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By Joshua Hoffman, William Chad Wedding, Braden Lusk

The University of Kentucky employs an explosively driven shock tube in the course of experimentation. A good deal of the work completed relates to the verification of blast mitigation products and strategies. The work is dependent upon reliably reproducing specific pressure time histories called out by the test in question. The facilities are located in the workings of an underground limestone quarry in Georgetown Kentucky. As such, the temperature maintains fairly consistent 60°F (15.6°C), making it a comfortable work environment year round. Unfortunately, the relative humidity follows the prevailing weather conditions allowing a wide variation, especially between the winter and summer seasons. A study was undertaken to gauge the influence of relative humidity on shock wave generation, including the positive and negative phases of the wave.

Jan 1, 2011

By Jorge Cárdenas, Gustavo Huerta, Regina Rocha Oriundo, Miguel Angel Humpire, Johan Salas Flores

Currently a critical activity for slopes stability and safety in mining is pre-split blasting to reduce damage from trim blast. Most common explosive used are based on packaged explosives, with 1 ½ in diameter cartridges initiated by detonating cord. Traditional loading process requires a significant amount of trained personnel, which in our application context could take up to 20 blasters. When pre-split blast is scheduled, it usually reduces the availability of the blasters on the total loading services at site which are also demanded to have production blasting ready at same 12-hour shift daylight time.

Feb 6, 2023

By Anderson Meireles, Leonardo Soares Chaves, Raul Carretero Hoz, Carlos Eduardo Soares Feliciano, Renato Jacome Costa

The large iron deposits in the northern region of Brazil located in the Amazon Craton have in common the presence of natural cavities. These cavities primarily occur in the upper layer of the ore body, formed above hematite mineralization. Their origin remains a topic of debate, often associated with hydrothermal drainage processes and erosive evolution. Over time, these cavities have become integral to the local environment, each contributing to the regional ecosystem of fauna, flora, and the significance of speleothems found within them. Managing these cavities poses a significant challenge for iron mines in the area. On one hand, they must preserve the cavities from anthropogenic actions, while simultaneously handling heavy equipment and large volumes. In 2023, the development of the mine took place towards the cavity under study, revealing systematic deviations in vibrations recorded during nearby detonations as the blasting got nearer. To address this, a work plan was put in place, emphasizing a straightforward approach: constructing lithology-specific vibration models, defining charge abacuses, and optimizing timing to reduce charge amplification. Implementing this methodology significantly improved adherence to the vibration limit, resulting in an around 50% reduction in standard error. This paper presents the consolidated work that allowed mining activities to continue in the area through controlled blasting, effectively mitigating potential anthropogenic damage in sensitive areas.

Jan 21, 2025

By Cary Moffat, John Kita, Rick Walker

The Lac des Iles Mine, in an isolated area of NorthwesternOntario is a relatively new open pit platinum and palladium mine. They were encountering problems with the equipment and production scheduling when ramping down to begin production on the subsequent benches. A co-operative effort between Lac des Iles Mine operation people, ICI Explosives, and the mines drilling and blasting contractor - Consbec Inc., resulted in a decision being made to use full depth sinking cuts to provide access to the next bench.

Jan 1, 1996

By Dipankar Gorain, A K. Vishwakarma, Vivek K. Himanshu, Murari P. Roy, Shubham Singh, R S. Yadav

The industrial establishments of a power plant consist of many important structures viz. cooling tower, wagon tippler, track hopper, plants and offices. The leveled foundation is the utmost need for erecting these structures. The leveling of the foundation is done by rock excavation, when the establishments have to be setup in hilly/rocky areas. Drilling and blasting is the cheapest and most dominant method of rock excavation. However, this method has associated hazards in terms of blast induced ground vibration, air overpressure, flyrocks etc. The foundation work and erection of the industrial buildings are done in parallel to achieve the faster construction of the establishment. The challenges to reduce the induced hazards in such cases are more. This paper presents a case study on the controlled blasting method devised for the rock excavation for construction of 2 × 660 MW Obra-C thermal power plant. The foundation work for this power plant was made by excavation of Dolomitic rock. The excavation work was performed in the proximity of the existing residence of the local people and Obra market. With the advancement of project, the excavation was also performed in the proximity to the ongoing construction work of various industrial buildings. Accordingly, the controlled blasting pattern was devised suitable to the specific sites. The pattern consisted of variations in blasthole diameter, burden-spacing, maximum explosive charge per delay, total explosive in a blasting round, initiation system and direction of initiation. The suitable muffling arrangements were also used, when the blast was conducted in the close proximity to the structures. The initial blasting pattern was established by analysis of blast vibration wave propagation characteristics. Thereafter, the final pattern was adopted for the safe excavation at the site. The safe excavation for the foundation work of this power plant has been completed successfully based on the devised controlled blasting pattern.

Feb 6, 2023

By Jesus Pascual, Benjamin Cebrian

A new Convention Center is going to be built in the millenary city of Toledo, right in the old city limits. The workings will need to excavate some 80.000 cubic meters of granite, which has, a trench-like structure already blasted for the construction (60 years ago) of a parking lot and a shopping area. Surrounding this trench, some few feet away, there are structures and buildings from the 16th century and remainings from previous times that need to be preserved from any damage caused by blasting. Because of this, a vibration analysis was designed according to the special characteristics of this work. Structures to monitor were located at several levels. It considered three different directions of study in order to evaluate the impact of vibrations of the structures located at three different heights of the granite trench. On top, the historical convent of Santa Fe, with some remaining from the 8th century (Muslim domination of the Iberian Peninsula), on the bottom, the Justice Hall of Toledo with 16th century walls, and, in the middle, a wall and a tower from times of the king Phillip II (16th century, the time of the Spanish Empire).

Jan 1, 2004

By Stephen Mansfield, Saran Sankar

The Sentinel open pit copper mine, operated by First Quantum Minerals Ltd, is located in the North West province of Zambia. The Sentinel orebody is a sediment-hosted, structurally modified deposit in which mineralisation is contained in the phyllite formation, which occurs as a series of layered, continuous sheets having a northerly 20 to 30⁰ dip. The persistent nature of the geological structure can lead to the generation of large slabs when joints are relatively close together or very large blocks when joints are more widely spaced. With standard blasting methodologies, the challenging fragmentation most commonly occurs in the stemming zone and blast interfaces, reducing excavation rates and increasing the risk of crusher bridging events and reduced throughput. A generalised approach to increase powder factor would increase in drill and blast costs and would not be sufficient to target the specific cause of the challenging fragmentation. Implementing differential blast energy based on post blast requirements for different material type, such as ore and waste, and rock mass characteristics is not new in the mining industry. High-energy blasts for ore aim to produce finer materials, enhancing downstream processes such as crushing and grinding, while reducing power consumption and increasing throughput. Conversely, waste rock often requires less energy in order to deliver optimised fragmentation for loading and hauling efficiency. Identifying and applying optimum blast energy to specific material type and geological domains will not only ensure smoother and efficient operations throughout downstream processes, but will have a direct impact on overall profitability of the entire operation. This paper will describe the methods used to model and implement differential blasting across a range of material types in order to deliver the required blast outcomes for ore and waste and the impact on downstream processes and drill and blast unit cost.

Jan 21, 2025

By Donald Wagstaff, D. Scott Scovire

The Coeur Rochester Mine is the largest primary silver surface mine in North America. Throughout its 17-year life, gold and silver grades leaving the tertiary crusher have typically been, on average, slightly below the mined bench grades as determined by blast hole assays. On a project-to-date basis, this grade variance is well within industry standards. While these variances are acceptable, mine personnel continue to study ways to further minimize the grade differences. One suspected cause for lower than expected head grades are ore loss and dilution resulting from blast-induced shot movement. In regard to grade control, the underlying design principle for non-electric blasts is the generation of uniform movement of the blasted rock material. Using one or two uniform directions of initiation, ore control methods at Rochester currently include adjusting flag lines on the muckpile in an attempt to account for displacement from original, pre-blast locations. To improve upon standard non-electric blasting practices, a series of evaluation blasts using an electronic initiation system (Orica i-konTM) was conducted in the summer of 2002. The primary objective of the evaluation blasts was to design shots that would segregate the ore and waste blocks into distinct muckpiles. Due to surface delay burning front limitations, truly effective ore and waste segregation blasting is difficult to accomplish with non-electric initiation systems for all but the most basic of ore geometries. The electronic detonator evaluation blasts produced visible boundaries in post blast muckpiles, identified by troughs or low areas, that closely matched the actual locations of pre-blast ore control flag lines based on blast hole assays. By blasting the ore and waste into distinguishable piles that were flagged and excavated accordingly, it is believed that blast-induced ore loss and dilution was reduced.

Jan 1, 2004

By Sunil Vytla, Akash Adhikari, Purushotham Tukkaraja

Blasting operations produces gases and fumes that may be toxic or non-toxic in nature. A detonation of commercial explosives such as ANFO, emulsion, and dynamite would ideally produce only nontoxic products such as steam (H2O), carbon dioxide (CO2) and nitrogen (N2). However, in the real world, the detonation of explosives produces toxic products such as nitrogen dioxide (NO2), nitric oxide (NO) and carbon monoxide (CO). The focus of this study is the blast fumes entrapped in the muckpile. Fume clearance and workplace re-entry time studies performed in the past have overlooked the toxic gases entrapped in the muckpile. Studies show that as much as 60% to 70% of the fumes or gases produced during blasting underground can remain entrapped in the adjacent rock mass or in the muckpile. The toxic fumes trapped inside the muckpile are slowly released and could be fully uncovered during the mucking process. Exposure to these gases or fumes is hazardous to mine workers. In this study, author have analyzed the nature of fume flow, i.e. accurately predicting where and how the fumes flow after an underground development/tunnel blast. This will help in determining i) precise re-entry times for the workers ii) rate and direction of the fume flow. Computational Fluid Dynamics (CFD), a mathematical simulation technique that predicts fluid dynamics phenomena is used for this purpose. CFD is preferred over physical models because it is inexpensive, once the accuracy is established, a wide range of scenarios can be simulated quickly, and the toxic gas flow patterns through underground openings can be analyzed efficiently. For this study, CFD is performed using SC/Tetra software owned by MSC software company.

By Andreas Gaich

A new 3D fragmentation analysis method for muck piles is presented. It works with aerial imagery from UAVs (drones) and handles entire muck piles with minimum user intervention.

Feb 1, 2020

By Tristan Worsey, Nathan Rouse, Evan Thibaud

Electronic detonators allow for variability and accuracy with blast delay selection and timing sequence. However, a single published guideline for selection of electronic timing delays is not available on the OneMine database. There are published documents that present options for timing with electronic detonators, some of which provide great detail and scientific evidence, but there is no single document that presents several different approaches with simple instructions on how to apply the various timing approaches. This paper reviews published electronic timing approaches and results, then presents guidelines for electronic timing for alternative mining methods, which include: bench blasting (ie. quarries) and crater blasting (ie. metals mines). Most of the approaches are based on calculating milliseconds per meter for rock types, as quantified by the rock sonic velocity. Guideline calculations are provided for recommended hole-to-hole delays and row-to-row delays for both free-faced bench blasting and crater blasting approaches. These are the two most common blasting methods for mining operations. Typically, free-faced bench blasting is the approach used in quarries with a bench height to burden ratio of around 4, and crater blasting is typically used in large blasthole diameter/short bench blasting in metals mines with a bench height to burden ratio of around 1. Mines may focus on fragmentation, mucking rates, ore movement distance and movement direction. Recommendations are also included to provide general recommendations based on a mine’s preference for movement and fragmentation. References include twelve studies on bench blasting and six studies on crater blasting. In addition, a discussion is included on the application of these recommendations at a full-scale surface gold mine.

Jan 21, 2025

By David Harrison

The Charleroi Locks and Dam (Figure 1) was completed in 1932 and is located on the Monongahela River, approximately 22 miles (35 km) south of Pittsburgh, in Charleroi, Pennsylvania. It is comprised of a 420 foot (128 m) gated dam, and a 720 foot (219 m) by 56 foot (17 m) land side lock which provides for a 16.6 foot (5 m) vertical lift.

Jan 1, 2015

By Glenn Tobin

The overarching goal in modern drill and blasting operations is that of optimising mining operations to achieve higher levels of productivity, safety, profitability and sustainability. Air decking, a technique used in drill & blasting to optimise explosive product use while achieving a target rock fragmentation1, is a technique that when executed correctly is proven to achieve consistent results independent of rock strength and the position of the holes (single, multiple, vertical, slanted), as well as being proven to reduce super-fragmentation (under-size or fines) while able to achieve optimal fragmentation, especially in the stemming zone2. The ‘shock absorber effect’ if the air deck reduces ground vibration and air blast3. Additionally, the practice of loading explosive product directly in saturated ground without dewatering or lining prior is an increasing global trend.

Jan 1, 2012

By Jan Westberg, Roger Holmberg, Bernt Larsson

Over the last couple of decades there has been an increased demand from the market for precision detonators, partly because of a need for better blasting results and partly because of a need for better vibration control. Today's detonators have a pyrotechnical delay element which gives a relatively high time scatter, increasing with the length of the delay time.

Jan 1, 1988

By Lazar Kricak, Vladislav Kecojevic, Dragan Bogunovic

In spite of many advantages explosives have, their usage may cause environmental problem such as seismic vibration. One of the solutions to this particular problem may be application of an artificial screen as a barrier to the seismic wave path. This paper presents the results of experimental research on the artificial screen concept, its characteristics and role in attenuation of seismic effects generated by blasting. More than 1,500 laboratory measurements were conducted with different combinations of screen sizes, positions of the screen to blasting source, and intensities of blasting impulses. The results of the study show a significant reduction of generated vibrations by employment of artificial screens.

Jan 1, 2007

By Aris Tambunan, Nella Lubis, Nurafrianti Saala, Komang Widhiayanto, Herry Saputra, Rudolf Sitorus

Maximizing mining recovery rates and minimizing ore loss are pivotal objectives for economic efficiency and operational effectiveness. This study explores methods to address these imperatives by enhancing ore production and recovery through improved blasting techniques and spillage control in the Martabe Gold Mine Project in North Sumatra Province, Indonesia. Between 2018 and 2021, the average mining recovery rate stood at 93%, resulting in a potential annual ore loss of 7% and a potential quarterly financial impact of close to $2 million. Maintaining and enhancing mining recovery became crucial, with a planned 30% increase in total material movement for 2022. The mining recovery target for 2022 was set at 96% based on best achievement historical data from 2021 to increase ore tonnage by 203 KTon per annum. To achieve the primary objective of increasing ore production by improving mining recovery, the study focused on predicting and controlling the movement of blasted ore to reduce spillage and enhancing the grade control model to reflect actual conditions post-blasting. Several alternative solutions were explored, primarily emphasizing drilling and blasting activities. Essential methods included capturing the actual blasting movement to adjust the ore block based on blasting design data and post-blasting muckpile topography. This approach minimizes ore loss by providing output as ore block adjustment based on post-blast movement data. In addition, the tie-up design was adjusted to control ore spillage outside the pit ridge. The implementation of these methods yielded significant improvements. Adjusting the ore block based on actual blasting movement contributed $1,545,764 in benefits. Controlling ore spillage outside the pit ridge achieved a 10% reduction in spillage, contributing $79,184 in benefits. These enhancements successfully met the 2022 mining recovery target of 96%, marking a 3% increase from 2021. Consequently, ore loss was reduced by 178 KTon throughout 2022, resulting in a financial impact of $7.3 million. The study underscores the significance of precise blasting techniques and effective spillage control in enhancing mining recovery rates.

Jan 21, 2025

By B Kniivila, A B. Andrews, T Lerick, Keith Jansen

Minntac Mine is a large, open pit taconite mine located at the center of the Mesabi Iron Range in northern Minnesota. The planned development of the Mine in the direction of nearby communities prompted a comprehensive study of off-site blast effects that resulted in numerous refinements in blasting practices.

Jan 1, 1984

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan, Alper Celtikci, Serdar Celik, Yucel Karakus

This paper presents bench blasting designs based on results of vibrations analysis on test shots organized in an open pit coal mine located near to Soma district at Manisa province in Turkey. There are some structures which can be adversely affected by blasting at the coal mine. The one of the main goals of this study is to perform a preliminary assessment of possible damage effect of ground vibrations induced by blasting at these structures by risk analysis based on ground vibration measurements. During this investigation, the data pairs of scaled distance and particle velocity obtained from the 36 event records belong to 9 test shots were statistically analyzed and a PPV prediction equation specific to this site with 95% prediction line were obtained. And also, this equation was used in the derivation of the practical blasting charts specific to this site as a practical way of predicting the peak particle velocity and maximum charge per delay for future blasting. A risk analysis was performed by using this equation. In the light of this analysis, preliminary blast design model was proposed to be used in this coal mine for overburden excavation.

Jan 1, 2012

By Jennifer Williams, Donald J. Berger

Originally built between 1913 and 1916, the Ashton Dam & Hydroelectric Facility has experienced various seepage and piping incidents since completion. Ashton Dam is located within 15 miles (24 km) of the historical Teton Dam failure site and about 2.3 miles (3.7 km) west of Ashton, Idaho. Numerous repairs conducted over the years ranged from filling sinkholes on the crest of the dam to placement of rockfill on the upstream slope to improve seismic stability. In addition, the existing low level outlet works was grouted full and abandoned in 1991 due to significant vibrations induced on the dam during its operation.

Jan 1, 2014

By Scott King, Norm Patterson, Ruilin Yang

The multiple blasthole fragmentation (MBF) model developed by Orica models the contributions from multiple blastholes to fragmentation at any given point in the rock and simulates a production blast with the actual geometry of the blasted overburden and free faces, explosive loading, multiple decking, and delay timing of each explosive charge. The model has been successfully applied to several open pit mines and quarries around the world, including Canada and the United States. The peak particle velocity (PPV) induced in the rock from the explosive detonation is used in the MBF model as the key parameter relating to the size distribution of the rock fragmentation. Relating the PPV to the rock fragmentation is based on earlier work relating the particle velocity to the dynamic strain in rock. A recent publication further revealed that the PPV is related to the maximum relative displacement that induces three dimensional strain at a point in the rock. The model can explicitly model most of the blast design parameters including explosive properties.

Jan 1, 2018