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By Ian Bell, Shahram Tafazoli, Bahram Sameti, Aylin Azmin, Edmond Chow, Nima Ziraknejad

Image-based rock fragmentation analysis methods have been applied by blast engineers to estimate rock size distribution for over 25 years. These methods utilize a wide range of image segmentation techniques, from manual to fully-automated, to delineate the edges of the rocks in the image. In most commercially available image-based rock fragmentation analysis systems, rock delineation results are converted to physical rock sizes by introducing one or more reference objects (e.g., basketballs or other objects with known geometry) to the scene as size-scaling references.

Jan 1, 2014

By David Hersey

The Paseo Bridge was located at the I-29/I-35/US-71 Missouri River Highway Crossing. It was built between 1952 and 1954 by Massman Construction Company. The 1,232 foot long, self-anchored suspension bridge was the longest of its type when built. On Jan. 22, 2003, a connector pin designed to allow the bridge to expand and contract during temperature cycles seized and caused a portion of the bridge deck to raise up and block traffic. This marked the beginning of the end for the old Paseo Bridge.

Jan 1, 2013

By L. A. Heim, E. A. McCullough, N. J. Amiotte

The explosives industry is subject to the laws of multiple jurisdictions, which means that several regulatory agencies are responsible for governing different aspects of the commercial explosives industry. Among these regulators are the Mine Safety and Health Administration (MSHA) who implements codes that better ensure both occupational and public safety which is influenced by professional blasting projects and the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), who enforces commercial explosives storage and security, among other responsibilities.

Jan 1, 2014

By Thomas L. Barkley

My historic auditing of Underground Drilling and Blasting Practices has demonstrated to the author the need for reviews of many mines' procedures in these processes. Poor understanding of the basic principles and practices of the drilling and blasting science in Underground Development Mining has created significant costs to mining operations in many instances.

Jan 1, 2019

By Steve Collinsworth

Sometimes, for those of us in the right place at the right time with the right product, necessity creates opportunity. Such is my case at a West Virginia coal mine where a mine manager was desperately seeking a way to eliminate coal damage on cast shots while maintaining cast percentage without the expensive process of secondary drilling. This paper will focus on how bottom hole air decking is solving the problem.

Jan 1, 2000

By Ed O'Connor, Per-Anders Persson, Manhong Zhou

This chapter deals with the concepts of shock waves and detonation waves together, because a detonation wave is really a shock wave, supported by the explosive reaction that the shock wave ignites and propagates as it travels through the explosive material. In the context of rock blasting, furthermore, there is justification for treating shock waves and detonation waves together, because the mechanical effect of the detonation in an explosive in a drillhole in rock is propagated and its effects are spread throughout the surrounding rock by means of a shock wave. The overall performance of an explosive in rock blasting or any other application is of course dependent on how much thermal energy is released in the chemical reaction that occurs when the material detonates, and on how much useful mechanical work the reaction products can do as they expand. A major portion of this chapter deals with the prediction and measurement of explosive performance, a subject which is now still in a process of rapid development.

Jan 1, 1997

By Per-Anders Persson

This chapter deals with the concepts of shock wave8 and detonation wavea together, because a detonation wave is really a shock wave, supported by the explosive reaction that the shock wave ignites and propagates as it travels through the explosive material. In the context of rock blasting, furthermore, there is justification for treating shock waves and detonation waves together, because the mechanical effect of the detonation in an explosive in a drillhole in rock is propagated and its effects are spread throughout the surrounding rock by means of a shock wave. The overall performance of an explosive in rock blasting or any other application is of course dependent on how much thermal energy is released in the chemical reaction that occurs when the material detonates, and on how much useful mechanical work the reaction products can do as they expand. A major portion of thii chapter deals with the prediction and measurement of explosive performance, a subject which is now still in a process of rapid development.

Jan 1, 1998

By Braden Lusk

This paper includes results from analysis of recorded Acoustic Responses of Structures to Blasting. The analysis was performed to determine specific characteristics of sounds experienced inside homes during blast events. Data was collected in a typical house within the Boone North No.2 Coal Surface Mine in Ashford, WV which was instrumented for several blast vibration and acoustic responses. The instrumentation consists of four acoustic microphones distributed throughout the internal areas of the house and three geophones buried near the house. Two additional channels collect the trigger signal and Air Blast information. For each blast event recorded by the system, the mine blast reports were used to obtain major blast characteristics such as distance from the blast to the instrumented house, weight of explosive used, number of boreholes, delays, and other important parameters. This information allowed study the relationship between the acoustic response and the blast design. From a database of 43 records, five records were chosen for complete analysis. These records were chosen based on distance from the blast to the house, and specific blast parameters. This paper presents the result of the relationship between the frequencies and amplitudes for the entire trace of acoustic records, the response due to ground vibration (GV), and the response due to air-blast (AB). Frequency content was obtained through Fast Fourier Transforms (FFT), using D-Plot software. The records have a typical shape that permits cutting and analyzing each part of the signal with respect to GV and AB separately. Some conclusions are reported concerning the relationship between blast parameters and acoustic response of structures.

Jan 1, 2009

By Kirk Yeager

During the last several years the FBI has been involved with a detailed study of explosives designed to replicate formulations utilized world-wide by terrorists. In addition, numerous formulations , based on literature and internet sources were examined. During the early stages of this work, a good many of the energetic mixtures studied were based on simple ammonium nitrate fertilizer. While the use of ammonium nitrate in commercial explosives is well studied and documented, the characteristics of the mixtures produced by criminals and terrorists have been less well researched. To aid law-enforcement in understanding the properties of these poorly understood formulations, a “cradle to grave” examination of their characteristics was conducted.

Jan 1, 2001

By Kurt B. Oakes, Brian M. Fortelka

Unimin Corporation operates an underground Silica Sand mine at Guion, AR located in North Central Arkansas. The Silica Sand deposit at Guion is part of the St. Peter Sandstone Formation, which is overlain by a competent dolomitic limestone from the Joachim formation, acting as the roof directly above. Both the St. Peter and the Joachirn Formations are of Middle Ordovician age.

Jan 1, 1999

By Roy McKinstry

In March of 2001, Barrick Goldstrike became the first surface gold operation in North America to evaluate the advantages of electronic detonators. A detailed study was conducted to quantify the benefits of the use of electronic detonators to the downstream excavation, crushing and ore processing operations. The following methods were used to quantify blast performance: High speed film and video monitoring Firing time and rock response analysis of the high-speed films Digital fragmentation analysis of the post blast muckpile Vibration waveform analysis (including Fast Fourier Transforms and seed waveform modeling) Excavator performance quantification Crusher, SAG mill and ball mill performance evaluation Ore recovery analysis Cost/benefit analysis

Jan 1, 2002

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 Benedict C. Di Duca

In the underground construction industry. when bidding work, not only is the contractor faced with determining if rock: is in existence within the parameters of his work. he must also estimate the quantity and the most efficient method of removal.

Jan 1, 1990

By Claude R. Ayoub, Charles A. Kliche, David G. McDowall

Homestake Mining Company's Open Cut Mine is located in Lead, South Dakota, in the northern Black Hills. The mine is within 300 feet of occupied residences on the south end, and within 1200 feet on the north end. Mining began at the north end of the open pit in October, 1983, and blasting related complaints began almost immediately. Noise and ground movement comprised the majority of the structural damage claims. As a result of these complaints, Homestake purchased a recording seismograph and began monitoring nearly every blast. In addition, the company hired a consultant to review Homestake's blasting and monitoring practices. He was also asked to do a single, one-time study of the cracks in six homes. This initial work led to Homestake monitoring all blasts with three seismographs and having South Dakota School of Mines and Technology do a year-long study of crack development and propagation in five homes in Lead.

Jan 1, 1989

By Donald Hurd, James Rowland, Richard Mainiero

In previous conferences the authors have reported on toxic fumes generated by the detonation of ANFO. The research reported here extends the earlier work to include an emulsion blasting agent and ANFO/emulsion blends. Explosive mixtures were shot in 4-inch Schedule 80 steel pipe (outer diameter 4.50 in (11.43 cm), inner diameter 3.83 in (9.72 cm)) in a chamber in the experimental mine at the Pittsburgh Research Laboratory (PRL). Following each shot, the fumes in the chamber were analyzed using on-line instrumentation.

Jan 1, 2001

By Tom Goforth, Rongmao Zhou

The interest of seismologists in mining explosions has increased substantially with the construction of the International Monitoring System (IMS). The IMS supports the Comprehensive Nuclear Test-Ban Treaty by providing global data coverage from seismic, hydro acoustic, infrasonic, and radionuclide sensors that will detect a host of natural and man-made events at regional (<2000 km) distances. Ideally, the recorded data can be used to identify those events that have explosive characteristics and therefore might be clandestine nuclear tests. The regional observations assure the detection of mining explosions, and these must be properly identified to avoid false alarms of the monitoring system. Cooperation with the mining industry, including documentation of the firing programs, provides critical information necessary to characterize the seismograms.

Jan 1, 2006

By Florian Bauer

The Fording River mine in British Columbia produces hard coking coal in an open pit operation. Coal seams are exposed by blasting overburden and digging blasted muck with rope shovels. The drilling and blasting process presents a considerable cost factor to the operation. Reducing the amount of explosives needed therefore contributes considerably to costs saving initiatives. However, reducing the powder factor only makes sense if the subsequent loading processes by the shovels are not compromised in terms of productivity.

Jan 1, 2014

By Y. Idrogo

Electronic delay detonators have been used in most types of blasting application with great success, with the accuracy and precision being used effectively to control negative environmental impacts like vibration. They have also provided consistent repeatable fragmentation and heave results. With the very wide choice in delay period and powerful timing design software, the choice of firing times to optimise blast results is not always clear to the designer. So the improved results achievable from the use of electronic delay detonators are often not optimally achieved.

Jan 1, 2018

By Alastair Torrance, Braden T. Lusk, MinGi Seo, Gary Cavanough

Velocity of Detonation (VOD) is the most commonly used method to determine explosive performance as VOD is a function of the confinement (ground conditions) density and composition of the explosive. Techniques used to measure VOD include resistance wire, time domain reflectometry, simple start stop and fibre optic methods. All these approaches require a cable of some sort to be inserted into each blast hole being monitored and the holes to be fired in a specific sequence. It is time consuming and fairly technical to position the cables correctly to gather the data from each hole. It slows down the hole loading process and increases the number of people on a bench at that time. The equipment and cable limits the measurements to a few holes, typically 5 or less, that are in close proximity. These measurements can generate useful information about the monitored holes but does not provide a full picture of how the explosive is performing across the whole blast and whether any change in performance is noted with changing ground conditions or confinement.

Jan 1, 2019

By Theirry Bernard

The era of non-electric systems as an initiating system has revolutionised the blasting world by introducing a very safe initiating system that is reliable, with initiation sequence possibilities that are superior to those of purely pyrotechnical or electric systems. Electronic initiation has brought with it accuracy, programming and controls that were lacking in the non-electric systems. However, it has also led to a certain degree of complexity, which works against user-friendliness, sometimes introducing a few constraints that are balancing out the intrinsic performance of electronic detonators. The introduction of a hybrid initiation system, Electronic and Non Electric, offers accuracy, and flexibility that were lacking in non-electric systems, whilst removing the inherent complexity of electronic systems. This paper endeavours to summarise the advantages and disadvantages of non-electric and electronic initiation systems that have been recorded after years of experience on site. The paper will then describe how a hybrid system only keeps the advantages whilst eradicating the disadvantages, via a case study.

Jan 1, 2007