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By James H. Owen

Because of price structure, ANFO is normally considered to be the most cost effective explosive used in quarry blasting. Results indicate that bulk smulsion can be more cost effective in applications where hole sizes range up to 6.5 inches in diameter while providing the simplicity of single product loading and storage. This can be accomplished without any fragmentation and/or movement loss usually in patterns which are about twice the size of ANFO patterns, allowing the combined drilling and blasting cost to be less when using bulk emulsions. Examples are presented supporting this concept using actual field results along with some simple calculations which take into account differences in the products such as density, matrix and detonation velocity.

Jan 1, 1998

By Wilfrid Comeau

While researching for a theme lecture (Comeau, 1993l) on: 'The Mechanics and Physics Explosives', the author of Energy Transfer in Rock Fragmentaion by was confronted with many conflicting concepts regarding: the current explosive rock fragmentation theories, the physical principles governing energy transfers, the mechanical properties of rocks, and observations and data from full scale rock blasting.

Jan 1, 1995

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan, Umit Ozer, Kagan Ozdemir

In the condition that drilling and blasting technique is inevitable depending on the rock mass and material characteristics on mining activities, the fragmentation rate and particle size distribution of the muckpile after blasting has important influences on the performance of subsequent mining activities such as loading, hauling, crushing, grinding etc. and the total costs of that mine. Drilling and blasting is an important step in this process chain and it's results such as fragmentation, muckpile shape and looseness, dilution, damage and rock softening effect the efficiency of downstream processes. There is an increasing body of blasting research indicating significant impacts in these downstream processes.

Jan 1, 2007

By Choon Sunwoo, Chang-Ha Ryu

There are various methods available for the recovery of dimensional stone in open pit quarries. Explosive blasting has more advantages in the economic point of view over the other methods but was not widely used in Korea because owner was concerned about much economic loss when it failed. Several years of efforts have been made in order to develop more effective cutting methods and to spread to the quarries for strengthening the competitiveness in the market. Rock cutting by jet flame and black powder was generally used in the early stage. Black powder was applied to cut the last horizontal plane after forming other vertical planes using the jet flame. Jet flame operation, however, is time consuming and produces excessive noise, and as the result, brings adverse effects on the operator as well as the complaints from the residence adjacent to the quarry. Some mechanical methods such as the slot drill, diamond wire saw or in-situ scale of diamond saw cutting were introduced. Most effective cutting methods using the explosive blasting were developed and applied successfully. Black powder was replaced with the detonating cord. A new air decking technique where plug was not used was developed. This paper reviews the technology for dimensional stone cutting and case study in Korea.

Jan 1, 2003

Drilling through unconsolidated material I need to drill blastholes through a mix of consolidated and unconsolidated material. This material is hung up in an underground ore pass. The total length of the holes would be approximately 200 feet. We have attempted to drill through the material with conventional ITH drilling, but were unsuccessful. Does anyone have a suggestion? I am more than willing to bring in a contractor to do the job, if they have solid experience with this type of problem.

Jan 1, 2011

By Yoshiharu Tanaka, Toshiyuki Ichijo, Masaaki Yamamoto

We utilized electronic detonators (EDs) to investigate the effect of high detonator delay accuracy on overbreak, remaining rock damage, and surface smoothness, in comparison with that of long-period delay detonators (0.25 sec interval) PDs. The experiments were conducted in a deep mine, in a test site region composed of very hard granodiorite with a seismic wave velocity of about 6.0 km/see and a uniaxial compressive strength, uniaxial tensile strength, and Young's modulus of 300 MPa, 12 MPa, and 73 GPa, respectively. The blasting design was for a test tunnel excavation 8 m in cross section, with an advance per round of 2.5 m. Five rounds were performed, each with a large-hole cut and perimeter holes in a 0.4-m spacing charged with 20-mm-diameter water gel explosive to obtain low charge concentration. EDs were used in the holes on the perimeter of the right half, and PDs were used in all other holes.

Jan 1, 1995

By Mike Lovitt

New Gold Inc. had commissioned Orica to assist with the design of the drawbell blasting at New Afton Underground copper/gold block cave at Kamloops, British Columbia, Canada. Orica have had much success in developing the single-shot drawbell method at Freeport Indonesia in 2001 in the Deep Ore Zone and they will be using it exclusively in their new Grasberg Underground Operation. RioTinto Northparkes have also used the single shot drawbell blasting in their Second Lift E26 Project and even in the E48 orebody which is a post undercut block cave, realising the safety and operational benefits of this blasting method.

Jan 1, 2013

By Charles E. Joachim, Christo V. Lunderman, Charles R. Wdch

The U.S. Army Engineer Waterways Experiment Station (WES) recently conducted a series of precision-scale water shock experiments which consisted of the detonation of several 8-gram, 10-gram, and 12-gram spherical explosive charges. The charges were fabricated from NAX 2000 Primasheet explosive and were center-detonated. Commercial tourmaline crystal water shock sensors were used to measure the induced pressure fields in the water. The measured water shock waveforms and related parameters from the precision-scale experiments were in general agreement with data from larger-scale experiments.

Jan 1, 1998

By Tom Watts

Bulk Security Best Practices

Jan 1, 2006

By Ken Roosa

Blue Circle Atlantic of Ravena, New York, operates a four million ton per year quarry. The quarry management objective is to maximize crusher throughput tonnage while optimizing the aggregate cost to drill, blast, dig, haul, and crush a ton of rock. To meet this objective, Blue Circle,s blasting program combines, large diameter production blastholes with medium diameter satellite blastholes.

Jan 1, 1989

By Split Engineering Chile Fernando Fernandez

Mathematical modeling in conjunction with mineral characterization is widely used as a method for design and optimization of comminution circuits, to simulate the processes of crushing, grinding and classification. An important input parameter to the simulation models is the Run-of-Mine Particle Size Distribution (ROM PSD). The run-of-mine size distributions due to blasting have a great influence on the performance of a semi-autogenous grinding (SAG) mill. In this paper, a mine case study was conducted where there are four primary geologic units and the material properties between the four units vary considerably. Also, the mixture of the four unit that will be mined at any given time also vary considerably. This presents a challenge in terms of optimizing the blasting for mill production throughout the mine life. As part of the case study, field rock mass characterization, laboratory rock mechanics tests, and laboratory breakage tests were conducted. The field characterization and rock mechanics tests provide material properties used to simulate the effect of different blast designs on run of mine particle size distributions (ROM PSD). The JKSimBlast software was used for these simulations. The rock breakage tests provide material properties used to simulate crushing and grinding performance. The JKSimMet software was used for these simulations.

Jan 1, 2015

By Thierry Bernard

This case study shows how a unique combination of field measurements and advanced technologies allowed blasters designing, loading and firing an incredibly challenging quarry blast.

Jan 1, 2015

By Cameron McKenzie

Flyrock is a complex issue involving interaction between the charging crew, the blast design, and the local geology, and once conditions on the shot meet certain criteria, the probability of a flyrock incident becomes unacceptably high. It is essential that flyrock awareness be built into the blast design process, requiring an engineering approach to understanding and controlling the outcomes and managing the associated risks. Based on previous studies of flyrock and published literature relating to fragment motion at high velocity in air, the equations to predict maximum flyrock range, and the size of particle achieving the maximum range, for blasts of varying rock density, hole diameter, explosive density, and state of confinement have been developed. These equations, and other associated correlations, permit the flyrock footprints to be established for any charge configuration, in any size blasthole, in rock of any density, and with particles of any known shape factor. The equations developed, and the mechanisms they reflect, allow engineers to go a long way towards understanding the primary factors controlling flyrock generation, including the rock mass, the blast design, and the quality of blast design implementation, i.e. the human factor. The paper presents guidelines as regards use of the equations to establish personnel clearance distances as a function of charge design and implementation, and equations to estimate appropriate stemming lengths when blasting must be conducted close to occupied or sensitive structures. The equations are amenable to definition of, and quantification of Flyrock Risk.

Jan 1, 2009

By John Babcock, Bryan C. Smith

In a partnership between Luck Stone Corporation and Loudoun Water, a 42” (1.067m) steel pipeline was constructed along the perimeter of an extensive permitted reserve of diabase rock Luck Stone was about to begin mining. Loudoun Water provides drinking water and wastewater services to over 75,000 households in Loudoun County, Virginia. In discussions to establish the 30-foot (9.1 meter) easement for Loudoun Water within the permitted reserve of diabase rock, Luck Stone and Loudoun Water agreed on the following basic conditions: • Luck Stone could execute production blasting as close to the easement as physical conditions of overburden depth permits. We estimated the minimum distance to be about 75-feet (22.86 meters) from the centerline of the pipe. • Loudoun Water would install strain gauges on the pipe every 500-feet (152.4 m) along the entire length of the future reserve area. This resulted in the installation of 18 strain gauges. • Luck Stone would contract a third-party vibration monitoring company, agreed to by Loudoun Water, to monitor the strain gauges and provide seismograph reading at appropriate locations along the pipe as mining progresses. All information would be provided to Loudoun Water. • Luck Stone’s blasting will be conducted in a manner that ensures the recommended strains are not exceeded.

Jan 1, 2019

By C. Braun, C. Kennedy, P. Katsabanis

A series of small scale tests, simulating multi-hole blasts have been performed to establish the effect of delays on blast fragmentation. The blasts were performed in high quality granodiorite blocks, which were cut from stone prepared by dimensional stone quarry operations. The pattern used was equilateral triangular, with a distance of 10.2cm between boreholes, which had a diameter of 11mm, were loaded with detonating cord and the coupling medium was water. The delays used were achieved using different lengths of detonating cord for the cases of delays between 0 and 100 microseconds between holes and a sequential blasting machine firing seismic detonators for larger delays up to 4ms. All fragments were collected and screened. The experiments showed that the coarsest fragmentation was achieved with simultaneous initiation of all charges. Fragmentation became finer with delay time between holes up to 1ms between holes. The results show that in moderate to competent rock, similar to the granodiorite of the experiments, fragmentation optimization requires delays of few milliseconds per meter of burden. In view of the findings, which agree with previous published work, the current trend of selecting fast firing times for fragmentation optimization is questioned.

Jan 1, 2006

By Joshua Taylor Drake

This report answers specific questions concerning underwater blasting considerations, and blasting safety. The blasting considerations discussed consist of basic blasting principles, and new variables to be accounted for. Blasting safety will include the safety of personnel and structures. The environmental considerations will also be discussed with mitigation methods. To be most effective, this document requires the reader to be familiar with key fundamentals of explosive engineering. In order for a blasting professional to benefit from this report, the following questions will be asked:

Jan 1, 2015

By Jackson R. Pressley, M L. Hopkins, R E. Danell, N T. Moxon, Andrew Bowman

Efficient and cost effective blasting is achieved by closely matching the explosive energy to the strength of the material in which it is being used. Although there are many empirical relationships wich approximate this situation complete the blast optimization can only be achieved by quantitatively assessing explosive/rock interactions and explosive performance. The performance of an explosive is essentially governed by its velocity of detonation or the rate at which the detonation wave travels through the explosive column.

Jan 1, 1991

By Jackson R. Pressley, Bruce Vandenberg

An explosive’s velocity of detonation, (VOD), can be used to indicate a number of important characteristics regarding the product’s performance, under specific field and test conditions.

Jan 1, 1997

By Saeed Karimifard, Saman Nouranian, Shahram Tafazoli, Bahram Sameti, Frank Chu, Caitlin McKinnon, Tetiana Konstantynivska, Glen Turner

Continuing blast optimization is the cornerstone of any mine-to-mill approach, and particle size analysis is a key metric for meeting blast targets to reduce overall energy consumption and operating costs. To ensure the statistical validity of particle size data, it is important to sample material frequently. In most mines and quarries, the blasted material is loaded onto haul trucks and then transferred to the crusher; measuring the particle size of each haul truck load therefore provides an adequate sampling rate. We propose a particle size analysis solution for haul trucks that does not impact current operational workflows. Using artificial intelligence (AI) and 3D imaging technology, our solution reliably localizes and identifies haul trucks as they drive by, then accurately calculates the particle size distribution of the visible material in each truck load. In this paper, we identify the challenges of designing and implementing the proposed solution and explain the strategies we employ to overcome these. We also discuss a method for boulder detection that leverages the existing deep learning architecture to significantly reduce crusher downtime caused by oversized rocks. Finally, we present field data from a trial installation. To evaluate each change made to the blast design, it is necessary to measure the effect on particle size. An accurate particle size analysis solution is therefore the first step towards optimizing blasting practices and reducing energy consumption throughout the comminution circuit.

By Greg Shapiro, Paul Dr. Worsey

Mining, quarry, and construction blasts are becoming more and more dependent on bench profiling. The use of accurate profiling gives the blaster better data for the most efficient blast results. So, we ask the question: What is the best method for measuring and analyzing burden?

Jan 1, 2019