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By David G. Borg, John Bussey

The new AIRDEK (tm) technique for pre-splitting in surface coal mines produces highwall conditions that have greater safety with lower costs for explosives, labor, and drilling. Successful applications have been made in highwalls ranging from 20 to 100 feet or more and in blasthole diameters from 3-1/2 inches to 12 inches.

Jan 1, 1988

By Carl Lubbe, Ron Frye, Wayne Curtis, Julie Pecori, Dan Leach

Blasting conducted in the USA using the new Electronic Initiation System developed by Altech has shown that an accurate delay system will benefit the customer. Results from test work clearly showed that improved fragmentation was effected and blast vibration was at least similar to that currently found at the test venue with improvements possible.

Jan 1, 1997

By Frank Sames

The control of the environmental effects, especially blast vibration and airblast, has become a dominating planning criterion for most surface blasting operations. Compliance with existing regulations is generally achieved through constraints in the blast design, or monitoring programs. Commonly, blast vibration and airblast signals are rated and compared only by their maximum amplitude and the principal frequency associated with the peak.

Jan 1, 1997

By Mike Cammack, Logan Huppert, Gustavo Azpilcueta

During the summer of 2015, Unisea Inc. sought proposals for the G1 Dock Replacement Project in Dutch Harbor, Alaska. It would be a one year project and construction was scheduled to begin in the spring of 2016. One aspect of the project was the requirement for a layer of armor stone to protect part of the dock. An estimated 30,500 tonnes (37,670 t) of armor stone were needed for the project. The source of rock was the Unisea Quarry due to its proximity to the project and the quality of the stone meeting all the required technical standards.

Jan 1, 2018

By Aloke Verma, R. Singh, S. Jana, C. Sawmliana, P. Pal Roy

On July 21, 2004, a trial blast using electronic detonators was conducted in India for the first time in an opencast mine at Pundi-E Quarry of TISCO, West Bokaro. Orica-IEL conducted the test using electronic detonators. To provide necessary technical feedback on wider applicability, CMRI scientists also participated in the trial blast.

Jan 1, 2006

By Paul Worsey, Dave McCool, Ryan Freeman, Chris Wolters, Rick Hines, John Bowles

Carroll Cave, located in Camden County, in south central Missouri, is one of the most significant caves in Missouri with over 12 miles of mapped passages and over 100 known but unmapped side passages. In the early 1990’s there was a breakdown of the originally excellent landowner/caver relations as the ownership of the only known entrance moved to a new generation and grottos squabbled for control. Subsequently the current owner of the natural cave entrance refused to grant anyone permission to enter.

Jan 1, 2003

By Donna Kliche, Charles Kliche

It has been previously documented that various weather conditions such as wind direction and speed, cloud cover and, especially, temperature inversions can significantly affect the overpressure generated by a blast event (Siskind et al, 1980; Oriard, 1999; Siskind, 2000). The overpressure can be magnified downwind and reduced upwind; a change in the regular profile of temperature with elevation can magnify or focus the sound intensity at some distance from the blast event.

Jan 1, 2011

By Steve Colburn

The CRITERION Survey Systems utilize both theodolite mounted and hand held reflectorless distance meters. These are eye safe, easy-to-use, and specifically designed to endure the harsh environments characteristic to the mining, quarry and explosives industries. Survey data collected by the systems is digitally stored in a ruggedized data collector and then processed with a specialized, Windows-based, interactive software program which can be run on’ any standard PC.

Jan 1, 1998

By V. A. Akinbinua

This work is intended to examine the relationship between rock fragments produced during compression tests using a soft testing machine, e.g. hydraulic press (the machine used in this work is Amlser rock testing machine), and the rock fragments size distribution produced by fragmentation of the same rock through application of explosive. The rocks tested are fine grained marble, medium grained tonalite and fine-medium grained granite, medium grained norite and medium grained gabbro. The rocks types are prepared according to ISRM methods to be tested for strength determination. The rocks are loaded at constant load until failure. The fragments resulting from the failure of each of the rocks types are collected for size characterization by sieve analysis. The same rocks tested under soft testing machine are also prepared into blocks of dimension 150 mm length x 100 mm width x 100 mm height for blasting by explosive application. Each block of the different rocks are drilled through with an 8 mm diameter drill to a depth of 80 mm. Each of the holes on the blocks is spaced from each other at 44.7 mm and with a burden of 28 mm. The holes therefore formed a rectangular blasting pattern. Each of the holes was charged with a 720 mg electronic detonator and fired instantaneously inside a cylindrical blasting chamber. After each shot, the fragments are collected for size characterization. The sizes distributions from blasting are compared with sizes distributions resulting from rock testing using the parameter Xc of the Rosin-Rammler distribution function (RR) and 75% cumulative percentage passing. The analysis and finding from this work is presented in this paper.

Jan 1, 2014

By C. Rutledge

The new mining method of multiple strata blasting, called StratablastTM, is described in a separate paper presented at this conference. The current paper presents three case studies where the technique was implemented in three different configurations in large-scale blasts in Australia. The first two blasts were in the Hunter Valley of NSW while the third was at Ensham Mine in Central Queensland. All blasts comprised multiple layers that were blasted in a single drill and blast cycle, with unique designs applied to each layer to achieve different blast outcomes from the various layers.

Jan 1, 2006

By Kameron Ray, Ruilin Yang

This paper compares the modeling results obtained by using a single seed waveform (SS) versus multiple seed waveforms (MS) as inputs to the Multiple Seed Waveform (MSW) blast vibration model. The field data for the comparison was collected at a coal mine. The results of the comparison showed that the MSW model yields more accurate predictions and significantly higher correlation to field measurement when using MS as input. When using a single seed waveform as input, different seed waves result in different predictions of PPV. In contrast, using the multiple seed waveforms as an input, more consistent results are obtained.

Jan 1, 2013

Numerical modelling was used to examine priming of bulk commercial explosives. Data for the HOM equation of state were calculated using a representative chemical composition, while Forest Fire model data were calculated, using a Pop plot which was estimated on the basis of existing sensitivity data, albeit for cap sensitive, small diameter explosives. The length and diameter of the primer, the location of the detonator in the primer and the shape of the primer form a set of parameters which are investigated. The effect of confinement and borehole diameter are also demonstrated, as reflections of shock waves create regions of high pressure in the explosive. The results are presented in terms of pressure and decomposition histories in the explosive and are interpreted in an engineering fashion to form rational suggestions for optimization of the priming process in the field.

Jan 1, 2002

By Tom Treleaven, Andrew Williams

Several contracts were let in Greenwich, Connecticut, for the installation of a sanitary sewer. The majority of the excavation was in rock and involved numerous challenges due to the following conditions:

Jan 1, 2003

By John A. Franklin, Tom C. Palangio, Norbert H. Maerz

WipFrag systems I and II have become the world standard in photoanalysis systems to measure fragmentation. Mines, quarries and excavating contractors can now easily measure blast results and track the progress of optimization efforts. This technology was developed and evolved to allow automatic measurements of the size distribution of patiicles on moving conveyors, in truck boxes and on crusher feeds. Production machinery can now be controlled by photoanalysis results and multiple cameras allow various locations to be monitored by a single system. Blast designs can be monitored on a shot by shot basis. Changes in delay times, explosives, patterns and hole sizes can be quickly evaluated. Along with this measurement capability has come a heightened awareness of the importance of “optimum size” and uniformity of particles for lowest cost production and material handling efficiency. In the past, savings in the “drill / blast” cycle of the operation were sometimes overshadowed by downstream production costs related to fragmentation. Now total production costs can be compared with fragmentation sizes which will immediately show the trend towards optimum size for economical production. No cost reduction program can be complete without this critical information.

Jan 1, 1997

By Enver Alan

This Research & Development (R&D) study was conducted in the field of applied blasting engineering in Ethiopia, within the AKH Railway Project, which was built in Girena, within the boundaries of the province of Mersa, in the Basalt Quarry at km 346, Ashangi Formation, occured in Eocene geological time in the aphanitic trachibasalt. Under the scope of the study, which has been performed to determine the effects of the artificial discontinuities at different depths and the effects of artificial discontinuities through structural damage risk, three test areas, at the same location and same formation, were considered. Six numbers of artificial discontinuities, each 10 m (32, 81 ft) transverse, were created by using pre-splitting and drilling-blasting technology. The number of sequential artificial discontinuities on each test area is two and they have the same length. The length of artificial discontinuities are; 6,80 m (22,31 ft) at the first test area, 13,60 m (44,62 ft) at the second test area and 17,00 m (55,77 ft) at the third test area respectively. The distance between sequential artificial discontinuities is 8 m (26,25ft) on each test area. Thirty-one shots were executed in order to produce vibration (10 shots on the first test area, 11 shots on the second area, 10 shots on the third test area). One hundred and twenty-three seismic recordings were obtained during the execution of the shots by using 4 seismographs. The closest distance between the shot points and the nearest measuring station is 5,30 m (17,39 ft). During the shots, the rock was cracked and there was no fragmentation and/or fly rock. At the first test area, measured PPV values are between 25,40-127,00 mm/s (1-5 inch/s) before the first artificial discontinuity and less than 50,80 mm/s (2 inch/s) after the second artificial discontinuity. At the second test area, measured PPV values are between 76,20-177,80 mm/s (3-7 inch/s) before the first artificial discontinuity and less than 76,20 mm/s (3 inch/s) after the second artificial discontinuity. At the third test area, measured PPV values are between 50,80-279,40 mm/s (2-11 inch/s) before the first artificial discontinuity and less than 50,80 mm/s (2 inch/s) after the second artificial discontinuity. Peak reduction rates in Peak Particle Velocity (PPV) values determined by measuring as follows: In the first test area 95,77% (106,00 mm/s to 4,48 mm/s) (4,17 in/s to 0,18 in/s), in the second test area 79,77% (176,00 mm/s to 35,60 mm/s) (6,93 in/s to 1,40 in/s), in the third test area 95,85% (from 205,00 mm/s to 8,55 mm/s) (from 8,07 in/s to 0,34 in/s). The arithmetic mean of the differences of PPV values (decrease rate) is 82,66% in the first test area, 69,37% in the second test area, and 92,03% in the third test area. The highest sound value is 138,50 dB and is defined as “noise”. When the measured parameter values are examined it was determined on the USBM norm graphs that these vibrations carry a risk of structural damage in the region before the first artificial discontinuity. While passing through artificial discontinuities the vibrations progress by losing energy and the vibrations passing through two artificial discontinuities do not carry structural damage risk under current conditions.

By Paulo José Costa Couceiro Junior, Manuel Lopez Cano

The biggest Port of Latin America - the Santos Port in São Paulo, Brazil - has been drilled and blasted by controlled underwater techniques in order to remove around 40,000 m3 (52,318 cubic yard) of rock divided in two outcrop rocks: Teffé and Itapema. Underwater pumped explosive, in combination with small cartridges areas, was successfully used in order to reach a target depth of -15m (-49 ft) and a width of 220m (722 ft) in the navigation channel. It was the first time that a pumped explosive was used in underwater blasting in Brazil and it represents a historic benchmark for projects of this kind in this country. The main challenges faced in this project include the control of the ground vibration, due to the necessity to carry out detonations 40m (131 ft) away from the quay wall - where the passenger terminal and the 80 year-old warehouse were located – and the rush schedule available, in order to finish the underwater drilling and blasting phase before the coming cruise season. Therefore, the perfect combination of an ideal pumped product with an effective pumping system has permitted to carry out the project in a record of less time than 3 months (against to the original expected time of 18 months), with all vibration events under control as result of the special ground vibration program carried out.

Jan 1, 2016

By Tjaar A. Louw, Albert P. Van Niekerk, Johannes J. Louw, Attie J. Goosen

Unlike molecular high explosives, commercial explosives based on ammonium nitrate do not detonate ideally according to the theoretical model for steady state, one-dimensional detonation. One of the reasons for this deviation from ideal detonation is the slower chemical reaction, due to less intimate contact between the oxidiser and fuel components. It is well known that the inclusion of gas pockets, such as microballoons, in the formulation of ammonium nitrate based emulsions and watergels enhances the performance of these explosives. Various different interpretations of the “hot spot” theory have been proposed to explain this phenomenon.

Jan 1, 1997

There remains considerable controversy in the industry regarding precision type detonators and where the end user can benefit from their use. In spite of the fact that electronic detonators and other prototypes were tested over one decade ago, explosive suppliers have hedged on full scale production for many reasons. Although some of the reasons were based on solid economics, others were strongly influenced by shear internal resistance within the corporate objectives, ultimate fear of market rejection, indecision as to what degree of precision was required and limited data on defining the real benefits to the end user.

Jan 1, 1992

By James Goldberg, Mark Withey

The Material Service Thornton quarry is a multi-million annual production tons complex. Surrounded by busy surface highways, and divided by a railroad on the north/south axis and further divided by a major interstate highway on the east/west axis, blasting is a daily challenge. This paper deals with the problems of production blasting in an area adjacent to that interstate highway, and paralleling a busy four-lane highway. Discussion includes primary blasting issues such as borehole size, drill patterns and flyrock controls. Discussion also includes blast designs, timing schematics, smooth-wall blasting solutions, traffic and vibration concerns and many other factors influencing the success of this project.

Jan 1, 2006

By Francisco Sena Leite, Pedro Brito, Auã Kiahla, Raquel Carvalhinha, Tomi Kouvonen, Vinicius Miranda

Shockwaves that generate vibration in the surrounding environment of a blast, are one of the most important factors to control drill & blasting works near delicate buildings as well as in sensitive structures (wall control). On top of the damage to the buildings themselves, sensitive equipment such as computers, measurement apparatus and medical devices can be also compromised. The most commonly measured values from vibration are PPV (peak particle velocity), acceleration and displacement. Some devices and techniques have been developed in the last decades to measure the impacts of these vibratory phenomena. This information can be used to predict levels of vibration for future blasts and improve their quality of design using the attenuation law. From traditional studies to modern seismographs, a range of solutions are used for this propose. The main problem of applying this kind of technology is the high cost associated with each measurement device. In order to measure the ground vibration using new technologies while lowering the cost, a device has been developed using a microcontroller and electronic sensors commonly found on the market. This new equipment was tested side by side with traditional seismographs and the results were sent to a server for analysis. After several blasts, the necessary data was generated for the validation of the prototype. Through numerical mathematical processing (Taylor’s approach and numerical derivation) the original data supplied by the accelerometer’s sensors was transformed into velocity and, after the data mining, a statistics residue analysis was applied in order to evaluate if the data from the prototype and from the traditional seismographs were similar. The data from each system was used to estimate the attenuation law and the results are shown in this paper.