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By Neal Lee

Often the effects of wet boreholes are not taken into consideration when designing a blasting program to exhibit a certain amount of explosive energy per unit of rock such as design by powder factor, expressed in lbs./bcy (pounds explosives per bank cubic yard) or kg/bcm (kilograms per cubic meter), often the effects of wet holes are not considered. This paper examines different methods of loading wet holes and the effects they have on actual explosive quantities/unit of rock. In particular, we are looking at the amount of water trapped within the explosive column (bulk loading from the collar), or the annular space left void of explosives product around and between cartridges (wet-bags) with many of the current wet hole loading methods in use. We will focus on the effect this has on actual powder factor relative to “as designed” dry hole loading values, as well as the effect on performance of the explosives.

Jan 1, 2011

By Brent Blanchard

As most veterans of our industry are aware, explosive demolition by its very nature is often a challenging proposition. Even under the best of circumstances, proper planning and care must be taken during a variety of processes to ensure a safe, successful result. However, every now and then a project suddenly arises where safety, timing and cost factors combine to form a critical scenario requiring rapid execution in an environment far more challenging than the norm. On these occasions, the stresses, complications - and most notably the dangers - related to the industry increase exponentially, and conspire to test the mettle of even the most seasoned experts.

Jan 1, 2003

By Regina Rocha, Miguel Humpire

One of the challenges within unitary mining operations is blasting, which has a significant downstream impact on the following processes, which is why mining companies ensure the results of the blasting process through joint work with explosives specialists’ companies.

Feb 6, 2023

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 Diane F. Baker, Cathy Aimone-Martin

A series of small-scale explosive experiments were conducted in a perlite mine near Socorro, New Mexico. These experiments were a joint effort between Los Alamos National Laboratory, New Mexico Institute Of Mining and Technology, Southern Methodist University, and Defense Nuclear Agency. The purpose of these tests was to measure the changes in the shock wave and seismic coupling as a function of depth of burial and structural setting. The size of the explosive charges ranged from 1 to 68 kg. Over 1150 measurements of velocity and acceleration were made on thirteen experiments using three component sensors. The sensors were placed to maximize the azimuthal coverage as well as to provide data at a variety of ranges from ~1 to 130 m A few far field measurements were made at ranges of ~2Êkm. While the bulk of the measurements were made on the surface, high g accelerometers were placed in one instrumentation borehole to provide some free-field measurements. Preliminary results indicate that significant differences in the amplitudes of signals can occur when the location of the explosive charges are changed by only meters. Part of the observed difference is attributed to variations in the rock immediately adjacent to the charge affecting the shock coupling; and part to the effects of the site characteristics.

Jan 1, 1994

By Joel Chipana, Roberto Laredo, Benjamin Cebrian

Ring blasting is a common production method in underground metal mines. As a drill and blast process, it presents particular features that do not correspond with bench blasting in open pit or underground mining.

Jan 1, 2017

By Nikolaos Petropoulos, Ulf Nyberg, Daniel Johansson

A series of signature boreholes were blasted to observe any difference between confined and free face blasts. Four geophones were used to capture the compressive wave. The conventional approach, i.e. the calculation of vectorized peak particle velocity (vPPV) did not show any difference. Also a wavelet transform was tested.

Feb 1, 2020

By A. Andrades, E. Arias, Y. Pizarro, J. Alarcón

Division Ministro Hales - Codelco (DMH) is located at 2600 meters above sea level, 10 km north of the city of Calama, Antofagasta region, Chile. In operation since 2010, it corresponds to a porphyry copper deposit that is exploited by the open pit mining method. The ore is mainly composed of sulfides, which is concentrated by comminution processes such as crushing, SAG milling and ball milling to liberate the mineral particles, and then separated from the waste (concentrate) in flotation stages, including a concentrate regrinding stage. Reports from the DMH processing plant area have identified a decrease in fine copper recovery, with the first hypothesis being the high percentage of ultrafine particles (% <45µm) in the flotation feed. Due to the above, DMH & Orica decided to carry out activities to identify the controllable variables that can impact the generation of low size particles in ore and adjust them to reduce the percentage of fine material generation, with special focus on the Drilling and Blasting processes. Based on the data provided by DMH, we evaluated what could be integrated to make an analysis. The different attributes associated with the ore and their effect on copper recovery were evaluated. In parallel, at the mine, a fragmentation measurement campaign was carried out at the loading faces and granulometric analysis of the drill cuttings. Once the correlations between the attributes and copper recovery were identified, hypotheses were established and reviewed with the Drilling & Blasting, Geotechnical, Geology and Process Plant areas. With the validations of the hypotheses and the results of the in-mine (cutting) measurements, we proceeded to review the criteria for the classification of Blastable Geotechnical Units and their associated D&B designs. Using software and the Crush Zone Model (CZM) tool, which considers rock and rock mass parameters, scenarios for various D&B design proposals were simulated with the objective of reducing the generation of ultrafine particles from the blasting process. Next steps include trial blasting with the D&B design recommendations, which will require follow-up to the flotation process to identify the impact on the reduction of ultrafine material from blasting.

Jan 1, 2024

By Dale S. Preece

A new three dimensional (3D) mechanistic model of fragmentation, called the Fracture Density Model (FDM) is used to simulate full-scale bench blasts at the Bararp dimensional stone quarry in Sweden. The model uses several computational mechanics algorithms to simulate the effect of blasting in different rock types

Feb 1, 2020

Hello, everyone. Way back in 1965, Devine and others at the US Bureau of Mines showed that a presplit fracture plane did not affect vibration levels transmitted across the plane (RI 6695).

Jan 1, 2010

By Andrew Moore

It has long been common practice to conduct drilling and blasting operations at surface quarries in the Midwest in close proximity to near-vertical highwalls. The main reasons for such an approach, and the limited use of adequate safety controls, can be associated with higher costs, operational constraints, lithological requirements, property boundary restrictions, inadequate quarry planning, or a lack of understanding of highwall risks. Working in proximity to highwalls, without effective controls, exposes personnel and equipment to increased risk of incidents. In recent history, there have been isolated incidents involving equipment damage, or personnel injury/fatality around the United States. However, the Midwest market has largely escaped the effects of such incidents, even though the exposure rate is high. Awareness about this matter greatly increased on January 19th, 2021, when a significant incident occurred at a quarry near Green Bay, Wisconsin. As a crew was loading a typical blast near a highwall, a ground fall occurred, and multiple rock fragments struck a laborer working on the bench below. This individual sustained significant and life-altering injuries.

Feb 6, 2023

By E Emery Gray, Gary Ard

Each year when hundreds of Engineers and Specialists in the explosives industry meet for the SEE Annual Conference, new ideas are exchanged and new business relationships formed. Harbert Construction Corp. and EGA, Inc., a company specializing in drilling and bIasting, formed such a relationship through mutual interest in such a manner.

Jan 1, 1981

By Harry Verakis, Thomas Lobb

Blasting accident data over a 30-year period (1980-2010) are summarized and presented for all types of surface and underground mining operations in the USA. The historical record of injuries from blasting accidents in all types of mines continues to show a significant decline. The overall decline in mine blasting injuries in the U.S.A. has resulted from advancements in blasting technology, training and improvements in blasting products and blasting processes. Some of the technology advancements such as safer blasting agents and computerized bulk vehicle loading, electronic detonators and remote operated blasting systems, and computerized blast design have and continue to significantly contribute to improvements in the historical blasting safety record. Also, the progress of significantly improving the safety of mine blasting has resulted from the combined efforts of miners, mine companies and operators, miners, unions, explosive and blasting product manufacturers, associations such as the International Society of Explosives Engineers and the Institute of Makers of Explosives and various government agencies.

Jan 1, 2012

By J. A. Sanchidrián, P. Segarra, S. Gómez

Blasting is a common activity in mining that can cause significant damage in the remaining rock mass. The most commonly used method for predicting vibrations is the Swedish or Holmberg-Persson approach. It is a simple and fast method that uses empirical formulation to estimate the vibration levels based on the explosive charge weight, distance to the source, and other parameters. However, it has limited accuracy and does not consider the effect of free surfaces or other boundary conditions. On the other hand, recently developed methods as the full-field solution (FFS) can provide more accurate predictions of vibrations due to excitations provoked by cylindrical columns of explosive, but the inclusion of free surfaces in analytical methods is a challenging problem. This paper presents a new approach that includes free surfaces in the FFS to predict vibrations analytically in the near-field. The main obstacle to including free surfaces in the FFS was the belief that the solution was non-decoupleable in P- and SV-waves separately. The Heelan's approach was previously used to decouple them, but it only provides valid radiation patterns in the far-field and does not account for intrinsic attenuation. In this paper, we address this problem successfully, allowing for the inclusion of free surfaces in the FFS.

Jan 1, 2024

By Weiying Zeng, Shouwei Wang, Jinbei Zhong, Xiangdong Meng, Lingtian Meng

"Due to a drainage problem, the Lanzhou to Chongqing high-speed rail line had been out of service during the 2015 wet season, so a drainage tunnel is to be constructed for the line and required to be accomplished before the 2016 wet season. This drainage tunnel is only 5 meters below the line which is in service, therefore blasting vibration needs to be strictly controlled. This paper introduces all theapplied blasting methods, parameters and detonation throughout the entire project, finally bringing in the electronic detonator stagger phase technique and corresponding time difference for detonation."

Jan 1, 2017

By Dr. Anurag Agrawal, Fathur Rozaq, Nella Lubis, Relinda Sanistya, Herry Saputra, Rudolf Sitorus

In mining operations, basic drone applications such as pre- and post-blast photo comparisons, blast video recordings, and sample-based fragmentation analysis are often used to assess blast performance. However, these methods lack the depth needed for comprehensive evaluations, leading to suboptimal results. This study explores the innovative integration of drone mapping technology with artificial intelligence (AI) at the Martabe Gold Mine in North Sumatra Province, Indonesia, to address these limitations. High-resolution drones and ground control points (GCPs) are utilized to create detailed orthomosaic maps, and advanced AI algorithms are applied to enhance the accuracy of blast performance insights. Field experiments reveal substantial improvements in comprehensive blast performance evaluations through this integrated approach. Enhancements include improved pre- and post-blast evaluations, AI collar detection, fragmentation size measurements, heave muckpile profiles, cast material measurements, floor prediction models, and muck pile topography volume, which is vital for ore tonnage predictions. Notably, this method achieves an average volume accuracy of 1% compared to light detection and ranging (LiDAR) technology. While LiDAR is known for its precision, the drone-based method offers a highly accurate, cost-effective, and user-friendly alternative suitable for mining applications. Despite LiDAR's superior precision, our approach provides a practical solution due to its accessibility and ease of implementation. In conclusion, the integration of advanced drone mapping and AI technologies has the potential to revolutionize blasting operations. By addressing the limitations of previous methods, this approach meets the evolving needs of the mining industry and sets new standards for accuracy and effectiveness in blast performance assessment. The combination of high-spectral drone images and AI-based software analysis demonstrated nearly 99% accuracy in ore tonnage prediction models compared to LiDAR, showcasing its promising capabilities.

Jan 21, 2025

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 A. Pope

I have attended two Explosives Engineers’ Conferences in the past 4 years. The first was in Brighton, England with the European Federation of Explosives Engineers in 2005 and the International Society of Explosives Engineers in New Orleans, USA in 2008. At both of these conferences I listened to papers presented on European and English training methodologies and ideologies. As I have been training Shotfirers for the past 18 years in Queensland and the Northern Territory for some 8 years previously, I would like to present our methods of training in Queensland, which I believe is among the best in the world. In Queensland, this training is carried out by a training organisation that is registered by the Department of Education, Training and the Arts under the guidelines of the Australian Quality Training Framework (AQTF). Not only is this Registered Training Organisation (RTO) required to operate under these very comprehensive guidelines, but also those designated by the Explosives Inspectorate of the Queensland Department of Mines and Energy.

Jan 1, 2009

By Norman Paley

A blasting project was undertaken at the Teck Alaska Red Dog Mine in 2005 to 2007 to determine the extent that using electronic detonators could increase Semi-Autogenous Grinding (SAG) mill throughput. The results of that project were reported at the 2010 ISEE Annual Conference. This paper is a postscript to that project and provides the fragmentation resulting from the implementation of a 15% pattern expansion using electronic detonators.

Jan 1, 2012

By Joshua Calnan, Braden Lusk, Kyle Perry

This paper presents detailed information and data regarding the load transfer characteristics of Blast Resistant Glazing Systems utilizing two different thicknesses of polycarbonate. A series of triaxial load cells, along with surrogates of identical stiffness characteristics, were placed around the glazing perimeter to directly measure the load transferred to the support system from explosions of varying degrees. The blast loads were developed using an explosive driven shock tube administered by the University of Kentucky Explosives Research Team (UKERT) in Georgetown, KY. Results presented include distribution of loading, maximum load transferred to connections, blast pressure-time data, glazing system deflection-time data, and final performance results of each system. The two glazing systems respond differently to the applied blast loading. Differences and similarities in the load transfer characteristics are discussed. The experimental results are then compared to a commonly used blast resistant glazing system analysis software tool utilizing a Single Degree of Freedom (SDOF) method of analysis for each system. Preliminary results show that currently used models do not correspond well with experimental data.

Jan 1, 2014