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By Conny Postnpaok, Mark E. Hammele

"A major problem that has continued to plague the surface oil industry is blast induced damage to the coal seam. Atlas Powder Company has addressed this situation through several years of field research in full-scale production environments. Many operations across the United States havebeen evaluated ."

Jan 1, 1989

By Pierre Allard, Wilfrid Comeau

Near-field and close-in blasting can be safe and efficient, near engineered structures, if the dynamic reaction of structural members to blasting vibrations are considered. Safe particle velocity criteria can be derived from allowable safe static flexural deflections and critical frequencies. Control of close-in blasting can be accomplished using low-pass filtering of the particle velocity signal at the critical frequency. The CETE Mediterranee laboratory at Aix-en-Provence, France, a branch of the Ministry of Roads and Bridges has -pioneered this approach and successfully applied it to major road cuts and tunnels in built-up areas, as well as a major powerhouse expansion project in Africa. This approach is presently being used for a spillway rehabilitation project in Quebec, Canada. This paper exposes- the theoretical aspects and gives case histories of its use. The SCS-15 an automated, peak reading, data acquisition device is described.

Jan 1, 1991

Case histories in blasting show that Livingston's cratering technology has been applied successfully to blast designs with explosives having a charge length to diameter ratio not larger than 6. But the evaluation of experimental results such as the crater volume is tedious and sometimes impractical. A key analysis presented in the study shows that the optimum scaled volume relates well with the optimum scaled rupture limit, and the latter can be determined by means of high speed photography without excavating the blasted material. Through the studies of harvesting gypsum from a dried up settling pond the high speed photography approach has demonstrated to be effective for determining the optimum design for blasting plastic material.

Jan 1, 1987

By N L. Thomas

Hole size affects many factors which directly influence fragmentation in the muckpile and hence, the cost effectiveness of the entire operation. These factors include production capability, explosives and accessories efficiency and usage and drilling accuracy. In addition, hole size should be chosen to suit the geological conditions. The paper concludes that the optimum hole size is generally the largest that can be used commensurate with production and environmental considerations.

Jan 1, 1986

By Kevin Cole, Dennis A. Clark, F William Laslow

Since 1976, the Metropolitan Sanitary District of Greater Chicago, (MSDGC), has commissioned the excavation of a tunnel system in the Chicago area, hundreds of feet below the surface in solid limestone. This paper outlines the blasting patterns, explosive selections, and monitoring techniques used to assure a satisfactory job completion, following the specifications.

Jan 1, 1982

By Stephen Hamilton

This case history details the issues surrounding the rock drilling industry’s growing demand for straight holes, the importance of straight holes and the introduction of a new production drilling systems that can effectively and economically drill a true bore hole. Since the introduction of the hydraulic rock drill, the rock drilling industry has asked for a drilling system that would provide the fast penetration and low operating costs of Top Hammer drilling systems combined, with the directional control of Tube or DTH drilling techniques.

Jan 1, 1999

By Kirstin Girdner, Vicki Seppala, Tom BoBo, John Kemeny, Mike Higgins

Optimal blast fragmentation is fundamental to all phases of comminution. Changes in blast design may affect efficiency and productivity of downstream processes such as crushing, milling and leaching, resulting in cost savings or losses.

Jan 1, 1999

By Calvin J. Konya

The Woodville Lime and Chemical Company Limestone Quarry is located in Sandusky County, Ohio. Fifty years ago, when quarrying began, it was situated approximately two miles from the town of Woodville. Today new houses border the quarry property within 1,500 feet of one of the working faces. During the past two years, the operation has systematically changed the blasting program to achieve better fragmentation, lower costs, and to maintain good relations with the local property owners. This paper will discuss systematic changes made in the blasting program to increase productivity and reduce costs.

Jan 1, 1977

By M S. Sandhu

Singrauli area of Madhya Pradesh in India has been developed as the power capital expected to produce around 11000 MW in near future requiring 65 million tonnes of Coal per annum. Thermal power plants were installed considering the vicinity of coal reserves which are minable by open cast mining methods. Crisis of oil in seventies further expedited the process of planning big open-cast projects in the area varying from capacity of 3 million tonnes of coal to 14 million tonnes per annum. A separate company - Northern Coalfields Ltd. was formed to ensure meeting the rising demand of coal required for energy production. Northern Coalfields at present is producing 35 million tonnes of coal and will reach the capacity of peak demand of 65 million tonnes by the turn of the century.

Jan 1, 1998

By Hans-Peter Rossmanith

Fracture mechanics (Atkinson 1987, Broek 1988, Rossmanith 1978-2002, 1983, 1997, Kanninen & Popelar 1985) and wave propagation (Graf 1975, Rinehart 1975) form the main ingredients in the new electronic detonator based blasting technology. The full potential of using short delay initiation timing in bench and underground blasting can only be exploited if the underlying physical processes are properly understood. From a structural geology point of view, in many open pit mine operations, blasting is performed in incompetent and/or loose rock. Under such conditions the stress waves produced by blasting very quickly dissipate in the rock mass and often their energy cannot effectively be put to work. This contribution shows the effect of open and closed joints – and to some degree also faulting – on the blast wave field and shows the influence of structural geology on the blasting result. A simple engineering method which combines wave propagation and impact mechanics is developed in order to assist the non-scientifically trained blaster in understanding blasting in blocky rock formations. Extensive use will be made of the so-called Lagrange diagram which was introduced in detail in the author’s previous lecture at ISEE 2003 (Rossmanith 2003). This presentation can be considered a continuation of the 2003 presentation.

Jan 1, 2004

By David E. Siskind

"This report describes recommended vibration monitoring and assessment practices at blasting sites.Intended is regular monitoring, tracking of trends, responding to complaints of alleged damage, and the technical and data aspects of addressing lawsuits."

Jan 1, 1999

By Frank Hammelmann, Peter Reinders

This paper briefly describes the past history of blast management. A modern blast management suite is then presented which demonstrates the current capability of the functional link between an electronic blasting system and blast design software. Finally, we look at the potential of tomorrow’s fully integrated blast management systems. From the first time blasting was introduced in mining as part of the production process, blasting technology and blast management have been interconnected. Over the past decades we have gained more recent experience with the new electronic blasting systems in mining, quarrying and construction. To start, the primary focus of electronic blasting was to increase timing accuracy. However, since then the technology has gradually developed, broadened and opened up new possibilities, including impressive flexibility in blast design and full in-situ verification of system functionality. To support this capability, modern electronic blasting systems are specifically designed to facilitate full two-way transfer of information between the office-based blast management software and field-hardened equipment. Blast management systems now comprise a suite of expert systems for planning, documentation, analysis, measurement and prediction of blasts. Within this blast management suite, the blast design software allows the transfer of the blast design information from a PC directly to the hardware of the electronic blasting system. The future development of this technology holds huge potential for the blasting industry.

Jan 1, 2004

By E. Contestabile, B. von Rosen

On August 5th, 1998, a tractor-trailer carrying approximately 18,000 kg of blasting explosives, struck a rock face on the side of the road near the town of Walden, Ontario. Eye-witness accounts of the incident state that there was an intense fire for approximately 30 minutes before the detonation. The detonation caused severe damage to the tractor-trailer, shifted the pavement and caused blast damage to the rock face. A rock fragment was recovered almost 2.5 km from ground zero and a 70 kg piece of an axle assembly was recovered over 1 km from the site. Windows were cracked at distances of almost 3 km.

Jan 1, 2001

By Robert Jacob Cefalo, Rio Tinto Kennecott

At the end of 2016, the Mine started a new ore phase in the section of the pit located on the East Wall. The East Wall geological structures required controlled blasting for peak particle velocity (PPV) frequency vibrations to protect the wall. Frequency controlled blasting using linear seed wave superposition modeling was required and implemented to reduce the far-field affects to the wall. This paper covers the work done by the drill and blast engineering group, controls used to protect the mine infrastructure, and the continuation of work-to-date of frequency controlled blasting for wall stability. The narrow width of the layback required the combination of hole sizes to blast large diameter production patterns with smaller diameter trim patterns in the same blast. A single blast had to use different burden & spacing and hole diameters and required the use of different timings throughout the pattern. Electronic detonators were required to limit blast vibrations and accommodate the specific timings needed to reduce low frequencies. The geotechnical group with the help of geotechnical radars worked with the drill and blast group on creating a tracking and reporting of blast performance. The radar readings informed the drill and blast engineers of the performance of the blast as it related to the long term performance of the highwall

Jan 1, 2019

By Francisco Sena Leite, Raquel Sobral, Vinicius Gouveia de Miranda, Céu Jesus

"This document investigates a newly developed technique with the objective of improving terrain triangulation models (horizontal/sub-horizontal and vertical/sub-vertical terrains), mainly blast free faces. The algorithm uses multi-linear regressions to generate the best point cloud projection plane by applying the residues modulus minimization so as to create the finest 3D triangulation model. A change of base is required to create a new set of coordinate axis and generate completely new projection planes. The projection plane residue analysis is inferred in order to avoid or reduce the outlier points. The dataset is composed of 12 terrain models obtained from photogrammetry and a 3D Laser equipment thatgenerates georeferenced cloud points. This new technique is validated by the analysis of the obtainedcritical burden by the improvement of the general aspect view of the terrains and the capacity of outlier’s detection. The result and the quality of the algorithm demonstrates the improvement in the triangulation mesh, reducing errors in the calculation of over/under burden, free face volumes, cavities and, therefore, in the estimations of clearance/safety distances."

Jan 1, 2017

By Brad Bockey

Whether you are a driver, blaster, or are in charge of filing, you must recognize the importance associated with DOT-required recordkeeping. As various agencies become intertwined with rules governing the explosives industry, the records we produce must be as accurate as possible. The time is right for reviewing your paperwork process from start to finish.

Jan 1, 2011

By Paul Worsey, Braden Lusk, Seokbin Lim

This paper discusses the theory and experiment involved in the discovery of the mechanisms of Linear Shaped Charges, which are much different from those for Conical Shaped Charges. Linear Shaped Charges (LSC) have been assumed to function in the same manner as Conical Shaped Charges (CSC) in the published literature on the subject. Much work has been done on CSC for military purposes, but there is limited information about the mechanics of LSC. Previous theories have cited the formation of a Monroe Jet as the dominant process. The Monroe Effect describes what happens to a target below the charge following detonation of the charge, and prescribes a fluid jet process for penetration. The fluid jet comprised of the liner material is the cutting device in CSC and has been extensively studied. Recent work at the University of Missouri at Rolla (UMR) cutting concrete with LSC has surprisingly shown that there is not a fluid jet process in LSC. After completing several reinforced concrete penetration tests, minimally deformed copper blades were found in the debris. Initially, the blades were suspected to be misfires or malfunctioned charge remnants. However, results were good and blades were found after every single test. Upon closer inspection, the ribbons were found to be folded copper and they were suspected to be the bottom liner of the LSC. A test series was conducted to verify the new theory by experiment.

Jan 1, 2005

By T. Szendrei, S. Tose

This paper will review several flyrock incidents that occurred recently in the South African mining industry to highlight that potential difficulties of the historical approaches to the problem of flyrock based on correlation studies and regression analysis, including artificial neural networks and similar techniques. These process are not capable of addressing two core issues – root causes of flyrock and projection velocity. A further shortcoming of correlation techniques is that they give no information on the influence of rock size and shape on the flight distance. The scaled depth of burial model for crater blasting in the collar zone and bench face does not specifically address the question of flyrock velocity. A third approach, based on flight trajectory calculations, often neglects the very significant effects of air resistance on the trajectory. Some trajectory models incorporate air resistance but use an implausible fragment velocity model that cannot propel sizeable rocks to distances much beyond 150 m. (Approximately 500 ft.) Nonetheless, trajectory calculation incorporating the effects of air drag affords the most promising approach to the prediction of flyrock range. A unique and insightful feature of the proposed realistic flight modelling is that it collapses all suspected causes of flyrock, many of which are not well understood, to just a single parameter – the launch velocity. This indicates that the root causes of flyrock lie in the mechanisms of momentum transfer to broken rock and suggests new avenues of study for the explosives industry. In this paper we use the trajectory model to identify certain conditions on the bench whereby the impulse of gas pressure acting on fractured material on or close to a free face is enhanced, resulting in a greater transfer of momentum to potential flyrocks.

Jan 1, 2024

By Dale Preece, Stephen Chung, D. Scott Scovira

The DMC_BLAST (Distinct Motion Code) has been developed to model rock motion and displacement during the gas expansion phase after the detonation of an explosive in a borehole. Recently, a designated delay firing order algorithm was written into the DMC_BLAST code. The model can now be used to analyze rock mass displacement for a V-cut, center opening, or sinking cut initiation sequences. This new feature allows the investigation of the effects of delay firing order on rock displacement when blasting complex inter-bedded and ore-waste structures. The model provides important ground movement and mixing indicators for dilution control in surface gold mining relative to the initiation sequences employed. Echelon blasts as compared to center opening type blasts show differences in their internal muckpile displacement. These displacement differences can be important to operations that mine narrow strike driven ore bodies. The model also has applications to through coal seam blasting and demonstrates that down-dip blasting is a better alternative than up-dip blasting. There is less disturbance to the dipping coal seam and less mixing of the rock and the coal.

Jan 1, 2000

By P Albert

A wedge-shaped underwater rock plug has to be blasted in order to tap the reservoir and furnish water to a new underground powerhouse at Manicouagan-5. The paper deals with the design and engineering aspects of drilling and blasting of this plug where the topographical configuration is extremely difficult. In this study small diameter vertical holes are considered with the OD-method and a fixed platform is recommended for drilling and loading operations.

Jan 1, 1984