Search Documents

By Guillermo Silva

A novel, ultra-low density explosive composition, particularly suited for wall control and other applications requiring customising of the explosive’s energy output, has been developed. Being reactive in nature, the low density explosive enables the controlled dilution of dry blasting agents from their nominal densities down to values slightly less than 0.10 g/cm3. The product has been detonated at densities of 0.07 g/cm3 in diameters as small as 50mm under confined conditions, using a 227 g (l/2 lb.) primer. Recorded velocities of detonation ranged between 1200 m/set and 2200 m/set for densities between 0.07 and 0.2 g/cm3. Theoretical velocities ranged from 1700 m/s to 2500 m/s for the same density range. The low density explosive was insensitive to initiation by a blasting cap which is a desirable feature for transportation purposes. Mixing of the product with ANFO has been accomplished with minimum segregation making it suitable for applications where reduction of pressures are necessary.

Jan 1, 2000

By Tristan Worsey, John Rathbun, Andres Malone

A run of mine, low grade gold heap leaching operation is currently looking to increase ounce recovery by decreasing run of mine fragmentation size. Current blasting practices have resulted in an average fragmentation size of 80% passing 7.05 inches (179 mm). It is estimated that a decrease of 2 inches (51 mm) in the 80% passing fragmentation size has the potential to yield up to a 2.5% increase in the overall life of mine recovery within this ore body. This potential recovery increase could lead to an increase in recoverable ounces which, in turn, would lead to a better profit margin. As this particular deposit is composed of predominantly low grade heap leach the capital investment in a crushing facility was cost prohibitive, it was therefore decided to look into the current blasting practices as a means to improve fragmentation.

Jan 1, 2015

By Tyler Rockley, Carla Reyes

Autonomous fragmentation measurement systems designed for shovels have been in operation for nearly two decades, however fragmentation systems capable of performing in the dynamic conditions of the front-end loaders (FEL) were only recently introduced to the market. This paper presents an in-depth evaluation of an automated digital fragmentation measurement system specifically designed to perform under the dynamic operational conditions of the FEL in two of Teck’s mine sites. As early adopters of this novel application, Teck embarked on a Proof-of-Concept (PoC) trial phase, defining a set of key performance indicators (KPIs) to qualify the performance of the digital solution in tough mining operating environments. The KPIs focused primarily on the hardware robustness, quality of image and segmentation, both day and night, availability of the system and sample ratio. The benefits expected from using this technology include increasing the safety of the current fragmentation measurement process, improving the quality of the analysis, increasing the sample representativeness, and using the attributes of the system to create an oversize detection alert to inform the loading operation process. A critical part of the evaluation was verifying the system’s effectiveness on the particle segmentation algorithm as this element often gets overlooked, especially when dealing with the large number of samples autonomous systems can generate; minor misclassifications due to inadequate segmentation are often dismissed as they might not be statistically significant, however systematic misclassifications can cause unacceptable deviation in the data and limit the intended application of the technology. The system’s performance was further validated through several tests that involved identifying objects of known sizes to ensure the reliability on the consistency of the particles’ segmentation.

Jan 21, 2025

By Alain Blanchier, Pascal Bernasconi

Blasting operations took place on Channel coast NW of France to extend Flamanville Nuclear Power Plant (EPR new generation). The closest operating reactor building was monitored by a 24 remote vibrations transducers network to fulfil, on one hand, the severe environment constraints and satisfy high degree of productivity required by the project, on the other hand. Although these requirements usually are incompatible, this challenge compelled to introduce a seismic modelling technique to optimize blast designs using electronic initiating system. The “Hybrid Seismic Modelling” (MSH) uses blastholes signatures (seismic vibrations records) which are greatly dependent on geology and alteration of rock mass, explosives, charge geometry, blast configuration, and the final excavation shape. In order to respect severe vibrations limits, excavation layout was divided into areas with specific blasting modules - type and number of charges, single charge, initiating sequence. Thanks to this technique, it has been possible to reach lowest blasts vibrations levels and a better productivity compared to classical blasting operation at the same location in the past. After the modelling method presentation - principle and use precautions, technical improvements are reported.

Jan 1, 2008

By S D. Cummings

"CRACKS CONCERN CORPORATION" Was the headline on the front page of the Terre Haute Tribune Star, March 1994. Having spent several years following up on blast-induced damage allegations made this article especially interesting. Knowing that there were no operating mines within 30 miles of this newly built, yet to be occupied building, also made the reading more enjoyable. The article went on to read, "Vigo County school officials have asked architects to find out whether some cracks in walls at the new school are due to NORMAL settling or if they indicate serious structural problems." It is obvious that if there were a mine within "Feeling" distance, blasting and the operator would have immediately become suspect as at least one of the potential causes. More alarming is that the investigation may have stopped there.

Jan 1, 1995

By Bryan J. Lane, Paul N. Worsey

The recommended maximum explosive weight for boulder blasting using internal charges is 0.1 O-kg/m” (3.5 oz./yd) (Olofsson, 1988). Normally this charge results in excessive scattering and flyrock, creating increased liability for the operator, especially in congested areas. An alternative technique using smaller explosive charges is being developed at the University of Missouri - Rolla. It is designed to reduce boulder scatter, flyrock and fumes and allows shooting in close proximity, using common blasting products.

Jan 1, 1999

By David Porter, Nathan Rouse

The implementation of presplit blasting has been widely utilized in open pit and underground tunneling. This case study works through the iterative process of developing a heading drill and blast design to control overbreak and limit backbreak in cut and fill headings. The initial design was based on rule of thumb parameters, and the design was then modified for the field conditions based on results. Throughout the design process the drill profile, explosive charge, and timing were modified to yield the best profile compared to design. Data collection during the design process was extensive to best understand the effect of modifying parameters, and gauge performance of design changes. Input from the miners as well as engineers was considered to allow for the best possible adaptation of the design change from existing practices. During the process resistance to change was realized and accounted for to understand the issues that the miners were facing and how to best address them while ensuring high quality blasting. Workforce buy- in was addressed by illustrating the long term benefits of higher quality blasting and the tradeoff of with a slightly more in depth drill and loading cycle.

Feb 6, 2023

By Adam T. Young

This paper will describe the process of using low density bulk emulsion as a means to maximize the production of an oversize or “rip rap” aggregate size range (8 inch to 72 inch) that the quarry customer has a market demand for. It will also discuss the pre-blast and post-blast metrics used during the product trials and evaluation.

Jan 1, 2017

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 J. P. Remi Proulx, Juan Camilo Gonzalez T., Winston B. Wilches

Alabama USA based Drummond Ltd. operates two open pit mines in the Cesar Coal Basin of Northern Colombia. The mines produce a combined total of over 25 million tons (22.7 Mt) of thermal coal per year which is transported by rail to Puerto Drummond, a direct ship loading facility, where it is exported to over 15 countries. The company has proven and probable reserves in excess of one billion tons of thermal coal.

Jan 1, 2015

By Rakesh Raghavaraju, Bibhu Mohanty

The paper analyzes the decay of shock pressure as a function of distance from the borehole, and its implication on shock-induced fracture properties of the target rock as the first step in predicting fracture and fragmentation behaviour in a well-characterized rock.

Feb 1, 2020

By Chris Breeds, Larry Leone, Jerry Wallace

One of the Authors was recently retained to provide a professional engineering analysis of the potential impacts from underwater blasts used to enlarge intake tunnels at the Cheesman Dam near Denver in Colorado and to design Blast Protection Bags that could be installed in each tunnel to protect the 100- year old downstream valve structures.

Jan 1, 2012

By Scott Rosenthal, Kyle Murphy

This paper discusses the trials and tribulations of obtaining Velocity of Detonation (VOD) readings in small diameter blast holes in an underground mine.

Feb 1, 2020

By Rakesh Raghavaraju, Bibhu Mohanty

Prediction of fracture and fragmentation characteristics of a rock mass subjected to dynamic loads, such as in blasting remains a major technical challenge. The present study is aimed at characterizing the shock transmission properties in controlled experiments in small scale in a well-characterized granitic rock, under varying borehole coupling conditions. Single blast-hole tests were conducted in a granitic rock sample of 145 mm (5.7 inches) diameter and height. The boreholes (in two diameters: 6.4 mm (1/4 inch) or 9.5 mm (3/8 inch)) were loaded with detonating cord of varying charge weight (5.3 g/m or 25 grains/ft to 31.8 g/m or 150 grains/ft of PETN). The effect of explosion gas penetration into the target rock was eliminated by inserting a thin-walled copper liner along the borehole wall. Embedded carbon composite resisters were employed at varying distances from the borehole to measure transmitted shock pressure for two coupling conditions (i.e. air and water) at distances of 1x to 9x the borehole diameter. The paper analyzes the decay of shock pressure as a function of distance from the borehole, and its implication on shock-induced fracture properties of the target rock as the first step in predicting fracture and fragmentation behaviour in a well-characterized rock.

Blastserve, ISEE’s Listserve is being replaced by our new Blasters Forum-online, an exclusive member benefit. Our goal is to provide an ISEE forum for you to network with your peers and exchange technical information and get answers to your technical questions. This forum is unique in the fact that only ISEE members are permitted to review or post on the site. Over time you will be able review the discussion history and use the archived discussion as a valuable resource for trends in the industry. The following are a sample of the discussions that too place recently on Blastserve

Jan 1, 2013

By Jonathan D. Aubertin

The unique nature of rock salt blasting is compared to traditional hard rock practices. Rock salt geomechanical nature is discussed in the context of rock blasting events. A cratering mechanism prevalent in soft rocks is presented and exemplified through a series of single hole blast tests performed in salt deposits.

Feb 1, 2020

By David E. Siskind

Increased mineral consumption and environmental concern have caused much interest in potential damage and annoyance from ground vibration and airblast produced by production blasting in surface mines and quarries. Ground vibrations are traditionally blamed for "shaking the house to its foundations," but often the airblast is responsible, particularly when the distances from mine to structure are large. Simultaneous measurements of ground vibrations, structure vibrations, and indoor and outdoor noise from blasting are being used by the Bureau of Mines to determine the relative importance of the ground and airborne blast energy in shaking the structure and making windows, dishes, etc., rattle.

Jan 1, 1977

By Guo Ziqing, Tang Qiuming, Liu Yuanyuan

The channel-type non-mechanical stirring production process is a new developed technology for emulsion explosives in recent years. It removes traditional equipment such as mechanical-mixing emulsification, mechanical-mixing sensitization, matrix pumping, and explosive pumping, and has been applied in China. This technique achieves a fusion of higher intrinsic safety and lower cost, as well as the excellent quality of products and high efficiency of production. The emulsion particle diameter is about 0.5μm. The storage period of emulsion explosive produced with span-80 emulsifier is more than 7 months.

Jan 21, 2025

By Kenneth Eltschlager

Post-blast assessment techniques using off-site data which includes location, seismograph and photographic data were discussed during the Blaster’s Weekend at this year’s ISEE Conference. Blast and property locations with commonly available GPS units allow for the spatial relationships surrounding the blasting to be documented. When distances are coupled with the charge weight per delay, the scaled distance can be calculated to any structure for either compliance with the rules, or to project limitations. When blasting seismograph data is obtained, the scaled distances are then able to be plotted against ground and air vibration levels for post-blast assessment purposes.

Jan 1, 2007

By Ann Barron, Paul Downing

Those employed in the explosives industry must have a keen familiarity of the explosives products they handle, the safety pro c e d u res they must follow, and the increasing number of laws and regulations governing blasting operations in order to perform their duties satisfactorily. For this reason, companies must make certain that their employees have the necessary knowledge and full understanding of their blasting and non-blasting responsibilities. Consequently, training is one of the most important elements in any company’s safety program.

Jan 1, 2004