Search Documents

By Tyler Rockley, Cara Rosen

Blasting at a granite quarry in eastern Maryland produces elevated air blast readings that can fall into the cautionary zone for the state of Maryland environmental regulations on a semi-regular basis. When designing blast patterns in this quarry, challenging geology creates rough and uneven blast faces that can be difficult to capture with 2D laser profiling fully. Utilizing several methods known to manage high air blast results like pattern adjustments, decking, and timing changes have not achieved consistent outcomes. Accurately capturing and modeling this geology is the key to controlling high air blast. 3D modeling and profiling by drone is the solution to understanding accurate face profiles and real minimum burdens. Using 18 months of blasting data and air blast results to establish a baseline, the comparisons between blasts designed with 2D profiling and blasts designed with drone 3D profiling show improvement in air blast levels. Additionally, shots with completed drilling were drone profiled to understand precise amounts of burden for each borehole. This 'audit' of a blast allows for custom loading of explosives, accommodating the amount of burden present on the blast face. 3Dprofiling is not a new tool in the blasting industry, but a drone alleviates some of the restrictions ground systems face. Controlling and managing air blast, as it pertains to face burdens, requires an understanding of those burdens from all angles. A drone provides that distinct level of insight. The results of this study indicate that drone profiling is managing the customer's air blast readings, allowing the customer to maintain their license to operate within the community.

By Debra Satkowiak, Ronald Thomas

The Institute of Makers of Explosives (IME), a non-profit safety and security organization founded in 1913, is known for its industry best practices, Safety Library Publications (SLP), some of which have been incorporated into rules by regulatory agencies. The IME developed the first commercial storage, quantity distance (Q/D) table titled “The American Table of Distances” (ATD). It was developed by IME’s legacy association in 1910 and was originally based on observations of structural damage from 117 accidental explosions involving small to very large amounts of explosives, primarily dynamite and black powder. In 1930, the IME published a book, compiled by Ralph Assheton, called the “History of Explosions on Which the American Table of Distances was Based”. The distance in feet in the ATD were founded on the measurements at which inhabited buildings sustained substantial structural damage from the accidental detonation of explosives. For example, minor damage such as window glass breakage and the “shaking down” of plaster was not considered substantial structural damage. Other damage to property that was readily repairable was also not considered “substantial.” It was concluded that unless some integral portion of the building was damaged, the occupants would not be subjected to serious risks.

Jan 1, 2017

By Tyler Rockley, J. P. Remi Proulx, Ruilin Yang

A highwall blast vibration project was carried out to quantify the level of blast vibrations produced from a trim blast in soft rock and a combined production and trim blast in hard rock. Combining production and trim blasts could be performed without exceeding the mine’s vibration limits.

Feb 1, 2020

By S. Mansfield, A. Sharma

At a large open cut copper mine, in pit crushing and conveying is used to shorten haul routes and minimise stockpiling of ore. This strategy decreases capital expenditure by reducing the number of haul trucks and excavators required and reduces the need to rehandle ore from stockpiles with a secondary load and haul fleet, with an overall goal of lowering operating costs and carbon emissions. As the mine has developed and expanded, it was necessary to extend the conveying network and install a fourth, semi-mobile crusher to increase the output of the operation, while maintaining the operational efficiencies. This required the blasting of a new tipping bench and pocket for the installation of one of the largest and most powerful semi-mobile, crushing plants. Fed by 360 tonne (396 ton) ultra-heavy class haul trucks, the KB 63-130 Pro gyratory crusher is the highest capacity available in the market. This paper describes the holistic process that was applied to model, design and execute the blasts required to create the pocket for the semi-mobile crusher, the surrounding tipping bench, plus the conveyor corridor and access ramp used by the ultra-heavy class trucks.

Jan 1, 2024

By L C. Taylor, H U. Lesiste

This paper provides a preliminary description of the properties of the output pressure (shock) wave of an end initiated, cylindrical charge of low height to diameter ratio in saturated sand. The properties of primary interest are the pressure wave velocity, peak pressure and rate of rise of peak pressure to within 1.4 charge diameters from the output end of the charge. The behavior of these properties is seen to be quite different from their behavior at more customary ranges in water.

Jan 1, 2013

By Felix Degold, Mark Ganster

Achieving a customer optimized fragmentation by using robust data from new technologies e.g. GPS positions of boreholes, fragmentation analysis to calibrate the geology and fragmentation prediction models. The inclusion of the collected data into the blast’s design makes it possible to accomplish a desired particle size distribution.

Feb 1, 2020

By A. Torrance

A better understanding of the detonation performance of an explosive charge can be gained by directly measuring pressure, temperature and velocity of detonation (VOD). This is particularly important with commercial explosives because their performance is directly influenced by the degree of confinement given by the borehole diameter and the surrounding rock mass. A project funded by the Australian Coal Association Research Program (ACARP) was initiated in early 2009 with the view to design and build cost effective prototype instrumentation to measure the relative differences in detonation pressures and temperatures of commercial mining explosives. The project’s primary focus was on low density explosives. Low density (also referred to as low shock) explosives have been available in various forms for nearly 20 years. Identifying the pressure release patterns of both conventional and low density explosives under different geotechnical conditions should provide the necessary information to both validate detonation codes and better define input parameters for breakage and fragmentation models. This paper gives a general description of the prototype instrumentation developed and reports on the results obtained to date in testing the proposed instrumentation in laboratory scale conditions.

Jan 1, 2011

By CVB Cunningham

"The Kuz-Ram model as originally proposed included an error in assuming that the mean fragmentsize predicted by Kuznetsov’s equation was actually the 50% passing size. In 2003 Spathis began discussions on this issue and recommended correcting the equation. The correction produced more fines in the predicted fragmentation, which had been a criticism of some users of the original model. Ouchterlony subsequently showed that the error had, if anything been beneficial, and that the Swebrec function adequately covered the fines. This author shows that the Spathis correction does not assist the fines correction in examples examined, but tends to underestimate coarser fractions. An intrinsic problem of communication between academics and engineers is a root of misunderstanding on both sides, and requires patience by both parties to enable value to arise."

Jan 1, 2016

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 Amanda Verno, Danilo Coppe, Andrea Reggiani, Adolfo Bacci

The methodological example that comes from the demolition of the Genoa grain silos, should not been considered as an auto-celebration of a difficult project successfully executed, but should serve as an example of a new generation of demolitions where different technologies, often in competition, come together to obtain the optimal solution of a problem. Dynamite, diamond wire and hydraulic excavators overcame the most impressive building in town, working in very little spaces and on a geotechnically difficult site; moreover, a study on the dynamics and the effects of the impact of the structure, an analysis of the presence of potentially explosive dusts and an extensive vibrometric monitoring supported the design and the development of the operations.

Jan 1, 2005

By Raúl Carretero de la Hoz, Leonardo Soares Chaves, João Paulo Soares Toneli, Francisco Felipe da Silva Dantas, Marcos Peres Lopes, Marcus Vinicius da Silva Gonçalves

The mining activity results in environmental impact and thus requires the adoption of techniques to minimize its effects. The rock blasting process is required to break up and move the rock enabling the haulage of the material, however, it might also cause undesirable effects such as flyrock, overbreak, excessive ground vibration or air-blast at the neighboring communities and damage to civil or geological structures located nearby. The Serra Sul mine, commonly referred to as S11D project, has obligations to preserve two natural tropical montane lakes and several maximum relevance natural cavities whose legal preservation radius represents constraints to the mine development and operation. Controlling measures are undertaken to ensure preservation of the cavities, especially during rock blasting stage, with limitations of the maximum instantaneous charge (MIC) and ground vibration control. The demand for high productivity and the large areas with hundreds of blastholes to charge are challenging factors to the charge control. This work presents the development and field application of a map for limiting explosive charges in the rock blasting process at the Serra Sul mine, used for the definition of maximum charges according to the blast location, ensuring the preservation and compliance with the defined ground vibration limits for each cavity. The map is applied at the mine for every blast and when there is a charge constraint, the map helps to define the areas with different charging profiles in the field contributing to higher charging productivity.

Jan 21, 2025

By Johan Gjødvad, Catherine Aimone-Martin, Charles Dowding, Mathias Jern

A residential structure adjacent to a quarry in Ohio was instrumented to record structure motions, resulting wall strains and existing crack displacements in response to close-in blasting within 82 m (270 ft). The project is a cooperative effort among international experts representing the European Federation of Explosives Engineers (EFEE) and ISEE supported by more than 21 persons from eight different countries to compliment prior work performed at the Aitik Mine in northern Sweden. The focus of this study is to compare blast-induced vibration measurements relative to regulatory compliance limits as a percentage of allowable velocities among eight different countries for a one-story residential wood-frame structure with a brick-and-mortar exterior and full basement. Participating counties included Austria, France, Germany, Norway, Sweden, Switzerland, the United Kingdom (UK) and the United States (US). Geophones were placed on the foundation and in the ground in accordance with each country’s regulations to record peak velocities as a function of frequency or distance to blasting. This study extends the work performed at the Aitik Mine to include interior corner geophones to calculate global wall strains and micro-m (micro-in) displacement gauges mounted over an existing drywall crack to measure blast-induced dynamic crack responses and climatological influences on daily opening and closing of a crack. Structure responses were documented for 68 blasts conducted north of the structure from February through September 2023 of which 17 blasts were selected for detailed analyses. The highest in-ground PPVs recorded were 43 mm/s and 59 mm/s at the NE and SW corners, respectively. Measurements from these blasts plotted within each country’s limits provided a comparison of stringency among the counties. The percentage of compliance limits among counties ranged from an average of 114% for the US, UK, and Austria limits to the highest of 585% for Switzerland. Despite these high percentages of compliance for all countries, the global tensile strains induced by these blasts were at most only 12 μ-strains and occurred with the highest velocity blast that exceeded each county’s limit. This high percentage of compliance and low strain level demonstrates the restrictive nature of the regulations studied. Peak dynamic crack opening and closing during blasting averaged 20 -m (0.0008 in) while the 12-hour weather-induced crack displacement during the time period over which blasting occurred averaged 200 -m (0.008 in) and the largest 12-hr change in crack width was 356 -m. This low level of crack response validates the observation that the studied regulations have highly conservative limits for cracking potential of standard building materials.

Jan 21, 2025

By Hideaki Kitajima, Ryo Sakamoto, Katsuya Sasaki, Maehata Hidehiko

The Electric Discharge Impulse Crushing System (EDICS) is a technology for carrying out crushing by using electrical power and nitromethane. It is designed for construction tasks such as splitting of concrete and rocks.The EDICS consists of an electric discharge generator that supplies a high-voltage high-current pulse, a cartridge that generates power by using electric discharge energy, and cables that connect the electric discharge generator and the cartridge. The cartridge contains a thin metal wire that evaporates because of the electric discharge energy and a nitromethane that reacts with this evaporated metal wire. The cartridge can be used to generate a high pressure on the order of gigapascals within a time interval of several hundred microseconds, and crushing power equivalent to that generated by explosives is generated during this period. In recent years, the EDICS has been widely used in Japan because of its good performance and favorable characteristics.

Jan 1, 2011

By Cristian Castro, Patricio Gomez, Jason Furtney, Augusto Lucarelli

Understanding the effect of blast-induced damage on wall stability is critical to safe and economical operation of a large open pit mine. In this paper, a numerical modeling methodology is used to investigate damage to rock at distances of greater than 10 m (30 ft) from a blast. Two applications of the model are demonstrated. First, the method is applied at a zinc mine to investigate the effects of pit blasting on underground stopes. The model predictions are compared with the scaled distance formula. Next, the model is used to investigate a common problem in which unfavorable jointing creates a rock wedge on the bench above a blast. The numerical predictions of wedge stability are compared to the wedge energy model described by Wong & Pang (1992).

By Cristian Castro, Patricio Gomez, Jason Furtney, Augusto Lucarelli

Understanding the effect of blast-induced damage on wall stability is critical to safe and economical operation of a large open pit mine. In this paper, a numerical modeling methodology is used to investigate damage to rock at distances of greater than 10 m (30 ft) from a blast. Two applications of the model are demonstrated. First, the method is applied at a zinc mine to investigate the effects of pit blasting on underground stopes. The model predictions are compared with the scaled distance formula. Next, the model is used to investigate a common problem in which unfavorable jointing creates a rock wedge on the bench above a blast. The numerical predictions of wedge stability are compared to the wedge energy model described by Wong & Pang (1992).

Feb 1, 2020

By Charles H. Dowding, Catherine T. Aimone

Rock particle sizes were measured at fourteen steep-slope Appalachian coal mines during production blasting. The distribution of rock sizes shows the effects of inter-hole timing, sequence of hole initiation, as well as charge distribution within each shot. Blast design parameters were selected to: (1) minimize displacement of broken rock conforming to throw control required of mining methods, (2) minimize seismic effects, and (3) create breakage at a cost economical to mining operations.

Jan 1, 1983

By Roger L. Keller

Cautious, productive blasting is employed in the adaptation of a mobile crushing system extending into a highway through cut. In Hong Kong's final chapter of infrastructure development in preparation for handover of sovereignty, the vital link to the new governing country, The People's Republic of China, is now being completed. The Ting Kau approach and Tai Lam tunnel involves the removal of 6 million cubic meters of rock by drill and blast means. For the main-cut excavation (because of removal Iogistics) a unique adaptation of a Lokotrack crushing and conveyor transfer system is being used. The characteristic narrow working area associated with through cuts, positioning of equipment, and production demand place many limiting factors on blasting. Add to this the strict criteria set by the local regulatory body, the Hong Kong Mines Division, and nearby vibration limiting structures (13mm/sec), has led to highly cautious, fine-tuned blasting.

Jan 1, 1998

By Tyler Acorn, Paul Worsey, Nathan Rouse

The effect of the hole diameter on vibration attenuation has not been incorporated in most vibration models in the blasting industry. In current vibration models, the charge weight and the distance from the blast are the two primary variables that are addressed. Charge weight is a function of explosive density, charge length, and charge diameter. This geometry-weight can complicate the isolation of the charge diameter variable.

Jan 1, 2013

By Dale Preece, Joergen Pilz, Zavis Zavodni

An overland conveyor was constructed at a surface coal mine to reduce the truck haul distance and make the operation more efficient. An important element in this system is a truck dump facility to transfer coal from truck to conveyor. Mechanically stabilized earth retaining walls were employed to accommodate the coal processing equipment, including the crusher, in this facility. These retaining walls are close enough to the pits being mined that blasting induced vibrations must be considered in analyses of the wall structural stability.

Jan 1, 2010

By Keith Best

It has been said that when a person does something right no one remembers but when they do something wrong no one forgets. This statement, when applied to the explosives industry, has never been truer. Think about it.How many times have you seen a news crew reporting on how well a blaster is doing his/her job? Normally, all you will see is how bad things are going and how much “damage” is being done.

Jan 1, 2008