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By Anthony Konya, Calvin J. Konya

The publication, RI8507, from the U.S. Bureau of Mines established an envelope equation that related scaled-distance to peak particle velocity in an attempt to predict ground vibration in the design phase of a blast. This has been further modified by Oriard, Dupont, Konya & Konya, and others to develop more refined prediction models for specific situations to obtain better predictions. While these equations can be an ideal starting point for a greenfield blasting project or a project with no given information, these equations can have errors.

Jan 1, 2018

By C. Breeds, K. Jeremiah, E. Jennings

Washington State has a well developed set of blasting regulations which have been promulgated by the Department of Labor using extensive stakeholder input, not only from citizens but also from manufacturers and representatives of IME, blasters in charge, blasting engineers, blasting companies, local and federal law enforcement agencies, fire officials, and local and state government representatives. WAC 296-52 therefore provides a foundation or platform for developing city ordinances for Washington State cities should a City wish to do so. On the other hand, Oregon’s code is based on OSHA 1926, Subdivision U, Blasting and the Use of Explosives which provides scant direction regarding the modern use of explosives. Reference is also made to ODOT Section 00335 - Blasting Methods and Protection of Excavation Backslopes. This paper examines two separate programs that have been developed by two Cities, one in Washington State and one in Oregon to further regulate blasting inside City limits and discusses why the lack of a regulatory foundation made one approach more difficult than the other. One of the authors was retained by the City of Kennewick, WA to develop their ordinance and has more recently followed and reacted to a pending ordinance for the City of Redmond, Oregon. The paper will compare and contrast the different approaches and comment on the reaction from both Blasters and the public. We also present a case study that involved blasting in an urban area of Oregon to prepare a foundation for a water tank. Controlled Blasting was carried out within 70-ft of residencies and within a community that had expressed reservations regarding blasting even though the work would make a significant contribution to the betterment of the community. Pre-construction surveys of residencies located in a large area surrounding the site were performed and a well-planned blasting program was carried out. Residencies were subject to vibration levels that were monitored using six seismographs that surrounded the site and these units measured vibration levels that were significantly lower than allowed by statute. There were complaints triggered by individuals reactions to blast vibrations which validated commonly held models of human perception but no damage was caused by the Blasting.

Jan 1, 2024

By Robert Hopler

GEO. M. MOWBRAY’S REFRIGERATOR CAR FOR THE SAFE CONVEYANCE OF EXPLOSIVES. It is a fact well known to all miners who have used nitro-glycerin, or any of its adulterations, commonly known as dynamite, rendrock, Hercules’ powder, dualin, vigorite, etc., that when congealed, these compounds cannot be exploded, and in this congealed state — say at temperatures below 40° F. — they can be handled with no more danger than a box of soap or a can of lard. If, then, the atmosphere by which this class of explosives is surrounded, during transportation, be maintained below 40° F., explosion is practically annihilated. Therefore, I constructed a refrigerator car, with cells for every box of the explosive; and two years of railroad transportation confirms our ten years’ experience in teaming in wagons, that this class of explosives can be transported in perfect safety, as above described.

Jan 1, 2011

By David Porter, Nathan Rouse

The implementation of presplit blasting has been widely utilized in open pit and underground tunneling. This case study works through the iterative process of developing a heading drill and blast design to control overbreak and limit backbreak in cut and fill headings. The initial design was based on rule of thumb parameters, and the design was then modified for the field conditions based on results. Throughout the design process the drill profile, explosive charge, and timing were modified to yield the best profile compared to design. Data collection during the design process was extensive to best understand the effect of modifying parameters, and gauge performance of design changes. Input from the miners as well as engineers was considered to allow for the best possible adaptation of the design change from existing practices. During the process resistance to change was realized and accounted for to understand the issues that the miners were facing and how to best address them while ensuring high quality blasting. Workforce buy- in was addressed by illustrating the long term benefits of higher quality blasting and the tradeoff of with a slightly more in depth drill and loading cycle.

Feb 6, 2023

By Ran Tamir

"This document introduces the use of drone generated aerial photography to collect and analyze fragmentation data for both muck piles and post crusher stockpiles in order to support the continuousimprovement process. In tandem with photo analyses software, drone imaging gives mines and aggregate sites a fast, accurate and economical method of benchmarking and optimizing the process of size reduction to spec."

Jan 1, 2017

By Scott Stephenson

Making a tunnel through solid rock can sometimes be a dangerous task. Many things must be considered in order to complete such a task safely, and efficiently. Prior to starting things must be known such as, the type of rock, the purpose for the tunnel, the destination point, then angle of decent (or ascent). Once these things are known, the method to proceed must be considered. Factors such as cost, feasibility, and time to completion must be taken into account.

Jan 1, 2009

By Tie-jun Tao, Ming-sheng Zhao, En-an Chi

"Karst landform is a special kind of geomorphic unit which is often accompanied by a large number of geological defects: caves. In blasting engineering, if there are karst caves around the blast-holes, it may result in higher boulder yield and the generation of flying rocks due to the change of burden which is very hazardous for the safety of surroundings. The models of rocks with karst caves from blasting holewere built by the software of ANSYS/LS-DYNA. The results of computation simulation show that thecave can increase more free surface for blasting and leads to a broken zone around itself. Thus rockmass around the cave will fly toward inside and it will result in undesirable result of whole rock mass to be blasted. In addition, the models of rocks with karst caves in different shapes were simulated and thecomputation results show that the caves in round shape have higher load resistance capability than that the caves in rectangle shape. All the simulation results can offer effective guidance for blasting design. The models of rocks with karst caves were built in different distances and shapes from blasting hole by the software of ANSYS/LS-DYNA. The effect of different karst caves on blasting stress and blastingresult were studied."

Jan 1, 2017

By Bilegt Batbold, Bayu Saputra, Chris Batten

The ability to fire multiple blasts simultaneously can provide significant benefits to any open pit mining operation. Reduced blast-related downtime by reducing blast events can increase equipment utilization and maximize material movement. Significant sequencing benefits can also be delivered, associated with reduced equipment relocation. This paper describes the work completed in partnership between Orica and Oyu Tolgoi to successfully demonstrate that combined production-trim and midsplit blasting could be implemented successfully while successfully managing the risk of increased damage to the final walls. The paper details the methodology used to assess key performance measures linked to final wall damage and compares the performance between the following blasting methods. • Free face trim blasting vs. combined production-trim blasting • Presplit blasting vs. midsplit blasting. The results of the initial trial blasts are presented, along with the method agreed by the key site stakeholders for ongoing application. The method used to keep the risk of final wall damage to an acceptable level is explained, along with the benefits delivered to Oyu Tolgoi operations associated with the initial 12 months of application.

Jan 21, 2025

By Randall M. Wheeler

Pre-blast surveys are used to document the condition of a structure prior to the commencement of blasting activities. They provide the best means of determining the pre-existence of visible cracking and deterioration in a structure before blasting is initiated. A small investment in a good pre-blast survey, coupled with good public relations, could mean a large cost savings for a company in the future.

Jan 1, 1992

By John Vynne, John Hutchings

There have been a number of recent technological advances in instrumentation for blasthole drills, and more specifically in drill monitoring and HPGPS guidance systems. Likewise, great strides have been made in the development of drill and blast software systems which are user friendly, while providing far greater capability to accurately design and monitor drill and blast patterns.

Jan 1, 2011

By Orica Peru, Pedro Lozada

Maintaining a continuous mining process during thunderstorms is one of the primary challenges in Peru's open-pit mines. Safety protocols necessitate the establishment of exclusion zones to minimize the risks of unplanned detonations. During such conditions, loading and hauling equipment must be relocated or, in the worst case, halted, directly affecting productivity (t/h). Implementing a wireless initiation system mitigates the risk of unplanned detonations during electrical storms by eliminating the use of electrical cables that are susceptible to electrical discharge. This study documents the implementation of this system in a copper mine located over 3,500 meters above sea level in Peru, where electrical storms between December and March necessitate modifications to blasting schedules and limit the number of drills fired per event. Through a test using wireless detonators, a key performance indicator (KPI) was established to ensure safe and continuous operation during thunderstorms. The results were significant: 20 blasts were successfully executed, firing approximately 5,000 holes and moving around 10 million tons of material, all without safety incidents or critical operational deviations, achieving zero misfires and no scheduled blast suspensions. Shovels SH001 (ore) and SH002 (waste) continued to operate together for an additional 100 hours continuously during thunderstorms, generating a potential saving of USD 3.3 million by continuously sending ore to the plant during the testing period under stormy conditions. Additionally, the blasting initiation time was reduced by 25%, eliminating two activities that involved the use of surface connection cables. This reduction led to over 150 hours of decreased personnel exposure to interactions with vehicles and environmental hazards such as dust and noise. Furthermore, the number of holes fired in a single event increased by 50%, enhancing the blast tonnage capacity and reducing equipment stops due to evacuation and reentry from two to one.

Jan 21, 2025

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 Hairong Zeng, Shahram Tafazoli, Edmond Chow

Blast fragmentation is one of the main parameters for optimizing mineral processing, but reliable data is difficult to acquire, resulting in unpredictable performance and efficiency. Crusher and grinder circuits are designed to process specific rock size ranges. Oversized rocks require extra energy to reduce before feeding into the process, and undersized rocks indicate that the process is not used to its full extent. Blast design is the key to controlling the blast fragmentation, so the ability to accurately monitor the particle sizes is imperative.

Jan 1, 2011

By Nikolaos Petropoulos, Ulf Nyberg, Ulf Stenman, Daniel Johansson, Håkan Schunnesson

The optimization of the explosive performance is of great importance since blasting is extensively used in civil projects and mining industry. An improved understanding of how the energy from the detonation of an explosive is transmitted to the surrounding rock mass is critical information for the proper selection of an explosive. Therefore, an extensive study was done on the influence of the blasthole diameter on the Velocity of Detonation (VoD) and the detonation front curvature.

Feb 1, 2020

By Armin Iravani, Changping Yi, Matthias Wimmer, Daniel Johansson, Santiago Gómez, Håkan Schunnesson

Sublevel caving (SLC) is a mass mining method based upon the utilization of gravity flow of blasted ore and caved waste rock. Drilling and blasting are the initial and the major impact on primary fragmentation and later material flow characteristics. The heterogeneity of rock mass has a great impact on materials’ mechanical properties and plays a significant role in rock fragmentation by blasting. In this work, a numerical model for sublevel caving based on 3D Voronoi tessellations was developed to section rock mass into arbitrarily shaped regions for modelling the heterogeneous rock mass. A coupled finite element and discrete element method was employed to investigate both the fragmentation due to blasting and the gravity flow of ore in a heterogeneous orebody. In the coupled model, the caved waste rock was modelled with loose discrete particles while the orebody to be blasted was simulated with bonded particles. The detonation of explosives was described with a particle blast method and a finite element model was used to model the remaining orebody. The results indicated that the fragmentation at the upper part of the ring is coarse while it is fine at the lower part of the ring. The heterogeneity of rock mass induced some boulders after blasting.

Feb 6, 2023

By Ben Barrett

Dangerous goods, known as hazardous materials in the USA, are subject to special controls during transport to ensure the safety of the public. Dangerous goods are divided into nine classes, and Class 1 is devoted to explosives. Unlike storage or manufacturing, explosive transportation crosses the political boundaries of localities and nations, and its regulation must be centrally managed to avoid duplicate costs of complying with multiple regulations. Additionally, the transport of dangerous goods occurs by four different modes – highway, rail, vessel and air. While each mode has differences which must be addressed, the fundamental principles of classification, packaging, hazard communication and documentation remain the same. When a shipment travels by multiple modes and across borders, consistent regulations become paramount to cost efficiency. This is a common occurrence in the growing global economy.

Jan 1, 2010

By Michael Wieland

Work-principle computations for explosions underwater or in rock reveal the way the thermodynamic characteristics of surrounding material influence the resulting shock and heave. To reach total thermodynamic equilibrium under such transitory dynamic circumstances, reactions must quickly readjust to changing circumstances, which works for molecular (military) explosives where the fuel and oxidizer type atoms are originally in close proximity. For non-molecular mixtures with their dispersed zones of oxidizer or fuel, in particle or droplet form, there are numerous unproductive collisions, increasing the wait time required to reach chemical equilibrium. Underwater test data for molecular explosives compare rather well with the shock and heave resolved from the work-principal model, while the non-molecular explosives normally used in mining tend to yield a noticeable discrepancy. Years ago, it was recognized that the underwater shock was lower than expected and the heave was higher than expected for ammonium nitrate fuel oil (ANFO), though their resultant sum for the total work was roughly what was expected. When the readjustment of thermodynamic equilibrium warrants quicker chemistry than occurs in underwater or rock shooting, the time-retarded chemistry reduces the shock and raises the heave within the surrounding material without reducing the total work, unless the reaction retardation is quite severe. This technical complication in reality is a nonequilibrium issue that is difficult to resolve with just thermodynamics, though a rational set of transformation factors is formulated herein to represent those circumstances.

Jan 1, 2008

By Peter Bellairs, Anthony Bubb

The Porgera Gold Mine is located at an altitude of 3000m in the central highlands of Papua New Guinea some 600 km Northwest of Port Moresby the capital city. Access to the mine is via a five hour trip on an unsealed road from Mount Hagen the nearest regional centre or 40 minutes via air. The mine operates on a fly in - fly out basis and currently produces ore from both opencut and underground operations with the former providing the bulk of the mill feed. Opencut mining utilises conventional truck / shovel, drill and blast methods on both 10 metre and 14 metre bench heights with the larger benches being restricted to the stripping areas. This paper presents the strategy used and the results of a blast optimisation process in the opencut that was a joint effort between the mine personnel and the explosives manufacturer/supplier.

Jan 1, 1997

By R. Sibley, K. Perry, E. McCorkle, M. Coy

Black powder has been used in fireworks since the 10 th century in China. To this day, black powder still has a variety of uses, including fireworks, and remains relatively unchanged. Black powder is used in the firework shell to help produce the effect and in the lift charge to propel the shell skyward. The performance of fireworks shells used in displays varies greatly. In fireworks shells, there are two different black powder charges that differ in construction based on the desired performance of the shell. The two charges consist of the lift charge and the break charge. The lift charge is the first to fire and propels the shell out of the mortar. The break charge is the second to fire and is initiated after a delay from the lift charge; its purpose is to burst the shells effect over the desired area of the sky. The lift charge provides the shell with its initial velocity by pressurizing the mortar below the shell body. The pressurization process is violent and occurs in fractions of a second. The purpose of these experiments are to better understand the pressures sustained in fireworks mortars during the firing process. Mortars and shells vary by size and weight. Pressures in each mortar were monitored at various heights along the mortar to provide a pressure profile during shell lift. A high-speed camera was used to measure shell exit velocity near the mortar’s muzzle. This information was correlated with the size and weight of shells and their respective lift charges

Jan 1, 2024

By J P. Tidman, I J. Kirby, G H. Harries

The SABREX computer model is based on the fact that both shock waves and gas pressure are important in describing a blast. The treatment of explosive-rock interactions includes the influence of non-ideal detonation to make use of recent advances in that field. Details of the blast layout are defined from a comprehensive list of conditions the blaster can control (drill pattern, charging and hook-up). The program gives practical and graphic information about fragmentation, muckpile, damage and costs.

Jan 1, 1987