Search Documents

By Douglas Rudenko

When blasting complaints come, as an industry we often immediately look to the ground vibration as the source of the trouble. Often times we overlook or place less emphasis on the collected air overpressure data. Air blast like ground vibration is an undesirable side effect of blasting and can produce considerable structural response.

Jan 1, 2002

By Daniel Vargas Quispe, Yorhinio León Robles, Marco Jauregui Vargas, Helen Espinoza Bailon, Oshin Quispe Luya

This project describes the methodology applied during the execution of tests to determine the multiple controls that mitigate damage to the final walls of the pit. The different tests were executed on production pattern, which considered: modification of the angle of pre-split drill line, damage evaluation in individual drills with different load designs, varied detonation sequences, capture and analysis of elementary waves. After the evaluation and analysis of the results obtained in the tests, we are in process to standardize various damage controls such as; the combination of pre-split drill line angles at 80° and 90°; charge design in buffer drills that reduce the angle of action of the explosive and a detonation sequence that involves the creation of a relief filter that is made up of the detonation of two rows next to the pre-split drill line, which will have the function of filtering the waves of vibrations produced by the detonation of the production drills and at the same time it modifies the direction of damage towards the blasted material. The analysis of the different controls, as well as their combination, will allow us to improve the compliance results of the formation of benches.

Jan 21, 2025

By John Brulia

"Definition of On-Site Security: All mandatory and non-mandatory, deterrent and loss control measures undertaken by an authorized explosives business tokeep its stocks of explosive materials and precursors from: • (1) THEFT • (2) LOSS"

Jan 1, 2006

By Alexander S. Escalante, Luis R. Ramirez, Nelson A. Arostegui

Research, analyze, discuss, design, and build an electric oven to perform one of the quality control tests the fanel or common fulminers to determine what temperatures they can detonate at. Give practical applications, conclusions, recommendations and bibliography.

Feb 1, 2020

By Kevin Dunfield

The Deltadet System is composed of: The Deltadet II electronic Detonator. A Field Terminal to create, modify or simply execute an existing blasting sequence. The radio remote controlled option is composed of a Base Station to program, calibrate and initiate the EDDs plus a Blasting Box to send commands to the Base Station. Blasting lines to connect the EDDs to the Base Station (100m) and Visual Blast software to create or modify a blasting sequence.

Jan 1, 2004

By Alain Blanchier, Pascal Bernasconi

Blasting operations took place on Channel coast NW of France to extend Flamanville Nuclear Power Plant (EPR new generation). The closest operating reactor building was monitored by a 24 remote vibrations transducers network to fulfil, on one hand, the severe environment constraints and satisfy high degree of productivity required by the project, on the other hand. Although these requirements usually are incompatible, this challenge compelled to introduce a seismic modelling technique to optimize blast designs using electronic initiating system. The “Hybrid Seismic Modelling” (MSH) uses blastholes signatures (seismic vibrations records) which are greatly dependent on geology and alteration of rock mass, explosives, charge geometry, blast configuration, and the final excavation shape. In order to respect severe vibrations limits, excavation layout was divided into areas with specific blasting modules - type and number of charges, single charge, initiating sequence. Thanks to this technique, it has been possible to reach lowest blasts vibrations levels and a better productivity compared to classical blasting operation at the same location in the past. After the modelling method presentation - principle and use precautions, technical improvements are reported.

Jan 1, 2008

By Dae-Woo Kang, Sang-Wook Kim, Shin Lee

The Air-tubes blasting method is provided in which a series of aligned boreholes are charged with explosive s and air tubes in a predetermined blasting pattern. The air tube is composed of cylindrical flexible tubes which have a predetermined width and length to be fit with the site boreholes. Within a preferred formation, each borehole is charged with the explo sives and detonators with an air tube installed just above the explosives. Stemming materials are filled above the air tubes. At the limestone mine of Sung-Shin Cement Co., in South Korea, these blasting tests were performed by a diameter 102 millimeter and 15 m long boreholes with the charging length of explosives was 8m to 10 m by the total weight of explosive 40 to 50 kg with 3m to 6m air tube which has a 76 mm diameter, and 1m to 3m stemming cover. Blasting results showed the about 10% to 30% explosives savings available and especially, the about 20% to 50% reduction of ground vibration with the low noise measures around 2dB to 5dB by this new blasting method which was compared with the conventional blasting methods. The explosives and air tubes may be alternately charged along the boreholes. The use of air tubes which were charged above an explosive layer allow to form the quantitative air decking in every blast hole. Therefore, the Air-deck effect can be easily obtained through this blasting method, and also easy to increase the fragmentation rate resulting in the more suitable mucking procedures at the working site with the minimum usages of explosives for the better economic operations in mine quarries.

Jan 1, 2005

By Unknown

ATF has provided a Guide to Recording Suspicious Persons Description in the Safety & Security Brochure. This guide may be useful for recording descriptive information on any suspicious individual. Suspicious activities can be reported to ATF’s 24-hour hotline listed in the front of the Guide or to your local law enforcement authority.

Jan 1, 2009

By Adrian Moore, Alan Richards

Time window techniques that limit the explosive charge mass being fired within a specified time window (commonly 8 milliseconds (ms)) have been used for many years and are widely accepted by explosives engineers. The 8 ms time window may be relevant for controlling ground vibration for small blasts at close quarters in a high frequency vibration environment. For controlling ground vibration from blasts in a low frequency vibration environment an 8 ms separation between blastholes is arbitrary and meaningless. The 8 ms time window was never intended as a means of controlling airblast. The use of time window techniques will, in many instances, result in airblast and ground vibration levels that are substantially greater than planned, with unfortunate outcomes. The uses of time windows that are inappropriate have been well explained in previous papers. This paper gives further examples of blast designs that satisfied time window considerations but have resulted in substantially greater airblast and ground vibration levels in certain directions, due to wavefront reinforcement or the combined effect of drilling pattern and delay sequence. Techniques that identify wavefront reinforcement, due to the combined effect of drilling pattern and delay sequence, can assist explosives engineers to avoid blast vibration problems that result from inappropriate time window techniques.

Jan 1, 2002

By V R. Sastry, D P. Singh, N R. Thote

Rock parameters which are uncontrollable impose restrictions on the procurement of desirable fragmentation. Blast design parameters which are controllable prove to be important tool in blasting operations. An attempt was made by the authors to investigate parameters which causes big oversize boulders in overburden blasting. A case study of coal mine is discussed in this paper.

Jan 1, 1995

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 Brent Blanchard

An emergency demolition project related to a bizarre plane crash has reportedly set a new world record for the tallest structure ever explosively demolished. On Sunday, April 22, 2001, 38-year old Gilbert Paquette was killed when his singleengine Cessna 150 struck a 1,217-foot tall communications transmission tower while flying in heavy fog over a remote region of upper Quebec Province.

Jan 1, 2002

By Tapan Goswami, Geoff Keith

"At Bulga Coal, the objectives of drilling and blasting are to maximise safety and to minimise the totalcost of mining. A recent audit of two overburden blasts established that the standard of drilling and blasting is excellent. No apparent hazards were identified. Laser profiling showed that highwall free faces are reasonably planar with some exceptions, thereby promoting uniform burden distances along front-row charges. However, in three isolated areas along one face, small burden distances existed. The mean and the standard deviation of errors in the collar positions of front-row blastholes was found to be 0.3 + 0.03 m. A borehole video camera was used to show that blastholes did not feature open bedding plane partings, cavities or damage produced by the blast in front of them."

Jan 1, 1999

By Dr. Bronwynne Victor, Quentin Steyl, D. Scott Scovira

Bulk emulsions and emulsion blends may be formulated with a single salt, dual salts, or multiple salts. Blasting professionals familiar with single salt ammonium nitrate emulsion products may be less acquainted with dual and multiple salt emulsion products that may include calcium nitrate, sodium nitrate, and urea in their formulations.

Feb 1, 2020

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 C. Mick Lownds, Dale S. Preece, Ali Bhuiyan

FDM (Fracture Density Model) is a three-dimensional mechanistic model of blast induced rock fragmentation. FDM uses several computational mechanics algorithms to simulate the effect of blasting in different rock types. Earlier, FDM was successfully exercised to simulate 29 small scale shots from the United States Bureau of Mines (USBM), and 6 full-scale bench blasts at the Bararp dimensional stone quarry in Sweden. Excellent agreement was obtained for those shots, and the results were documented in earlier publications. One of the drawbacks of previous ver- sions of FDM was its inability to predict the fines, specifically in Bararp quarry simulations. Ac- curate predictions of fines can be very useful in reducing energy consumptions during down- stream comminution processes and improve the mine-mill operation efficiencies. In this paper, we propose a newer algorithm that can predict the fines as well as the coarse fragments in Bararp with reasonable accuracy. The model was also applied to an open-pit Copper mine with heavily jointed rocks, and it produced very good fragmentation predictions for the full range of fragment sizes. Comparisons with the sieved fragmentation data (for both Bararp stone quarry and the open- pit Copper mines) show great potential for this updated version of FDM in modeling the entire range of fragment size distributions in mining and quarrying applications.

Feb 6, 2023

By Tuan Nguyen, Dirk Hummel, Ruilin Yang

In a tunnelling site in Japan, it was found that detonators failed to initiate with their shells and primary explosive intact. Their capacitors, however, were discharged due to some damage on the application-specific integrated circuits (ASICs). These detonators are distinctly different from other commonly observed failures, where the shells are rather crashed due to excessive dynamic pressure received from neighbouring blastholes which fired earlier. Such incident has not been reported elsewhere. Detonator failures during a blast are deemed not safe and can cause disruption on the project productivity. It is therefore desirable to understand the origin of such event. Various measurements were conducted to diagnose the problem, but the root cause had yet to be identified. This paper applies a discovery from a 60-year-prior-laboratory experiment and formulates a theory that could explain the observed detonator failure and predicts the measurements and observations.

Feb 6, 2023

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 P. Katsabanis

Numerical modelling was used to examine damage in wall control operations. Decoupled charges appear to create larger damage zones than fully coupled low density charges with similar charge distributions: Air was shown to be a very efficient coupling medium, while water coupling resulted in significant damage. However, Mach stems are formed when air is used as a decoupling medium, leading to compression of the charge ahead of the detonation wave. Air decked charges generate two damage zones, one close to the charge and another close to the air-deck/stemming interface, where pressure pulses are reflected. The extent of the latter depends on the length of the air-deck.

Jan 1, 2001

By Winston Wilches B., Scott Scovira

This paper discusses recent changes to the emulsion blend blasting agent used at the Drummond Pribbenow Mine in Colombia, one of the world’s largest open pit coal mines, and the resulting improvements in rock breakage and excavator productivity. Based on field evaluations, the use of High Density Ammonium Nitrate (HDAN) can be effectively implemented in an emulsion blend blasting agent, yielding excellent results in terms of energy release, shelf life and velocity of detonation (VOD). Field evaluations showed that formulations using HDAN exceed the performance of the actual 50%/50% emulsion/ANFO blend using Porous Prill Ammonium Nitrate (PPAN). PPAN is conventionally used for emulsion blend manufacturing, with physical characteristics to facilitate sensitivity during the detonation process.

Jan 1, 2014