Search Documents

By Shad M. Sargand, Glenn A. Hazen, A M. M Jayasuriya

Various types of waves originate from a blast source to propagate through rock/soil media away from the blast. Input vibration to a structure depends on the soil-structure interaction which varies with the dynamic properties at the intersection as well as the stress and strain levels developed from the vibration of the structure-ground system. Hence it is important to study such effects on the response of a structure due to blast loads and this knowledge can be used in the design and control of blasts that are carried out close to buildings, highways and other structures.

Jan 1, 1994

By Duane A. Houkom

Down time in the Oil Refining and Petro Chemical Industry is extremely expensive. Each day of non-production may easily cost several million dollars. Explosives have been accepted by this industry to solve many of its problems. Explosives offer a solution which is faster, more economical and most important, safer than many of their methods. Our specialties for these industries include: Refractory removal, industrial cleaning, metal cutting and concrete removal. This report does not include information on concrete removal.

Jan 1, 1982

By Raymond M. Dixon, Dale L. Ramsey

Upon being introduced to the MAGNETIC COUPLING concept,Balsinger,Inc. wanted to conduct field trials to explore the potential of Magnetic Coupling in the U.S.. Although the Magnetic Coupling Concept has been widely used, the U.S. proposed blasting criterion not previously addressed by the system. Modification to the system assembly and blasting accessories had to be made to make the system adaptable to our specific requirements. The field trials and system modifications are the basis of this paper.

Jan 1, 1990

By S. Nakamura, H. Taniguchi, K. Noguchi, H. Sugihara, T. Matsuzawa

It has been reported that expanded poIystyrene and ANFO prills ‘were mixed on a blasting site for controlled blasting (ISANOL). Although there seems to be few possibility of their segregation because mixing on a blasting site is done, there is a great possibility of segregation in packing, transportation and loading of the product due to the different densities of the two ingredients in Japan where mixing on a blasting site still remains inoperative. The fiee-flowing property of ANFO prills was lost with the passage of time because the Abel oil infiltrated into the expanded polystyrene and that gave the product high viscosity.

Jan 1, 2001

By Mark S. Stagg, Steven V. Crum

The Bureau of Mines is conducting research to develop methods to control fragmentation and improve productivity in surface mine blasting. As part of this research, PRONT02D, a two-dimensional finite element computer program developed at Sandia National Laboratories, was employed to model the fragmentation produced from RS-50, a single hole, reduced scale bench blast in a massive dolomite. The fragment size distribution obtained from the computer simulation was calculated using a submodel that utilizes the crack density and nominal flaw size values computed by PRONT02D.

Jan 1, 1989

By Jianjun Tang, Wenjuan Bai

This paper presents a new method of formulation design for multi-component composite explosives. Based on the thermochemistry of the detonation process, the mathematic model of formulation design is established by optimization mathematics. Using the heat of detonation as target functions and taking the constraint conditions such as oxygen balance and costs etc into consideration, this model can provide an optimal solution quickly by means of personal computer. Using this method, the calculation and the simulation tests for a series of constituent sets and various constraint conditions can be conducted easily. In this way, the optimal formulation for the explosive can be determined, on the basis of the maximum heat of detonation and the lower cost.

Jan 1, 1997

By Mark S. Stagg, David E. Siskind

Five major environmental effects of rock blasting are ground vibrations, airblast, flyrock, dust and fumes. What makes them "environmental" as opposed to occupational health and safety issues is that their impacts are felt off the mine, quarry or construction site. For some impacts, safe zones are defined through experience, flyrock being a good example. Flyrock at a mine can be 1) rock thrown beyond the blast area or expected hazard zone, 2) rock thrown beyond the permit area, or 3) rock thrown more than 1/2 the distance to the nearest non-mine structure (OSM rule for surface coal mines). Rock throw of less than the "flyrock" range is then a safety issue.

Jan 1, 1997

By Charles G. Wade

In the ensuing years nitroglycerin-based dynamites will continually be replaced by water-based explosives. Until recently, the choice of a high explosive water-based product was limited to some type of water gel. Now, there is another choice. New emulsions are available having several degrees of sensitivity over a wide range of diameters. This paper discusses the properties of these new emulsions, e.g., physical and thermochemical; the relationship between diameter and explosive properties; and the effects of aluminum on total energy. There is also discussion of some of the unique properties of emulsions, their advantages, and how they differ from water gels.

Jan 1, 1978

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan, Simav Bargu, Savas Gorgun, Derya Kucukbrtem, Esat Tansev

Although many research studies had been carried out in the past in order to eliminate environmental issues produced from blasting unfortunately a general approach or formula has not been established yet because of the complexity of the matter. In addition to the wave and ground motion characteristics, the complexity of blasting parameters and site factors restrict the developing of a general criterion. So experimental site-specific studies should be still done in order to predict and control blasting effects.

Jan 1, 2002

By D. K. Ingram, G. L. Mowrey, T. R. Rehak

This paper summarizes flyrock and blast area security fatalities from 1989 to 1999 and examines the causative factors. Coal and nonmetal mining used about 43 billion pounds of explosives and blasting agents between1989 to 1999. A majority of this consumption was used at surface mines. Accident data indicates that flyrock and lack of blast area security were the primary causes of blasting related injuries in surface mining. Fatal injuries due to lack of blast area security were attributed to: failure to clear blast area; failure to follow instructions; inadequate guarding; inadequate blasting shelter; and unsafe location.

Jan 1, 2002

By Joseph W. Hejny, Marlyn G. King

Coal mining in the Powder River Basin has changed in recent years to accommodate the large quantity of coal produced. With strip ratios of one to one and up to three to one, extensive amounts of overburden have to be removed to get to the large thick seams of coal. Larger shovels and trucks have been implemented in the removal of this overburden. The addition of draglines and continuous miners have been added to increase the production of coal. Drills used today are capable of drilling up to 13.5 inch blast holes.

Jan 1, 1994

By Virgil J. Stachura, Larry R. Fletcher, Paul V. Sterk, Matthew N. Plis

The large diameter blastholes now being used in underground mining have caused concern because of their increased potential for damaging openings and creating rockfall hazards. In response to this situation, the Bureau of Mines is conducting research to reduce the amount of overbreak and damage to the perimeter of underground openings. This paper presents the results of tests with decoupled charges in 6.5 inch diameter blastholes, and unloaded guide holes, in Vertical Crater Retreat (VCR) stope panels at the Homestake underground gold mine in Lead, SD.

Jan 1, 1991

By R C. Berglund

Since the Republic Mine began production in the mid 1950's, drilling and blasting practices have continually changed. In recent years, progress has been achieved through the development of more precise blast engineering methods, in greatly increasing the use of non-water resistant ammonium nitrate explosives, and in changing to a non-electric in-hole delay initiation system. Also, recent experience indicates that ammonium nitrate fueled with nitropropane and methanol is a viable substitute for aluminized AN-FO.

Jan 1, 1980

By Michael S. Wieland

This report discusses the U.S. Bureau of Mines research regarding the desensitization and malfunction of cap-sensitive explosives deployed in underground coal mines. Delay blasting in underground coal generates severe shock waves and rifting forces that fracture and heave coal. These dynamic interactions can damage other charges still remaining in the delay pattern. The debilitating impacts precipitate degrees of reduced charge performance ranging from misfires to weak detonations or out-of-sequence firings. Damaged charges react poorly, perform less useful work, and/or generate atypical fumes with higher toxicity.

Jan 1, 1993

By Ettore Contestabile, Cameron Thomas

Implosive-type electrical/mechanical connectors such as XECONEX have been used extensively for joining electrical transmission lines. This implosive action of explosives has also been applied to other forms of high energy metal working with excellent results. However, as with many other products, the inherent blast energy of these units has caused some environmental concerns especially when used in proximity to inhabited areas.

Jan 1, 1995

By J Edmund Hay, T S. Bajpayee

The Bureau of Mines is developing a test to determine the initiating strength of commercial detonators. Various tests of "detonator strength" are in use, but many of them do not correlate well with each other, and so far, there is little evidence that any of them correlates well with the ability of detonators to initiate detonation in an explosive. Therefore, the Bureau decided to attempt a measurement of the ability of detonators to initiate detonation. To this end, an explosive mixture of adjustable sensitivity was developed. This mixture was nitromethane sensitized with ethylene diamine, the sensitivity being "fine-tuned" by the addition of nitropropane.

Jan 1, 1992

By S. Mandal, R. Singh

The demolition of structures with explosive though most rapid, safe and efficient requires planned blast design parameters with respect to geometric and strength properties of the structure to be demolished. The paper, here deals with successtil demolition of three old bridge piers by different blast designs. These piers were 11 m tall and very close to the existing bridge, The plan distance of the old piers from the existing bridge varied between 43 m and 14,25 m. The paper also deals with the mathematical concepts for the causes of such action of demolition/dismantling of structures.

Jan 1, 2001

By Robert Hopler

Accidents associated with the storage of explosives prompted regulating the locations of such storage at least as early as 1719, when an act was passed in Great Britain. During the following years various refinements to the regulations were made, but a major explosion in 1864 in which there was destruction and loss of life as far away as 10 miles, led to the landmark Explosives Act of 1875. This act certainly had influence on regulators in the United States: when Massachusetts established an explosives distance/weight table in 1904 they referred to the prior British work. Later, Colonel Dunn of The American Railway Association convened a conference of explosives manufacturers to discuss safe storage. From this conference the American Table of Distances was established in December, 1910.

Jan 1, 2007

By LaRay Collyer

San Juan Mine began pre-splitting the highwall prior to cast blasting in August 1986. The first pre-split shot used six inch PVC (polyvinylcloride) pipe inside a 10 5/8 inch hole, drilled at a 74 degree angle. The powder factor was about .90 pounds per cubic yard.

Jan 1, 1990

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