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By Dave Otto, Ron Elliot, Ed Hatch

This paper is a summary of the work carried out by an international team of specialists in the successful explosive compaction of the sand fill core of the Molikpaq offshore oil production structure. The sand fill core is an essential element for the stability of the structure. The sand core must resist liquefaction forces caused by heavy wave action, ice loading, and earthquakes. Explosive compaction methods were used to improve the stability of 220,000 cubic meters of coarse dredged sand placed in the core area. This project was challenging for a number of reasons. It was performed offshore in Russia, seven kilometers off the East Coast of Sakhalin Island. Logistics were a challenge, not just in getting the men and materials to the site, but also working with restricted headroom inside an operating oil drilling platform. This project called for the use of specialty explosives, strict blast vibration controls requiring a complex sequential blast design, and use of custom designed drill rigs. As Russian equivalent explosives were not available, the project involved getting approval for use of North American explosives in Russia, and use of a combined Russian - Canadian blasting crew. The blasting program was carried out successfully, meeting the required densification target _in a safe, effective manner, with no damage to the structure.

Jan 1, 2000

By Francisco Sena Leite, Pedro Brito, Gean Frank, PhD Soeiro de Carvalho, Jose, Vinicius Miranda

The consequences of rock blasting with explosives are directly related to the accuracy of drilling and, because they have an effect on fragmentation and ground level, they should be controlled to ensure a problem free production, increase work safety and reduce environment impact. Safety control is one of the most important processes in detonation, since it can compromise the worker security on site and, eventually, neighboring communities. Due to the technology advancements, it is possible to build a hole deviation control device with “of the shelf” parts, and for that reason the authors decided to evaluate the possibility of measuring hole deviation by creating a portable prototype using an electronic sensor capable of measuring the acceleration on objects, that is, to measure the own acceleration of a system, known as "accelerometer" and a micro-controller to handle and treat data. The main idea behind this paper is to validate the power of the Euler method, given the stepping limitations of the sensor and micro controller in order to reproduce of the hole shape. A case study was carried out, comparing the measurements of borehole deviations made by a traditional equipment and the prototype. A mobile application was also created in order to recover and treat and display the data to the user. For validation of the prototype, several holes were measured using the two devices. A residue analysis was used to validate the data obtained. After analyzing and confirming the effectiveness of the new equipment, the normality tests prove a symmetric distribution with null expected residual mean and minimum variance. Consequently, the accuracy of the prototype is evidenced. Thus, the authors aspire to emphasize the potential of using these sensors allied to a traditional numerical method for analysis of hole deviation.

Jan 1, 2019

By Dale S. Preece, Stephen H. Chung

Explosives energy can be used effectively in breaking and displacing large volumes of rock in mining and quarrying industries in both open pit and underground. The blast result, however, may not be economical if the applied explosives energy distribution is not properly applied to match a given set of geometries. However, this engineering problem can be resolved by using a modeling approach in the blast design process. Starting with a given set of blast design parameters that include explosive, elastic properties of rock, geometry of the blast pattern as well as the delay firing time, this paper shows how a discrete element blast model can be set up to allow the examination of the effect of critical design input parameters on blast results. Examples are given in this paper to help visualize the value and application of blast simulations. They are (1) regular and terrace bench blasting models for throw control, (2) underground blasting including a drop raise opening and (3) collapsing of a multiple room-pillar structure with proper firing sequence to control the mixing of blasted materials.

Jan 1, 2005

By Donald F. Rapp, Thomas E. Brown

The application of commercial explosives in an underwater environment, sometimes referred to as submarine blasting, presents the blaster with a unique set of demanding conditions which require exacting detail in design and application. There are two basic methods for removing rock under water: 1) "the drill and blast method"; and 2) "the dobying method." Because it is a far less effective method of blasting, dobying will not be addressed in this 'paper but suggested criteria can be found in the 16th Edition of the **DuPont Blasters' Handbook" page 371. Some examples of submarine blasting utilizing the drill and blast method include channel expansions, harbor construction, bridge pier footer excavations, utility excavation and demolition work.

Jan 1, 1994

By Jerry Wallace

The goal: At an industrial site, sever a well pipe containing an interior obstruction in a timely, cost effective manner by using a shape-charge to cut through the casing more than 50 meters below ground surface from the outside, doing so while inside a larger pipe, without damaging the larger pipe. The problem: Pumps and retrieval tools stuck nearly 50 meters below ground surface inside a 305 mm diameter by 9.5 mm wall thickness water well casing. The well, depth of 185 meters, had to be inspected for contaminates then properly decommissioned before industrial expansion could take place overhead. The limitations: A 508 mm diameter pipe had been driven around the 305 mm pipe to a depth of 63 meters. The usable internal diameter of the larger pipe was about 480 mm while the smaller pipe had buckled at one point forming a 350 mm wide spot. The charge thickness was limited to less than one-half the difference. Additionally, water that filled the annular space between the two pipes had to be displaced for the charge to work properly. The solution: Enlist the support of the shape-charge manufacturer to design, build and test a charge to work under the conditions present, then make it work in the field.

Jan 1, 2000

By Benjamin Cebrian

Wall control blasting is an expensive and labor intensive operation. Obtaining a good design is a first step that is not enough to ensure desired results. Experience shows that designs are not always well implemented, not only in the contour blast itself, but also in surrounding production blasts that can affect the final pit wall. In this paper techniques and reference indicators are described in order to audit and evaluate if correct implementation of designs have been done.

Jan 1, 2013

By Rapheal Trousselle

For over 5 years, Davey Bickford has been developing and testing an electronic detonator blasting system. These new-technology detonators provide more accurate timing than conventional systems that rely on the combustion speed of a pyrotechnic composition.

Jan 1, 1997

By Craig Wilbour, John Stimberis, Rob Gibson, Lee Redden

An avalanche is a snow slide. A simple explanation is that the snow on a slope will slide (avalanche) when the snow strength can no longer support its own weight. Snow avalanches happen when the load from snowfall or ram on a snow slope increases faster than the stre n g t h of the bonds between snow crystals. Avalanches can also happen when the strength of a buried layer decre a s e s . Active avalanche control is the intentional triggering of slides. Washington State Department of Tr a n s p o r t a t i o n (WSDOT), does avalanche control to minimize the chance of natural avalanches into traffic. Avalanche control work is done all over the world by: highway departments, ski resorts, railroads, mining operations, utility companies, and other activities threatened by avalanches. The majority of active avalanche control is done with skis, by explosives, or exploding projectiles. Blasting techniques and practices have evolved to fit the specific needs of avalanche contro l . Passive avalanche control is the use of engineered s t r u c t u res such as snow sheds, bridges, or snow supporting devices, to permanently protect a specific location from avalanches. The problem is that these struct u res are extremely expensive. There are a variety of passive avalanche control measures as well as the active m e a s u res used to protect the highway over Snoqualmie Pass. As traffic volume and use expectations incre a s e , m o re extensive passive measures will be needed to keep avalanches from affecting the highway.

Jan 1, 2004

This paper is concerned with the blasting of rock in mining. The most common purpose of blasting rock is to cast it or to disrupt its structure sufficiently for effective digging and subsequent removal.

Jan 1, 1991

By O E. Jr Crenwelge

Frequency domain, single-charge vibration signatures are used to interpret the characteristics of explosive impulse excitation and ground vibration transmission. The effects of charge height, charge splitting, and different blasting agents are first discussed. Then the effects of rate of change with distance of overburden material properties and layer or surface geometries are illustrated.

Jan 1, 1988

By Richard E. Danell

"Blasting is a principal step in the surface mining process for breaking and, in the case of overburdencasting, moving rocks and minerals. As many surface mines are coming to the end of theiroperational life, blasting can once again play an important role through the earthmoving operationsrequired to rehabilitate the minesite. Since blasting is such an energetic and destructive process, itis difficult initially to envisage its use in rehabilitation. However, blasting has found applications inmany civil engineering projects aimed at rehabilitation, including well digging, channelling and soilcompaction. For surface mine rehabilitation, the main purpose of earthmoving operations is toproduce a stable landfonn that will sustain revegetation. In particular, blasting can be applied toreducing the slope of steep walls left by quarrying and open pit mining through a modified form ofthe overburden casting technique. Blasting can also be applied to breaking up pit floors andbenches to speed and improve revegetation of these areas (subsoiling)."

Jan 1, 1994

By He Guangyi

Combining living examples, the paper introduces the controlled chamber standing shot of more than 3000t explosives initiated at one time with Nonel under complicated circumstances and the experience obtained to keep environment safe and favour mechanical rock cleaning.

Jan 1, 1998

By T. Bernard, P. Dozolme

Electronic initiation devices appeared on the market more than 15 years ago and have definitely changed the rules of blasting. It becomes clear that this technology represents a powerful alternative to the traditional accessories. Electronic Delay Detonators (EDD) have attained solutions that were difficult and even impossible to achieve with the previous technology, thanks to the accuracy, usually inferior to one millisecond, and flexibility of the programmability range offering thousands of timing possibilities. Technological progress is long awaited to represent a step ahead compared with the last generation of products. In the case of electronic initiation, some limits nevertheless rapidly appeared, leading to the paradox of loosing operative and safety benefits, compared with the traditional technology it was supposed to outclass.

Jan 1, 2006

By Robert B. Hopler

The hazards which naturally prevail in underground coal mines, always severe and unpredictable due to the loosely-consolidated strata in which coal is frequently found, are increased by the commonly-occurring combination of coal dust, methane, and explosives. It was recognized by the mid-nineteenth century that coal dust was the basic factor contributing to disastrous explosions killing hundreds of miners, and that the ignition of methane gas was often the source of the coal dust explosions. It was apparent that preventing the ignition of methane was a critical part of avoiding these disasters, and it was also apparent that one cause of such ignitions was the firing of explosives. In addition, it was found that dust explosions were often initiated by blown-out shots of explosives in the absence of methane.

Jan 1, 1996

By Cceliksirt, V Erkan

This computer program has been developed under the field conditions for use in control of surface drilling-blasting operations. This paper outlines the relevance of fragmentation to quarrying, open pit mining or road cutting and key features and operating principles of the software (DelPat for Windows 95).

Jan 1, 1998

By William Wilkinson, Vladisla Kecojevic

Current three-dimensional (3D) computer design technology leveraged into drill and blast planning and operations is changing the way engineers and operations approach drill and blast design. Additionally, Global Positioning Systems (GPS) technology that is now readily available to the civilian population is being implemented into the mining sector with a variety of new products specifically designed for drill and blast operations. The objective of this article is to discuss the steps involved with 3D Computer-Aided Design (CAD) of drilling and blasting, and the benefits such a design can provide in conjunction with GPS and drill monitoring systems.

Jan 1, 2004

By Paul Worsey, Seokbin Lim

There are two major types of shaped charges, conical and linear (Ref 1, 2). Conical shaped charges are used to perforate targets and are mainly used by the military as anti armor weapons and by the oil industry for oil well perforation. In contrast, linear shaped charges are primarily used to cut metal in the demolition industry with other uses including separating devices in the space industry. There is a large amount of material published on conical shaped charges because of the high level of defense industry research and funding, however in stark contrast there is very little published on linear shaped charges.

Jan 1, 2003

By Cathy Aimone-Martin, Caitlin Woznick, Brent Meins

This study is a continuation of previous work in which the responses of tall structures to close-in construction blasting at two rock excavation sites are evaluated. A total of eight buildings were instrumented to calculate blast-induced wall strains. Of these structures, five high-rise buildings measuring 166 ft (51 m) to 294 ft (90 m) in height (15 to 24 stories), were included for this study and compared with the results of previous studies that included one to three story residential structures and mid-rise structures (four to six stories). All five structures were built between 1908 and 1940 with interior walls comprising aged plaster. Three of the structures are designated Landmark, subject to a 0.5 in/s (12.7 mm/s) regulated peak particle velocity (PPV) limit. The regulated PPV limit for the two other structures was 2.0 in/s (50.8 mm/s). To date, a total of 450 close-in construction blasts have taken place over six months at the two adjacent projects, blasting three to six times per day at each site. Seismograph instrumentation included tri-axial geophones in the ground and bi-axial geophones (horizontal components only) mounted on structure exteriors at the corners closest to blasting. Peak global wall tensile strains were calculated from time-correlated differential structure displacements in two horizontal directions as measured by upper and lower geophones mounted near the roof and at street levels. Wall strains were correlated with ground excitations to establish a stiffness factor for each structure defined as the upper bound linear regression slope for strain as a function of ground displacement. In addition, a structure-specific regression best-fit function was established to relate horizontal components of displacement to velocity. These two functions were used to determine the maximum ground motion velocity for a desired limit placed on wall strain. A 25 ?-strain limit was suggested for both projects to protect interior plaster walls. To date, global wall strains have not exceeded 0.53 ?-strains (or 47 times the project limit) for peak particle velocities up to 3.49 in/s (88.6 mm/s). This demonstrates the low strain response of tall structures to ground velocities well above regulated limits. The stiffness factor computed for the most flexible high-rise building was 688 in-1 (17475 mm-1). In comparison, stiffness factors for the most flexible residential and mid-rise structures previously studied were 8651 in-1 (219735 mm-1) and 4387 in-1 (111430 mm-1), respectively. Based on a large number of measurements made at these study structures, the maximum horizontal ground velocity needed to achieve 25 ?-strains in walls ranged from 36 in/s (914 mm/s) to 192 in/s (4877 mm/s) because of the high stiffness of these buildings. Such high amplitudes of ground vibrations can never be safely achieved during close-in blasting in urban environments. These excessive values stand to show how unfounded the current limits of 0.5 in/s (12.7 mm/s) and 2.0 in/s (50.8 mm/s) are when applied to massive, tall structures. This study demonstrated that upper structure motions are highly attenuated from the lower (street-level) motions because of the long travel distances up the buildings. High-rise structures are far stiffer than mid-rise and residential structures and can withstand ground vibration amplitudes far greater than the currently enforced blasting limits in New York City.

Jan 1, 2015

By Larry: McAnuff Schneider, Edward Walter, Gordon Shaw, Daniel Grieco, Dennis Clark

During the 1998 Annual Conference of the International Society of Explosives Engineers (ISEE), the Seismograph Section established a subcommittee for the purpose of compiling a list of all regulations pertaining to limits imposed on ground vibration generated by blasting. The goal of this project was to determine the vibration regulatory levels being enforced, with the further intention of examining their scope, and uniformity. A secondary purpose was to evaluate the consistency of the existing regulations with the current scientific findings on structural response and damage potential.

Jan 1, 2001

By John A. Franklin, Tom C. Palangio, Norbert H. Maerz

No blast evaluation is complete without fragmentation measurements which until now were inaccurate, costly, time consuming and created delays in production. “WipFrag.s”is a fully automated PC based fragmentation analysis system that uses digital photo analysis techniques to measure broken rock. Fragmentation can be measured in minutes using compact videocameras for image acquisition. Even subtle changes in rack quality can be detected providing the information necessary for pattern optimization, explosives evaluation, timing selection, benchmarking and blast model validation.

Jan 1, 1995