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By Richard J. Mainiero, Eric S. Weiss

This project investigates the behavior of blast waves from the detonation of high explosives in an underground mine. A series of explosive tests was conducted in the underground and surface facilities at the Bureau of Mines' Lake Lynn Laboratory to evaluate the potentially dangerous effects of blast waves produced by open shooting, blown out holes, or accidental detonations of explosives. Shots of C4 and TNT were fired at the dead end of a 6 ft high by 20ft wide entry, at the intersection of two entries, and on the surface. C4 and TNT were chosen for this research because they exhibit very consistent performance. Behavior of the blast wave was evaluated through recording of the pressure as a function of distance from the explosive detonation.

Jan 1, 1995

By E. Contestabile, B. von Rosen

On August 5th, 1998, a tractor-trailer carrying approximately 18,000 kg of blasting explosives, struck a rock face on the side of the road near the town of Walden, Ontario. Eye-witness accounts of the incident state that there was an intense fire for approximately 30 minutes before the detonation. The detonation caused severe damage to the tractor-trailer, shifted the pavement and caused blast damage to the rock face. A rock fragment was recovered almost 2.5 km from ground zero and a 70 kg piece of an axle assembly was recovered over 1 km from the site. Windows were cracked at distances of almost 3 km.

Jan 1, 2001

By David Kosnik

This paper describes the technology and methods deployed in the continuous autonomous remote monitoring of cracks in interior and exterior walls of a residence near a limestone quarry. The objective is to quantitatively compare crack response due to blast-induced ground motion to that induced by diurnal temperature changes, weather fronts, occupant activity, and other phenomena. The remote monitoring and communication technology developed to obtain and disseminate crack response data for this study may provide the means to mitigate the effect of public concerns about potential impacts of ground vibrations inherent in construction and production of raw materials; it is critical to address these concerns because subsequent litigation may result in delays and increased costs.

Jan 1, 2009

By Daodu Opeyemi

This paper describes several damages of blasting operations on some case studies, analyzes causative factors, and emphasizes preventive measures. Due to several complaints from some host mining communities as a result of blasting operations; two quarries from Nigeria suburbs were visited for study. The blasting design parameters in the mining companies were examined. Also, the history and existing conclusion of the neighboring buildings were studied using structured questionnaire, personal contact and visual examination. From the study carried out, it was discovered that varying negative environmental and socio economic problems resulted from the effects of vibration and flyrock on the nearby agro mining communities. The consequences are not limited to distortion of landscape but also include extinction of some animals, poor agricultural productivity; such as damages to economic trees and reduction in the yield of crops, health problems as a result of shock resulting to psychological disturbances, communal conflicts, blast induced cracks of structures and sometimes total collapse of host agro mining buildings, thus indicating that most mines did not comply with the safety concept of the existing environmental laws and regulations. Based on the results of the study it was recommended that proper blast design of quarries/mines should be conducted and the compulsory use of seismograph will be crucial in developing predictions. Environmental impact assessment should always be conducted before, during and after each blasting operation. Other possible control of vibration, flyrock and airblast, are also discussed in the paper

Jan 1, 2009

By Brad Johnson

Homestake Mining Corporations' open cut operation at Lead SD. experienced a highwall failure in October of 1993. The failure released a 75' section of rock wall at the 5280' level. It came to rest on the 5200' safety bench. Since work was in progress below the failure, this rock had to be removed for safety.

Jan 1, 1995

By Lewis L. Oriard

Some two million cubic yards of sandstone and orthoquartzite were blasted and excavated at Upper Stillwater Dam, located high in the Uinta Mountains in northern Utah. The material was processed to produce concrete aggregate for the construction of the largest roller compacted concrete (RCC) dam ever constructed, and one of just a few in existence. The dam cross-section is shown in Figure 1. The aggregate was sound rock produced from required dam foundation excavation and from a quarry located about 1/2 mile from the dam site. Representative compressive strengths of the sandstones and quartzites were in the range of 20,000 to 30,000 psi.

Jan 1, 1993

By Virgil L. Lewis

On September 7, 1994, a Burlington Northern coal train crashed into a parked train in the downtown Gillette, Wyoming rail yard. I would like to address two issues in regards to this accident. One, a slide presentation of the damage created by the accident and the resulting required clean-up and two, a simulation of "what if" had there been an explosion during the course of the crash.

Jan 1, 1996

By Dieter Froelich, Giles Turcotte

In the near future, Bong Mining Company (BMC) will start mining a new deposit known as Zaweah II which is a narrow iron orebody requiring multiple row blasts with the bench floor as a free face. This called for the development of a new blasting technique. The article delineates the problem and its restrictions related to blasting. It also describes the approach which was taken for developing this new blasting technique which is essentially an application of the cratering theory with near spherical charges. Basic crater tests were conducted using various combinations of hole sizes, explosive strengths and delay patterns. From the results obtained, several alternatives were considered for production blasts and the most promising ones were evaluated.

Jan 1, 1980

By Virgil J. Stachura, Calvin L. Cumerlato

The U. S. Bureau of Mines is conducting research on blasting methods that reduce highwall overbreak and the associated rockfall hazards. This paper presents the results of tests using a low-density water gel to improve the quality of air-decked presplit blasts at a surface coal mine in New Mexico. The explosive's specific gravity averaged 0.50 and was bulk loaded using a modified truck which injected the gassing agent. Reductions in overbreak and resulting rockfall were achieved in comparison to a highwall presplit with ANFO. The test sections used 15° angled blast holes and resulted in 1,119 m (3,672 ft) of air deck presplit highwall using a low-density water gel which was then compared to 894 m (2,934 ft) of highwall shot with an ANFO air decked presplit design. The total quantity of explosives per hole ranged from 68 to 113 kg (150 to 250 lbs) and the 27 cm (10-5/8in) holes were 19- to 33-m (62- to 108-ft) deep on 5.5 m (18-ft) centers. Periodic visual examination and photographic surveys of the highwall test areas were used to document the amount of rockfall. In addition, laser profiles of selected sections were conducted to further delineate the damage and highwall contour differences.

Jan 1, 1995

By Mark D. Kirkbride

This paper outlines the process for designing a hard rock blast in an underground coal mine. The coal mine is located in Western Kentucky and operates four continuous miner units at 7 unit-shifts per day. The mine operates in the Western Kentucky No. 11 Seam with local variations from 4.5 - 5.5 feet seam thickness. The seam has sporadic siderite deposits. Usually these deposits do not significantly interfere with the mining process. When previous siderite deposits were encountered they were small enough to drop an entry for a couple of crosscuts. The blasting plan was called for after a siderite deposit was encountered in the belt entry at about one third of the panel length. The other sides of the panel had been previously mined and sealed so the decision was made to mine through the siderite deposit with the continuous miner instead of abandoning the panel. The deposit was approximately 300 feet in length down the belt entry. Mining through the deposit with the continuous miner was expensive in both terms of production and of wear and tear on the continuous miner. A blasting plan for the siderite deposits was designed to minimize damage to the continuous miner should a similar situation occur.

Jan 1, 1999

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 Anne Caroline Costacurta Polli, Jose Rojas Cáceres, Roberto Mahler de Morais, Thais Costa Silva

The technology and the knowledge about the behavior of explosives and detonation accessories allowed to create new products for different situations by the restrictions imposed by the market. In a Brazilian underground copper mine the restriction occurred in the use of high grammage Det Cord in the development heading blasts perimeter holes. Enaex Brazil has developed Densiex UG™ (Low-Density Bulk Emulsion), a water-resistant bulk gassing emulsion with a density ranging from 0.60 to 0.90 g/cm³ to replace the high grammage Det Cord in blasts. That product is pumped in the same Mobile Manufacturing Unit (MMU) as Enaex Brazil's standard underground (UG) bulk emulsion. This product has a Lower Velocity of Detonation (VOD), vibration, and detonation pressure, which contributes to a better finishing of the drift, lower impact in the support structures, and lower generation on unstable rocks in the perimeter of the drift. This case aims to summarize the results of the work on the application of the Low-Density Bulk Emulsion in perimeter holes in an underground development gallery at an underground copper mine in Brazil. During this work, 10 horizontal drift blasts were performed using the Low-Density Bulk Emulsion, which presented an average density of 0.64 g/cm³, increasing safety, a 25% reduction in overbreak, a 23% reduction in scaling time, elimination of rework, and a saving of $135,000 per year for this business partner that immediately implemented this new product in all blasts at this mine.

Jan 21, 2025

By Roger L. Keller

This paper covers the design and test blast procedures for several drop shafts and edits leading to the completion of a recent Rochester Pure Waters Expansion Project . Due to the projects "in-town" presence, and its close proximity to many sensitive vibration sites, very stringent ground vibration limitations and guidelines for blasting were places on each site.

Jan 1, 1991

By John R. Schuring, Walter Konon

The 2.0 in./sec. peak particle velocity criterion traditionally used to protect structures from blast induced vibration damage is non-conservative for landmark structures. Various factors which must be considered in establishing vibration criteria for landmark structures are discussed. Existing criteria by past investigators for this class of structure are presented.

Jan 1, 1984

By Isaac E. "Chip" Harris

Any contractor who agrees to supply materials or to perform services for a sum, is well aware of the importance of proper pre-bid information. Being able to properly plan costs and methods results in profits that allow the contractor to prosper. The paper discusses procedures used in estimating pre-bid cost; in particular, drilling and blasting cost for highways, dams and general construction projects. It breaks cost down into five categories and relates them to a total estimate used in bidding and budgeting a construction project.

Jan 1, 1975

By Mauritz Kotze, Jason Furtney, Ewan Sellers, Sandy Etchells, Tom Szendrei

The development of a simple model for gas flow and burden movement has driven the need to improve our understanding of burden breakage mechanisms for single hole blasts and the interaction between multiple holes in solid and jointed rock masses. Conventional analytical understandings of the burden breakout using the elastic-tensile fracture model were studied and found to provide a breakout angle that is independent of burden in contradiction to experimental data. By considering rock fracture in terms of Mohr-Coulomb plasticity using analytical expressions from the field of cavity expansion analysis an improved relationship between breakout angle and burden is derived until the point of critical breakout at which the angle of breakout suddenly changes from between 90 degree and 100 degrees to zero. This suggests that the critical burden occurs at about 0.6 times the radial fracture zone calculated from the analytical solutions.

Jan 1, 2013

By Advanced Initiation Systems Inc

10 years in R&D Last 5 years available commercially Worldwide Met strict approvals for manufacturing and use

Jan 1, 2004

By Selamawit Asfaw, Mohamad Sharif

In recent years, the use of modal analysis has increased to include many different aspects of the construction industry. Computer modal analysis can be used in determining the dynamic properties of a structure by mathematical equations and knowledge of the structure’s physical properties. This technique can now be used to predict the level of vibration induced by blasting on adjacent structures. Ground vibration induced by buried explosives is a major concern for contractors when excavating near utility pipelines such as gas and water lines. The size limitations placed on easements causes the necessity of additional utility lines to be placed in close proximity to existing lines. Through the development of computer models of the pipe, stress analysis can be performed prior to blasting. Based on the calculated dynamic properties (natural frequencies and modal shapes) and the maximum allowable displacements and stress levels (which are established by the pipe manufacturer) the allowable maximum charge weight per delay can be selected for the blast. The selected maximum charge weight per delay will ensure that the resulting pipe peak particle velocity level is within 95% confidence. This means, statistically, there exists a 95% probability that the actual pipe peak particle velocity would be less than the predicted value. The pipe is then instrumented with vibration measuring sensors to ensure that vibration levels are within the allowable maximum pipe strength. In conclusion, this technique can assist the engineers and blasters, to establish the proper blast design. It allows for safe and efficient installation of additional utility lines adjacent to existing lines. This technique can also be applied to predict the structural response to blasting induced vibration for a variety of complex structures. A detailed explanation of this technique, as well as an example of application including formulas used for this technique will be provided in this paper.

Jan 1, 2000

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 Natalie Zeleznik, Brian Hawkins, David Bradley, Rachel Gooding, Patrick Wilson, Brian Somes

"To perform a probabilistic risk assessment (PRA), a method of quantifying the risks associated withinfrequent, high consequence events, consequence models that generate representative estimates of human health consequences for a wide variety of representative scenarios are commonly used. Criteria that suitable models must possess include: (1) input requirements necessary to generate large volumes ofprobabilistic simulations; (2) the capability to output injuries with the necessary details and resolution;(3) the ability to capture the variety of different scenarios inherent in an assessment; (4) acceptablecomputational requirements; and (5) sufficient stakeholder buy-in for community acceptance."

Jan 1, 2017