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By Steven Putt

The paper presents new results from Datacloud during recent Seismic While Drilling trials in iron ore, metallurgical coal, and hard rock mines around the world. The measurements are compared with wireline geophysical logs, core data, drill cuttings, and conventional measurement while drilling (MWD) systems to validate the technology and show how the data can be used.

Feb 1, 2020

By William. J. Birch, Catherine. E. Johnson, Robert Farnfield

Rocks and other materials can be characterized by their elastic properties. However, seismic velocities represent a more practical set of physical properties for seismic methods. Seismic velocities define the speed at which various elastic deformations propagate through different rock types. Seismic velocities for a given material can be expressed explicitly in terms of their elastic properties. It is widely accepted that the peak particle velocity and associated frequency of ground motion are important parameters for determining a safety criterion to minimise the potential for both damage to structures as well as nuisance to people. Whilst the key considerations are the blast design parameters, the seismic velocity is important as particle velocity is dependent in part on the powder factor [blasting ratio] which in turn is found to be dependent on the seismic velocity.

Feb 6, 2023

By Dennis Wilzbacher, John Wiegand

In an effort to reduce the cost of bulk explosives, Vigo Coal Company found that the addition of coal mined at their Friendsville Mine, not only reduced explosive costs, but also appeared to actually enhance blasting performance. The Friendsville Coal lies at the base of the Mattoon geologic formation within the Mcleansboro Group of the Missourian Series of the Pennsylvanian Geologic System in Southern Illinois. Vigo Coal Company commissioned VIBRONICS, INC., an independent blasting consulting company to quantify actual blasting performance. Insitu sonic velocity testing of overburden was conducted to determine the P-wave velocity of the sandstone present at Vigo’s Cypress Creek Mine, where the initial testing was conducted. Numerous VOD (velocity of detonation) recordings were obtained for varying blends of ANFO/Coal (now named Carbo*Prill). Cast blast percentages were determined for both Carbo*Prill and non coal blended bulk explosive blasts. The VOD of the coal blended product was intentionally reduced so as to more closely match the P-wave velocity of the sandstone overburden. Explosive blends containing as much as 40-50 percent coal were tested. Explosive blends containing greater than 30 percent coal, have been used in Cypress Creek Mine overburden production blasts. The coal blends appear to produce better fragmentation and yield excellent cast blast performance. Safer mining conditions were also observed. Flyrock potential was reduced. The blasts produced less back break, producing a safer highwall. Stripping dozer and shovel production rose during the testing period and equipment repair costs were lowered due to an increase in overburden fragmentation. Blasting vibrations were reduced, in part due to the lowered detonation velocity of the ANFO/Coal mixture. The Friendsville Coal Seam appears to contain inherent chemical and physical properties that enhance blasting performance. The use of Carbo*Prill has been approved by MSHA, BATF, the State of Illinois, and the State of Indiana. This paper will provide details concerning testing procedures, blast performance analysis, recommendations and conclusions for using this alternative blasting mixture.

Jan 1, 2007

By Carlos Pañura, Michael Geldres, Alejandro Rojas

The vibration waves are produced by the detonation of the explosive charges of each blasthole, analyzing the vibration waves produced by each blasthole, allow us to determine the optimal time between the detonation of each blasthole to reduce the vibrations of the production shot. Once the optimal time is found, it is possible also, to predict the vibration of the production shot (considering times and sequences) using predictive models. The waveform recorded includes information regarding the particle velocity and the dominant frequencies of the vibration.

Feb 1, 2020

By Braden Lusk

Vibrations as a result of blasting practices in mining engineering are a complex phenomenon controlled by many variables. Mine blast vibration modeling and prediction is becoming more important as a consequence of the general negative perception of mining activity by the public. Many communities (all over the world) close to mining activity often complain about airblast and vibrations produced from blasting activity. It is important for the mining industry to have tools and understandable methodologies to model and predict blast vibration. These tools can then be used to control vibration at neighboring structures.

Jan 1, 2013

By P A. Lang, J G. Ayotte, R W. Humphries

Atomic Energy of Canada Limited (AECL) has the responsibility for research, and development of technologies, for the safe and permanent disposal of Canada's nuclear fuel wastes. As part of this comprehensive program, AECL is constructing an Underground Research Laboratory (URL) near Lac du Bonnet, Manitoba, to evaluate aspects of the concept of waste disposal deep in stable geological formations. No nuclear wastes will be used in the URL program.

Jan 1, 1986

By Ann Barron

Even though you think your company’s safety program is the best it can be, equipment, processes, supplies, surroundings and people do not always behave or react as expected. Consequently, needless accidents occur each year at quarries, construction sites, surface mines, and other locations where explosives are used. While blasting accidents account for only a small portion of the total accidents reported, the severity rate for blasting accidents is higher than for any other accident category.

Jan 1, 2007

By S. Green, R. Yang

Blasting is a commonly used method for rock fragmentation in mining operations for mineral extraction. It involves breaking the rock mass into small pieces, and ideally creating micro fractures within the small pieces. Such micro fractures could significantly reduce the energy required for subsequent processes like crushing and comminution. Additionally, micro fractures would enhance the rock-fragraments fluid permeability thereby enhancing desired chemical reactions during certain processing operations. This paper presents recent developments of the Multiple Blasthole Fragmentation (MBF) model, which simulates blasting rockmass fragmentation. The MBF model allows estimating rock strains experienced during the blast, for various blast design parameters and geometries. The intent is to correlate these strains with created micro fractures in the blast rock fragments. Adjusting blast design parameters in the MBF model of explosive loading and delay timing allows blast optimization. Such optimizing would create desirable strains to enhance micro fractures within the rock fragments. This would improve mining operations by enhancing downstream operation efficiency, thus reducing costs.

Jan 1, 2024

By Rob Farnfield, Ben Williams

The A5 road in the United Kingdom forms an ancient and well-used route through the hills and mountains of North Wales. In the 1990?s a programme of work was conducted to upgrade the road to modern standards. As part of this work a new cutting was constructed to bypass a portion of road routed through a gorge close to the village of Ty Nant. This new cutting was formed by drilling and blasting and included much pre-splitting and extensive rock bolting. This operation caused much concern to local residents relating to vibration, air overpressure and flyrock.

Jan 1, 2011

By Scott Gustfason, Richard N. Snyder

What is a safe stand-off distance? Recent mishaps using conventional blasting equipment have seen flyrock as distant as 3,750 feet from the blast area, or close to three-quarters of a mile, therefore, whether below ground, under water, in surface quarries or at a structural demolition site, data signals riding a radio wave promise a new horizon for the users of both electric and non electric blasting circuits.

Jan 1, 1987

By William H. Snyer, Hank Cox

A high explosive device using Linear Shaped Charge (LSC) (to rapidly cut vent and drain openings in a rail tank car) is described. In the event of damage to a tank car loaded with a pressurized flammable fluid, it may sometimes be necessary to perform controlled on-site vent, drain and burn operations. Existing techniques required refinement to achieve the desired safety and procedural reliability for use in emergency situations.

Jan 1, 1994

By Evan Boone, Peter Bellairs

A technical services visit was conducted to determine the initial parameters to successfully presplit several benches for an input crusher installation at the Wolffdene quarry. The paper details the preliminary design utilising both detonating cord only and specialised presplit product charges and compares these to the final designs utilised based on site experience. The role of accurate drilling, explosive loading and geology in obtaining successful cost effective presplits is highlighted.

Jan 1, 1998

By Marcus Neves, Eventomar Junior, Adilson Castro, Leandro Silveira, Sérgio Augusto

The collapse of the Vale S.A. mining tailings dam in 2019, a tragic event that shook Brazil and the world, had consequences that transcended the immediate pain and devastation. Among them, the suspension of rock blasting activities in several mines in the Quadrilátero Ferrífero region of Minas Gerais, Brazil. This measure, taken as a precaution and with the aim of ensuring the safety of nearby geotechnical structures and the population, had a significant impact on the mining production chain. To overcome these challenges and resume blasting activities in a safe and sustainable manner, the mining industry has been dedicated to developing and improving solutions. One of the promising alternatives is the signature hole technique, used in conjunction with attenuation laws. The complex geology of the Quadrilátero Ferrífero, with lenses of compact ores immersed in friable materials, the presence of discontinuity families, and the emergence of geological faults, requires detailed analyses and specific adaptations of the signature hole technique and constant monitoring of the vibrations to calibrate the attenuation laws to ensure compliance with permissible limits and safety of the operations. To demonstrate the methodology, a case study in Abóboras Mine was described. Additionally, the challenge of achieving the desired level of production while controlling vibration and slope damage has driven the development of new charging and timing techniques. To address this challenge, a comprehensive approach was undertaken. A substantial database containing more than 4,000 registers of blasting-induced vibration events from 520 blasts was meticulously compiled from 2020 to 2023, 6 different attenuation laws were established and continuously calibrated with 99.3% of compliance regarding permissible limits of vibrations. The successful implementation of these actions allowed for the resumption of blasting, increasing production from 10 million metric tons to 43 million metric tons per year assuring sustainable operation.

Jan 21, 2025

By R E. Langston, S M. Gazioglu

A preconstruction inventory program was conducted to determine the existing conditions of residential, non-residential and all other structures within 2,000 feet of the blasting limits for a highway excavation site in Asheville, North Carolina. Prior to major production blasting, eleven test blasts were detonated to establish site specific propagation parameters in order to develop contours of maximum allowable explosive charge weights per delay. The method of scaling distance by the square root of charge weight per delay was utilized in developing the contours of allowable charge weights. The charge weight contours were revised during blasting operations as additional vibration data became available. The effects of blast induced vibrations on a nearby water storage reservoir, a nearby vehicular tunnel and other adjacent residential and non-residential structures were observed and monitored over a period of two years of blasting operations.

Jan 1, 1980

By M. Szumny, P. Mertuszka, K. Fuławka

Mining-induced seismicity is one of the adverse side effects of mining with the use of explosives at great depths. Disturbance of the primary stress state by the development of the network of excavations combined with the continuous generation of dynamic loads by the detonation of explosives in mining faces has a negative impact on the level of safety of crew and machines. To ensure the stability of excavations it is necessary to identify in detail the nature of the seismic hazard by means of continuous seismic measurements. Unfortunately, the technologies used so far are characterized by high costs of installation and further maintenance, which clearly limits the possibility of using a large number of stations in a small area. A breakthrough in this matter may be the technology of microelectromechanical systems, which is several times cheaper than standard solutions used in mining seismology. This technology, with the appropriate configuration of devices, can be successfully used to monitor dynamic phenomena generated by mining activities. As part of this study, the assumptions and configurations of a prototype 42-channel accelerometer network using MEMS technology have been presented. The network was installed in the Lubin underground copper mine in Poland in a seismically active area, where multi-face destress blasting are conducted regularly. As a result, 14 tri-axial accelerometers were installed in the immediate vicinity of the active mining front at a distance of about 1,000–4,000 ft (300–1,200 meters) from the closest faces. Highfrequency recordings are collected based on algorithms that trigger the system when the Peak Particle Acceleration set value is exceeded or on the basis of a manual external triggering device connected to the blasting machine. During the measurement period, several high-energy seismic tremors and several dozen of waveforms generated by blasting were recorded. The obtained results are the basis for assessing the effectiveness of the destressing measures and for the analysis of geomechanical risk based on periodic analysis of the velocity of seismic wave propagation

Jan 1, 2024

By Lawrence C. K Hu

The release of load mechanism during rock breakage by explosives was founded by Dr. T. N. Hagan & published at the Sixth International Colloquium on Gasdynamics of Explosions and Reactive Systems Stockholm, Sweden, 1977.

Jan 1, 1995

By Callie Covert

This paper describes the application and results of a more efficient method of breaking boulders using dynamite and water. This method is being used for the disposal of boulders that result from pinnacle and cap rock remaining after blasting on highways and job sites. This method is a faster and less expensive use of dynamite to reduce oversized boulders than the conventional rock hammer. The problem with excessive fly rock has been substantially reduced when using this technique over traditional methods.

Jan 1, 2001

By Türker Hüdaverdi, Özge Akyildiz

"Efficiency of blast operations depends on fragmentation, overbreak, muckpile profile anddisplacement, vibration, airblast, flyrock and damage to wall or slope stability. To provide all these conditions at the optimal level, determination of rock mass properties (in-situ block size, joint spacing and orientation) is the very first step during design stage of rock blasting. Image analysis software is used not only to determine the fragmentation level of muckpile but also to characterize the bench face. In this study, an image analysis software was used to determine apparent block size of bench face and to measure blast fragmentation of muckpile. The source of errors and the vital points to be taken into consideration were explained for bench face characterization andfragmentation measurement. Since it provides much better results than previous techniques and it is not intrusive to production process, image analysis technique is considered as one of the most efficient and preferred way for fragmentation analysis. Besides these advantages, there are some weak points of image analysis software. Lighting is one of the most important factors for photographs captured for in-situ block size analysis and fragmentation analysis. Lighting determines shadow formation. In an ideal image, particles are clearly delineated by soft shadows. If shadows are too strong (dark), analysis suffers. Appropriate scale should be replaced onto blast muckpile during site measurements. The location of the scale in image affects the results of analysis. Also, the densityand orientation of discontinuities should be considered during application of image analysis technique to characterize bench faces. In this study, image analysis software was applied in thesandstone, limestone quarries of Istanbul region and an open pit boron mine. All image analysis, evaluations and results were made based on the site measurements."

Jan 1, 2017

By Roger G. Sprague

With the passing of time, changing marketplaces and years of hard service, coupled with new machines, increased productivity, rapidly improving technology, equipment which used to be the latest in modern mining have now slipped into obsolence. Mining companies need reliable, productive equipment in order to compete in today's market. In Western coal mining, as coal seams become deeper, older equipment must be replaced with that which can do the job more efficiently.

Jan 1, 1998

By R. F. Favreau, Patrice Favreau

"Ever since we have started to assist those responsible for blasting with blast simulation studies, we havebecome aware of an interesting aspect, namely that in 90 % of cases we are asked ‘‘Can you seek ablasting method which gives better fragmentation than the method which we use now’’. But after a visit to the site, and the evaluation of the fragmentation obtained with their present blasting method, it very often becomes evident that it is the ease of mucking and not the fragmentation which requires improvement. Hence we then proceed to do a simulation study the results of which are improved mucking rather then more fragmentation, and those responsible for the blasting always become very satisfied."

Jan 1, 2017