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By Winfried Rosenstock

AEBT has been available for a couple of years and is successfully applied in Australia. Up to now it was mainly used in coal surface mining at the Australian East- Coast. Presently, the proved results reach ~ 50 % reduction of Drilling & Blasting costs and a productivity increase of between 10 and 20 %. In 2003 it was for the first time used in surface metal-mining. The mine features for the time being an extremely difficult geological environment and had above to be carried out in the transition level waste/ore. Reductions of wall control, powder factor and vibrations were the main target.

Jan 1, 2004

By Catherine Johnson, Barbara Rutter

The shock tunnel located at the Missouri University of Science and Technology Experimental Mine is 65 feet 9 inches (20.0406 m) in length. The tests performed inside of this tunnel are either arena tests or shock interaction and transfer (SIT) tests. Arena tests simulate a large open air blast, with lower explosive weights, by elongating the impulse of the blast wave. SIT tests are conducted to determine how the produced shock wave interacts and transfers its energy into a target object located at the end of the tunnel. The target used in this research is multilayered, with each layer being a different material. The targets are 2 ft. by 4 ft. (0.6096m by 1.2192m) pieces of Medium Density Fiberboard (MDF), DOW polystyrene foam insulation, and gypsum drywall. The order of these materials varies with each test. This shock tunnel is unique, because the geometry changes along its length. To fully understand how the shock waves are affected by these changes, a working model was needed. The second purpose of this model is to confirm the maximum charge size of 400 grams (14.11 oz.) of C4 that can be detonated inside the tunnel without causing damage to or failure of the tunnel, thus reducing the amount of time needed in downtime and repair. The model predicts pressures in various locations both within the tunnel and the attached target, thus assisting in determining where failures would likely occur. In the process of generating this model, several problems were encountered, including filling the tunnel with air, meshing the complex geometry, and creating the tunnel in a CAD system. This paper will discuss how these problems were solved. A working model was created by using ANSYS Explicit Dynamics and ANSYS Autodyn. The tunnel geometry file was created using SolidWorks and includes the complex geometry changes along with the target and its mount located at the end of the tunnel. The results produced by the model were compared to the field SIT tests. The comparison of the results from both the model and the experimental testing showed a similar trend in the pressure traces.

Jan 1, 2018

By Benjamin Cebrian

Rock blasting at quarries represents multiple challenges not easy to see at first sight. Aggregate industries face similar or superior prices for explosives while extracting a material that usually is of less value of metal mining operations. Therefore, learning to optimize a quarry operation can be a perfect training for a position in blasting at larger metal mining operations.

Jan 1, 2010

By Denis Rickman, Jon Windham, Stephen Akers, Byron Armstrong

The soil crater formed by detonation of an explosive charge is of considerable military interest because of the common use of explosives to create soil obstacles. The soil crater is also an important piece of forensic evidence for the investigation of terrorist bombings. With recent advances in numerical codes, modeling and simulation of explosively-formed soil craters is becoming an attractive means of analyzing this phenomenon. Consequently, the need exists to better understand the relationship between soil properties and the resultant soil crater. An extensive database has been developed for the case of explosives detonated in or above in-situ soils of various types. However, in most cases, the soil properties were either not adequately quantified or the soil materials themselves varied such that the gross properties were poorly understood. A research program is underway to improve methods of relating soil crater dimensions to soil identification properties such as USCS classification, particle-size distributions, and Atterberg limits, as well as to soil composition properties such as density, moisture content, and volumes of solids, water, and air. As part of this effort, both explosive detonations conducted over well-controlled and well-documented soil backfills and companion numerical simulations were studied. This paper presents an overview of the effort.

Jan 1, 2010

By Frank Huber, Ed Fulop, Neil Singh, Ron Elliott, Blair Gohl, Lewis Clarke

This paper covers the successful application of explosive compaction technology for the densification of the foundation soils for the seismic upgrade of the Seymour Falls Dam, Vancouver, BC. The original earthfill embankment constructed during 1958 to 1961 was upgraded in 2004 to 2007 to withstand the effects of a maximum credible earthquake. This paper provides general background information on the theory of the explosive compaction of soils, history of use, geology of the site, project constraints, explosives selection, blast designs, instrumentation used, problems encountered and solutions implemented, and the results achieved.

Jan 1, 2009

By Ulrich Leiste

If the iron ore loss is 15% in the process of mining, the total iron ore loss in the world will be about 461 million tons, this is equal to the total production of 230 iron ore mines each of which produces 2 million-tons of iron ore per year. Based on a series of blast tests in the Malmberget mine, this paper shows that ore recovery can be markedly increased by improving blasting technology such as choosing a correct primer position and making use of shock wave collision. The paper further suggests that a high ore recovery can not only reduce natural resource loss and mining cost but also prolong the life of a mine. In addition, the paper shows an example of reducing blast-caused rock damage in the roofs and walls of underground drifts (tunnels) by using new blasting methods in the Malmberget mine. Finally, the paper shows how the Malmberget mine has successfully reduced the ground vibrations, without adversely affecting fragmentation and ore recovery in sublevel caving mining.

Jan 1, 2014

By Anthony Konya, Calvin J. Konya

The publication, RI8507, from the U.S. Bureau of Mines established an envelope equation that related scaled-distance to peak particle velocity in an attempt to predict ground vibration in the design phase of a blast. This has been further modified by Oriard, Dupont, Konya & Konya, and others to develop more refined prediction models for specific situations to obtain better predictions. While these equations can be an ideal starting point for a greenfield blasting project or a project with no given information, these equations can have errors.

Jan 1, 2018

By R. Narendrula, S. P. Singh

The productivity of a loading machine is affected by several factors. One of the most significant is the characteristic of the muck being loaded. A study was conducted to examine the effects of the looseness, angle of repose, size distribution and moisture content of the blasted material on the efficiency of the loading machine. The study was conducted in the following stages: (a) controlled experiments in the lab, (b) tests with loader simulator and (c) field work in an operating mine. It was found that looseness (%void) in the muck increases with the increase in the value of the mean particle size and index of uniformity of the fragmented rock. Looseness and angle of repose affect the fill factor and the digging cycle time of a loader and in turn the productivity of the equipment. Moisture content affects the angle of repose as well as the stickiness of the material to the loader’s bucket. It was observed that the angle of repose increased with the increase in the mean particle size and the moisture content of the muck. It was also found that the bucket full factor and rate of scooping decrease with the increase in the values of mean particle size and index of uniformity. This was also conformed during fieldwork that bucket fill factor decreases with the increase in the mean particle size as well as the index of uniformity.

Jan 1, 2005

By Adrian Moore, Alan Richards, Andrew Brodbeck

Structural blast vibration limits should be based on the strength of the structure, the stress induced by blasting, and a responsible factor of safety. In this paper a methodology that uses direct strain measurements to determine the stress induced by blasting is described

Feb 1, 2020

By S. M. Geerts, M. T. Wild

In this paper the performance effects of various shaped charge liner designs will be discussed. Several different charges will be tested and the liner design will be reviewed based on the performance in testing. The first type of shaped charge to be tested is a conical charge with dual confinement. For the purpose of this paper, dual confinement is a shaped charge with two liners but containing one explosive charge. Several charges with different dual confinement designs will be tested. Variations in configuration include charges with similar angle and similar diameter. The second type is a double conical shaped charge configuration. A double shaped charge will be considered to be two complete charges formed into a single cone. The goal of the project is to determine if any of the designs increase the efficiency and/or effectiveness of the shaped charge in comparison to the standard conical shaped charge. A standard conical charge will be detonated against a witness plate to get a standard depth of penetration or a baseline. All charges will have a seven cone diameter standoff, allowing the data to be compared to the control charge. Computer modeling will be used to predict the results of the testing that will be conducted. The actual results will be compared to the computer simulation for validation.

Jan 1, 2010

By Dale Ross, Bill Clements, Jim Spanos

Current world conditions are forcing the search for "green" energy technology in every aspect of our daily lives. Finding alternatives to petroleum fuels seems to be at the top of the list. The search for the "perfect" alternative is something like the never ending quest of the perpetual motion machine. Unfortunately, the laws of physics prevent us from getting something for nothing, and Murphy's Law normally gives us nothing for a lot of something. Regardless of Murphy, the quest goes on, and in our industry cheaper ANFO seems to be the popular subject.

Jan 1, 2012

By Clayton Thompson

Linear detonation wave generators (DWGs) shape a detonation wave so that every portion of the wavefront reaches the target “line” simultaneously. A projection-type linear DWG uses Gurney plate velocity predictions and Taylor deflection angle predictions to estimate the angle at which a thin projected flyer (typically metal) will impact a target. A mousetrap-style planar DWG consists of two projection-type linear DWGs working in succession to create a planar wave-front through shock initiation of each successive target explosive. The angle of deflection is critical to yielding a planar or linear wave profile. Gurney predictions, nominally accurate to within 10% of empirical results, may not yield ideal linear or planar detonation behavior when used with a grazing projection-type DWG, which typically requires accuracy within 2%. Simulations were conducted using AUTODYN hydro code to compare deflection angle prediction methods. Ranges of minimal error between Gurney and Taylor predictions and the results from the hydro code were determined, using PBX-9404-driven polyethylene flyers.

Jan 1, 2011

By Valeri Mitkov

Studena Quarry is one of the main suppliers of inert materials for concretes production in Sofia. It is characterized by massif heterogeneity in density and fissuration. Failure to take into consideration this fact during the planning of the blasting works recently had unsatisfying results in their carrying out – obtaining of materials with too small dimensions or high percentage of outsize material. Series of test blasting were carried out to find the relations for calculation of the main parameters of the drilling and blasting works. The blasting network was enlarged to 6 x 6 m, the diameter of the shot-boreholes was changed from 110 to 152 mm, the stem of the boreholes was significantly reduced and the relative consumption of blasting agents as a whole was reduced to 0,37 ?g/m3.

Jan 1, 2010

By Zhiwei Jiao, Ziqing Guo, Mushen Wang, Yueda Fang, Qiuming Tang

In order to achieve anti-terrorism, production safety, better explosive performance, lower cost, and environment protection, we developed HMS (emulsification in borehole).Long-process PM (plant-mixed) and SM (site-mixed) emulsion trucks are reviewed and compared to a new type of short-process HM (hole-mixed) truck for onsite emulsion manufacturing. The short-process HM truck has demonstrated many advantages over its PM and SM counterparts in areas such as process safety and security, energy efficiency and environmental impacts: 1) No emulsion matrix is manufactured in the plant, transported on public roads, or even present on the surfaces of blasting job sites. Such characteristics are certainly beneficial in eliminating risks of the product being diverted and used by unlawful players; 2) This short-process involves "micro-fluid control to form super oil phase-rich" in tubular emulsification process, making it intrinsically safe; 3) There is basically no residual matrix left in the truck or on the job site to clean up, which greatly reduces environmental impact of the process; 4) Comparing with typical PM and SM trucks, the HM truck has eliminated the needs of many power equipment and critical pump pressure for turbulent flow forming a static emulsification with super oil phase -rich is only 0.2Mpa. These is therefore quite energy efficient.

Feb 1, 2020

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 P J. Dailey, S L. Burchell, R F. Chiappetta

High-speed motion picture photography and its application to the mining, quarry, construction, and explosive industries has proven to be a valuable diagnostic tool. The techniques developed allow one to evaluate blasting performance, compare explosive efficiencies in relation to burden velocity, and estimate optimum delay times to provide adequate forward relief.

Jan 1, 1983

By Ravi Sahu, Brad Gyngell, Oktai Radzhabov

Design machine learning approach to simulate the process of muckpile throw distribution before blasting.

Feb 1, 2020

By Robert Jacob Cefalo

In 2019, the Bingham Canyon Mine, owned by Rio Tinto Kennecott Utah Copper Company, mined through the active underground that dewaters the pit. The active underground required the limitation of vibrations to avoid catastrophic damage or damage that would require work to the shotcrete and additional roof support. The surface design of the current sector was mined next to and through portions of the active underground.

Feb 1, 2020

By William Hissem

When we look out on our business landscape today, the words higher, faster, fdwther come to mind. Compliance issues, business integration, increasing production and profitability demands are converging in an age old industry and giving it a new twist. Not that the rock changes, rather that as the variables of our business change, the resulting “cut-off grade in business” turns ore into rock or rock into ore. The trick is to emphasize the latter. As with the miners of yore, what was recovered from the business enterprise had a lot to do with tools and skill. So it is today. When the casual observer looks at drilling and blasting operations today, many see the same basic offering in terms of equipment types and process. Looks, however, can be deceiving. As with the aviation sector, a given machine might took similar to previous generations of equipment, but in fact is radically different in terms of power, efficiency, accuracy, and range. So it is with hydraulic top-hammer drills today.

Jan 1, 2000

By Joshua Hoffman, Braden Lusk, David McLane, John Rathbun

The research conducted previously on Shock-Tunnel Waveform Analysis gave a brief insight into the propagation of a shockwave within a shock-tunnel compared to that of an open air arena test. As a refresher, a shock-tunnel is an energy channeling device used to simulate the effects of a large scale detonation with significantly smaller charge weights; having the ability to conduct tests in this fashion can greatly reduce the costs of testing products.

Jan 1, 2012