount of high-frequency energy is filtered out, and the overall energy distribution exhibits a trend toward the low-frequency domain. [ABSTRACT FROM AUTHOR]

Cut patio construction was a critical process in the medium-deep hole or deep hole mining methods, which mainly included staged blasting or one-time grooved blasting. Cut patio was essential in the medium-deep hole mining technology. The common method, the conventional raising, cage raising and climber raising method was usually used to construct the cutting patio, which has great safety risks and low excavation efficiency, which seriously affects the mine production. In recent years, Sanshandao Gold Mine has researched downward sublevel filling mining with medium and deep hole blasting. This research was currently facing the problem of cut patio construction under the backfill roof. This study demonstrated a one-time grooved blasting method fitting the backfill roof condition and its application. By comparing the characteristics of the straight-hole cutting method and the blasting crater method, the straight-hole cutting method was selected for the cut patio construction. By calculating blasting parameters, the diameter of the charging hole was Φ65 mm, and the diameter of the compensation hole was Φ110mm. The distance between the charging and empty holes was 0.3m, which could meet the requirements of blasting compensation space and free surface. In consideration of the surrounding rock stability conditions, a nine-hole cutout method was selected, containing 29 holes, where the cutout hole was designed with 1 central charging hole, 12 empty holes as compensation holes, 4 auxiliary holes, and 12 peripheral holes, after determining the blast hole plugging length, explosive selection, charge structure, differential time, detonation sequence and other process parameters, an in-situ industrial test of cut patio construction was carried out. The industrial test showed that the one-time grooved blasting plan for patio construction was feasible. The blasting rock particle size is uniform with no large blocks and excessive powder, the blasting disturbance is minor, and the blasting patio dimensions meet the design requirements. Overall, this test provided experiences and a reference basis for other one-time grooved blasting technical applications with similar conditions. [ABSTRACT FROM AUTHOR]

In the repair works of Japan's infrastructure maintenance and management, there is a need to develop a technology that can easily remove coating and rust without a thermal effect on the base material, and the laser blasting technology, which can achieve this by only emitting laser beams, is a candidate for this goal. In various fields of infrastructure maintenance and management, we have been progressing on an agile system product development based on customer's feedbacks in accordance with our in-house systematized new business development process. In this report, we will describe the development of the "InfraLaser" system and the laser blasting technology, where we apply a high-power laser and the processing technology that we have cultivated. The laser blasting technology can remove coating and rust faster than existing methods without affecting the base material, and is expected to be friendly to both workers and environment. [ABSTRACT FROM AUTHOR]

As a widely used rock excavation method in civil and mining construction works, the blasting operations and the induced side effects are always investigated by the existing studies. The occurrence of flyrock is regarded as one of the most important issues induced by blasting operations, since the accurate prediction of which is crucial for delineating safety zone. For this purpose, this study developed a flyrock prediction model based on 234 sets of blasting data collected from Sugun Copper Mine site. A stacked multiple kernel support vector machine (stacked MK-SVM) model was proposed for flyrock prediction. The proposed stacked structure can effectively improve the model performance by addressing the importance level of different features. For comparison purpose, 6 other machine learning models were developed, including SVM, MK-SVM, Lagragian Twin SVM (LTSVM), Artificial Neural Network (ANN), Random Forest (RF) and M5 Tree. This study implemented a 5-fold cross validation process for hyperparameters tuning purpose. According to the evaluation results, the proposed stacked MK-SVM model achieved the best overall performance, with RMSE of 1.73 and 1.74, MAE of 0.58 and 1.08, VAF of 98.95 and 99.25 in training and testing phase, respectively. [ABSTRACT FROM AUTHOR]

Building a new tunnel adjacent to an existing tunnel has become a common means of transformation in engineering. Existing tunnels are prone to some deterioration, such as cavities and cracks under long-term traffic load. This kind of deterioration tunnel is prone to collapsing under the action of blasting. Therefore, the vibration caused by blasting should be strictly controlled. Based on the reconstruction project of the Bo Jiling Tunnel, this paper puts forward the method of mechanical cutting in a central position combined with an ordinary detonator to reduce blasting vibrations. ANSYS/LS-DYNA version 19.2, was used to simulate two conditions of full-section blasting and central mechanical cutting blasting. By comparing the stress and velocity of the existing tunnel, the damping effect of mechanical cutting blasting is analyzed. Via field experiments, the superiority of the mechanical cutting method in reducing blasting vibration is further discussed. At the same time, the relationship between the main vibration frequency and the peak velocity of the existing deterioration tunnel is obtained by wavelet packet analysis of the field experimental data. The frequency band energy distribution in each direction of vibration velocity is also obtained. The results show that the central mechanical cutting increases the blasting free surface, and the mechanical cutting method reduces the vibration velocity by 36.3%. The third frequency band (31.25~46.875 Hz) is the most concentrated, which is the dominant frequency band of the signal. The novelty of this paper is to propose mechanical cutting of the central hole instead of traditional blasting for existing deterioration tunnels. The feasibility of this method is verified by numerical simulation and field tests. The relationship between peak vibration velocity, band energy, and tunnel frequency is clarified, which can better control blasting vibration and ensure the safety of existing deterioration tunnels. [ABSTRACT FROM AUTHOR]

Blasting technology is widely applied in various engineering applications due to its cost-effectiveness and high efficiency, such as in mining, transport infrastructure construction, and building demolition. However, the occurrence of cracking in the rear row has always been a major problem that disrupts mining bench blasting. To address this issue, a three-hole simultaneous blasting technology is proposed in this study. Both numerical simulations and onsite blasting experimental testing were conducted. To aid this endeavor, the three-hole simultaneous blasting and the hole-by-hole blasting methods were adopted to comparatively analyze the severity of the damage caused to the original rock and the effect of rock fragmentation in the rear row. The obtained results highlighted that the outcome of the blast produced by the three-hole simultaneous blasting method is satisfactory, with fewer flying stones and concentrated blasting piles required. Additionally, the original rock in the rear row showed no obvious sign of tensile damage and had uniform fragmentation. It was also found that a block size of less than 60 cm accounts for 100%, while a block size of less than 50 cm accounts for 98.7% of the whole blocks, with no large blocks reported. Moreover, a penetrating horizontal crack occurred in the direction of the connection of the blast hole center when the three-hole simultaneous blasting method was adopted. This resulted in a smooth and flat rear part of the rocks at the interface. Compared to the hole-by-hole blasting method, the three-hole simultaneous blasting method improved the effective stress and displacement at each measurement point. At the measurement point directly at the front of the borehole, the maximum effective stress attained 67.9 GPa, and the maximum displacement reported was 31.9 cm. Overall, it was shown that the three-hole simultaneous blasting technology is applicable in similar applications of mine bench blasting, which is conducive to addressing the rear row original rock strain for onsite bench blasting. [ABSTRACT FROM AUTHOR]

Currently, double-hole complementary ventilation is a mature ventilation method for operating tunnels, but how to carry out it in the construction tunnel poses a new challenge. Due to the desynchronization in the construction period of the double-hole tunnel, there is an instantaneous difference in the air flow demand between the two working faces. The study analyzes the impact of geometric parameters, specifically Lt (the distance from the traffic cross passage to the working face of the advance side tunnel), Lp (the distance between the pedestrian cross passage and the working face of the advance side tunnel), Ht (height of the upper step), and Lw (safe step distance of the double-hole working face) on ventilation network stability. The results show that with the increase of Lt and Lp, the Rm resistance of each branch changes non-uniformly, and the stability of the ventilation network is significantly different. Then, when Lt, Lp = 80 and 180 m, the air flow directions of the double-hole tunnel are the same. Finally, when Lt and Lp = 130 m, the air flow directions are inconsistent, which indicates that in the range of 80 m < Lt or Lp < 180 m, the cross-section size of the cross passage affects the stability of the ventilation network. However, when 2.5 m < Ht < 3 m, or 30 m < Lw < 50 m, the stability of the ventilation network is not affected, and the flow field of the double-holes does not interfere with each other. The conclusions obtained confirm that the double-hole complementary ventilation method is available in construction tunnels, and has potential for implementation. [ABSTRACT FROM AUTHOR]

One of the most critical complications of blasting in open-pit mines is blast-induced damage such as back break, which affects various aspects of safety and economy. Recognizing the effective parameters and predicting the amount of blast-induced damage can lead to reduce and prevent it. Therefore, several studies have been conducted on the effects of various parameters such as discontinuities conditions, host environment, and rock physical and mechanical properties on blast-induced damage. However, the effects of parameters such as discontinuity orientation, delay time, and different blasting patterns have been less studied due to the complexity of their modeling. In the present study, the effects of the various delay times, the square and stagger blasting patterns, and discontinuity orientation on blast-induced damage are investigated using numerical modeling. Finally, to assess the capability of different behavioral models to numerically simulate the blast-induced damage zone (back break), the Cohesion Weakening Friction Strengthening (CWFS) models were implemented and compared with the perfect plastic model. The results showed that although the delay time reduces the damage and vibration, very high delay time values are not effective. Also, some vibration frequencies have very low amplitudes in models in which the delay is applied. A comparison of square and stagger patterns showed that the possibility of damage is higher in the stagger pattern, but the vibration is almost the same at the far-field from blasting. Comparing the back break extension of the Calamine mine with the results of the perfect plastic and the CWFS models shows that the CWFS model predicts relatively more accurate. [ABSTRACT FROM AUTHOR]

A large number of burnt rocks in some open-pit mines in Xinjiang, Inner Mongolia and Ningxia have a great influence on the blasting effect. For this kind of rock, through the analysis of physical and chemical changes, combined with ANSYS/LS-DYNA and PFC 2D numerical simulation software, a burnt rock model with multiple joint cracks and irregular distribution is constructed to simulate the blasting process of burnt rock under the combined action of stress wave and detonation gas. The results show that the fracture of rock mass affects the propagation of blasting cracks in the fracture area, resulting in stress concentration and stress hindrance. The action time of stress wave is reduced, and the energy of blasting gas is partially absorbed by the fracture, resulting in uneven stress on the burnt rock bench and seriously affecting the bench blasting effect. [ABSTRACT FROM AUTHOR]

In the process of drilling and blasting construction of large-cross-section tunnels, the layout of wedge-shaped cutting holes has a great influence on the effect of blasting. In this study, theoretical analysis and numerical simulation were used to assess the effect of different forms of cutting hole placement on blasting effectiveness. First, the fissure-inducing angle was proposed, a three-dimensional model of wedge-shaped cutting considering the effect of shear-tensile resistance was established, and theoretical analyses of cutting holes with different cutting angles and fissure-inducing angles were carried out. Second, the parameters of the Riedel–Hiermaier–Thoma model were determined based on the experimental data, and verified. Third, three-dimensional numerical models were established, and analyze the influence of different forms of hole deployment on the blasting effect from the perspective of stress wave propagation and dynamic damage to the surrounding rock. Finally, based on the theoretical analysis and numerical simulation results, the wedge-shaped hollowing holes were re-designed, and 20 tunnel blasting tests were carried out using this deployment method for large-section tunnel blasting, which verified the feasibility of this deployment method. The results of the study show that for level III surrounding rock, the angle of wedge-shaped cutting holes should meet 68° ≤ θ ≤ 70° and 70° ≤ β ≤ 72°. This study provides a kind of refined and efficient blasting for the drilling and blasting excavation process of large section tunnels. [ABSTRACT FROM AUTHOR]

To quickly determine the blasting block degree and conduct an accurate and objective analysis of the tunnel blasting effect, this study has enhanced and improved upon the traditional genetic algorithm and Otsu algorithm. It has combined it with the marking watershed method and utilized ground digital acquisition to capture images of blasting debris. These images are then used in our custom-developed blasting analysis software to calculate the blasting block degree distribution and provide a quantitative analysis of blasting block degree. The research results show that the optimized image segmentation algorithm effectively improves the traditional threshold segmentation method on the poor effect of segmentation of the edge of the adherent block or the direct application of the watershed segmentation of the over-segmentation problem, to improve the segmentation accuracy based on the new segmentation technology is close to the traditional technology in terms of time. Through the self-developed software, the construction personnel in the project site to quickly obtain the blasting block degree histogram, block degree cumulative curve and other important indicators of the evaluation of the effect of blasting block degree, to provide data support for on-site construction, to assist in the modification of the blasting program, and to improve the efficiency of construction. This study realizes the rapid detection and block identification of blasting blocks, provides data support for the optimization of blasting parameters, and has good application and promotion value. [ABSTRACT FROM AUTHOR]

The tunnel construction by the drill-and-blast method can have a significant impact on the adjacent buildings, especially the historical buildings with poor structural performances. Based on a special explosive case of Nanjing Metro Line 4, an in-situ blasting test for vibration safety evaluation on the Nanjing Drum Tower was carried out. According to the site geological investigation, the location of the blasting test was selected near the planned tunnel. 6 blasting was carried out in terms of sing-hole blasting and millisecond-delay blasting. The attenuation of the ground vibration and the structural vibration responses of the historical Drum Tower were analyzed. The test results also showed that the Nanjing Drum Tower was not damaged by this blasting test. For single-hole blasting tests, the peak particle velocity increased with the increasing of the explosive charge, but decreased remarkably when using the millisecond-delay blasting technology. The horizontal and vertical ground vibration attenuation patterns were consistent, which can be described by the Sadowski formula. The ground vibration response was dominated by the horizontal vibration, and the velocity amplification factor in the case of the single-hole test with a charge quantity of 400 g reached 2.4, which was observed the most remarkable amplification effect. [ABSTRACT FROM AUTHOR]

This paper demonstrates the application of the Johnson–Holmquist II (JH-2) model with correlated and validated parameters to simulate the behavior of a sandstone. The JH-2 model is used to simulate various tests, including single-element tests, structural quasi-static uniaxial and triaxial compression tests, and the split Hopkinson pressure bar test. Additionally, the model is used to simulate drop-weight impact test using a ball bearing and two loading scenarios involving small-scale blasting and projectile impacts. Quantitative and qualitative comparisons demonstrate that the JH-2 model agrees well with both experimental and analytical results. Limitations of the model are also highlighted, particularly for quasi-static problems, as the model was originally developed for high-strain-rate simulations. Ultimately, this study demonstrates that the JH-2 rock constitutive model can obtain reasonable results for a material other than the material for which the model was originally correlated and validated. This paper provides valuable guidance for modeling and simulating sandstone and other rock materials subjected to dynamic loadings. [ABSTRACT FROM AUTHOR]

Multi-layer wound cylindrical shells are the preferred structures for storage vessels working in high pressure and hydrogen atmosphere. However, they are susceptible to external blast loads from accidental hydrogen explosions. In order to study the response of such structures under external blast loading, a numerical model was developed, which combined a thermo-viscoplastic constitutive model and a fluid-structure coupling approach, and was subjected to external blast loads of different TNT equivalency weights. The strain responses and initial velocity fields of the structure were analyzed. A rigid-plastic theoretical model was also developed to calculate the maximum displacement of the inner shell and was compared with the simulation results. Moreover, the axial velocity vibration histories and dominant frequencies at different locations of the steel belts were numerically obtained. In addition, four vibration modes of the steel belts were presented in this paper. Furthermore, strain growth was observed in the high-frequency vibration area, and the possible reasons for the strain growth were analyzed and discussed in detail. The results will be useful for predicting the deformation modes of such multi-layer wound cylindrical shell structures under the risk of external hydrogen explosions. • Blast wave propagation and dynamic structural response were coupled together. • Maximum deformation of inner shell was calculated by rigid-plastic modal solution. • Vibration pattern and frequency of outer shell were revealed. • Superposition of vibrations with high frequencies causes strain growth. [ABSTRACT FROM AUTHOR]

The excessive destruction of surrounding rock in deep tunnel will change the original environmental state and destroy the natural ecological balance. Research on the dynamic response characteristics and damage thresholds of rock masses in deep environments plays a crucial role in determining the excavation range of blasted rock and establishing safety construction scheme. This study employs numerical simulation techniques to investigate the dynamic response characteristics of surrounding rock under different ground stress conditions. By introducing the dynamic ultimate tensile strength criterion, critical fracture stress threshold, and maximum damage radius of rock under coupled dynamic-static loading conditions are determined. The research shows that under uniaxial ground stress condition, increasing ground stress inhibits damage to the surrounding rock and the extension of cracks in the excavation area, while imposing restrictions on the attenuation rate of explosive stress. Under bidirectional equal ground stress condition, an increase in lateral pressure coefficient inhibits the development of damage zones along the excavation contour, yet enhances the extension of cracks in the maximum principal stress direction. Moreover, when lateral pressure coefficient becomes excessively large, the attenuation rate of explosive stress significantly increases. Based on the threshold values of peak particle velocity (PPV), the functional relationship is established to predict safety criteria for deep blasting excavation. [ABSTRACT FROM AUTHOR]

In response to the problem of small layered thickness and low production capacity of the subleve caving mining with spherical charge, based on the theory of bunch-holes blasting, the bunch-holes crater retreat mining method (BCR) is developed. Bunch-holes blasting has the enhancing rock breaking effect. When using equivalent spherical charge(ESC)of a bund--hoes with 4 -- 5 holes, the basing layering height is 2 --3 times that of a single hole. The BCR mining method uses equivalent spherical charge(ESC) crater for blasting with deep bunch-holes, and the spacing between bunch-- holes is 7-- 8 m, and the ordinary industrial explosives are used. Each layered Wasting has a height of 5 -- 8 m. The dilution rate is 8%, the loss rate is 10%, the large block rate <5% and the production capacity is 1 800 -- 2 400 t/d. Compared with the sing! hole spherical charge blasting VCR method, the large block rate is reduced by 10%--20%, and the stope production capacity is increased by more than twice. BCR mining method is a large-scale and efficient mining method suitable for thick and large ore bodies, medium thick and steeply inclined ore bodies. [ABSTRACT FROM AUTHOR]

Regular blasting in opencast coal mines generates significant ground vibrations, impacting mine slope stability and posing risks to life and property. This study focuses on monitoring ground vibrations in an opencast coal mine through near-field monitoring and investigating the impact of blast-induced seismic loading on slope stability. The approach involves a pseudostatic method utilising Strength Reduction Factor (SRF), based on Finite Element (FE) numerical modelling software. The study examines a pit slope with a tension crack under seismic loading, varying the intensity of seismic coefficients (Ks) from 0 to 0.5. These coefficients are determined through field vibration monitoring during production blasts. In numerical modelling, seismic loading is considered in both horizontal (outward of slope face) and vertically downward (in-line with gravity) directions. Numerical modelling incorporates dimensionless horizontal seismic coefficient (Kh) and vertical seismic coefficient (Kv), and both directions which is expressed as Seismic Coefficient Ratio (SCR) which is the ratio of Kv and Kh for interpretation of results. Although SCR induces changes in the Factor of Safety (FoS), its impact is minimal compared to seismic loading solely in the horizontal direction. Consequently, increasing SCR leads to a decrease in FoS. The study observes that Peak Ground acceleration (PGA) in the longitudinal direction has greater dominance than in the transverse direction. Additionally, the seismic wave in the horizontal direction destabilises the slope more than the corresponding vertical seismic wave. These findings are elucidated in the context of the Critical Slip Surface (CSS). [ABSTRACT FROM AUTHOR]

An underground ore body of a mine is within the security pillar range of a surface highway.In order to ensure the stability of the highway, Flac3D numerical analysis method was used to conduct a mining impact analysis, and the impact of mining blasting on the highway was demonstrated.The results show that the maximum subsidence of surface highway is 1.2 mm, the maximum slope value in the x direction of the surface is 0.185 mm/m, and the maximum slope value in the y direction is 0.13 mm/m after mining the ore body at-300 m level; the maximum curvature value in the x direction of the surface is 0.011×10-3m-1,maximum curvature value in y direction is 0.012×10-3m-1;the maximum horizontal deformation of the surface in the x direction is 0.15 mm/m, and the maximum horizontal deformation in the y direction is 0.12 mm/m, both of which meet the requirements of relevant specifications.The surface particle vibration velocity during mining blasting is less than the safety allowable vibration velocity specified in the specification, so it is considered that stope blasting has little impact on the surface.The research results provide technical support for the deep mining of the mine. [ABSTRACT FROM AUTHOR]

Rock mass explosibility is an important index to measure the difficulty of rock mass blasting, and an accurate evaluation of rock mass explosibility can provide a basis for reasonable blasting design.In this paper, rock density, uniaxial compressive strength, rock tensile strength, rock brittleness index, dynamic load strength, and integrity coefficient are selected as the indicators of rock mass explosibility data set.The data set of rock mass explosibility is standardized by Z-Score, and the influence of dimension on model prediction is eliminated.Naive Bayes, support vector machine, and XGBoost models are used to classify rock mass explosibility.The results show that XGBoost model can accurately evaluate rock mass explosibility and provide a new method for rock mass explosibility evaluation. [ABSTRACT FROM AUTHOR]

According to the traditional blasting theory and practice, the slotted cartridge blasting can form straight cracks extending along the slot direction and achieve directional fracture. In this paper, an experimental study has been carried out to determine the influence of incident stress waves and reflected stress waves. Under the influence of stress waves, the propagation path of the main crack in slotted cartridge blasting is not straight, and the directional fracture effect is inadequate. Under the experimental conditions in this paper, the propagation of main cracks mainly experienced three stages: directional propagation stage, counterclockwise deflecting propagation stage, and clockwise deflecting propagation stage. The difference between incident stress waves and reflected stress waves results in the difference in the deflecting direction, transforming the main crack into a wing shape. In rock roadway drilling and blasting engineering, the propagation path of main cracks produced by peripheral boreholes using the slotted cartridge blasting is also affected by the incident and reflected stress waves. These stress waves are inevitably generated from free faces and adjacent boreholes; however, these are rarely considered in the design of blasting parameters. Therefore, the design and optimization of blasting parameters considering the interaction of stress waves and main cracks in the slotted cartridge blasting need to be further developed. [ABSTRACT FROM AUTHOR]

Far-field blast loading has been studied extensively for decades. Close-in, confined, and semi-confined detonations less so, partly because it is difficult to obtain good experimental data. The increase in computational power in recent years has made it possible to conduct studies of this kind numerically, but the results of such simulations ultimately depend on experimental validation and verification. This work thus aims at using reliable experiments to validate and verify numerical models developed to represent blast loading in general. Test rigs consisting of massive steel cylinders with pressure sensors were used to measure the pressure profiles of semi-confined detonations with different charge sizes. The experimental data set was then used to assess numerical models appropriate for simulating blast loading. In general, the numerical results were in excellent agreement with the experimental data, in both qualitative and quantitative terms. These results may in turn be used to analyse structures exposed to internal blast loads, which constitutes the next phase of this research project. [ABSTRACT FROM AUTHOR]

High in situ stress is a typical geological characteristic of tunnel excavation in hydropower projects in Southwest China. First, the spectrum characteristics of the vibration induced by the blasting load and transient unloading of in situ stress in the surrounding rock masses were calculated for the full-face millisecond-delay blasting excavation of a deeply buried circular tunnel. Then, the methods of time–energy density and amplitude spectra were employed to analyze the spectral characteristics of the vibration monitored in the excavating and adjacent tunnels at Pubugou, Shenxigou, and Jinping II hydropower stations. Finally, the low-frequency characteristics of vibration induced by transient unloading of in situ stress, hidden in the monitored vibration, were discovered, and their influence on tunnel safety was analyzed. The results showed that under low in situ stress levels (1–10 MPa), the peak value of the vibration induced by the blasting load was larger than that caused by transient unloading of in situ stress, and the difference in the excavating tunnel was notably larger than that in the adjacent tunnel. With an increase in in situ stress (more than 20 MPa), the peak value of vibration induced by transient unloading of in situ stress exceeded that produced by the blasting load in the adjacent tunnel; the same rule was found in the excavating tunnel under high in situ stress (50–70 MPa). A lower frequency and larger amplitude indicate that the vibration induced by transient unloading of in situ stress is much more dangerous than that produced by blasting vibration. [ABSTRACT FROM AUTHOR]

Flyrock is one of the major safety hazards induced by blasting operations. However, few studies were for predicting blasting-induced flyrock distance from the perspective of engineers. The present paper attempts to provide an engineer-friendly equation predicting blasting-induced flyrock distance. Data used in the present study contains s seven blasting parameters including borehole diameter, blasthole length, powder factor, stemming length, maximum charge per delay, burden, and flyrock distance is obtained. Data is inputted into Random Forest for feature selection. The selected features are formulated as two candidate equations, including Multiple Linear Regression (MLR) equation and Multiple Nonlinear Regression (MNR) equation. Those two candidates are respectively referred by Particle Swarm Optimization for searching optimum values for the coefficients of selected features. It is proved that MLR equation has better accuracy. MLR equation is compared with two empirical equations and the MLR equation based on least squares method. It is found that the coefficient of correlation of the proposed MLR equation reaches 0.918, which is the highest compared with the scores of other three equations. The present study utilizes feature selection process to screen inputs, which effectively excludes irrelevant parameters from being considered. Plus the contribution of Particle Swarm Optimization, the accuracy of the obtained equation can be guaranteed. [ABSTRACT FROM AUTHOR]

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In this study, a micropowder blasting system with varying processing temperatures was proposed to control the cross-sectional shape of a channel processed on a glass substrate. Based on an analysis of the processing temperature-dependence of the dynamic viscoelastic properties of a commercial mask material for micropowder blasting, a processing temperature control system that can be installed in a micropowder blasting machine was designed. The erosion of the mask during micropowder blasting depended on the loss tangent in dynamic viscoelasticity, and showed a maximum value at a processing temperature of 100 °C. Moreover, we confirmed that the maximum decrease in the width of the processed microchannel was 30 µm (12%) by mask erosion, and this change was large compared with the maximum change in the thickness of the eroded mask. These results clarified that varying the processing temperature using a mask could control the cross-section of the processed line pattern profile on glass, and a small-width channel was realized at a processing temperature of 109 °C. [ABSTRACT FROM AUTHOR]

This research investigates the impact of vibrations produced by blasting activities at the PT Semen Padang Mine, with a focus on vibration analysis and experimental characterization using the Micromate tool. The main objective of this research is to understand the vibrations resulting from blasting, analyze the impact of variations in PVS (Peak Vector Sum) values, and evaluate the effect on the surrounding environment, especially employee housing around the mining area. The research method used involves several important stages, first of which is the use of a Micromate tool to measure the vibrations produced during the blasting process. Micromate is a tool that can record and analyze vibrations with high accuracy, thus providing reliable data for further analysis. Apart from that, this research also uses power regression analysis to understand the relationship between PVS and Scaled Distance variables. This analysis is important to determine how variations in blasting distance and intensity affect the resulting PVS values. Then, a distance analysis was carried out to obtain a PVS value below 3 mm/s, which is considered a safe threshold to prevent structural damage to the building. The research results show several important findings. Even though the measured vibration values ​​are below the Threshold Values ​​set by environmental regulations, it is important to comply with all existing regulations to avoid long-term negative impacts. The power regression analysis carried out shows that there is a significant relationship between PVS and Scaled Distance, which means that the greater the distance between the blasting point and the measurement point, the smaller the PVS value detected. The validation results of this analysis are also in accordance with the empirical data collected during the research. In addition to these main findings, this research also provides several practical recommendations. One of them is setting the explosive charge to reduce the impact of the resulting ground vibrations. These arrangements include reducing the amount of explosive per blast or changing the blasting technique to reduce vibration intensity. In conclusion, this research provides an in-depth understanding of the factors that influence vibrations from blasting in a mining context. The results of this research have important implications for the development of more accurate and effective vibration measurement methods as well as for mitigating environmental impacts caused by blasting activities. This research not only provides new insights for the mining industry but also helps in formulating better policies to protect the environment and communities around mining areas. Thus, this research contributes to ongoing efforts to achieve a balance between industrial activities and environmental sustainability.

Seismic waves caused by blasting activities can be a source of damage to structures. The most common damage is the appearance of cracks or the widening of existing cracks. Structures are also affected by environmental factors. Depending on the conditions, temperature and humidity can cause a stronger reaction in the cracks than blasting. However, the effects of non-blasting factors last much longer than those of blasting, so the load gradually increases, allowing for an even and timely distribution of stress around the crack tip. On the other hand, blasting factors act over a short period of time, resulting in a rapid increase in the stress intensity factor at the crack tip and a faster release of stress energy. The FEM (finite element method) analysis of these impacts was conducted on a model in the ABAQUS CAE software. The results of the analysis show that the influence of blasting factors is significantly higher compared to the influence of non-blasting (environmental) factors. The strain energy and the stress intensity factor per unit time are much higher under the influence of blasting factors. The strain energy is 9.58 × 1010 times higher, and the stress intensity factor at the crack tip is 309583 times higher due to the dynamic load, observed over a period of 0.033 seconds.

Majdanpek is located right next to the mine, so blasting at the Open Pit North Mining District could have an impact on the environment. If the intensity of that impact exceeds the prescribed limits, the harmful and dangerous consequences could be for people and facilities. In order to protect the environment from the harmful effects of blasting, the standards for protection and limits for the intensity of manifestation the certain effects of blasting at a certain distance are prescribed. This paper shows the determination of safety distances during blasting due to the seismic waves.

The development of modern technologies has enabled the application of specialized softwares in the field of mining through various segments and processes, including in works related to drilling and blasting. The application of specialized software for drilling and blasting with the use of modern technologies such as photogrammetry enabled more accurate data from the field for later processing. By processing data and creating a 3D model of the terrain for drilling and blasting works, it can obtain precise data, which serve us for the optimization of drilling and blasting parameters, as well as their analysis. The application of this type of specialized software, in this case, the O-Pitblast software, provides an overview of all parameters, as well as possible corrections and different scenarios regarding the results of the blasting itself. Optimization and analysis through this software can improve the results of blasting in terms of fragmented material size, and reduce the unwanted effects of blasting, such as the flyrock or blast vibration. The software has different types of tools that allow a detailed review and insight into the entire process from the beginning of planning drilling and blasting works to the very end and also printing of reports after the work is done.

The Vranduk I bridge is located on the motorway route, on the part of the subsection: Zenica Municipality Northern Administrative Boundary - Zenica North. The bridge consists of two parallel structures, one for the left side, and the other for the right side of the motorway. The Vranduk I bridge rests on three piers. The paper deals with the excavation of the pier site S1R and S1L by controlled blasting. By correctly choosing the equipment for drilling blast holes, defining the drilling and blasting parameters and excavation steps, a minimal zone of damage to the surrounding rock outside the line of excavation of pier sites S1R and S1L, which is inevitable during blasting excavation, has been achieved, which has the effect of preserving the bearing capacity of the rock mass as the most important supporting element.