Search Documents

By Jason M. Ryan, T Michael LeBlanc, John H. Heilig

"Drill trajectory deviation is a recurring problem in vertical retreat stoping operations. As a result of thisdeviation, 60 kilogram (165 millimetre diameter) and 103 kilogram (203 millimetre diameter) explosive charges are routinely detonated beyond ore/waste contact zones. Consequently, there follows a reduction in finished stope wall stability and an increase in ore dilution."

Jan 1, 1996

By R Heater, G Glynn

Various small diameter commercial grades of slurry and emulsion explosives were tested and compared. Velocity diameter curves for confined and unconfined charges were established and the effects of temperature and hydrostatic pressure on critical diameters and minimum primer weights were determined.

Jan 1, 1984

By J. Meissner

In this paper vibratory crack response is compared to that produced by volumetric changes in foundation soils induced by natural events. These natural phenomena include changes in the water table, changes in soil moisture, and formation of ice lenses to name a few. Previous papers have compared vibratory responses of cracks to atmospheric effects such as those produced by the passage of weather fronts and daily changes in temperature and humidity. Periodicity of these atmospheric effects is on the order of a day to half a dozen days. Thus it is possible to observe atmospheric effects with measurement over a period of weeks to several months. On the other hand, crack response produced by volumetric changes in foundation soils occurs over a period of many months and/or may be seasonal in nature if not longer in the case of drought. Thus its measurement requires long periods of observation (many months to significant fractions of a year) or observation during critical seasons. Since it occurs over long periods of time, its observation may be obscured by climatologically induced crack response. These soil volume changes are compared with climatic data to describe the correlative nature of crack response in time with the soil volume change phenomena and likely climatic causes.

Jan 1, 2009

By Ravi Sahu, Brad Gyngell, Oktai Radzhabov

Design machine learning approach to simulate the process of muckpile throw distribution before blasting.

Feb 1, 2020

By Larry Schneider

In the construction field and to a lesser degree in mining, flagman are often necessary to move traffic and or pedestrians through work zones. Everyone readily recognizes that they are essential for the safety of the general public and the employees on the job. What is not often considered is the safety of the flagmen themselves. Actually, let’s call these employees “flaggers” recognizing the fact that there are as many women as men doing this job. The first problem we need to overcome is the misperception that flagging is a low skill function that can be done by any untrained employee. The reality is that the flagger works in a very hazardous position with serious responsibility for the safety of his fellow employees and the public at large. And to do this job properly re q u i re s that the flagger receive sufficient training before being sent out to the highway. It is also necessary to convince the flagger of the value and importance of their job in order to motivate them to do a professional job.testing, documentation of both, and accurate re c o rdkeeping are key aspects of HM126F. Of course, training and documentation requirements will vary depending on the type of operation involved, and there may be some differences in the application of requirements depending on your jursdiction. Nonetheless, failure to train and properly document such training can result in heavy fines and/or penalties.

Jan 1, 2004

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 Lee Wehner, Daryl Kin, John Bolger

The Maumee Quarry, located in the city of Maumee, Ohio, has large in-situ cavities, ranging in size from 3 ft (.91 m) in diameter to over 15 ft (4.5 m). The drill/blast team challenge is to drill, load and shoot the geologically disturbed rock in a safe, cost efficient manner, while in close proximity to a commercial area. A continuous improvement process, managed by a Blast Optimization Team (BOT), was implemented to quantify the innovative explosive loading techniques that have been implemented. Borehole camera monitoring, modified loading practices, the need for accurate drill hole logging and open communications between the drill and blast crew proves critical to the success of the operation. Safe Standard Operating Procedures (SSOPs) have been developed and are strictly enforced for the drill/blast cycle. All blasts are monitored with seismographs and recorded on video to provide detailed information as part of the Blast Management Plan. Despite the geological challenges, the measurement of rock fragmentation index versus loader dig rates has provided near optimal crusher throughput.

Jan 1, 2007

By Ruilin Yang

This paper presents a fragmentation model for large production blasts. The model uses peak particle velocity (PPV) induced from the blast as a controlling parameter to predict the fragmentation size distribution. The PPV can be related to shock pressure or strain under a given rock condition. The fragmentation size is calculated at three-dimensional grid points within the blast volume. The grid size defines the calculation resolution of the model. The fragment size distribution is assumed to be in the same form as the crack distribution within a cube (of the size equals to the grid size) surrounding a grid point. The crack distribution in rock from impact is based on the finding from previous researchers (Seaman et al., 1976). The fines and oversized blocks are calculated explicitly. The summation of the size distribution at all calculation grid points over a specified volume of the blast yields an overall size distribution for the volume.

Jan 1, 2015

By Ron J. Elliott, Corry Coumans

The following is a detailed description of the blasting procedures used in the successful demolition of the Stave River bridge, Mission, British Columbia, Canada. This highway bridge spans a highly sensitive salmon-spawning river. Demolition of the bridge took place in a high liability situation in close proximity to sensitive structures. The new highway bridge carrying an exposed 150mm diameter gas line was located only 1.5 meters away. The bridge piers were blasted only seven meters from overhead power lines. Control of blast vibration, flyrock, and underwater overpressure was critical to the success of the operation. Electrical sequential blasting was used to ensure that blast vibration on the new bridge structure was kept below 50mm per second.

Jan 1, 1998

By D Wilson, E Nagy, R A. Augsten, R R. Vandebeek, R L. Guilbeault

The Canadian Explosives Research Laboratory (CERL), is evaluating the status of the Schedule IV explosives container as it presently pertains to the industry. The Schedule IV container serves the same purpose in Canada as the IME 22 container does in the United States. That is, to transport detonators on the same vehicle which is carrying explosives.

Jan 1, 1990

By Wiliam Reisz

As we approach the peak season for thunderstorm activity it’s important to keep in mind that lightning still poses a serious threat to drilling and blasting operations. Lightning remains the number one cause of accidental detonation of explosives.

Jan 1, 2008

By Nickolas Vlahopoulos, Nicholas Stowe

A concept has been proposed for the focusing of underwater energy. An array of spherical TNT charges is used to achieve this aim. The goal of the present research effort is to model such a system and identify optional arrangement and detonation timing schemes. A fast-running model is necessary to perform optimization analysis due to the highly iterative nature of most optimization algorithms. This requirement renders the use of sophisticated numerical solvers impractical. An analytical, physics-based model must be developed to satisfy the demands of the multiple charge optimization problem. This model must capture shock propagation speed, pressure-time histories throughout the fluid domain, and multiple charge interaction phenomena. Such a model is presented herein.

Jan 1, 2012

By Larry Schneider

In 1998, the Blast Vibration and Seismograph Section of the International Society of Explosives Engineers formed a working group to collect and compile a list of regulations limiting ground vibrations from blasting. The goal was to locate those countries, states, provinces, and cities that have such regulations, identify which governmental body enforces them, and determine what limits on ground vibrations are imposed upon the blasting operations. In the course of this study, data was collected from over 60 jurisdictions where peak particle velocity restrictions range from non-existent to very stringent. Some of the regulations were found to be based upon standards grounded in good science, while others possess little or no technical justification. This presentation will summarize the findings of the subcommittee, focusing primarily on what the limits are, which type of blasting operations must adhere to them, and to what structures they apply. The degree to which these regulations are based upon valid scientific and engineering research will be discussed. A listing of specific locations having such regulations and information about those regulations will be provide

Jan 1, 2000

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

By Joseph Meyers

Explosives techniques and technology are constantly evolving and improving, yet basic communication and business skills are not being used regularly. Many potential blasting projects never occur due to simplistic, basic factors, such as a lack of communication. Articulate communication is the key component in the blast approval process, which has changed remarkably from how business was conducted fifty years ago. Imperative to the approval process is communication outlining the safety and benefits of the blasting project. Information and transparency with the stakeholders and the Authority Having Jurisdiction (AHJ) will greatly improve the chances of having a blasting project approved. This open communication starts at the inception of the project when the memorandum of understanding (MOU) is obtained, and involves the AHJ through all steps of the approval process. The blasting industry and regulators must work collaboratively to improve safety, security, regulations and licensing. Implementing state of the art blasting techniques, security, safety measures, vibration monitoring and strict licensing allows the AHJ and all stakeholders to remain integrated and informed, contributing to process approval. Regulatory operators should strive to achieve success thru communication, cooperation and compliance which is accomplished thru continued education and transparency. These steps, combined with regular meetings, has proven to be a benefit to both industry and regulators. Relationships are built through trust, teamwork, transparency and communication –including the take holders and AHJ in the approval process from the inception solidifies these relationships and improves teamwork

By Nathan Rouse

This blast mitigation study examined the effects of a barrier wall on explosively driven pressures. This area of blast mitigation is of interest due to the many different applications involved in protecting a target from an explosive attack.

Jan 1, 2012

By Phillip R. Mulligan, Catherine Johnson, Edward Kinzel, Cody Lough, Jason Ho

A shaped charge is an explosive device used to focus detonation energy in a desired direction. Shaped charges have numerous applications in several industries such as oil extraction, weaponry and demolition. The focusing of the detonation energy is the result of the Munroe Effect, which greatly increases the penetration properties of the explosive due to a void in the explosive’s volume. The void in the explosive is lined with a metal substrate that becomes a super-heated projectile when the explosive is detonated. Additive Manufacturing (AM) can allow greater design freedom and geometric complexity for the liner portion of the shaped charge. Specifically, hierarchical structuring and functional grading can potentially provide greater velocity, directionality, and efficiency. By utilizing AM, the conventional use of shaped charges can be greatly expanded upon and may open new possibilities. In this work, selective laser melting (SLM) was used to explore different conical shaped charge (CSC) liners made out of stainless steel 304L. A series of liners were tested that had varying densities and were compared to conventional liners. The CSCs were filled with the high explosive Composition C-4 and detonated to evaluate performance. The blast events were recorded using break wire screens to calculate the velocity of the jet through steel target plates over a standoff of 6 times the charge diameter. A high-speed camera recorded the blast event to calculate the velocity of the jet through the air. The depth of penetration into the steel target plates was also used as a measurement of the effectiveness of the CSCs. The aim of this work is to show the potential for advanced shaped charges produced using SLM.

Jan 1, 2019

By Jason Baird, Seokbin Lim

Run up is a factor in Linear Shaped Charge (LSC) cutting for which an account must be made. It occurs on the initiation segment of the charge, and the cutting performance during this period is significantly lower. Previous investigations by the UMR Explosives Group observed that similar effects occur not only with LSCs but a wide range of other explosives applications, including explosive-driven flux-compression generators. Prior to this investigation, it was believed that the main contributing factors to run up were from the combined effects of explosive run up (detonation pressure), lack of confinement at the free, initiation end of the charge, and penetrator transition from segmented pieces to a long-rod penetrator blade. As an initial step to understanding the mechanics of LSC run up, a series of investigations was performed in which the testing series was divided into several sub-categories (explosive detonation pressure run up, lack of confinement and long-rod penetrator concept) in order to reveal the effect of each on the run up. Predominantly, commercially manufactured LSCs were used for the investigation, and the entire testing was completed by the UMR Explosives Group.

Jan 1, 2006

By Charles Zdazinsky

Back-break induced from blasting is a concern in open pit metal mining because it compromises the conditions of the pit’s final walls. Final walls that have excessive blast induced damage commonly require extra attention and can often lead to increased cycle times. Most importantly however, the safety conditions of a back-broken region can be significantly compromised and it must be addressed to prevent injury and/or damage to equipment. This occasionally results in the necessity to alter mine plans to prevent an incident from occurring in a back-broken region which can be costly to the mine.

Jan 1, 2014

By A. Ribeiro

The effective utilization of resources and process optimization play a crucial role in the sustaining and growth of overall businesses. This principle holds true in the mining sector, where particular attention is required during the comminution steps. This necessity arises from the fact that mining operations often consume substantial amounts of energy in mineral processing. Therefore, it becomes imperative to thoroughly study the integration of comminution steps. In many instances, an approach to be studied is the operation commencing with the drill and blast phase and culminating in the grinding product process. Nevertheless, establishing an optimal integration between drill and blast operations and the grinding phase is a complex undertaking due to the direct influence of rock characteristics on this process. And in many cases, the complexity and variability of such physical characteristics makes mining operations to ignore such influence. Consequently, Enaex Mining Technical Solutions (EMTS), in collaboration with Lundin Mining's Chapada Mine engineering team, and with the assistance of Hatch Consulting and Technology, has undertaken a comprehensive study aimed at enhancing mill throughput at the Chapada operation. The basis of this study lies in characterizing the rock masses present in the Chapada Mine to gain a deep understanding of the material that needs to be comminuted. Subsequently, the mineral processing team determined the most suitable size distribution for the Run-of-Mine (ROM) material. With this information, the drilling and blasting team built a site-specific blast fragmentation model, able to simulate various blast design scenarios. This approach enabled to optimize the utilization of available drilling and blasting resources while striving to achieve the optimum ROM characteristics. Since 2021, the Mine to Mill methodology has been progressively implemented at the Chapada Mine. As a result, the blasting engineering team now utilizes the blast plans generated by the fragmentation model simulations as a foundation for designing blast plans that align with the operational and financial capacities of the mine. Overall, it was predicted that this implementation could lead to an average increase in mill throughput of 13-22 % depending on blend feed, once all recommendations are implemented. Even with partial implementation, plant results demonstrate a 5 % increase compared to the period before the Mineto-Mill project, without any coarsening of the associated grinding product size.

Jan 1, 2024