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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 Shazad Hosein, Rob Farnfield, Bill Birch, Liam Bermingham

The propagation of a shock wave through air as a result of quarry blasting consists only of one type of wave, the compression wave. This is in marked contrast to seismic waves where a number of different types of wave are generated by the one blasting event. Even so the interaction of the burn time of a single hole and the resulting air overpressure is still too complicated to be able to be accurately modelled from first principles. It is considered that the best way forward is to monitor an individual single hole to obtain a signature wave form that has resulted from this complex interaction. Once this wave form is known, the variation in geometry of a mutli-hole blast and the timings of the successive detonations can be modelled to give a sufficient degree of accuracy to recreate the likely magnitude, duration and wave form of a multi-hole quarry type blast. This can then be directly compared with actual air overpressure wave forms from quarry blast to verify the model.

Jan 1, 2012

By Leslie Taylor, R. Reed Skagga, William Gault

The ultimate aim of our overall task, of which the effort described in this paper is a part, is to be able to model the impulsive output of buried charges and the response of targets of interest. It is not practical or cost-effective to determine the response of all targets of interest to buried charges of all sizes by testing them. In order to have confidence in our models, however, they must be validated by a modest number of tests. A critical element in modeling the response of a target is the ability to model the loading function. The load a buried charge applies to a target above it when the charge detonates can be characterized in terms of the vertical impulse. The vertical impulse is a function of the size of the charge, its depth of burial, and the properties of the soil in which it is buried. The primary objective of the effort described in this paper is to determine the load a known charge places on a non-responding target so the data can be used to validate our models.

Jan 1, 2005

By Christodoulos Xiouris, Ali Reza, James Karnesky

A rocket parachute signal flare is often used to signal a maritime emergency. In the general operation of these devices, a solid rocket motor propels a metal body to an altitude of approximately 1000 ft (305 m). At the end of the rocket motor, a propelling charge drives a signal flare and parachute out of the metal body and ignites the flare, which then burns for approximately 40 seconds as it falls to earth. In this paper, we describe an engineering investigation of an accidental ignition of a rocket parachute signal flare, which caused injury to the user. T

Feb 1, 2020

By Christodoulos Xiouris, Ali Reza, James Karnesky

A rocket parachute signal flare is often used to signal a maritime emergency. In the general operation of these devices, a solid rocket motor propels a metal body to an altitude of approximately 1000 ft(305m).At the end of the rocket motor, a propelling charge drives a signal flare and parachute out of the metal body and ignites the flare, which then burns for approximately 40 seconds as it falls to earth. In this paper, we describe an engineering investigation of an accidental ignition of a rocket parachute signal flare, which caused injury to the user. The components of the flare involved in the accident were inspected via x-ray and microscopic imaging techniques, and compared with those of unfired flares recovered from the same vessel. Chemical analysis of residue on recovered components from the accident flare was also performed. These comparisons were used to determine the likelihood that the actuation mechanism had been deliberately manipulated. In the subject model of the flare, ignition of the rocket motor is accomplished through a percussion cap which is struck by a firing pin. Prior to activation, the firing pin holds down a pre-compressed spring. We present a comparison of the ignition system of the incident flare with those of other rocket parachute flares, which do not incorporate any stored mechanical energy.

By Claude Cunningham

Blasthole pressure is the starting point for many blast design calculations, but the way in which it is usually derived, from measured detonation velocity, indicates that more thought is needed as to its true meaning and implication. The general impression is given that the energy in the hole is defined by VoD, but rarely is this the case. VoD is defined by the energy released in the Detonation Driving Zone between the shock front and the Sonic (or 'CJ') surface, and for commercial explosives it is normal for reaction not to be complete within this zone. Reaction and energy delivery continues behind it, not reflected by VoD. Thus it would be more appropriate to use the theoretical VoD, not the measured VoD, to derive the starting pressure, since this would reflect the energy input of full reaction. In decoupled situations, the derivation of pressure at the blasthole wall using a polynomial decay concept is also of debatable value, and an alternative is offered.

Jan 1, 2006

By John Brennan

Necessity, they say, is the mother of invention. Certainly that sentiment held true during the early stages of explosive engineering. While seaside forts were concerned over static ignition of their black powder caches in the 14th century1, the mining industry in the 1800s were plagued by accidents surrounding the ignition methods for their black powder blasts.

Jan 1, 2011

By James Keenan

Mesabi Range blasting has evolved in over a century of mining. The obstacles including: hard and heavily jointed rock, bitter winters and frequent wet holes; combine to create a unique challenge for blasters. This paper documents current pattern designs, powder selection and loading practices for these seven mines that consumes as much as 130 million lbs of explosives each year. Blasting is characterized by wide burdens and spacings, large diameter holes (up to 16-inch) and bulk loading of augered and pumped emulsion/prill products.

Jan 1, 1996

By Gregory L. Hempen

"Pressure waves from submerged blasting can have adverse impacts on nearby structuresand on aquatic fauna. Underwater blasting is not allowed for some situations withoutmitigation of these adverse pressures. Two states currently require bubble-curtain, pressurereduction of underwater shooting for environmental concerns. St. Louis District hasconducted field monitoring of scaled testing and demolition shooting with air-screenmitigation. The deployment of compressed-air manifolds and air-entrained packagesheeting effectively reduces underwater blast pressure. St. Louis District is preparing areport on optimum use of underwater-blasting mitigation measures."

Jan 1, 1993

By Alan B. Richards, Aleks Todoroski

The undesirable effects of blasting fumes can be controlled by minimising the amount of fume created, and by avoiding the movement of the fume plume to sensitive locations. Substantial progress has been made by the blasting industry to reduce the amount of fume typically created by blasting, but at this time no specific blast can be guaranteed to be ‘fume free’.

Jan 1, 2017

By Greg Mclellan, Mark Johnson, John Pepper

In this paper, the measured vibrations are plotted in terms of the individual PPV components versus Scaled Distance (SD) on logarithmic scales. The maximum PPV is pIotted on a separate graph and equations are presented to predict the maximum PPV based on sealed distance and prediction level usmg power fits. The prediction levels include a 99.9% curve, which encompasses the data points and provides an envelope formula for determining the maximum PPV at South Florida sites. The dominant frequency distribution is established for the PPV components.

Jan 1, 2001

By Greg Quinn

After a long week of work in Colorado Springs this past July, I was looking forward to flying home to start a long anticipated family vacation. As I grabbed my seat on the plane, a man sitting next to me innocently inquired, to the row as a whole and not to me in particular, “I wonder what the weather will be like in Phoenix”? To most people, this is a common (maybe the most common) topic of casual conversation. To a meteorologist that just dealt with six thunderstorm delays at a major golf event over 4 days, well, lets just say the smirk on my face said it all. After giving my flight mate a detailed forecast and a short explanation on why I would know such information, I sensed, correctly, the inevitable follow up question was coming. “Why would you need a meteorologist at a golf tournament?”

Jan 1, 2012

By Larry R. Fletcher

The Bureau of Mines obtained blasting accident data from the Mine Safety ant Health Administration (MSHA), U. S. Department of Labor. These data were analyzed to determine the most frequent causes of accidents in mine blasting. Accident totals for 1971 through 1981 are tabulated for metal-nonmetal and coal mines both surface and underground. In the past 11 years (1971-1981, inclusive) there has been an annual average of 9 fatal and 121 nonfatal blasting accident victims. Underground mining averaged 6 fatal and 93 nonfatal injuries each year.

Jan 1, 1983

By Norman S. Smith, Richard L. Ash

Relationships between the three design factors of borehole burden, spacing, and length that control rock breakage were examined by means of reduced-scale bench blasts in dolomite. A set of three indices were developed for analyzing the differences between fragment-sizing distributions obtained from various design combinations. It was found that the factors were interdependent and the indices were directly related to the common stiffness relationship for solid structures. The burden-spacing-length combinations that produced the best and poorest overall breakage, maximum and minimum overbreak, and least and most toe were determined.

Jan 1, 1977

By Masanobu Morita, Koichi Kurokana, Kenji Hashimoto, Yoji Tasaki, Yukio Iida

"It has been the long desire of blasting engineer to realize the automatization of tunnelblasting to improve the safety and efficiency. As for bore hole drilling, the automatizationhas been achieved by the improvement of drilling machine. However, the firing process isstill depending on the hand-operation. We developed the wireless initiating system using amacrowave power as a step for automatization of tunnel blasting operation. In this paper,we present the outline of the wireless initiating system and the results of experimentalstudy of the wireless detonator which is key component of the system."

Jan 1, 1993

By John C. Adams, Darrel D. Porter

After conventional drill and shoot methods were determined to be unfeasible due the fractured nature of the ground, a "coyote" blast was designed to produce 250,000 tons of rock from Rhone-Poulenc's Maiden Rock silica pit located near Butte, MT. This paper will cover the design and excavation of the explosive drifts, the placement and priming of 190,000 pounds of explosives, and the backfilling of the drift to provide confinement of the charges.

Jan 1, 1993

By George D. Raitt, Rudy Lyon

Until fairly recently, Down-The-Hole (DTH or DHD) hammer drilling was never really a factor in large scale open pit surface mining. It was a method confined to water well drillers, aggregate quarries and limestone mines where the hole size rarely exceeded 6-1/2" (165 mm). Also it was somewhat limited to the harder rock areas such as the North East and South East United States. The trend in the big mining pits for coal, copper, gold and iron, was for the big rotary drill rigs with lots of muscle in pulldown, bitload and rotary torque.

Jan 1, 1998

By P D. Katsabanis

Image analysis has been proposed to be an accurate and convenient means of measurement of blast fragmentation. The paper compares the results of image analysis to screening using laboratory scale rock piles. The muckpiles ranged from uniform distribution samples to well graded samples following the Rosin-Rammler distribution.Deviations between screened and imaged distributions were observed in most cases due to the loss of fines. Addition of fines in the system improved the result derived by image analysis considerably. It is suggested that techniques for the prediction of fines be evaluated for modifying the size distributions produced by image analysis.

Jan 1, 1999

By Calvin Konya, Theodore R. Myers, Robert Lundquist

The design of a single, large mass blast using ring drilling may take two to three months. This time requirement inhibits the evaluation of multiple designs. It also reduces the flexibility to redesign a blast when a parameter affecting the blast changes. Manual preparation exposes the design of a ring blast to a greater probability of human error. The use of Computer Aided Design (CAD) can help to overcome the shortcomings of manual design preparation. High speed electronic calculation, as well as programming, allow for many designs to be considered before blasting. Parametric programming allows single or multiple parameter changes to be introduced into an existing design, such as changes in drilling equipment, variations in ore density or changes in explosive. Exposure to human error is reduced by programming that performs calculations and produces graphical displays for review by the designing engineer. The goal of achieving desirable fragmentation for the minimum cost, when using ring blasting, is obtainable using blasting design techniques and CAD. Multiple designs can quickly be generated and costed, producing cost curves that indicate an optimum design with respect to cost.

Jan 1, 1990

By Paul Worsey, Randall Franklin

This paper is based on an undergraduate research project undertaken for the explosives emphasis in the UMR mining engineering degree program by the first author. The purpose of the selected research topic was to investigate the impact sensitivity of commercial detonators to determine their relative safety for handling and how much abuse they can take without accidentally firing. A modified BAM tester was used for the investigation. Both electric and non electric detonators were impacted at incremental positions along their length to determine the relative effect of their various components. Repeat impact tests were also conducted to see how a damaged cap would react to repeated abuse. The results indicate that it takes a significant amount of impact energy to initiate commercial detonators. They also indicate that repeated abuse can increase sensitivity. Modern commercial detonators appear to be relatively insensitive to impact (an order of magnitude above RDX in the standard BAM test) and this is mainly due to their construction. This explains why damaged caps with exposed powder are more sensitive. Their measured insensitivity correlates with rough handling not being a major cause of blasting accidents.

Jan 1, 2004