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By Dennis Alan Clark

An increase in construction and quarry operations has necessitated blasting activities in areas once considered rural and in the close proximity of transmission pipelines. A method to determine the maximum allowable bending stress by the formulas outlined by the Battelle Memorial Institute report of October, 1962, and the assumed stress comparison with actual measured data is presented. A direct relationship between pipe stress and ground particle velocity is shown, and a method to predict stress by relating stress to charge weight and distance from the shot point is discussed.

Jan 1, 1976

By Ruilin Yang

This paper presents a fragmentation model for large production blasts. The model uses peak particle velocity (PPV) induced from the blast as a controlling parameter to predict the fragmentation size distribution. The PPV can be related to shock pressure or strain under a given rock condition. The fragmentation size is calculated at three-dimensional grid points within the blast volume. The grid size defines the calculation resolution of the model. The fragment size distribution is assumed to be in the same form as the crack distribution within a cube (of the size equals to the grid size) surrounding a grid point. The crack distribution in rock from impact is based on the finding from previous researchers (Seaman et al., 1976). The fines and oversized blocks are calculated explicitly. The summation of the size distribution at all calculation grid points over a specified volume of the blast yields an overall size distribution for the volume.

Jan 1, 2015

By Franklin J. A, Tam C. Palangio, N H. Maerz

WipFrag systems I, II and III have become the world standard in photoanalysis systems to measure particle sizes. 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 particles on moving conveyors, in truck boxesand 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, 1998

By Split Engineering Chile Fernando Fernandez

Mathematical modeling in conjunction with mineral characterization is widely used as a method for design and optimization of comminution circuits, to simulate the processes of crushing, grinding and classification. An important input parameter to the simulation models is the Run-of-Mine Particle Size Distribution (ROM PSD). The run-of-mine size distributions due to blasting have a great influence on the performance of a semi-autogenous grinding (SAG) mill. In this paper, a mine case study was conducted where there are four primary geologic units and the material properties between the four units vary considerably. Also, the mixture of the four unit that will be mined at any given time also vary considerably. This presents a challenge in terms of optimizing the blasting for mill production throughout the mine life. As part of the case study, field rock mass characterization, laboratory rock mechanics tests, and laboratory breakage tests were conducted. The field characterization and rock mechanics tests provide material properties used to simulate the effect of different blast designs on run of mine particle size distributions (ROM PSD). The JKSimBlast software was used for these simulations. The rock breakage tests provide material properties used to simulate crushing and grinding performance. The JKSimMet software was used for these simulations.

Jan 1, 2015

By Andrew Ritter, Victor I. Montenyohl, Stephen R. Winzer

Thirty-seven open pit production blasting operations have been monitored using high-speed cameras running between 500 and 7000 frames per second. Analysis of the resulting films reveals irregularities in timing including sequencing errors and crowding (holes firing less than 8 ms apart), confirming results of laboratory testing of ms delay blasting caps (Winzer, 1978). Where blasting parameters are otherwise constant and within recommended guidelines (stemming, spacing, burden, etc.), timing problems dominate the overall performance of the blasting operation. Model tests in layered Homalite 100, designed to simulate joint or bedding planes in rock, indicate the importance of the stress waves generated by the explosive in developing the crack network which is ultimately responsible for the fragmentation seen in the resulting muckpile. These mechanisms are strongly supported by high-speed film studies at Pinesburg, Maryland. Experiments in controlling relief in deep shots (where depth approaches the lateral extent of the bench blasted) using borehole geometry and hybrid initiation systems (electronic timer and pyrotechnic delays) were carried out. The results suggest that the 1 me/ft. of burden guideline developed by Bergmann et aI., 1974 is too short, and that much longer times are necessary to optimize fragmentation and muck digability. Longer times are found to reduce noise, vibration, and flyrock.

Jan 1, 1979

By Dennis A. Clark, Richard E. Calvin

As the scarcity of mineral resources increase and subsurface mining activities expand along with simultaneous surface mining in coal, industrial minerals and rocks, along with metals, the need to insure safe conditions is paramount.

Jan 1, 1981

By E Castelli, M Fomaro, R Mancini, M Cardu

The economic return of rock blasting is not provided by brute volume of broken rock, rather by the amount of marketable product. That is the case of the porphyry quarries of Trento district, whose output is mainly absorbed by road paving and building facing elements production.

Jan 1, 1995

By J R. "Dick" Daniel

One of the more common tasks in blast management is the adjustment of: shot geometry, explosive energy, and shot timing parameters to achieve changes in blast outcomes and costs. Many of these shot parameters, once a delayed blast is initiated, are modified by the development of new free faces which change the original or static input values to dynamic values. These newly generated dynamic values are easily calculated and find use in fine tuning shot adjustments and in rationalizing blast outcomes in a systematic manner.

Jan 1, 1996

By D Larson, M Finger

Chemical explosives may become a key element in many of the in situ energy and mineral recovery methods under development. This paper discusses the potential role of explosives in deep rock mining for resource recovery. Several energy and mineral recovery programs described are an outgrowth of the Plowshare Program and Explosives R&D conducted as part of the AEC/ERDA mission at Lawrence Livermore Laboratory. Several important aspects of the use of explosives in deep rock mining are reviewed. First, the status of knowledge of deep rock fracturing to create permeability underground is discussed. Completely contained blasting has not been a widely applied tool used in the mining industry. We conclude that data available on deep rock fracture is minimal and that the mechanisms that control the processes must be understood before technical and economic feasibility can be established. We also discuss the unusual problems in the selection of an explosive or blasting agent for deep rock applications including emphasis on the functioning at depth and safety aspects. Finally, a brief review of similar activities within the U.S. is given.

Jan 1, 1976

By Joshua Micah Hoffman

While it is easy to state that meaningful involvement of the community can play a critical role for a successful blasting operation, following through with this involvement is not an easy task. Structured Public Involvement (SPI) is a developed protocol for involving communities in project planning decisions and could be readily applied to the blasting industry. SPI was developed for the purpose of collecting quality public input about public transportation projects. The purpose of SPI is to bring about stakeholder satisfaction with potential projects by allowing controlled input from the stakeholders. It was designed and intended for democratic societies that have come to expect a voice in public projects. While blasting operations are not always in the domain of public projects, the fundamental process outlined by SPI can be useful for collecting feedback from the immediate public around blasting operations.

Jan 1, 2014

By Edward J. Jr Walter, Edward J. Walter

The vibration problem is approximately fifty years old. The original investigation of the U.S. Bureau of Mines was begun in 1930. Significant investigation into the problem was done by Crandell, Langefors, et al, Edwards and Northwood, and again by the Bureau of Mines. This resulted in an effective Safe Limit standard expressed in particle velocity as 2.0 inches per second.

Jan 1, 1979

By Terri Jordan, Kenneth Hollingshead, Mary Jo Barkaszi

The Port of Miami, Miami-Dade County, Florida (Port) is the largest container port in the State of Florida. However, it is located in the center of a diverse ecosystem. Biscayne Bay surrounds the Port and portions of the bay have been designated as a National Park, a Florida Aquatic Preserve and a state Critical Wildlife Area. The bay is home to many protected, threatened and endangered species including the Florida manatee, five sea turtle species, American crocodile and bottlenose dolphin, in addition to important recreational and commercial fish species.

Jan 1, 2007

By John W. Brown

During the summer of 1994 the mining industry experienced numerous accidents involving blasting related incidents. The Tri-State Chapter of Explosives Engineers planned a meeting to discuss three of these accidents.

Jan 1, 1995

By Thomas A. Simpson, Yung-Kwaun Jow, Dennis L. Gamble

Construction of the $200 million Riverchase Galleria Mall in Hoover, Alabama was started in early 1984. The construction area consists of about 70 acres. The extensive building complex requires heavy concrete foundations which have to be poured during the early stages of construction and on a nearly daily situation so that contractual agreements can be met on a timely basis.

Jan 1, 1985

By Roger Keller, Jason Ryan

A number of studies have evaluated excavation methods for the construction of subsurface facilities for a potential deep geologic repository for the disposal of nuclear waste at Yucca Mountain, NV. Many of these studies suggest that where TBM (tunnel boring machine) methods are not applicable and alternative mechanical excavation methods can not efficiently excavate harder rock drill and blast methods may be the most efficient means of excavation. However, a number of concerns regarding drill and blast applications have been raised in these evaluations, most notably the affects of blasting on the surrounding perimeter, as isolation of the waste by the natural barrier of the surrounding rock is a key element in the concept of a deep geologic repository.

Jan 1, 2001

Bloomfield Collieries Rix’s Creek Mine is an open cut coal operation located in the Hunter Valley region of Australia. The mine produces approximately 1.1 mt of saleable product per year and routinely employs cast-blasting practices for its unique dragline-truck overburden excavation method.

Jan 1, 2006

By Lawrence W. Hallanger

Anaheim Bay, located at Seal Beach, California, is the site of the Huntington Harbor development of waterfront homes and marine facilities. The main entrance to Anaheim Bay is a relatively narrow channel connecting the bay with the Pacific Ocean which runs under California State Highway One. During the development of Huntington Harbor the old highway bridge was replaced with a new, higher bridge to allow for boat passage through the channel. At that time only the main span decking of the old bridge was removed, leaving the support pillars and the approach ramps in place (see Figure 1). The narrowness of this channel, plus the increasing boat traffic created a situation in which public demand for the removal of the old bridge became significant. Because the bridge was located within the boundaries of the Seal Beach Naval Weapons Station (see Figure 2) the Navy became involved in the bridge removal. Eventually the task was assigned to the Naval Amphibious Construction Battalion One and work began in early 1974.

Jan 1, 1975

By Remi Proulx, Ruilin Yang

The effectiveness of presplit in soft or fractured ground is hard to visualize or quantify. There have been many attempts by the blasting community to measure and quantify the effectiveness of presplit blasts. Various methods have been adapted by different researchers, and the results are debatable.

Jan 1, 2019

By Leslie Taylor, W. L. Fourney, Uli Leiste

Over the past few years, our laboratory has been investigating the loading on vehicles due to the detonation of buried explosives. We have been using target plates to represent the bottom of the vehicles that were being subject to the forces from the detonating explosives. Parameters shown to be important in the blast loading were type of soil, stand off distance (distance from the surface of the soil to the bottom of the target plate), and depth of burial (distance of the charge center of gravity to the sand surface). We conducted over the first year of our work a large number of tests which looked at the impulse being applied to the plates as a function of depth of burial, stand off distance, and type of soil. Of the three parameters we found stand off distance to be most important, depth of burial to be the next most important parameter, with type of soil least important. We also found that impulse could be scaled with explosive size quite accurately and that results (for impulse) were quite repeatable from one test to the next.

Jan 1, 2008

By NA NA

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Feb 6, 2023