Search Documents

By William Wilkinson, Vladisla Kecojevic

Current three-dimensional (3D) computer design technology leveraged into drill and blast planning and operations is changing the way engineers and operations approach drill and blast design. Additionally, Global Positioning Systems (GPS) technology that is now readily available to the civilian population is being implemented into the mining sector with a variety of new products specifically designed for drill and blast operations. The objective of this article is to discuss the steps involved with 3D Computer-Aided Design (CAD) of drilling and blasting, and the benefits such a design can provide in conjunction with GPS and drill monitoring systems.

Jan 1, 2004

By S. K. Chan, C. Badeen, S. Goldthorp, H. Feng, I. Alilovic, R. Turcotte

Over the last few decades, water-based explosives and their precursors, despite their apparent insensitivity, have been involved in a number of accidents around the world. A large proportion of these accidents occurred when these emulsions were pumped either for their manufacture, transport, or handling. In Canada, this has led to the development of “Guidelines for the Pumping of Water-Based Explosive”, which state that “using pumping pressures well below the laboratory measured minimum burning pressure (MBP) of the corresponding emulsions or watergels is a good safety practice”. However, in the above document, there is no description on how the MBP should be measured. In the last few years, a research program at the Canadian Explosives Research Laboratory (CERL) in collaboration with Orica has been focused on the development of a validated measurement protocol for realistic MBP measurements.

Jan 1, 2014

By Larry: McAnuff Schneider, Edward Walter, Gordon Shaw, Daniel Grieco, Dennis Clark

During the 1998 Annual Conference of the International Society of Explosives Engineers (ISEE), the Seismograph Section established a subcommittee for the purpose of compiling a list of all regulations pertaining to limits imposed on ground vibration generated by blasting. The goal of this project was to determine the vibration regulatory levels being enforced, with the further intention of examining their scope, and uniformity. A secondary purpose was to evaluate the consistency of the existing regulations with the current scientific findings on structural response and damage potential.

Jan 1, 2001

By Earl C. Hutchison, Wade C. Hutchison

T 0 effectively evaluate property damage that is claimed to have been caused by blasting activities and in order to lay the proper foundation to build the best legal defense, identification of the actual causation for the damages are necessary. For the past twenty years, engineering personnel from VCE, Inc. (previously Vibration Control Engineering, Inc.) have been evaluating claimed blasting damages with pre- and postblast inspections, with analysis of seismic levels, blasting amounts at given distances, and with other engineering considerations. In addition to these evaluations, they have also documented other causes for damages which are of the types that are often claimed as blasting damage.

Jan 1, 1995

By Rufus Flinchum

Two of the most critical concerns a blaster faces today are airblast and flyrock. Airblast, sometimes called noise or overpressure, can cause damage to neighboring structures, especially windows. It also is the cause for many vibration complaints. The human sense of hearing is often more acute to identifying source than the sense of touch. When a blast occurs, the airblast is what identifies the event. The vibration that may be felt is then associated with the airblast. Vibrations of greater magnitude, such as passing trucks or construction work on the house, go unnoticed because their sounds are familiar or expected. Flyrock is the number one killer and cause of damage. Elasting laws provide limits for these two concerns. Failure to comply may result in fines, closing of the operation, and even prison. Airblast and flyrock originate from two distinct areas, the open face and the bench surface. Each of these areas is addressed in the detailed proven procedures that follow, and if used by the blaster in conjunction with his own blasting knowledge, a sound blasting plan can be developed to minimize the occurrence of airblast and flyrock.

Jan 1, 1992

By W. J. Birch, L. Bermingham

Air overpressure is becoming an increasingly problematic issue within the quarrying industry. With blasting operations moving ever closer to residential properties, the number of complaints about air overpressure is beginning to increase. It is therefore important for operators not only to have a greater understanding of the blasting parameters that give rise to air overpressure but also the factors which have an effect on air overpressure levels as it attenuates with increasing distance from the location of the blast.

Jan 1, 2013

By Robert B. Hopler

Explosives, originally used only in fireworks and warfare, became legitimate contributors to human progress when miners in Eastern Europe began using them to break rock in the early 1600%. Since that time these powerful materials have had a dual role in the world: as agents of destruction in war, and as irreplaceable tools necessary to advance civilization. In the latter role, they serve as agents to enable mankind to produce metals, build roads, and drive tunnels. In other words, to provide those materials, services, and infrastructure without which the modern world could not exist.

Jan 1, 1997

By Robert B. Hopler

Emplacing explosives in the borehole by bulk methods is utilized today for about 35% of all of the explosives used in the United States. Although different from today's methods, some bulk emplacement has been utilized throughout the history of explosives. This paper provides an overview of the evolution of the industry from primarily packaged to primarily bulk materials and methods.

Jan 1, 1992

By Douglas Anderson

Even though there is always a feeling of anticipation before a blast is detonated, most blasts are part of a day’s work. Once in a while there is an event that impresses even the most jaded blaster. Few blasts have had the impact of the Kingdome implosion in March of this year. Fortunately for both the Seattle area and the explosives community, the “impact” of the implosion was far less than many local residents had feared. This outcome, of course, was not by chance, but the result of careful planning and design. An urban implosion requires a mix of engineering, logistics, and public relations. Unique challenges on this project tested the resourcefulness of the entire team.

Jan 1, 2001

By Italo Onederra, Jason Furtney, Ewan Sellers

The detonation reactions occurring during rock blasting result in high pressure gas phase products from the condensed explosives typically used in mining applications. After detonation and the initial fracturing, the work done by the expansion of this gas contributes to burden movement and further rock fracturing. Before all of the energy in the reaction product can do useful work on the rock, some of this energy is lost to crushing and possibly to gas venting to the atmosphere. Borehole gas pressure decreases by three principle mechanisms: (i) expansion of the borehole cavity, (ii) flow into the fracture network, and (iii) flow through the stemming. To simplify the problem and to get a better understanding of the interaction of these mechanisms, a simple model for each of these mechanisms is developed. A comparison is made of the time-scales and the influence on burden movement for each. A comparison of gas flow behavior is made between typical ANFO and emulsion products.

Jan 1, 2012

By AJ Rorke, JD Botes

Presplit blasting in strip mines is aimed at creating a safer wall to work under during the coaling operations. Good quality presplits are also necessary for effective throw blasting and drainage of the blast block. A less obvious but important function is full coal recovery. Optimum Colliery has been experiencing rock freezing against the presplit highwalls. The rock formed in patches along the highwall and trapped coal beneath it. The material that was &ozen comprised the rock between the back row of holes and the presplit and was often up to 3 m thick (the stand off distance between the back line and the presplit). The cozen rock formed predominantly along the bottom halfor bottom two thirds of the highwall. Along the top portion of the highwall, the presplit crack was usually well formed with visible barrels. This problem, or similar variations of it, is common on many South African strip-mine operations. Investigative work was carried out at Optimum Colliery to correct the problem. This paper presents the information and measurements that were made and discusses the solutions that have been applied to solve the problem. It was found that there were two independent causes for the tiozen material, with each contributing more or less to the frozen rock along the highwall. It was found that the presplit was not forming properly in places, especially closer to the bottom of the highwalls. The reasons and the solutions are presented. The second cause was found to be associated with reduced detonation velocity in the back line holes coupled with low confinement from long delay periods. Emulsion explosive that is sensitised with air bubbles was found to be prone to this phenomenon near the back of high-energy blasts. A change in the explosive formulation in the back-line holes, together with reduced delays in the back line, has resulted in significant improvements. The details are presented in this paper.

Jan 1, 2000

By Yoshikazu Hirosaki

How big or small is the Japanese explosive market? Who are the major explosive customers? Is there any big construction project in which a large amount of explosives is expected? What is the future of the explosives industry in Japan? Is it true that there are no ANFO trucks? What is the licensing system for blasters? Is there any education system for blasters?

Jan 1, 2001

By Dale S. Preece, Stephen H. Chung

Electronic detonators and the attendant precise detonation timing that they facilitate are having a measurable effect on rock blasting in terms of improved fragmentation and vibration control. These improvements are increasingly well documented which is driving the expanding use of electronic detonators. In spite of the growing body of positive evidence concerning the benefits of precise delay timing, very little work has been done to document the impact of electronic detonators on the movement of rock. In this study 3-D computer programs, used to predict blasting induced rock heave, including the effects of detonation timing, are used to simulate the effect of precise timing on rock movement. Implementation includes quick, precise timing between blastholes going down a row and then much longer delays between rows of blastholes. For example an effective blast design might call for precise 3 ms delays between blastholes along a row and then 60 or 72 ms between rows. Several options are studied in this paper using computer simulations to draw some conclusions about the underlying physics affecting the process and how precise timing might have a positive impact on blasting induced rock motion.

Jan 1, 2005

By Randall S. Marks

Bonneville Dam, completed in 1938, included the smallest and busiest lock on the Columbia and Snake River Navigation System. To expedite barge traffic through this restriction, a new larger lock was designed and contracted by the U.S. Army Corp of Engineers.

Jan 1, 1997

By David Harrison, Edward J. Walter, Meitra Ferek

Agreat tool in the prevention of blasting complaints and subsequent damage claims. In today’s highly competitive industry, we are always looking for ways to become more cost effective. This article investigates the importance of pre-blast surveys-not just for regulatory compliance, but as an overall long term cost cutting and public relations tool.

Jan 1, 1995

By Robert Benedetti

This paper describes various mitigation methods in order to reduce the maximum acceleration of the floorboard of hulled vehicles when explosive charges buried in water saturated sand were detonated beneath them. The effects on floorboard acceleration of adding a vehicle hull, several types of floorboard bracing, the use of foam to fill the gap between the floorboard and hull, and the use of foam to isolate the floorboard from the hull have been investigated. Small scale testing was conducted, which used bar magnet velocity gages to measure the velocity as a function of time of the center of the floorboard, directly over the charge, where the acceleration was expected to be greatest.

Jan 1, 2012

By Sushil Bhandari, S. S. Rathore

Controlled drilling and blasting continue to be an important method of block production and for block splitting. Drill and blast technique has disadvantage that sometimes, it produces cracks in uncontrolled manner and also produces micro cracks in the block as well as in remaining rock, if not carefully carried out. Recovery by this method is low compared to other methods. Therefore, attempts have continued to develop controlled growth of crack in desired direction. In this paper a series of tests are described using detonating fuse in marble. Economics of different methods is also compared. In comparison to conventional use when holes are lined with inexpensive cardboard or plastic liners with a slit, the cost and damage is the least and development of crack is in desired direction.

Jan 1, 2002

By Steve Dillingham

Here in the United States, as well as around the world, pose a daily dilemma - to wash or not to wash. Let’s face it, all trucks, especially our industry work horses - bulk trucks - get dirty. We all know that these units can be very expensive and washing them keeps your business investment looking new, improves public relations, fuels company pride, and facilitates equipment safety and preventative maintenance inspections.

Jan 1, 2001

By Steven A. Mathe, Seokbin Lim

Current analytical models can accurately predict the final velocity of explosively driven flyers and can somewhat predict the acceleration profile, but do little to address the deformation of the flyers. Explosive systems such as linear shaped charges and explosively formed projectiles, which can be described as multiple interacting explosively driven flyers, often involve interactions between the flyers that occur much before the flyers reach their predicted final velocity. In this regime, it is important to accurately understand both the acceleration profile and the deformation profile of the flyers, as both significantly affect the functioning of the explosive systems. Previous work proposed an analytical model to meet this need. As the expanding gas cloud of detonation products drives the flyers, rarefactions impinge upon the gas cloud from around the flyer edges, which produces a pressure difference across the back face of the flyer leading to deformation of the flyer. Previous research condensed the effects of the rarefactions into a single term, the pressure release ratio, ?, which was calculated based on hydrocode simulations of a block of explosive only and an assumption of isentropic expansion. This work intends to determine the value of ? for different explosive compounds. The results of this analysis were compared to hydrocode simulations of an open-faced sandwich configuration explosive/flyer system with an average accuracy of 15% across the tested compounds.

Jan 1, 2015

By P J. Hommert, D S. Preece

"Commercial development of the United States Oil Shale reserve will require substantial amounts of mining. In fact, even a modest 500,000 barrels per day industry requires a mining effort equivalent to nearly half of the current U.S. coal mining industry. Obviously, mining efforts on this scale will benefit from technological advances. There are a number of areas where advanced technology could impact mining. These include continuous miners, shale transport systems, and blasting. This paperexamines recent developments in computer modeling of blasting and assesses the likelihood of these advances being applied to practical oil shale mining problems."

Jan 1, 1989