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By Joshua Micah Hoffman

While it is easy to state that meaningful involvement of the community can play a critical role for a successful blasting operation, following through with this involvement is not an easy task. Structured Public Involvement (SPI) is a developed protocol for involving communities in project planning decisions and could be readily applied to the blasting industry. SPI was developed for the purpose of collecting quality public input about public transportation projects. The purpose of SPI is to bring about stakeholder satisfaction with potential projects by allowing controlled input from the stakeholders. It was designed and intended for democratic societies that have come to expect a voice in public projects. While blasting operations are not always in the domain of public projects, the fundamental process outlined by SPI can be useful for collecting feedback from the immediate public around blasting operations.

Jan 1, 2014

By Donald Wagstaff, D. Scott Scovire

The Coeur Rochester Mine is the largest primary silver surface mine in North America. Throughout its 17-year life, gold and silver grades leaving the tertiary crusher have typically been, on average, slightly below the mined bench grades as determined by blast hole assays. On a project-to-date basis, this grade variance is well within industry standards. While these variances are acceptable, mine personnel continue to study ways to further minimize the grade differences. One suspected cause for lower than expected head grades are ore loss and dilution resulting from blast-induced shot movement. In regard to grade control, the underlying design principle for non-electric blasts is the generation of uniform movement of the blasted rock material. Using one or two uniform directions of initiation, ore control methods at Rochester currently include adjusting flag lines on the muckpile in an attempt to account for displacement from original, pre-blast locations. To improve upon standard non-electric blasting practices, a series of evaluation blasts using an electronic initiation system (Orica i-konTM) was conducted in the summer of 2002. The primary objective of the evaluation blasts was to design shots that would segregate the ore and waste blocks into distinct muckpiles. Due to surface delay burning front limitations, truly effective ore and waste segregation blasting is difficult to accomplish with non-electric initiation systems for all but the most basic of ore geometries. The electronic detonator evaluation blasts produced visible boundaries in post blast muckpiles, identified by troughs or low areas, that closely matched the actual locations of pre-blast ore control flag lines based on blast hole assays. By blasting the ore and waste into distinguishable piles that were flagged and excavated accordingly, it is believed that blast-induced ore loss and dilution was reduced.

Jan 1, 2004

By Alyse Munro Hindley

The increasing negative public opinion toward blasting has led to stricter regulations and increased costs. This paper outlines alternative methods of rock excavation and the safety regulations and certification required by blasting professionals. Most importantly, however, it showcases the benefits and accomplishments that controlled blasting bring to society, giving the public a better understanding of the necessity of blasting in modern society.

Jan 1, 2015

By Neal Lee

Often the effects of wet boreholes are not taken into consideration when designing a blasting program to exhibit a certain amount of explosive energy per unit of rock such as design by powder factor, expressed in lbs./bcy (pounds explosives per bank cubic yard) or kg/bcm (kilograms per cubic meter), often the effects of wet holes are not considered. This paper examines different methods of loading wet holes and the effects they have on actual explosive quantities/unit of rock. In particular, we are looking at the amount of water trapped within the explosive column (bulk loading from the collar), or the annular space left void of explosives product around and between cartridges (wet-bags) with many of the current wet hole loading methods in use. We will focus on the effect this has on actual powder factor relative to “as designed” dry hole loading values, as well as the effect on performance of the explosives.

Jan 1, 2011

By Lizbeth A. Escobar, Phol M. Llanos, Maritza Y. Avila

The present research develops the estimation of critical parameters such as the distances and times between holes to avoid failure due to dynamic pressure in electronic detonators based on the near-field ground vibration model of Holmberg & Persson and the hydrodynamic model of Neyman.

Feb 1, 2020

By Denis Rickman, Jon Windham, Stephen Akers, Byron Armstrong

The soil crater formed by detonation of an explosive charge is of considerable military interest because of the common use of explosives to create soil obstacles. The soil crater is also an important piece of forensic evidence for the investigation of terrorist bombings. With recent advances in numerical codes, modeling and simulation of explosively-formed soil craters is becoming an attractive means of analyzing this phenomenon. Consequently, the need exists to better understand the relationship between soil properties and the resultant soil crater. An extensive database has been developed for the case of explosives detonated in or above in-situ soils of various types. However, in most cases, the soil properties were either not adequately quantified or the soil materials themselves varied such that the gross properties were poorly understood. A research program is underway to improve methods of relating soil crater dimensions to soil identification properties such as USCS classification, particle-size distributions, and Atterberg limits, as well as to soil composition properties such as density, moisture content, and volumes of solids, water, and air. As part of this effort, both explosive detonations conducted over well-controlled and well-documented soil backfills and companion numerical simulations were studied. This paper presents an overview of the effort.

Jan 1, 2010

By Ambrose Buchanan, Rob Farnfield, Charles Adcock

Beginning on 7th September 1940 the City of London was subjected to 57 consecutive days of bombing in what became known as the ‘London Blitz’. To commemorate the 70th anniversary of this event a television series was commissioned that required the open detonation of World War 2 equivalent bombs close to purpose built structures constructed using period design and materials. The structures were built on a remote test facility in the North of England that is able to fire large quantities of explosive in the air.

Jan 1, 2011

By Dave Weymer

Falling timber in BC has always been a hazardous job. Huge, often rotting trees and steep, rugged terrain combine to create difficult and dangerous conditions. Death and injury rates are among the highest of any occupation in North America. In BC, the men that head out, saw in hand, are called fallers.

Jan 1, 2013

By A. Ravi Kumar

A trench is a structure to accommodate fluid carrying pipelines for water, gas, petroleum products etc. Trench serves the purpose to haul the fluids in bulk over long distances safely and economically. Use of pipeline for moving oil and gas was essentially a post World War II development, but now it has acquired its own importance.

Jan 1, 2008

By Lloyd Litwin

The ARTA 2008 Project (Alpha Ridge Test of Appurtenance) was a Canadian Government sponsored deep water seismic survey carried out on the high arctic permanent polar ice cap. This Geological Survey of Canada operation was the second seismic research project in the high Arctic and was monitored by the Danish Government. Utilizing 100% air support from Eureka and then helicopters from an ice based tent camp north of Ellesmere Island, the five week study was accomplished in the early spring just after the sun returned to the far north.

Jan 1, 2011

By Rachel Bauer, Jacob Henderson, Dr. Catherine Johnson

Capital Quarries in Owensville, Missouri faces several challenges when designing a blast that allows for ease of movement while maintaining controlled throw and compliant air over pressure. The primary challenge is the nearest non-owned structure (NNOS) is a residential home located 250 feet from the quarry. Another challenge is a production bench which is 100 feet tall and separated from the NNOS by Pennsylvanian fire clay that filters out high frequency waves from the blast. Material from the blast must also be less than 5 inches in order to be processed by the crusher in the quarry. To provide as much relief as possible, production shots will consist of a single row with the minimum required burden. To design the shot, signature hole analysis was used to determine the optimal timing between powder columns. Electronic detonators provided an accurately timed shot to minimize the amplitude of the vibrations while maximizing the frequencies. Boretraking and 3D profiling with Renishaw laser profiler and Strayos drone photogrammetry provided an accurate burden measurement. Powder factor was kept at 1.3 tons/lb using bulk emulsion. The boreholes were split into 5 powder columns with the top of the hole firing first in order to blast to floor grade. The resulting shot produced good fragmentation and shot to floor grade. Seismograph readings showed air over pressure vibrations within legal limits. Due to this success, multiple shots will be designed using the process described.

Feb 6, 2023

By Keith Best

It has been said that when a person does something right no one remembers but when they do something wrong no one forgets. This statement, when applied to the explosives industry, has never been truer. Think about it.How many times have you seen a news crew reporting on how well a blaster is doing his/her job? Normally, all you will see is how bad things are going and how much “damage” is being done.

Jan 1, 2008

By N. Skopak, W. Birch, A. Douglas, C. Johnson

Determining the origins of air overpressure has been a long-debated topic within the explosives engineering community. Historically, it has been accepted that the initial face movement gave rise to air displacement, resulting in an air overpressure pulse. Later research proposed that the air overpressure pulse resulted from the shockwave rapidly propagating through and impacting the quarry face. Most recently, researchers have derived that air overpressure is associated with the gas phase from which a gaseous product from explosives rapidly pours out the quarry face under high pressure. Significant research has strongly indicated that the time at which the air overpressure pulse exits the face fails to coincide with either the arrival of the shockwave at the free face or the initial face movement. Research has consistently shown that the shockwave arrival at the face occurs before the air overpressure pulse leaves the face. Therefore, to best determine which blast mechanism contributed to the initial air overpressure pulse, testing was aimed at verifying the precise time at which the air overpressure exited the faces compared to when the face first moved. This research describes tests using scaled concrete blocks, which provided the ability to control the key parameters necessary for the research to be successfully concluded. Black powder was selected as the energetic material to eliminate the production of the detonation wave while still inducing other gas-producing effects. The components evaluated were air blast arrival times in front of the face, the initial movement of the blast face, the precise initiation time of the blast hole, timing of pressurization within the rock mass (between borehole and face, or adjacent borehole), and the speed of sound in the air. A detailed timeline was created which portrays the actions within the blast to promote an understanding of the sequencing of events. The results showed that the initial face movement occurred at 17.57 milliseconds (ms) while the calculated time at which the air overpressure exited the face occurred at 7.07 ms. The large disparity continues to reaffirm the premise that the origin fails to coincide with the air pressure pulse. Average pressurization through the block occurred at a rate of 341.23 feet per second (104.15 meters per second) which resulted in the gas release pulse being calculated to exit the face between 4.41 and 6.21 ms. This pulse correlates more accurately with the air overpressure origin timing which will be the focus of continued research. Knowing the precise origin of blast-induced air overpressure will assist in being able to better control it through appropriate blast design.

Jan 1, 2024

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 Donald H. Matthews

Drilling and blasting is an every day, sometimes routine activity, that is always fraught with catastrophic capabilities. Under the best conditions it is hazardous, time consuming and expensive. Under the worst conditions it may be impossible to perform by any but the most skilled specialists. Under all conditions drilling and/or blasting jobs are relatively difficult and require specialized equipment, materials and skills that are uncommon. This paper reviews some-of the jobs and problems handled by one drilling and blasting specialist to show the many varied types of problems requiring the services of specialists.

Jan 1, 1976

By Bruce R. Leland, Steven H. Smith, John D. Paulson

The USDA - Wildlife Services has been removing beaver dams with explosives for over 30 years. This paper will discuss the history of the explosives program, summarize how we've evolved, and highlight our work removing beaver dams in unique locations.

Feb 1, 2020

By Mathias Jern, Ruilin Yang

A blast vibration model has been developed that simulates effects of almost all blast design parameters on the blast vibration peak particle velocity (PPV) from a production blast with multiple blastholes at a given point of interest in the rock. The velocity of detonation (VoD), initiation points, explosive types (density, VoD, energy), charge decoupling, and decking in each blasthole are simulated along with other blast design parameters. The information from signature hole blast vibration and the blast design are the input to the model. The model can be used to assess blast damage in proximity of blastholes as well as far field vibration PPV.

Jan 1, 2019

By (Journal for the Fields of Gunpowder and Explosives) Germany (1914 Issues)

RBH Note: The following items are a deviation from the usual content of these articles, but I thought they were kind of interesting from an historical point of view (other than just explosives-history historical.) The interesting things to me are the military-related products, keeping in mind that World War I didn’t start until August, 1914, and then it was kind of an accident of political alliances gone awry. Obviously companies in Germany saw it coming. Of course, all the ads also included dynamite and safety explosives for mining and tunneling as well as the military items.

Jan 1, 2015

By Julia Creasey, Natalie Hodgson, Claire Ward, Craig Davies, Helen Sarginson

"Emulsion explosive producers are attempting to lower the cost of emulsion production by using lowquality ammonium nitrate in emulsion formulations. Low quality ammonium nitrate contains additivessuch as anti-caking agents and crystal modifiers which contaminate the emulsions causing instability. This presents a need for an effective emulsifier that will maintain emulsion stability under thesechallenging conditions."

Jan 1, 2017

By Baron Fidler, Dave Lilly, Matt Budin

Cumulative sum (CUSUM) statistical process control methods have been used in many industries to monitor quality control results. CUSUM charts are a method to determine when small changes in data indicate a major change in results. E.S. Page at AT&T developed the method in 1954. In many blasting situations, vibration and air blast readings vary slightly from blast to blast. Whether the change is significant or not can be hard to interpret from the raw data. CUSUM charts can assist in determining whether a major change is taking place and when the change began.

Jan 1, 2009