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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 TH Kleine, AR Cameron

Size assessment of fragmentation is all about estimating the population of fragment sizes in the rock pile. A knowledge of the size distribution of particles can be used in applications from evaluating the stability of a waste dump, to optimizing a blast design to achieve a required fragmentation, to on-line control of a crushing and sieving operation.

Jan 1, 1997

By J. D. Aubertin

Rock blasting is a complex engineering process that requires in-depth knowledge of operations and geomechanical conditions. Acknowledged design precepts are based on cratering behavior associated with stiff hard rock masses. Other cratering mechanisms may however arise under certain geomechanical conditions such as extremely fractured rock masses, or with soft rocks such as rock salt and potash. The burden dimension also plays an important role in the prevalent cratering mechanisms of a given blasting condition. The present article investigates the variability of cratering profiles and geometrical trends based on characteristic geomechanical differentiation and considering the influence of burden. The differences in observable mechanisms are examined through small and large-scale single hole blast (SHB) tests. SHB tests involve a series of individual shots blasted parallel or sub-parallel to an open face. The burden dimension is varied to obtain burden dependent characteristic trends. The breakout shape is represented by a crater model in the form of a power law equation capable of describing prismatic, concave and convex cratering. The formulation comprises two reference index parameters that can describe the geometrical and geomechanical conditions. SHB test campaigns conducted in rock salt, limestone, massive amphibolite, pinolite, and grout blocks are compiled in quantitative manner to demonstrate the influence of geomechanics on cratering profiles. The observed trends are corroborated through numerical modelling carried on Finite Element Model (FEM) LS Dyna to investigate the prevalence of specific cratering mechanisms. A series of SHB tests at large and small burden values are also used to showcase the influence of geometry on the prevalent cratering mechanism and the resulting crater

Jan 1, 2024

By Richard D. Love

Competition in the aggregate industry of the 90's will be an over increasing really. With this in mind a quarry manager should always be comparing new and innovative concepts to increase productivity and reduce operating costs. In this paper, the author will present a comprehensive history of a drilling and blasting program that achieves these results. By employing proven methods and implementing new concepts, this program was proven to be a success over a ten year period.

Jan 1, 1991

By Joshua Micah Hoffman, Catherine E. Johnson

The recruitment and retention of future talent into the explosives industry is becoming increasingly important. One potential area from which future talent can be recruited is local student chapters. Many of the student chapters are closely connected with engineering programs. While this makes sense and both entities benefit from these arrangements, there is a trend of job placement primarily in the engineering industry. Before the explosives industry can begin to compete with other industries, it should be determined what is drawing the students into these other fields. The work presented in this paper sought to better understand the collegiate student population from which a portion of future explosives professionals will emerge. This was done through the use of an anonymous online survey distributed to the student members of the International Society of Explosives Engineers, as well as, members of SEE student chapters. The survey contained questions about future job and career plans, ideal job placement, and expectations of salary. The purpose of the survey was to determine what these students expect or require from a career in the explosives industry. This information can help steer recruitment activities and job offers. Through understanding what is incentivizing these students who have accepted or plan to accept jobs in other industries the explosives industry can better posture itself to be more competitive in recruiting from the collegiate talent pool.

Jan 1, 2014

Current research in comminution includes efforts to increase the efficiency of mineral processing systems and reduce the amount of electrical energy needed for size reduction. In most mining operations, comminution begins with blasting. Normally, blast design focuses on loosening material for excavation and sizing the product for efficient haulage. It is likely that blasting also results in internal damage to rock fragments within the blast pattern which may provide subsequent comminution benefits. If substantial comminution benefits exist, appropriate modification to blast pattern design may reduce the overall electrical energy needed for mineral liberation.

Jan 1, 1996

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

By Satish Kate

Mining of Iron Ore in India is done by Surface Mining methods and most of the deposits are massive and are occurring in Hills, surrounded by green forest cover. While majority of iron ore produced are from mechanized mining systems, some quantities are also produced from semimechanised mines. In mechanized mines, apart from state-of-the-art level of mechanization, the Run-off-Mine ore is subjected to multi-stage crushing, screening and washing/beneficiation, for improving the grade and ensure segregating of different size range. The steel plants within the country have been operating their own captive mines, where both lumps and fines are used in their furnaces. In case of mines, which exclusively supply ores to export market, the lumps produced yield very high price and thus efforts are being made to maximize lumps recovery. The mine, where the author had been associated, is an export-oriented mine which supplies iron-ore to Japanese steel plants.

Jan 1, 2004

By Carl R. Peterson, Robert G. Lundquist

The development of a remotely-controlled drill and blast excavation system is desirable both because it is potentially more economical than mechanical tunneling in hard rock and for safety. A serious impediment to such development is the problem of relocating and reentering previously drilled blast holes to place the explosives.

Jan 1, 1983

By Robert B. Hopler

Hercules Incorporated has developed and introduced a totally new non-electric delay blasting cap system which utilizes a low energy gas detonation to activate the caps. Unlike any other initiation system, there is no hole-to-hole connection other than empty plastic tubing until the blast is to be set off. Only at that time, when all personnel and equipment are in the clear, is the special gas mixture introduced through the tubing. The actual time of firing is completely under the control of the operator, by pressing the fire button on the blasting machine.

Jan 1, 1977

By John L. Floyd

A personal computer is a valuable tool for blast design and analysis. Programs designed for the personal computer, such as the electronic spreadsheet, can be used for a wide range of applications. The spreadsheet formats discussed in this paper are used for explosive comparison, inventory/shot records, and timing design analysis. Each template can be adapted to fit the individual needs of the end user. An example of a graphically orientated blast design program, written in the BASIC programming language, is also discussed.

Jan 1, 1987

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 George P. Schivley

The careful positioning of the drill rigs that drill the holes into which explosives are then loaded is critical to the success of the subsequent blast. Today a system of satellites in space, each transmitting radio signals, is being used to provide the data to allow for tracking and positioning of various types of ground-based mobile equipment. The system is the Global Positioning System or GPS for short. This paper focuses on the application of GPS to surface mining and in particular the navigating of rotary drills from hole-to-hole and their final precise positioning to drill each blast hole.

Jan 1, 1996

By David A. Paul

Over the past several years a great deal of information on blasting vibrations and their effects on structures has been generated. Much of this knowledge has been gained through the use of ground vibration measuring equipment. While this type of information is valuable and gives us great insight into damage that can be incurred by structures from this source, very little, if any, information of this quality is available for the vast majority of cases in which an engineer is called upon to investigate alleged damage from ground vibrations. For the investigative engineer, then, the problem becomes one of accumulating whatever data is available and drawing a conclusion as to whether or not the subject structure was in fact damaged by the blasting vibrations. Such an analysis certainly requires a working knowledge of the literature on the subject and as much experience as he can bring to bear. Even thus armed, however, the data is often ambiguous, confusing, and/or contradictory. A practical approach is presented herein to aid the engineering investigator in arriving at the best possible conclusion available with the information at hand.

Jan 1, 1983

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 Dale S. Preece, Ruilin Yang

"Air-decks are often employed for presplitting along the final highwall of a blast and are sometimes also included at the bottom or in the middle of explosive columns in the production portion of a blast. Shock wave physics is an important part of air-deck behavior since the bulk explosives in the column impart a shock into the air-deck where the air shock then passes through the air-deck at a rapidlyattenuating velocity. Through both high-fidelity modeling and shock physics theory it is shown that theresulting pressure in the air-deck is two orders of magnitude less than the detonation pressure of theexplosive."

Jan 1, 2017

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 Michael Wieland

Work-principle computations for explosions underwater or in rock reveal the way the thermodynamic characteristics of surrounding material influence the resulting shock and heave. To reach total thermodynamic equilibrium under such transitory dynamic circumstances, reactions must quickly readjust to changing circumstances, which works for molecular (military) explosives where the fuel and oxidizer type atoms are originally in close proximity. For non-molecular mixtures with their dispersed zones of oxidizer or fuel, in particle or droplet form, there are numerous unproductive collisions, increasing the wait time required to reach chemical equilibrium. Underwater test data for molecular explosives compare rather well with the shock and heave resolved from the work-principal model, while the non-molecular explosives normally used in mining tend to yield a noticeable discrepancy. Years ago, it was recognized that the underwater shock was lower than expected and the heave was higher than expected for ammonium nitrate fuel oil (ANFO), though their resultant sum for the total work was roughly what was expected. When the readjustment of thermodynamic equilibrium warrants quicker chemistry than occurs in underwater or rock shooting, the time-retarded chemistry reduces the shock and raises the heave within the surrounding material without reducing the total work, unless the reaction retardation is quite severe. This technical complication in reality is a nonequilibrium issue that is difficult to resolve with just thermodynamics, though a rational set of transformation factors is formulated herein to represent those circumstances.

Jan 1, 2008

By Agus Setiabudi

East Pit Wira II Project in South Kalimantan, Indonesia with a radius of <500 meters (1,640 ft) from residential has about 454,168 tonnes of coal reserves, with a total remaining reserves of 3,369,383 tonnes (topography per end of June 2011). Thus, reserves may be lost as much as 13.48%. Therefore, it is needed to determine safe blasting technique which meets the Indonesian National Standards (SNI) No. 7571:2012 of vibration threshold, the maximum vibration of 3 mm/s (0.118 in/s) and air blast of 120 dB.

Jan 1, 2014

By Mark D. Kirkbride

This paper outlines the process for designing a hard rock blast in an underground coal mine. The coal mine is located in Western Kentucky and operates four continuous miner units at 7 unit-shifts per day. The mine operates in the Western Kentucky No. 11 Seam with local variations from 4.5 - 5.5 feet seam thickness. The seam has sporadic siderite deposits. Usually these deposits do not significantly interfere with the mining process. When previous siderite deposits were encountered they were small enough to drop an entry for a couple of crosscuts. The blasting plan was called for after a siderite deposit was encountered in the belt entry at about one third of the panel length. The other sides of the panel had been previously mined and sealed so the decision was made to mine through the siderite deposit with the continuous miner instead of abandoning the panel. The deposit was approximately 300 feet in length down the belt entry. Mining through the deposit with the continuous miner was expensive in both terms of production and of wear and tear on the continuous miner. A blasting plan for the siderite deposits was designed to minimize damage to the continuous miner should a similar situation occur.

Jan 1, 1999