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By Tristan Worsey, Nathan Rouse, Daykin Schnell

The authors were retained by a proposed underground metals mine operation to evaluate the potential blast vibration amplitudes that could be generated at surface structures above the proposed mine. Literature reviews of published blasting documentation gave little information, data, or models on surface blast vibrations produced by underground mines. At the client’s request, the authors contacted a number of underground mining operations to evaluate interest in sharing blast vibration data with the authors so that the authors could develop an underground-to-surface blast vibration regression equation.

Feb 1, 2020

By Matthew Clay, Colin Chambers, Susan Hookham

Opencast (quarries) and underground mines around the world use blasting methods to mine valuable ore. Traditional blasting systems use technologies such as electric delay detonator systems (developed in the 1950s) and non-electric detonator systems (developed in the 1970s) to initiate a detonation train to blast rock more effectively, and so retrieve valuable product more efficiently. However, the lack of precise control over blast timings with these approaches can result in undesirable outcomes such as significant flyrock, excessive ground vibration, uneven grade of rock and misfires (in which sections of the blast can remain unfired). The development of Electronic Initiation Systems (EIS), first used in the 1990s, introduced a higher level of control over the blast. These systems greatly reduce the negative issues associated with blasting. However, this precision introduces complexity, and with this complexity comes difficulty in demonstrating the predictability, safety and reliability of such systems.

Jan 1, 2017

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 Santiago Gómez, Pablo Segarra, José A. Sanchidrián

In this paper, differences between the industry-standard Holmberg-Persson (H-P) approach and a semi-analytical vibration prediction model called full-field solution (FFS) are analized. The analysis is conducted at two levels: vibrations and rock damage.

Feb 1, 2020

By VIVEK KUMAR HIMANSHU, Murari Prasad Roy, Kaushik Dey, Rakesh Kumar Singh, Ashish Kumar Vishwakarma

Sublevel stoping is commonly adopted method in underground hard rock mining. Proper planning and its execution is the key requirement for stope extraction using this method. The stope extraction has been a challenging task since decades. The major reason being the unavailability of free faces as compared to open cast bench blasting. The geological and geotechnical parameters changes gradually even within the stope itself. So the blast design parameters should be planned according to the scenario of upcoming ring. Blast design parameters like burden, toe spacing, inclination of blast holes, diameter of blast holes, charge density of explosive etc plays an immense role in rock damage. For the proper breakage of rock, the movement of burden is prime objective. To study this, explicit dynamic based modeller of M/s Ansys was used. The burden values were varied from 20-65 times diameter to assess optimum burden value during the study. The models were simulated for the rock having 35 MPa uniaxial compressive strength and 102 mm blast hole diameter. Altogether three holes were blasted having hole depth 14-14.5m. The blast design parameters and respective blast induced ground vibration has been measured at the experimental site. Core sample of the rock of experimental site has been used for the evaluation of geotechnical parameters. These geotechnical parameters were inserted into the simulation model. The volume of rock excavated along free face has been calculated in each model. It has been found that the burden value can varies from 35-40 times blast hole diameter (3.6-4.1m) to achieve greater volume of rock along the free face for 102 mm blast hole diameter and rock of 35 MPa uniaxial compressive strength.

Feb 6, 2023

By William Gates, Gabe McClain, Thomas Pallua, Joe Schrank

The Tennessee Capitol Corridor connects the Cordell Hull Building (CHB) to the State Capitol, which isa 232-foot-by-124-foot (71 x 38 m) structure in Nashville that includes porticoes built from local massive limestone. This connection was affected by the Capitol Connector Pedestrian Tunnel (CCPT) project, which is part of the overall Cordell Hull State Office Building and Central Services Demolition, New Construction and Renovation Project (Cordell Hull Renovation Project). To construct this connection, the two existing elevator shafts and a new emergency stairwell in the State Capitol were extended down to anew lobby area—the elevators by about 50 feet (15.2 m) and the stairwell by about 60 feet (18.3 m). This lobby was connected to the CHB by a 435-foot-long (133 m) pedestrian tunnel. It was predicted that most of the tunnel would be excavated in a relatively strong limestone; therefore, considering the project features and constraints, drill-and-blast techniques were selected as the primary excavation method. Because of restrictions on blasting in urban areas and, more importantly, the proximity of this construction to national historic landmarks, blasting operations were extensively monitored to measure and correlate ground vibrations as peak particle velocity (PPV), frequency, and strain—these being the major factors that would impact the surrounding buildings. As a result, copious amounts of data were gathered and interpreted within a short time to estimate blasting parameters and optimize the subsequent blast rounds. To calculate the ground response factor, the scaled distance of each shot was compared to the ground vibration as PPV, generating a subsequent regression curve with an R2value of about 0.7. Using the best fit curve equation, the estimated ground response factor was about 150 for the best fit line. Other than some cases with relatively high (> 2 in./sec [51 mm/sec]) recorded PPV values, the blasting operation was successfully conducted as planned and the observed strain on the monitored buildings was very low, mainly within ±2 με (0.0002% elongation). (In general, the recorded PPV was lower than 2 in./sec at frequencies of more than 50 Hz.). The strain gauges at key locations (cold joints and old fractures) in the Capitol and on other critical structures demonstrated strain was insignificant in relationship to ground vibrations from the blasting operations. The apparently small vibration-induced strains were related to the massive limestone construction of the Capitol and ancillary buildings, as the induced strain plus the existing strain did not exceed the critical strain of the massive structures.

By Cristian Rodriquez, Fernando Fernandez, Rodrigo Fuentealba, Tom BoBo, Maria Rocha, John Kemeny

This paper describes a case study that was conducted at a new mine in South America. This mine has significant geologic variations that will result in different distributions of hard and soft ore being mined at different periods of time over the mine life. A study was conducted to determine the optimum blast design that will meet the mill throughput requirement of 95,000 tonnes (104,720 tons) per day for the first 10 years of the mine life. As part of this study, field rock mass characterization and laboratory tests were conducted. This includes standard rock mechanics tests as well as rock breakage tests used in mill simulations. The geology of the ore body was broken up into four Geologic Units, and statistical variations in the properties were determined for each unit. Using this data along with the data on the occurrence of the different geologic units over time, simulations were made of the run-of-mine (ROM) fragmentation due to different blast designs, and these results were used in simulating the resulting throughput after crushing and grinding. Four blast designs were considered with powder factors of 0.44, 0.54, 0.64 and 0.94 kg/t. The results of this study show that determining the proper blast design is important in ensuring that the mill throughput requirement will be met over the mine life.

Jan 1, 2015

By P McConnell, T Garrigan

Tara Mines Limited, in Ireland, is Western Europe's largest zinc mine. Annual metal production, from 2.5 million tonnes of ore, consists of 180,000 tonnes of zinc and 34,000 tonnes of lead.

Jan 1, 1989

By M. Ganster

Austria’s biggest supplier of oil and gas, transports gas through the West Austria Gasline for domestic consumption. In addition, the OMV also works as gas carrier and ensures the transit into neighbouring countries.

Jan 1, 2010

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 María Rocha, Benjamín Cebrián, Roberto Laredo

"Ring blasting designs have to achieve different goals in order to become efficient whether is done in up hole or downhole fashion. Ore recovery/dilution control, fragmentation and drift integrity all have to be taken into account when selecting parameters such as burden, spacing, linear explosive density and stemming. Blast energy simulation allows identifying contours of rock breakage and fragmentation, thuschoosing a combination of spacing at the end of holes and appropriate burden. Also, simulations are keyto concentrate energy levels on the mid part of the ring while making sure there is not too high of energy concentration around the drift, which integrity is needed for a safe ore mucking."

Jan 1, 2017

By S. Geerts, J Davidson

The purpose of the experiment was to determine detonation characteristics of various improvised explosives. The test consisted of detonating a pipe filled with an explosive compound inside of a plywood arena. The pipe will be located in the center of the arena to ensure even distribution on the witness panels. Details on pipe dimensions, weights of the pipe and explosive, and the density were recorded prior to testing for use in the model calculations. The same size pipes were used throughout to minimize the variables inherent in testing. The plywood witness panels will capture the fragments so that penetration data was obtained, primarily the surface area of impact and depth of penetration. Through the use of the penetration data in conjunction with a mathematical model the original fragment velocity was determined. The mathematical model was developed to measure lethality of fragments from explosives and was modified to determine the original fragment velocity instead. From this model other variables such as the Gurney velocity were calculated. This test was done with an explosive compound that was commonly found, and numerous improvised compounds. In order to guarantee accurate data all of the explosives used for testing were cap sensitive, to eliminate the need for a booster charge which would introduce many unknown variables. The one common explosive compound that was used was C-4 which has known data in order to show accuracy of the model and calculations. The other 5 compounds chosen will not have this data as they will primarily be improvised mixtures.

Jan 1, 2011

By John Atkinson, Steve Repola

This paper will describe two blasting plans that have been developed for American Aggregates' Marble Cliff Quarry located near Columbus, Ohio. Two different limestone formations are mined on different levels of the quarry. Each formation requires a different blasting plan which address vibration considerations, crusher productivity, drilling and blasting costs and adjacent neighborhood concerns. Controlled blasting is critical to continued mining operations in this Midwest urban setting.

Jan 1, 1993

By Gabe McClain, Thomas Pallua, Joe Schrank, William C. Gates

Because of restrictions on blasting in urban areas and, more importantly, the proximity of this construction to national historic landmarks, blasting operations were extensively monitored to measure and correlate ground vibrations as peak particle velocity (PPV), frequency, and strain—these being the major factors that would impact the surrounding buildings. As a result, copious amounts of data were gathered and interpreted within a short time to estimate blasting parameters and optimize the subsequent blast rounds

Feb 1, 2020

By Abraham Lindo

Taboguilla is a small island located 10 miles outside the Panama Canal Pacific Entrance. In 2002 a fuel distribution facility was installed in order to supply fuel to vessels passing thru the canal. The current capacity of the tank farm is equivalent to 1,100,000 barrels. The demand for marine diesel at this location still exceeds the current capacity, thus an expansion project is currently underway to increase the available space for diesel tanks. There is a total of 800,000 cubic meters to be excavated in order to create the new space. 400,000 cubic meters of that total is basalt rock which will need to be blasted

Jan 1, 2011

By Barbara Rutter, Shonn Kevin McNeil

"This study discusses how a prototype was built to measure the sonic velocity in powdered explosives.The sonic velocity of an explosive is a benchmark to determine if the explosive deflagrates or detonates;however, little work has been done to determine this value for powdered explosives. This paperdiscusses the results of the initial prototyping tests where two known mediums, air and water, were used for validation. The prototype did record the sonic velocity within the known velocity ranges of air and water; however, a few depths did not fall into this range. This prototype could be used for testinggranular materials."

Jan 1, 2017

By Vitor Barcelos, Eduardo Elói, Gabriella Vaz, Davi Oliveira, Leandro Silveira

Following a routine production blast at Vale S.A.'s Itabira Mine in the Quadrilátero Ferrífero region of Minas Gerais, Brazil, nearby residents registered complaints about blast-induced vibrations. Analysis of the blast footage revealed that multiple blastholes were detonated simultaneously, resulting in a higher-than-expected charge per delay, ground vibration and cratering even though the electronic delay timing was configured correctly. Subsequent blasts within the mine's soft schist region confirmed the occurrence of sympathetic detonation. Mitigating or eliminating this phenomenon is critical for the mine's operation. Two dynamic pressure tests were conducted using carbon resistors together with typical VOD monitor maintaining the standard booster, electronic detonator, and a blend of 70% emulsion with 30% ammonium nitrate explosive. The tests involved increasing the distance between the central hole (detonated first) and the four surrounding holes in a five-hole sequence. Unfortunately, sympathetic detonation occurred in all these tests. To address this issue, a new explosive with a lower density and detonation velocity was tested. This approach proved promising, as no sympathetic detonation occurred. By leveraging the data obtained from this study, engineers can now identify situations at risk of sympathetic detonation and implement preventive measures, such as selecting the appropriate explosive and recommending safe minimum burden and spacing settings as well as confinement level for each blast while maintaining the desired level of rock fragmentation.

Jan 21, 2025

By Gregory Hempen, Thomas Keevin, Russell Wilcox, William Wild

The Department of Defense Strategic Environmental Research & Development Program (SERDP) awarded funding for evaluation of procedures to mitigate peak pressures and energy flux density in the water column from ordnance being detonated on the ocean floor. The research purpose was to conduct scaled testing to resolve whether a theoretically-viable covering technology was operationally effective in reducing blast effects and the impacts of shrapnel. An additional objective was testing effectiveness of this method for hard-bottom units (rock or coral) and (unconsolidated) sediment substrate.

Jan 1, 2011

By Darío Innamorati, Jorge Oliva

Cerro Vanguardia is a known gold and silver deposit located in the province of Santa Cruz, Argentina. The mine has been in operation since 1998 and is thought to be one of the most important mines in Patagonia. More than 102 epithermal quartz veins have been identified in the area, with variable lengths, thicknesses, orientations and dips that constitute what is possibly one of the most extensive outcropping vein systems on earth. Veins are vertical and have variable depth. For this reason, the deposit is currently mined with a variety of extraction methods. This operation is made up of more than 60 open pits and 20 underground access ramps to exploit the deepest high grade narrow veins. This study is focused on the combination of underground exploitation with open pit blasting. That is, those production stopes in the upper levels of underground mines and their interaction with the damage levels in the final slope of open pit mines, as well as in the study of the impact of the generation of vibrations from the blasting of open pit mines and their influence on underground mines. Considering the current stage of the mine, after 20 years of operation, Cerro Vanguardia faces the need to mine deeper deposits in the face of increasing costs and declining grades. For this reason, it is essential to study the interaction of these exploitations. From a personnel safety point of view, this interaction must be well coordinated so as not to affect people and equipment. Likewise, the generation of vibrations due to blasting must be studied, which would produce new cracks, potentially generating overbreak and dilution. The main objective of this study is to determine the possible causes and influences of the blasting interaction in open pit and underground mines, seeking an optimization of the blasting process and a safety standard for personnel and equipment. To achieve these goals, this study includes a vibration monitoring plan to analyze the charge performance and determine rock constants. With the use of specialized software, damage modelling and simulations are used to determine values of damage in order to reduce overbreak. In addition, this plan contemplates the estimation of flyrock in blasting where underground work is connected to the surface, determining safety distances when carrying out a blast.

Jan 21, 2025

By Ali Kahriman, Olivio Angelini, Ibrahim Sefer, Burak Ekmen, Koray Arpak, Ertugrul Kaya, Yucel Karakus, Abdullah Sak, Aziz Ozdemir

In recent years, in order to bring solution to traffic intensity arising from transportation problems and facilitate public transportation in the modern world in paralel to urbanization and to the increase in population, it’s well known that, the construction of Access tunnels is inevitable. The driving of the tunnels is a subject of special interest in the technique of rock blasting. The essential factors in terms of tunnel driving and safety in tunnel blasting that is applied in metropolitan areas, an in depth knowledge of ground vibrations and the ways of reducing them to safer levels.

Jan 1, 2010