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By Nadir Plasencia, Rogerio: Neves Mota

The evaluation of vibrations induced to build structures is one of the main concerns when dealing with blast works. EDP, the main Portuguese producer of electricity is presently incrementing energy production in some old hydropower dams by installing new production plants. The need for not disrupting production during the upgrading works causes some concerns related with vibrations induced to the production engines. Vibration estimation was performed in two of these dams, constructed in a granite environment, by performing controlled blasts. For each dam site, some vibration transmissivity laws were developed with the fitting process.

Jan 1, 2008

By Allen Kinney, P. T. Freeport

This paper presents the methodology for final wall-controlled blasting utilized at the Grasberg Mine. The resulting optimized slopes representa14%and17% increase to bench face angle (BFA) and inter-ramp slope angle (ISA), respectively. The corresponding increase in both copper and gold recovery was more than 40% greater than forecast for each material. The Grasberg open pit mine is located in the remote jungle province of West Papua Indonesia, at an elevation of 4,200 meters(13,780 ft).With a diameter of approximately 3.5km(2.2 mi), anddepthover1.2km(0.7 mi),P.T. Freeport Indonesia (PTFI)has mined billions of tons of rock from one of the world’s largest gold and copper deposits. Grasberg Operation and Engineering implemented a quality driven slope optimization program for the final pushback, with the goal to safely increase recoverable metal through steeper slopes, while utilizing existing infrastructure and equipment. This paper focuses on controlled blasting initiatives, blast monitoring, and as-built slope measurement tracking, although many groups contributed to the success of Grasberg slope optimization. The potential slope optimization area was divided into two sections based on geologic assessment: Area A at radial 200°-270° and Area B at radial 270°-360°. Original slope designs for areas A and B specified ISAs of 51° and 52°, respectively, with all BFAs in the pit at 70°. Through continuous development, collaboration and achievement, the Grasberg final pit accomplished a BFA increase to 80°for all areas, and an ISA increase from 51° to 56°in Area A, and 52°to 60° in Area B.

By Thierry Bernard

New technology to automatically design a blast based on autonomous drone. The process of flying a drone, calculating the 3D cloud of points, generating the critical face profiles and placing holes automatically according to burden specification becomes fully automatic. A nice time saving with more efficiency

Feb 1, 2020

By Kenneth Medearis

The accurate prediction of possible damage to historic structures subjected to blasting-related ground motions is not infrequently the dominant factor in whether or not a mining or quarrying operation is allowed to proceed. A recent scenario involving an 1802 Pennsylvania Historic House was resolved satisfactorily, primarily because of the use of modern structural dynamics analysis techniques rather than simplistic peak particle velocity guidelines. One of the associated dominating factors was the truly significant agreement of the analysis results and the values obtained from actual on-site test shot blast motion recordings.

Jan 1, 1993

By Ed Jr Smith, Calvin J. Konya

The purpose of this paper is to describe the case history of a blasting project conducted jointly by Precision Blasting Services and Cherokee Explosives. It is the intent of the authors to show how blasting could be done in controlled fashion near very expensive computer controlled machinery. The job was done in minimal time with no complaints or allegations of damage in spite of the fact that blasting was conducted within five feet of the equipment and with the 32 acre plant fully operational, with machine operators working within 10 feet of the blasting site.

Jan 1, 1986

By Tapan Goswami, Michael Croucher

At Bayswater Colliery various methods of controlling highwall stabii were investigated. The use of presplitting was trialled and its effectiveness measured. The presplit hole spacing and explosive charge were based on those succes& lly used in other coal mines in the Hunter Valley. The major presplit design parameter to be determined was the stand-off distance between the presplit line and the back row of the production blast. This could not be transfmed directly from other sites due to the difference between the Bayswater’s production blast geometry and geology to that of other sites. Using highwall face surveys and Orica’s SUR..YPlus@ software, the average back-break behind normal production blasts was determined. This was then used to select the stand-off distance between the back row production blastholes to the presplit line. While presplit designs are normally based on powder factor (kg/m2), the use of energy factor (MJ/m2) was also investigated as a possible design criteria.

Jan 1, 1999

By Pierre De Pasquale, Gilles Jauffret, Ricardo Chavez

"When blasting in quarries or mines, the main source of inconsistent results is directly related to thenon-homogeneous energy distribution through the rock-mass volume. This variation has differentorigins: drilling deviations, geometry differences from one borehole to another (burden, spacing ...),and inherent geological conditions."

Jan 1, 2016

By Pierre Auger, Benoit Levesque, Richard Martel, Guy Sanfacon, Louis-Charles Boutin, Marc-Andre Lavigne, Patrick Brousseau, Luc Trepanier, Louise Galarneau

Explosives used for blasting operations in civil engineering works, like construction of piping systems under roads, of pools, of houses and buildings can generate large volumes of carbon monoxide (CO). Carbon monoxide can represent between 1 to 3% of the gases produced by usual explosives. The production of 10 to 24 1 of CO by kg of explosives blasted is theoretically anticipated. CO is a gas that has no characteristic colour, smell or taste. It can migrate in the fractured rock of the blasted areas on fair distances, and then infiltrate in closed spaces like sewage systems, manholes, but also in basements of houses. In Quebec, in the last 10 years, 7 people were poisoned by CO in their houses to the point that they had to be treated in hyperbaric chambers. In the USA, many accidents have occurred and one worker died in a manhole. From the review of intoxication cases, the distance of migration of CO may reach 55 m if a conduit is present underground. Underground conduits broken by blast, tilling around underground conduits in road or house trenches, or fractured rock created by blasts between houses or between a house and a road, are the different pathways identified in the Quebec incidents. Field tests were performed at sites close to CO intoxication locations in order to evaluate the behaviour of CO in fractured rock following blasting operations. From these tests, the following conclusions may be drawn. The structural geology of the rock formation (schistosity, family of joints, fractures) plays a role in the direction and extent of gas migration in fractures generated when rock is blasted with explosives. The confinement of the rock can affect the quantity of gas migrating in the fractured rock. Significant concentrations of CO may persist in the fractured rock even 7 days after a blast. Advection is the initial mechanism of CO migration in fractured rock generated by the blasts or naturally occurring before the blast. The distance of migration with this mechanism is short (5 to 8 m). In trenches of muck (equivalent to tills under roads) the distance of CO migration by advection is 12 to 20 m. In the 2 to 3 days following the blasts, further CO migration up to 15 m is made by diffusion in the induced fractures, or up to 30 m in the trenches. To minimise CO production and migration in the fractured rock during blasting, special procedures can be applied by the blasting contractors: (1) do the complete excavation of the overburden before drilling and put mats for each blast; (2) do the complete excavation of the muck after each blast; (3) the last blasting should be the one for the private services entrance of the house and the excavation of the muck should begin at the junction between the road trench and the services entrance trench. Another technique consists in the pumping of interstitial air in the muck with a vacuum truck immediately after each blast.

Jan 1, 2002

By Joshua Hoffman, Rob Farnfield, Catherine Johnson, Braden Lusk, Morgan Lane

IMESAFR (IME Safety Analysis for Risk) is a quantitative risk assessment software tool developed by the Institute of Makers of Explosives (IME) and A-P-T Research, Inc. It is used for managing risk in the commercial explosives industry, the newest version of the software was completed in 2012. This paper discusses the use of this software package in conjunction with data collected for a television series on the reenactment of the ‘London Blitz’, a 57-day bombing of the City of London in 1940. In this reenactment, purpose built structures using period design and materials were constructed at a test facility in the North of England. Five devices ranging in size from 20 kg (44 lb) to 1100 kg (2400 lb) were detonated at varying distances from the structures; each blast was monitored by EPC-UK and the resulting structural damage was analyzed. Data recorded from the blasts included high-speed videos, photographs before and after each event and air overpressure readings. The same data was inputted into the IMESAFR software package to assess the risk imposed on the residents of London during this time. The appropriateness of this tool for evaluating structures built using historical practices is discussed. Data from the full scale tests is compared to effects predicted by IMESAFR. Further analysis of the risk recommendations produced by IMESAFR is compared to the actual damage assessed during the large scale tests.

Jan 1, 2014

By J Lyall Workman, Peter N. Calder

"Presplitting is a technique mines and quarries may use to produce high quality final pitwalls. Damage from backbreak can be minimized, thereby insuring the final pit walls standat the designed angle. Thus costly excess waste removal is avoided. Safety in the pit isenhanced. Control blasting is an essential component of procedures to maintain the stabilityof final pit walls prone to failure."

Jan 1, 1993

By Thomas Palangio, Blessing Taiwo

Image-based fragmentation analysis is increasingly utilized in blasting operations to evaluate particle size distribution in a non-intrusive and efficient manner. However, the accuracy of optical granulometry systems can vary significantly with particle size. Higher precision is typically achieved for larger fragments, generally those greater than golf ball size when using drone-based orthomosaic analysis. In contrast, the detection and delineation of fine particles become less reliable due to constraints such as pixel resolution, particle overlap, and partial burial within the muck pile. This variability does not undermine the value of image analysis but rather highlights the need for a deeper understanding of its operational thresholds and the integration of complementary methods or calibration approaches to improve its reliability across the entire particle size distribution. Technologies such as WipFrag, originally developed in the 1980s, are designed to conduct in-situ fragmentation analysis within complex blast environments, where fines are often obscured by larger fragments. The challenge becomes more significant in blast rounds exhibiting wide gradation ranges and increased fines, particularly resulting from excessive energy concentration in high-pressure zones near the borehole. Previously, this issue was addressed through methods such as analytical correction, zoom-merge correction, and empirical calibration using Rosin-Rammler and Swebrec distribution models. However, these traditional empirical calibration approaches, particularly those tied to distribution functions like Rosin-Rammler have shown limitations, especially in accurately representing the fine region of the fragmentation curve. In contrast, the recently developed xP-fan model, which incorporates the relationship between powder factor and fragment size, introduces the fragmentation energy fan principle which Kuz-Ram model does not entail. This paper presents a study on the application of the novel xP-fan calibration to enhance the accuracy of optical granulometry systems. The findings demonstrate how xP-fan help calibrate the fine region of the PSD without deflecting the maximum size.

Jan 26, 2026

By W. Jiao, Y. Yongqi, R. Shan

Soft rock mines are distributed through out P.R.C. And drilling and blasting is still the main method of driving a tunnel in these mines. Traditional smooth blasting has been widely and deeply studied and put into practice in P.C.R since 1970s. But the cartridge and blast hole are both columns, the stress field in the rock around blast hole at the beginning is symmetry around hole axis, and the original cracks in the rock can be activated randomly. So serious overbreak and underbreak at the boundary of an excavation occur often, especially when the excavation is in soft rockmass, and the rates of half-hole marks are generally about 50% in medium rock, and 20-30% in soft rock in Chinese coal mines. For the sake of overcoming the situation, we have been studying directed crack blasting since ten years, and have got some obvious achievements in this respect. Slotted cartridge control blasting in soft rock is studied in this paper. Through model experiments, reasonable decouple coefficient range and slot width are gotten, and unsymmetrical dynamic strain field is analyzed. Through underground test in soft rock with a strength lower than 1OMpa in Dayan Mining Bureau, The results of which the rates of half-hole marks and the nonsmooth grades of the cut contours are 83.3% and 1OOmm respectively have been achieved.

Jan 1, 2000

By James Rowland, Richard Mainiero

When most people think of explosives transport they think of a hazardous operation. We all know that we aren’t allowed to transport explosives through tunnels and are discouraged from traveling through heavily populated areas. Popular opinion suggests that explosives transport is a very risky operation. The authors decided to look into this a little more thoroughly and found just the opposite to be true.

Jan 1, 2008

By William Everett, Jack Eloranta

United Taconite is an iron ore mine operated by Cleveland-Cliffs Inc (Cliffs) located near Eveleth, Minnesota. The mine, originally known as Eveleth Taconite Mines, was purchased in December 2003 by Cliffs (70%) and Laiwu Steel (30%). The mine site, known as the Thunderbird Mine, produces taconite ore for delivery by rail to the company’s Fairlane plant, located approximately 10 miles to the south near Forbes, Minnesota. At the plant, the crude ore is ground, concentrated and processed into pellets for steel industry customers. Total pellet production capacity is about 5.4 million long tons (Ltons) per year.

Jan 1, 2006

In this paper, the author points out the need to beware of simple time correlations as proof of cause and effect when comparing building cracks and blasting operations. There is a need to be aware of the many other causes besides blasting which affect buildings. Some of these have histories of cyclic behavior; others have a long-term increasing effect on aging and deterioration, often with poorly defined time histories. Many are so strongly site specific that generic relationships are difficult to quantify.

Jan 1, 1981

Blastserve, ISEE’s Listserve is being replaced by our new Blasters Forum-online, an exclusive member benefit. Our goal is to provide an ISEE forum for you to network with your peers and exchange technical information and get answers to your technical questions. This forum is unique in the fact that only ISEE members are permitted to review or post on the site. Over time you will be able review the discussion history and use the archived discussion as a valuable resource for trends in the industry. The following are a sample of the discussions that too place recently on Blastserve

Jan 1, 2013

By Kwang-Yeom Kim, Dong-Gyou Kim, Hyo-Kwan Yoon

This study was intended to simulate the blasting model using notched-hole with numerical approach. Numerical analysis approach was applied to compare and evaluate the blasting model using notched-hole and circular hole. To implement non-linear dynamic blasting model, blasting analysis was carried out with AUTODYN code. Behavior of two models was compared and evaluated using AUTODYN and visual analysis and quantitative evaluation based on pressure and stress to verify the effect to induce the destruction territory to the specific direction when blasting with notched hole was attempted.

Jan 1, 2010

Electronic detonators are receiving increasing acceptance in the blasting industry. Electronic detonators offer several distinctive features over electric and non-el (shock tube) detonators including better timing accuracy resulting in excellent fragmentation and vibration control, field programmability and digital safety means. Several electronic detonator systems are available commercially today serving the surface, underground and seismic needs.

Jan 1, 2010

By S. Evans, J. Phillips-White, D. Morton

The partnership between Orica and MMG at the Dugald River Zinc mine in Australia has led to the first global field trials and deployment of Orica’s Subtek™ 4D™ (hereafter referred to as 4D) Bulk Systems underground bulk emulsion blasting technology. This technology offers advantages over conventional bulk explosives by extending the range of energy and length of explosive column that can be charged in underground production. 4D gives blast designers energy options between Relative Bulk Strength (RBS) 50 - 150, delivered uniformly along the entire column in most blasthole conditions along with the ability to instantaneously modify the energy within an individual blasthole. During Phases 1 – 3 of the project from October 2022 to January 2023, over 57 tonnes of the 4D Underground emulsion were loaded in 17 stopes. The primary objectives of this phase were to reduce hanging wall dilution and improve stope recovery. While drilling and other parameters remained unchanged, the energy selection was tailored for specific situations, guided by a revision to the site's drill and blast standard. The design used low energy (RBS 50 - 70) in holes adjacent to the hanging wall and high energy (RBS 130 - 150) where stope recovery had historically been challenging, such as at the toes of long downholes. Initial results of the project focused on five stopes selected for their similarity to those used for the baseline data set. Although the 4D data set was small, the post-blast scans indicated favourable results for recovery and dilution. This suggests that selecting and delivering bulk explosive with tailored energy levels can improve stope performance.

Jan 1, 2024

By Langdon T. Mitchell, Karl Ingmarsson

The title is not referring to jewelry; nor is it about diamond core drilling. This article is instead about an emerging application for diamonds, hard rock percussive drilling with diamond drill bits. Diamond’s outstanding wear resistance has long been taken advantage of in core drilling. However, until now diamond has been less successful in hard rock production drilling in the mining and quarry industry.

Jan 1, 1999