Search Documents

By P. N. Worsey, M. Schmidt

Many advanced military systems and civilian power generation concepts postulate the availability of compact sources of electrical power capable of delivering gigawatts over microsecond time scales. For example, such a compact power source is essential for future practical pulsed high-powered microwave sources. An explosive-driven flux-compression power generator (EDPG) could fill this requirement. A basic strength of this concept capitalizes on the inherent high energy density storage capacity of modern chemical explosives. It relies on the physics of magnetic flux compression to convert that stored chemical energy into very large amounts of electrical power over short time scales. The generator also has the additional advantage of employing the same types of explosives that are already routinely used in conventional munitions. However, the self-destructive nature of this type of power generator places serious limitations on power pulse-lengths and ranges of applications. This paper describes how a multi-disciplinary team led by researchers from the University of Missouri-Rolla (UMR), Texas Tech University (TTU), and Texas A&M University was awarded a grant by the U.S. Air Force Office of Scientific Research to perform basic research to resolve several fundamental EDPG problem areas. Described are the utilization of UMR’s extensive explosives research expertise and facilities to investigate questions of energy conversion efficiency and the mechanics of energy production. Also, UMR explosives researchers will provide inputs to improved dynamic computer models of the complex, intertwined physics and chemistry operative in these devices. In addition to explosives expertise, UMR provides facilities for basic explosives material research, as well as the storage, machining, and formulation of explosives. UMR researchers are also using test facilities and data collection equipment at the Rock Mechanics and Explosives Research Center and at the UMR Experimental Mine to perform “proof of principle” and subscale tests of explosive-driven flux-compression power generator components. An integral part of the paper is a description of the development of an extreme intensity flash system by UMR and TTU to allow for the high-speed photography of EDPGs in operation. This multi disciplinary research program offers major advances regarding the size, weight, and electrical characteristics of compact EPDGs. Such breakthroughs could dramatically accelerate the practical realization of systems currently under study. Also, these power sources may have far reaching relevance to other Department of Defense and certain commercial compact power applications.

Jan 1, 2000

By Paul Worsey, Matthew Coy

In the blasting industry, many different techniques are used to estimate and examine the effects of varying explosives and blast designs on the breakage of a rock mass. The overall objective is to find a cost-minimized blasting solution that also conforms to the legal and environmental concerns related to blasting. A major drawback to current blasting methods is the inability to account for "caprock," or a thick overlying layer found in sedimentary rocks that creates large amounts of oversize blasted material, especially on the top of a muck pile. This can lead to underestimating oversize in shots with massive top layers. A better fundamental understanding of blasting processes with caprock is required.

Jan 1, 2018

By Drew Martin

In March 2010 the Boral Linwood Quarry, Adelaide South Australia, implemented the blasting contractors Monte Carlo Blast Vibration Model as part of their blast design process. The Linwood Quarry was developing an area where blasting activities were marginally complying with the statutory vibration limits. Compliance to the statutory limits was only being achieved through the use of small blasts (less than 15 000 T (14 763 ton)) at a high cost to the quarry.

Jan 1, 2012

By Francisco Sena Leite, Thomas Palangio, Vinicius Miranda

With an increasing pressure to find efficiencies in the mining industry, operations are looking for continuous improvement tools to validate blasting procedures, a crucial and often overlooked area of the process. Using case studies completed at both small and large-scale mining operations, this technical paper proposes a practical methodology for pattern expansion studies, taking into account terrain parameters, rock quality and explosive strength. This technical paper will use a series of tools geared towards an economical continuous improvement procedure, using UAV particle size analysis to optimize blasting based on “generalized reduced gradient” for non-linear problems, with cost savings being the main objective. For the validation of this methodology, one scenario was created based on the operation’s budget: an economical continuous improvement plan that relied on manual data collection methods in order to baseline and optimize procedures.

Jan 1, 2018

By (Journal for the Fields of Gunpowder and Explosives) Germany (1914 Issues)

RBH Note: The following items are a deviation from the usual content of these articles, but I thought they were kind of interesting from an historical point of view (other than just explosives-history historical.) The interesting things to me are the military-related products, keeping in mind that World War I didn’t start until August, 1914, and then it was kind of an accident of political alliances gone awry. Obviously companies in Germany saw it coming. Of course, all the ads also included dynamite and safety explosives for mining and tunneling as well as the military items.

Jan 1, 2015

By Ryan Brogden

On the 5 September 2014 a road train (tractor-trailer) with two trailers carrying ammonium nitrate was involved in a single vehicle accident on the Mitchell Highway, 30 kilometers (18 miles) south of Charleville in Central Queensland, Australia. The ammonium nitrate was being transported to a mine site for use as a blasting explosive. The truck came to rest in the creek bed adjacent to a road bridge and caught fire. The vehicle burnt for over one hour before the load of ammonium nitrate exploded. Miraculously there were no fatalities; however eight people nearby sustained injuries, some seriously. The road and rail bridge over Angellala Creek were destroyed and vehicles in the nearby vicinity were seriously damaged. The truck carrying the ammonium nitrate was completely destroyed with over 2500 pieces of debris scattered up to one thousand yards (one kilometer) from the blast site.

Jan 1, 2018

By Quentin L. Rhoton

"The use of explosives in a surgical manner was approved to facilitate, due to time constraints, anextremely significant paleontological find in the Plunket Point area of the Dominion Range, Antarctica. The organic material revealed by surgical blasting techniques may have altered basic scientific dogma on Antarctic glaciation theory."

Jan 1, 1999

By Kris Shukla

Noise and vibration produced by blasting generate curiosity and concern from neighbors. Experiments conducted in Sweden, Canada and U.S.A. have established that fine cracks in the plaster--the weakest part of building components--appear at a particle velocity of 4.0" per second or more. Taking into account the margin of safety, the safe zone criteria of 2.0" per second has been established.

Jan 1, 1978

By Dan McCutchen, Oettmeier

Kelly bar drilling and blasting is unique to Florida, the' Bahamas and other marine limestone areas in the world where blast holes are required but will not remain open for the loading of explosives. This type of rock formation usually yields 1.5 tons of recoverable rock compared to 2.2 tons per cubic yard for competent limestone. The loss of .7 tons per cubic yard is due to voids and sand in the formation. These deposits all contain water to the top of the blast holes which are collared only a few ft. above the ground water level. The working pit is a water filled lake which is excavated from the bank by draglines. These drills have been used in Florida for many years to depths of 65 ft or less.

Jan 1, 1991

By Norman Paley

A blasting project was undertaken at the Teck Alaska Red Dog Mine to determine the extent that Semi-Autogenous Grinding (SAG) mill throughput could be increased by using electronic detonators. The Julius Kruttschnitt Mineral Research Centre (JKMRC) blast fragmentation, jaw crusher, and SAG mill breakage models were used to relate changes in the blast fragmentation measured with the SPLIT image analysis system to the SAG mill performance. For optimum performance a SAG mill requires a particular size distribution; a number of large rocks to facilitate breakage by impact, as few as possible middle size rocks that become critical size, and the maximum fines which will pass quickly through an open-circuit mill. Physical constraints of drill and charging equipment size limit the extent that pattern geometry can be changed, and the powder factor increased, to maximize fines. However, a growing number of studies have shown that the use of electronic detonators can lead to increased fragmentation and greater muckpile uniformity, providing an alternate means of increasing primary breakage by blasting. Unfortunately results in the literature rarely quantified the changes to the fragmentation distribution. The measured gyratory crusher fragmentation of 2,750,000t of ore was used to compare stockpiles constructed from shots using pyrotechnic detonators to those using Orica i-kon electronic detonators. In the first stage of the study, stockpiles shot using 25 ms inter-hole timing with pyrotechnic detonators were compared to stockpiles shot using the same inter-hole timing with electronic detonators. In the second stage of the study, stockpiles shot using 17 ms inter-hole timing with pyrotechnic detonators were compared to stockpiles shot using 8 ms inter-hole timing with electronic detonators. When electronic detonators were used with the inter-hole timing kept constant, fragmentation uniformity was slightly increased, but mean fragment size increased by 20%. When electronic detonators were used with faster inter-hole timing, fragmentation uniformity was slightly reduced, but mean fragment size decreased by 30%. Modeling was used to determine the SAG mill throughput which could be expected from this change in fragmentation to determine the pairs of pyrotechnic and electronic blast pattern geometries that would provide similar throughput. The economic benefit from the electronic detonator shots was calculated to assist in determining the optimum blast designs for their use.

Jan 1, 2010

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 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 James L. Wilcox, Douglass P. Bacon

As the U.S. Environmental Protection Agency (USEPA) and state regulators increase the stringency and enforcement of regulations concerning emissions produced by open-air detonation of energetic materials, research must provide the means of obtaining emissions data. The BangBox emissions testing program established the technical foundations for emissions characterization which have been accepted by the USEPA and other regulatory agencies; the technical issues remaining are nettlesome and require new approaches in test procedures.

Jan 1, 1996

By James C. Irvine

Meramec Mining Company's Pea Ridge underground mine is presently involved in a large scale pillar recovery program and has made use of both rotary and down-the-hole drills for large diameter blastholes. Groups of pillars have been blasted with water gels in massive blasts which have broken in excess of one million tons of ore per blast. An outgrowth of the pillar recovery program is the combination of rotary and down-the-hole drills to develop vertical "raises" between mine levels. This paper outlines the Pea Ridge procedure for pillar blasting including the use of non-electric caps. Techniques and loading rates are discussed, and safeguards against blasting damage which were developed as a result of the program are presented.

Jan 1, 1976

By Peter Dare-Bryan, Will Hunt, Lee Julian

It is well-known that blasting has an economic effect on grade control activities. However, until recently, methods did not exist for measuring the grade control value change caused by the blast. Rules of thumb were the best method to minimize ore loss and dilution, as simulation has been traditionally constrained by time and computer power. Even with these rules followed, an extensive study performed on over 150 blasts showed that the value change caused by the blasts followed a normal distribution – some blasts created value, and some blasts destroyed value. The question naturally asked was “How can we ensure the blast designs are optimized to create value?” Recent advancements in computer power have enabled real-time blasting simulations that create post-blast grade control models before the blast is fired. Understanding what will happen before it happens allows blasters and grade control personnel to iterate designs, searching for the highest value achievable.

Feb 6, 2023

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 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 Sharkey Bowers

This study was undertaken in order to determine a conservative estimate of the attenuation rate of vibrations through the shallow limestone in South Florida due quarry blasting. The natural limestone bedrock in occurs at or near the surface in southeastern peninsular Florida. While the shallow overburden soils is advantageous for mining purposes, vibrations from blasting has been a contentious issue in South Florida due to the proximity of the mines to several residential communities. White Rock Quarries and Krome Quarries are two active mining facilities in South Florida which generate numerous complaints, insurance claims, and lawsuits from residents in nearby communities who claim that the vibrations cause damage to their houses. Both quarries are located on the eastern edge of the Everglades, with thousands of nearby residences at the western edge of development in Broward and Miami-Dade Counties. Data obtained from over 400 publicly available blast monitoring and associated seismograph reports from White Rock Quarries were reviewed and compiled. The data was used to emperically develop a conservative estimate of the ground attenuation rate based on the scaled distance from the blast origin, which can be compared to Figure B-1 from USBM RI 8507 to determine whether it is feasible if damage could have occurred at a given property.

By Brian Hawkins, David Bradley, Rachel Gooding, Lucas Rodriguez, Patrick Wilson, Kevin Wegman, Dhruv Mittal

To better protect the nation and inform difficult defense and preparedness decisions, the Department of Homeland Security (DHS) is performing a probabilistic risk assessment of explosive terrorism risk to the US homeland. After assessing existing models against requirements, well-developed mathematical descriptions and algorithms associated with explosives hazards were combined with probabilistic modeling techniques used in DHS chemical, biological, radiological, and nuclear (CBRN) terrorism risk assessments to create a suitable interior explosive consequence model for assessing the impact to human health.

Jan 1, 2018

By Ali Kahriman, D. Adiguzel, R. Ulger, U. Akkaya

The environmental problems arising from ground vibration has been faced and discussed frequently in various industries such as quarry, mining, civil works, shaft, tunneling, pipe line and dam construction etc. where the blasting operations are unavoidable. This paper presents the results of ground vibration analysis induced by blasting during the construction of the Istanbul Kadiköy-Kartal metro tunnel. Different rock formations in this tunnel route which is 21.6 km in length were encountered during the excavation process by blasting. As a first stage, Hoek’s Geological Strength Index (GSI) values of rock units were determined by using inverse distance weighting method. The GSI values which were obtained from boring data were used when evaluate the data. GSI values were estimated by inverse distance method (figure 3) along with the tunnel route. Afterwards, ground vibration parameters induced by 21 shots which were made in different locations was monitored and passing routes of vibration waves determined. Weighted averages of GSI values were calculated according to distance of the regions where vibration waves passed. Multi regression analyze were made with using frequency, charge per delay, GSI and the distance between the shot point and monitor station. The main goal of this study is to investigate the relationship between ground vibration frequency induced by blasting and GSI.

Jan 1, 2011