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By Daniel Roy

This paper introduces a new, safer bulk emulsion loading system for underground mining operations. The features and benefits of the equipment, along with the use of Dyno Nobel Inc. patented gassed emulsion technology, is summarized in the application of a stope blast with very difficult and complex ground conditions. The paper describes methods used to optimize the amount of energy required to break the ore while protecting the integrity of the surrounding backfilled pillar.

Jan 1, 2003

By John Watson

New Technologies, New Challenges and New Opportunities For quite some time now, numerous explosive manufacturers have spent untold man-hours and millions of dollars trying to develop a blast initiation technology that would “once and for all” provide users with what was once believed to be only a theoretical possibility...nominal timing. Zero “cap scatter” (the amount of variation of delay timing from the targeted nominal) has been the industry’s goal ever since delays were first introduced into the marketplace. Just as adding delay time between blast-holes improved blast performance since their introduction, having the wrong delay or a poorly timed blast has proven to be very inefficient and in many cases hazardous. The question of how precise a blast initiation system needs to be still remains unanswered, but electronic detonator systems being used today indicate that significant improvements can be achieved over conventional pyrotechnic detonators. These systems can typically provide single digit millisecond ranges of variability, if not sub-millisecond in some cases.

Jan 1, 2003

By Türker Hüdaverdi, Özge Akyildiz

"In this research, image analysis technique, Kuz-Ram and KCO Models were used to examineefficiency of the quarry blasts. Investigations were performed in Cendere region, Istanbul. As a firststep, image analysis software was used to determine particle size distribution of muckpiles.Additionally, the results of KuzRam and KCO fragmentation models were compared to the results ofthe image analysis technique. The efficiency of KuzRam and KCO models was investigated and theimportant points to be considered were explained. Additionally, the effect of the rock factor valueson the size distribution curves was investigated. The blasthole diameter is 89 mm. (3.5 in) in thestudied quarry. Each measured blast has a different burden, spacing and stemming length. Blastholes was drilled in a staggered pattern. It is concluded that, KuzRam and KCO models can be successfully used to determine fragment size distribution in Cendere Region Quarries, Istanbul. Site engineers can predict blast fragmentation using the theoretical fragmentation models and they may change blast design parameters before blasting operation if necessary. It is possible to calibrate the Kuz-Ram and KCO fragmentation models using the measurements obtained by image analysis technique."

Jan 1, 2016

By Gregory B. Poole

As part of a $3.5 billion program to improve the antiquated waste water system in the city of Atlanta, the Nancy Creek Tunnel is being constructed across the northwest portion of the city. This tunnel is over eight miles long and is being constructed using Tunnel Boring Machines (TBM) for the majority of the tunnel and conventional drilling and blasting for three shafts, starter and tail tunnels and four connecting tunnels, totaling 2400 feet in length. An extensive public relations program was developed for this project. A group effort by the owner, engineer and contractor produced a public relations program that both informed and educated the public of the anticipated perceptions and effects of the blasting and TBM activities.

Jan 1, 2005

By Roger S. Jackson

"This study interprets vibrations produced by single underground shots, recorded on surface by 135 digital seismographs laid out in four linear arrays. Several vibration anomalies were observed and are investigated. A novel method of displaying the blast-induced vibration iso-contour data relative to the three-dimensional representations of the geological rock units and structures leads to the following interpretations:• The identified faults commonly dampen or amplify vibrations, on the evidence of the peak particle velocity,• Strong anisotropy of geologic formations produces different vibration attenuation in the various directions of interest,• Low-vibration “depressions” can be related to the presence of faults, and• Higher vibration levels than expected based on ‘scaled-distance’ principles are observed close to intersecting faults.The interpretations from this study document a better understanding of the geotechnical influences on blast induced stress wave propagation in a geologically complex area. The practical benefit of this understanding is better control of surface vibrations, experienced from underground mining activities."

Jan 1, 2010

By Oliver Finn

Gold dredging has made such rapid strides of late and there is such a widespread interest in this branch of mining that I venture to contribute a detailed account of the way in which a Keystone driller was used by me in California to loosen, by blasting, a very tight gravel deposit, preparatory to dredging. There is a great difference between “cemented gravel” and “tight gravel.” A truly cemented gravel is not a dredging proposition, while the tightest possible gravel, where there is no cement, can be made easy working by the following method of blasting:

Jan 1, 2008

By David Siskind

The authors studied small seismic exploration blasts for vibration characteristics and effects on structures in Mexico. Obtained were 267 three-component recordings of ground vibrations and structure responses from 62 test blasts at six single-story masonry structures. Charges were 4.55 kg (10 lb) of Vibrogel expolsive at depths of 20 and 30 meters. Initial blasts were 240 meters distant and proceeded towards the structures to as close as 5 meters. All blasts were in soil media in two basic types of terrain, low saturated areas and upland dry areas. Structural inspections were before, during, and after the test blasts.

Jan 1, 2002

By Stacy Loizeaux

The Beirut Hilton Hotel, which was built in 1975, but never occupied, was imploded on Sunday, July 14, 2002 by Controlled Demolition, Inc. (CDI) of Phoenix, Maryland and their client, Optimal Engineering Consulting & Contracting, SARL, (OECC) of Antelias, Lebanon to make room for a new hotel. Twenty-seven years ago, just days before the grand opening, the Hilton Hotel became the site of fighting in Lebanon’s Civil War. Christian and Muslim militiamen fought room to room for control of the building and other nearby hotels. The Hilton, two other major hotels and other high-rise buildings were ravaged by the fighting. The building was one of the three major hotels badly damaged, but not rebuilt, in Lebanon. Located in the City Center, the Hilton stood out in a major redevelopment area which, in recent years, had erased the scars of the 15 year long Civil Wa r.

Jan 1, 2003

By Chris Breeds, Ken Johnston, Omar Fulton

This paper describes the process typically involved with obtaining permits for quarry blasting in urban, suburban, and rural areas, including: content of SEPA (State Environmental Policy Act) driven documentation; regulatory review and comment; public interaction; public hearing(s); periodic regulatory review(s); negotiated solutions; monitoring; and the role of public interaction, demonstration(s), and education in the process. Case studies will be presented of projects undertaken in the State of Washington that illustrate the approach and regulatory interaction as well as the importance of public interaction throughout the process. Reference will be made to the role of national and state regulations and local codes and ordinances that provide additional limitations on blasting practice. The paper will also present regional blast monitoring data that are used in the permitting process and the layout and design of blast monitoring systems typically required as conditions of the quarrying permit. Our presentation will include tools, which we have developed to assist with explaining blast related phenomenon to both regulators and the public.

Jan 1, 2003

By Keith Pucalik

Understanding Vibrations fr om Blasting focuses on explaining blast vibrations and their effects on people and homes while keeping an eye on the importance of the use and significance of explosives in our daily lives. Unlike many predecessors, this film will help blasting pro f e s s i o nals explain blast vibrations and address many of the layman’s most fre q u e n t l y asked questions. The film can be used in pubic hearings, given to homeowners during preblast surveys, or played at educational seminars for professionals. The film can also be used after blasting has begun and residents have already experienced vibration events.

Jan 1, 2004

By J A. Singer, S R. Iverson, C A. Link

High resolution seismic refraction tomography has proved to be a useful tool to effectively estimate depth of blast induced damage in a mine face. Excavation blast damage can be as shallow as 1 to 2m and requires resolution at a fraction of a meter for effective imaging. We used an accelerometer with flat frequency response to 1000Hz to record data at spacings of approximately 0.25 to 0.5m along mine walls. First arrival times from the seismic data were used to produce P-wave velocity tomograms. The tomograms show transition from low velocity zones to velocity associated with competent rock. We interpret the low velocity zones to indicate residual fracturing from blasting. Experiments on a concrete test block and at two underground mine locations give results that are consistent with fractured rock transitioning to competent rock. Our method can be applied efficiently in an underground environment to provide continuous velocity information with depth into a mine wall over a span of approximately 10m.

Jan 1, 2009

By William D. Hissem

For those blasthole applications which require the use of holes ranging from 1” to 5.5” in diameter, the use of top hammer drills has been the equipment of choice for several generations of drillers. Pneumatic compressed air and hydraulic compressed oil systems represent the primary technologies which are available to the drilling practitioner. While both employ the same operating principals, the characteristics of performance, cost, and reliability can be markedly different between technologies and manufacturers.

Jan 1, 1998

By Jean-Sébastien Lambert, Serge Roberge

"At the end of 2014, Holcim Canada (Demix Aggregates Division) considered the possibility of drillingand blasting a big volume of rock in order to expose a high-quality limestone bench in one of their urbanarea quarries in Laval, Quebec (Canada). The project includes many challenges and has thus been qualified as a high-risk operation."

Jan 1, 2016

By Mansour Asri, Philippe Somogy, Youssef Daffi, Amor Karim

Very few cases of Cast Blasting use in phosphate mining are reported. However, in open-cast coal mining, Cast Blasting is a common practice. And yet, the geological structure of both types of deposits is similar. Accordingly, advantages for phosphate open-cast mines are manifest, especially as future conditions of phosphate deposits fit quite well with the approach.

Jan 1, 2015

By Paul Kunze

When a new bridge was needed across the upper reaches of the Yellowstone River in Montana, removing the old concrete bridge piers became an environmental concern for the highway department engineers. The location is about fifty miles downstream from the north edge of Yellowstone Park. The determination was made by the federal and state agencies charged with protecting the resource, that the old piers had to go but the river bed had to remain unchanged. Concerns were expressed that removing the concrete presented the potential for environmental damage to this protected portion of the river. These concerns prompted the state to place stringent restrictions on the contractor in the way they carried out the demolition and disposal of the piers. The reinforced concrete masses had to be removed to an elevation at least fifteen feet below the river bed and every bit of concrete debris had to be removed from the river channel. Explosive removal was discouraged, but the only other options: saw cutting, mechanical or chemical breaking, were not viable.

Jan 1, 2014

By Dale S. Preece

"Detonation delay timing has been an important aspect of quality rock blasting for decades. Detonators that enable delay timing have improved over the years especially with the recent advent of precision electronic detonators. The positive effects of precision delay timing have been observed repeatedly in the field with improved fragmentation, heave and overall blast control. Three-dimensional computational capabilities in terms of software, material models and computer speed have recently made possible the computer simulation of multiple blast holes in a bench configuration with precise delay timing between holes. Some of the key physical phenomena enabled by precise delay timing include: 1) collision and interaction of stress waves produced by adjacent blast holes, 2) reinforcement of stress waves from multiple holes as they reflect from the bench face and ground surface, 3) reflection of stress waves from “dynamic free surfaces” created by previously detonating holes, and 4) deformation induced fracturing, cracking and fragmentation. Simulating rock blasting in 3D has shed light on the physics involved and is resulting in an evolution of our understanding of fragmentation mechanisms. Routine use of these 3D computational tools will result in a much better understanding of the complex physics set in motion by the rock blasting process and allow predictionof improved blasting."

Jan 1, 2009

By Dean Nichols, Matt Ortel

Explosive accidents in the United States have brought increased attention to emergency operation plans (EOP) at all facilities that manufacture, transport, or store hazardous materials – particularly explosive materials. Explosions are sudden, powerful, and complex events that are difficult to characterize in terms of the thermal, over pressure, and debris effects. Industry, regulatory, and public officials require emergency response planners to not only anticipate the blast effects of an explosion, but also to prepare an appropriate response.

Jan 1, 2016

By D S. Preece

The aim of the present work is to investigate the effects of shooting multiple explosive charges, in the same borehole, on the amplitude and frequency content of the generated seismic wave. The work also investigates the effect of the coupling medium used in the borehole on the quality of the generated seismic wave. The delay period between the shots is on the order of months and up to a year. The investigation utilizes a numerical modeling approach which is capable of modeling the detonation of explosives as well as shock and stress wave propagation in solids.

Jan 1, 2012

By Trevor Howie, Mal Edwards

"Thiess Contractors Pty Ltd. designed and operate the Mt Owen Mine in the Hunter Valley of NewSouth Wales, Australia on behalf of the owners of the mine, BHP Coal Pty Ltd. The mine is a multiseam open cut coal operation. Mining by Thiess commenced in September 1996 following thecompletion of the coal preparation plant. The location of the mine is shown below on Figure Al."

Jan 1, 1997

By R Yang, M Lownds

This paper reports studies showing the effects of delay scatter on the peak particle velocity (PPV) of blast vibration using a multiple seed wave (MSW) vibration model developed in recent years. The case studies also show the advantage of accurate delay timing on frequency control of blast vibration. The site parameters used in one of the studies are from a case in which the MSW model has been tested and confirmed to yield accurate predictions. This study uses an open pit blast design and a tunnel design in which blast vibrations using electronic detonators are compared with those from pyrotechnic detonators. Mean peak particle velocity (PPV) and the 97.5% upper bound PPV are compared. It is found that both these values increase significantly with the increase of the coefficient of variation of the site parameter. Using an open pit blast design, the modeling shows that electronic initiation shifts vibration energy to the expected frequency for a selected point of interest. However, for the same design of nominal initiation timing pyrotechnic detonators fail to shift vibration to the expected frequency due to its large scatter of timing.

Jan 1, 2011