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By Dale Preece, Stephen Chung

Blasting induced rock fragmentation is an art that has been developed and refined for hundred’s of years through blasting and recording the results. Good blasting fragmentation practices were thus developed through experience. However, this method requires a history that is typically developed in a mine over a number of years and sometimes at considerable expense. Quantification of fragmentation as a function of rock-mass characteristics and blast design is attractive. Developments towards this end have included semi-empirical methods as well as computer codes that explicitly treat shock wave transmission and the subsequent rock breakage. This paper will present predictions of fragmentation resulting from rock blasting using the computer code AUTODYN and a new state-of-the-art material model for brittle rock and concrete.

Jan 1, 2003

This paper is concerned with the blasting of rock in mining. The most common purpose of blasting rock is to cast it or to disrupt its structure sufficiently for effective digging and subsequent removal.

Jan 1, 1991

By Dale S. Preece, Matthew A. Reisenmay, Avione Northcutt

The ability to simulate the explosive effects of land mines on military vehicles is a valuable capability in the defense community. The current competency levels of such simulations, however, are in need of improvement. Experiments have been conducted to measure the explosive induced impulse of a land mine on a steel plate placed above the explosive charge. The purpose of this paper is to report the findings of a variety of simulation tests conducted in order to correctly predict the empirical impulse data gathered in corresponding experiments. The computer hydrocode, AUTODYN v5.0.01 (Century Dynamics, 2003), is the simulation code used to simulate, and process the results. The experimental data has not been made available to allow computer analysts to exercise their codes on the problem without the temptation to tweak parameters in order to match computer code predictions with experimental results

Jan 1, 2005

By Benjamín Cebrián, David Flores, María Rocha Gil

This document shows the evolution of drilling and blast digitization process, savings and trends in a mine, using new technologies that creates business opportunities and general improvement of D&B process.

Feb 1, 2020

By Victor C. Bryan

One of the most sought after answers in any consideration of blasting activities relative to mines and quarries is how to safely and efficiently use explosives. While that discussion might be relatively straightfonvard in a “site specific” situation. it becomes more complex when viewed from a broad geographic perspective. Such is the case in considering the operations of one United States producer of crushed stone with surface and underground mines spread over a thirteen state area. Differing geologic environments set conditions that dictate to the blaster as now specifically to get optimum results from the blast hole. This treatise is a discussion of the various methods, materials, and principles used in conducting such blasting operations.

Jan 1, 1991

By Terra Dinamica, Frank Lucca

This paper discusses blast design for vibration control in tight construction blasting. Topics include blast pattern geometry, blast design formulas, loading, explosives & initiation selection, and utilizing borehole deviation equipment and lasers, and rules of thumb. The paper will also explore vibration prediction, neighbor relations, and related topics, such as blast plan submittal. Various projects from metropolitan construction blasting operations will be used as examples. Examples include blasting in the inner city, next to pipelines, and in housing developments.

Jan 1, 2005

By Benjamin Cebrián, María Gil, David Flores

In many occasions during the Mining operation life, blasting engineers find different and controversial results of fragmentation, dilution or wall control for the same geotechnical domain and blast design (pattern and explosive charge). Most of the times, the difference between same blast designs is not measured, not controlled. Once a blast designed is defined, the most important part of the process after that is the implementation of every step of the blast on site. Almost nobody is measuring it, controlling it, but just controlling implementation is possible to relate blast design with results in a consistent way, to optimize the full process of D&B. Controlling implementation not only per event but also to check and change trends and decision-making is paramount for optimization and saving millions of extra costs every year. The lack of resources and the hardness to manage all the info created every day in a blast make this process very tough and difficult to maintain in long term. The use of new technologies on site and software that allows a best, more consistent and continuous control of blast implementation have been proved to be the key for optimizations and cost saving. This document shows the evolution of drilling and blast digitization process, savings and trends in a mine, using new technologies that creates business opportunities and general improvement of D&B process.

By R. Reed Skaggs, William Gault, Douglas Kooker

Both armored personnel carriers and light combat vehicles are increasingly vulnerable to a variety of highly lethal antitank land mines. As a result, there is a need for modeling and understanding the interaction of mine blast products with respect to the resulting loading and damage mechanisms inflicted by explosive blast and impact on vehicle structures. However, the mechanics of blast soil interactions are still poorly understood. The objective of this investigation is to computationally simulate a series of experimental buried mine explosions in saturated sand soil -- over a wide range of scale – and compare the predictions of blast loading to data. Small scale tests have recently been conducted at the University of Maryland with a few grams of RDX acting against an aluminum plate, while recent full-scale tests at ARL involve several kilograms of TNT against 12,500 kg of RHA. The ARL measurements reported here are based on the Vertical Impulse Measurement Fixture (VIMF) facility, a structural mechanical device that responds to blast loading by measuring the vertical displacement of a fixed mass vertical guide rail, which is a direct measure of the imparted impulse. CTH predictions for vertical momentum of the target plate are within 60 – 80 % of the reported impulse data for this wide ranging set of tests. One of the comparisons, however, suggests that the TNT charge in a particular VIMF test may not have fully reacted.

Jan 1, 2005

By Jack Elorenta

We often hear that, "Blasting was an art, but now blasting is now a science". 'Scientific' blasting implies that we have quantified and reproducible measurements of the feedstock and product of the blasting process. However, the industry's reluctance to adopt two key technologies, drill monitoring and optical size analyzers, sheds doubt on the claims of scientific blasting.

Jan 1, 2003

By G. R. Adhikari

Step 4: Selection of explosives and initiation system Various types of explosives are manufactured in India and a wide choice is available among them that include nitroglycerin based explosives, slurries, emulsions, ANFO (ammonium nitrate mixed with fuel oil) and heavy ANFO. The choice is also available between cartridged and bulk loading systems. In Indian mines, much importance is unduly given to the cost of explosives alone which is not conducive to optimization of blast design parameters. The concept of energy per meter of blasthole and the way in which the total explosive energy is partitioned between shock and heave is not considered in the prevailing practices. Besides, very little efforts are made to objectively evaluate the performance of explosives for a given site condition. Tailoring explosives is limited to changing the density of the bulk explosives. Cartridged explosives are still being extensively used in large operations where bulk explosives should be the preferred choice.

Jan 1, 2002

By Bruce Vandenberg, Andy Bartfay-Szabo, Steve Conway

Recent advances in solid-state, field portable, fast framing video camera systems and PC based frame capture hardware now allow blast imaging up to 500 frames per second. Up to 8 seconds of data can be stored directly into the unit, downloaded to a PC or archived to a standard VCR without data compression. Since no film processing is involved, motion analysis can be performed instantly and on-site within a few minutes. This paper will describe the design features and applications of the SVClOOO system and compare these with the analogous aspects of film based cameras.

Jan 1, 1995

By James Rowland, Marcia Harris, Richard Mainiero, Michael Sapko

All explosive materials produce a cloud of reaction products, the most toxic of which is nitrogen dioxide (NO2). In the study reported here, 4.5-kg (10-lb) charges of blasting agent confined in either thin-wall 10-cm (4-in) diameter galvanized pipe or 10-cm (4-in) schedule 80 seamless steel pipe were detonated in a closed chamber. The detonation gases were analyzed for NO2, nitric oxide (NO), ammonia (NH3), hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), nitrogen (N2), oxygen (O2), and methane (CH4). Data were evaluated to determine the kinetics of the oxidation of NO to NO2. Analysis revealed that the only mechanism for NO loss for the conditions existing in the chamber was the reaction 2NO + O2 6 2 NO2. The rate constant was 2.08 ?? 10-38 cm6 molecules-2 sec-1 for the rate equation -??d [NO]/dt = K ?? [NO]2 ?? [O2] for NO concentrations up to 100 ppm. The rate constant is in agreement with that recommended by Baulch, Drysdale, and Horne (1973).

Jan 1, 2006

By Ray Jambakhsh, Gabrielle Bourget

In the summer of 1998, Ontario Hydro awarded a contract to demolish an obsolete and inefficient chimney by blasting. The Ontario Hydro Thunder Bay Thermal Generating Station (T.G.S.), is a fully operational hydro thermal generating station located in Thunder Bay, Ontario, Canada. The Chimney was a 356 ft (108 m) high freestanding structure constructed of reinforced concrete with a brick liner. Falling the chimney required careful planning due to the highly sensitive structures and equipment which surrounded it. Damage either sustained to the existing systems through ground vibrations or direct contact would have resulted in expensive power outage and/or lost production. The role of Explotech Engineering Ltd. on this project was to provide and evaluation of the proposed demolition procedure, defme the predicted and maximum seismic vibrations at sensitive structures including underground services, conduct pre-blast / post-blast inspections and recommend various safety precautions. The general contractor for the project, LeBrun Northern Contracting Ltd., of Thunder Bay, Ontario was responsible for all site preparations and post-blast clean up. All demolition blasting calculations and operations were conducted by Dykon demolition experts from Tulsa, Oklahoma. On September 13, 1999, the chimney was successfully demolished. Extensive analysis of the vibration records and visual post-blast inspections of the surrounding structures concluded that the demolition event induced no damage to any of the Ontario Hydro facilities.

Jan 1, 2000

By T. Bernard, P. Dozolme

Electronic initiation devices appeared on the market more than 15 years ago and have definitely changed the rules of blasting. It becomes clear that this technology represents a powerful alternative to the traditional accessories. Electronic Delay Detonators (EDD) have attained solutions that were difficult and even impossible to achieve with the previous technology, thanks to the accuracy, usually inferior to one millisecond, and flexibility of the programmability range offering thousands of timing possibilities. Technological progress is long awaited to represent a step ahead compared with the last generation of products. In the case of electronic initiation, some limits nevertheless rapidly appeared, leading to the paradox of loosing operative and safety benefits, compared with the traditional technology it was supposed to outclass.

Jan 1, 2006

By A J. Rorke, U Chhika

"A series of tests was carried out on a dry blend of PPAN and LAN prills (LANFO). The objective of thetests was to determine detonation stability and VOD performance compared to ANFO. Heave andfragmentation results in the field were also evaluated visually. A number of factors were behind for.mulating this blend. A lower cost is combined with higher in-hole energies, but at slower reactionrates and lower peak borehole pressures. The resultant effect is improved heave characteristics andlower energy losses caused by inefficient crushing of the rock immediately around the borehole.The test results indicate that IANFO is ideally suited to blasting in softer midburden and overburdenrock types often encountered in coal strip mines."

Jan 1, 1995

By Noel Dent

The Electrodet@ Electronic Detonation System Wilere are we going with regard to Accurate, Reliable, Easy to Use and Cost Effective Initiation using electronic initiation techniques? Improvements and applications in theJierd

Jan 1, 1995

By Dale S. Preece

A Discrete element computer program named DMC @istinct Motion Code) has been developed for modeling rock blasting. This program employs explicit time integration and uses spherical or cylindrical elements which are represented as circles in 2-D. DMC calculations have been compared with measurements on bench blasts in the field with relatively good comparison. Structural rock mass characteristics have a significant impact on any blast and DMC has not, until now, included these effects. This paper discusses a recently added DMC capability for treating joints and bedding planes in bench blast simulations.

Jan 1, 1995

By Kwang-Tae Kim, Yong-Kun Choi, Jeong-Soo Chong, Yun-Jae Lee

An annex building at the former Agency for National Security Planning(NSP) complex located in downtown Seoul was demolished by progressive collapse method. This work was done as a part of efforts to restore the landscape of Namsan Mountain which lies in the Center of Seoul. The five-story reinforced concrete structure was razed in 5.5 seconds by the 29kg of high powered explosives which were placed in some 320 holes in the building with floor area of 2,577 m². The asbetos and all the other finishing materials in the building were removed before the demolition and the specially coated wrap minimized the spread of blasting dust. Seismic and air overpressure waves were monitored at 8 points, which were below safety limits and the continuous communication with neighborhood prevented any complaint.

Jan 1, 1998

By Kenneth Eltschlager

Business says that location is a primary component of being successful. So too is the importance of location in blasting. For blast seismograph data to be useful, the location of the blast and seismograph must be clearly documented. Another location of importance is that of a nearby structure. Establishing the spatial relationships between the blast, seismograph and nearby structures, allows the blaster to correctly interpret the data, evaluate the performance of the blast and gauge the validity of any complaints.

Jan 1, 2004

By Ann Barron

Commercial drivers have new guidelines regarding how long they can stay on the road without taking a break. Transportation officials say the new Hours of Service rule that took effect January 4th will reduce driver fatigue and prevent hundreds of injuroes, thousands of crashes and save the American economy about 628 million dollars a year.

Jan 1, 2004