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Case histories in blasting show that Livingston's cratering technology has been applied successfully to blast designs with explosives having a charge length to diameter ratio not larger than 6. But the evaluation of experimental results such as the crater volume is tedious and sometimes impractical. A key analysis presented in the study shows that the optimum scaled volume relates well with the optimum scaled rupture limit, and the latter can be determined by means of high speed photography without excavating the blasted material. Through the studies of harvesting gypsum from a dried up settling pond the high speed photography approach has demonstrated to be effective for determining the optimum design for blasting plastic material.

Jan 1, 1987

By Roger N. Prescott

This report presents a new process in delay blasting with the use of ANFO and slurry explosives.

Jan 1, 1977

By Byron Groen, Corry Goumans

Description of Project: Project location is at WAC Bennett Dam in Hudson’s Hope, British Columbia, Canada.

Jan 1, 2014

By Paul D. Dupree

This paper discusses the drilling and blasting techniques used in blast casting at a large western coal stripping operation.

Jan 1, 1986

By Pierre Mousset-Jones, Geraint W. Harris, Robert Karlin, Jaak Daemen

In order to minimize the ore dilution induced by blast movement in surface mines it is necessary to quantify such movement. This will make it possible to more accurately locate the grade boundaries on the surface of a blasted rockpile prior to excavation. This paper describes the development and testing of a method to accurately measure the direction and magnitude of sub-surface blast movement. The technique involves the use of magnetic "radiometry, using a cesium vapor "radiometer and real-time differentially corrected, GPS system, to locate the post-blast position of magnetically enhanced target objects, whose pre-blast locations are known, without disturbance of the blasted rock. The objective is to design an accurate and efficient technique which can be integrated into a mines production cycle.

Jan 1, 1997

This paper presents a brief discussion of three case histories to illustrate several aspects of the question of blasting in or immediately adjacent to concrete. The results demonstrate a need to make dramatic upward revisions in previous criteria, whether it be the standard particle velocity criteria or damage response spectra bounds, - especially those which include conservative upper limits of constant acceleration for the high-frequency portion of the spectrum. It is demonstrated, also, that conventional off-the-shelf blast-monitoring instruments are not capable of monitoring small blasts at close range. Both the frequencies and the levels of effect are beyond the range of such instruments. These case histories suggest further that there is a need to review the applicability of certain wellknown equations of elasticity.

Jan 1, 1980

By Steven V. Crum, Willard E. Pierce

Concern has been raised about the adequacy of current regulatory guidelines designed to protect homes from unwanted blast damage due to low frequency ground vibrations; in particular those with predominant frequencies below 6 Hz. This report summarizes and updates the preliminary results of a continuing Bureau of Mines investigation which will be completed later in 1995. Four structures at four different surface coal mines have been studied by examining their response to ground vibrations created from overburden blasting. House response to ground vibrations with dominant frequencies down to about 3 Hz were recorded. Many of the blasts produced ground vibrations with peak amplitudes above expected crack-producing thresholds. Response motions were compared to those predicted by theoretical single degree of-freedom response models.

Jan 1, 1995

By Lawson J. Taylor, Paul N. Worsey

Recent reputable evidence conclusively indicates that conventional chemical delay elements in delay detonators are notoriously inaccurate and can thus seriously affect blasting efficiency.

Jan 1, 1983

By W. Reisz

Blast area security is the responsibility of everyone involved in the blasting operation and goes well beyond simply controlling access by unauthorized personnel.

Jan 1, 2009

By Jeff Wachendorf

As the title "Cast Blasting Around Town" implies, this paper details the starting of a cast blasting program in and around the town of Colstrip, Montana. As strip ratios have increased, the need to adapt and find solutions to provide coal at a reasonable cost to the captive power plants has risen. Colstrip, Montana has a long history of coal mining which dates back to the early 1920's when Foley Brothers began supplying coal strictly for powering locomotive engines. Early mining days starting in the 1920's and the progression up through the 1970's when mine mouth power plants were built will be discussed. To accomplish the desired results, early mining techniques included steam and electric powered equipment as well as a lot of actual horse power.

Jan 1, 2009

By Mo Jadbabaei, Scott Harrison

There is very limited information available regarding the air pressures, flow rate, and velocity profiles in blast hole air drilling applications. Currently, many people are using incompressible flow correlation to calculate the bailing velocity. In this article, air pressure, flow rate, and velocity profiles are calculated using compressible flow theory. The airflow at the bottom of the hole is simulated using the jet flow theory. The concept of choking condition is introduced, and it is concluded that the velocity at the nozzle exit cross section cannot exceed sonic velocity. The minimum pressure required for achieving choked condition at the nozzle cross section is calculated. Choked and overchoked flow conditions at the nozzles are examined, and the maximum achievable cleaning power is correlated to the nozzle size and pressure.

Jan 1, 1999

By John Manka

Emulsion manufactures often spot buy the diesel fuel used in their fuel phases from various sources. Because their diesel source changes, there can be large fuel variation which may affect the quality of the resulting emulsions. This paper shows that the diesel fuel used in manufacturing emulsion explosives has a significant impact on emulsion stability and that the fuel additives dosed into the diesel fuel as it is made also have an impact on the emulsion characteristics and stability. We found that fuels with higher distillation ranges improve emulsion stability. We also found that while none of the diesel fuel additives affected the initial formation of the emulsion, some fuel additives did affect the characteristics and stability of the emulsions as measured by emulsion viscosity, droplet size, high and low shear testing, bin storage testing and freeze thaw cycling.

Jan 1, 2002

By John L. Floyd

One of the key factors that controls the overall profitability of surface operations is the required volume of excavated material. If the overall angle of final walls can be maximized the amount of material excavated will be reduced. However, as the slope angle becomes steeper the wall's factor of safety decreases. As a result, the development and implementation of efficient wall control blast designs becomes critical to achieving stable walls. Many site specific conditions should be taken into account when defining the methods that will be used to lessen blast induced wall damage. This paper will discuss the steps needed to properly evaluate the site and develop efficient designs. Four variations of wall control blast designs will be evaluated in terms of cost and performance. In addition, the paper will include the quality controls needed to successfully implement and refine the blast design.

Jan 1, 1998

By Alan R. Cameron, Alastair C. Torrance

An explosives underwater test facility has been established and commissioned in the Hunter Valley, New South Wales, Australia which allows the measurement of the actual shock and gas energies of the explosive

Jan 1, 1990

By Edward J. Jr Walter

This paper discusses the use of slant hole drilling and water matting as an effective method of reducing costs in shaft sinking operations through a general review of cost priorities for the contractor.

Jan 1, 1976

By Douglas R. Burns

During the summer of 1989, Maine Drilling and Blasting of Gardiner, Maine was contracted by Cayer Corporation of Harvard, Massachusetts to drill and blast an interceptor trench at the Nyanza Chemical Superfund Site in Ashland, Massachusetts.

Jan 1, 1991

"Blasting is an inherently destructive process and inflicts damage to the immediateperiphery of an excavation, which is later manifested as ground control and dilutionproblems. Different explosives release their energy and interact with the rock in differentways."

Jan 1, 1993

By J. Esterle, J. Kruttschnitt

Fragmentation modelling in soft rocks presents a challenge due to their propensity to further fragment after blasting during normal handling. Coal and some iron ore deposits are examples of materials that undergo significant degradation during the extraction, hauling and dumping process of the mining operation. The Kuz-Ram model is an empirically derived predictor of size distribution from blasting hard rock. Little breakage occurs during excavation and subsequent sizing of hard rock, so the measured Run of Mine (ROM) size distribution is essentially the same as the post-blast (before excavation) size distribution. However, for soft rocks, each step of the excavation and hauling operation imparts energy to the rock particles so the measured. ROM size distribution will be significantly different from the postblast size distribution. In order to calculate the ROM fragmentation at any stage of the extraction (or sizing) operation, the JKMRC has developed a model that combines both blast fragmentation and degradation through subsequent handling.

Jan 1, 2001

By Zhang Yangde

"This paper reports the clinical research work of Micro-explosion of Biliary Calculi . In theprogram the technique of directional micro explosion applied to disintegrate the biliarycalculi of body and decreases the rate of operation. Up to the present, 235 cases of biliaryduct calculi have been successfully treated by use of implusive force of micro-explosion .The success rate of blasting stones was 100% by the use of the directionalmicro-explosive instrument made by us , the once success ratio of micro-explosion was93.2% and tl~o rmulb of treatment were satisfactory. . Considering the density of theblood vesselsiD the human liver, limitation of space in the h~patic.ducb, the securiey andadaptation, we have designed two types of micro- explosives equipment called ZS device,electric initiation and nonelectric initiation to initiate explosion. The head diameter of thedevice ie 1.5-1.8 mm . It is applicable to all kinds of fiber endoscope by inserting ZSdevice under grossing eyes or TV set ."

Jan 1, 1993

By Earl C. Hutchison, Gene Smith

Extensive blasting was required to construct an underground tunnel for a 90 inch sewerage relief line. The tunnel and required excavation extended under an upper middle-class residential area in Atlanta, Georgia for more than a mile and a half and required the use of more than a half million pounds of explosives in the immediate vicinity of houses and residential apartments valued at more than 16 million dollars. Other houses and property valued at more than 80 million dollars were within range to claim blasting damages. An effective blasting damage control program was carried out which limited the number of blasting damage claims to less than 2-1/2% of the total number of potential claims. All but three of the small number of blasting damage claims which were made were effectively denied without any resulting legal actions and less than $3,800 was paid for settlement of the three claims.

Jan 1, 1981