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By C. Breeds, K. Jeremiah, E. Jennings

Washington State has a well developed set of blasting regulations which have been promulgated by the Department of Labor using extensive stakeholder input, not only from citizens but also from manufacturers and representatives of IME, blasters in charge, blasting engineers, blasting companies, local and federal law enforcement agencies, fire officials, and local and state government representatives. WAC 296-52 therefore provides a foundation or platform for developing city ordinances for Washington State cities should a City wish to do so. On the other hand, Oregon’s code is based on OSHA 1926, Subdivision U, Blasting and the Use of Explosives which provides scant direction regarding the modern use of explosives. Reference is also made to ODOT Section 00335 - Blasting Methods and Protection of Excavation Backslopes. This paper examines two separate programs that have been developed by two Cities, one in Washington State and one in Oregon to further regulate blasting inside City limits and discusses why the lack of a regulatory foundation made one approach more difficult than the other. One of the authors was retained by the City of Kennewick, WA to develop their ordinance and has more recently followed and reacted to a pending ordinance for the City of Redmond, Oregon. The paper will compare and contrast the different approaches and comment on the reaction from both Blasters and the public. We also present a case study that involved blasting in an urban area of Oregon to prepare a foundation for a water tank. Controlled Blasting was carried out within 70-ft of residencies and within a community that had expressed reservations regarding blasting even though the work would make a significant contribution to the betterment of the community. Pre-construction surveys of residencies located in a large area surrounding the site were performed and a well-planned blasting program was carried out. Residencies were subject to vibration levels that were monitored using six seismographs that surrounded the site and these units measured vibration levels that were significantly lower than allowed by statute. There were complaints triggered by individuals reactions to blast vibrations which validated commonly held models of human perception but no damage was caused by the Blasting.

Jan 1, 2024

By Jason Baird, Philip Mulligan

This report details the preliminary calculations governing the underwater collapse of an oil pipe via explosive lensing. An explosive lens changes the detonation wave produced by an explosive by changing the geometric conditions of the explosive (Zukas and Walters, 1998). Multiple lenses can be focused on a central location, generating a series of precise detonation waves collapsing in on a specific point. This report will assume a spherical-shaped, single explosive charge and explain how the authors determined the explosive charge size needed to seal a metal pipe while focusing on one explosive charge acting on part of the pipe. Future calculations will analyze the combination of multiple explosive charges acting on the pipe as a whole.

Jan 1, 2013

By Alan Bauer

During the past several years, the trend to large-diameter blastholes in both open pits and underground mines along with the continuing developments in slurried explosives and delay systems has kept things exciting for the drilling and blasting engineer. This has been particularly so in underground mining, where new mining systems having lower cost and higher productivity have emerged. Crater technology has produced new large-scale methods for resisting front penetration in tar sand mining and also new underground retreat mining methods and methods of raising.

Jan 1, 1978

By Eric Reale

The New York City Department of Environmental Protection (DEP) is currently building City Water Tunnel #3 beneath the city. The purpose of this tunnel is to improve water distribution to the city and to allow the DEP to inspect the older tunnels and make the necessary repairs. These older tunnels have been in continuous operation since the early 1900's. Construction on the Third Tunnel is planned in four stages. The Nelson Street Shaft, which is the focus of this paper, is part of the second stage.

Jan 1, 1989

By Eric C. Gerst

"In this current era of soft commodity and coal prices the mining industry is turning towards optimizingall levels of production to reduce operating costs. Part of this trend includes the automation of miningmachines. As the first tier of the mining process blast hole drill automation offers benefits through the entire value stream from drill bench to material processing."

Jan 1, 2017

By Nathan Rouse

This blast mitigation study examined the effects of a barrier wall on explosively driven pressures. This area of blast mitigation is of interest due to the many different applications involved in protecting a target from an explosive attack.

Jan 1, 2012

By Tamara Wiseman, David Stewart

"A Quarry located in Georgia is a green-field site established in 2011. The quarry lies in the eastern part of the Georgia Piedmont area. It is within a distinctive, northeast-trending belt of relatively high-rank metamorphic rocks known as the Kiokee Belt, a poorly mapped sequence of units that largely consists ofamphibolite and various schists and gneiss that are host for relatively young granite bodies andassociated pegmatite and aplite dikes."

Jan 1, 2017

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 R. Narendrula, S. P. Singh

The productivity of a loading machine is affected by several factors. One of the most significant is the characteristic of the muck being loaded. A study was conducted to examine the effects of the looseness, angle of repose, size distribution and moisture content of the blasted material on the efficiency of the loading machine. The study was conducted in the following stages: (a) controlled experiments in the lab, (b) tests with loader simulator and (c) field work in an operating mine. It was found that looseness (%void) in the muck increases with the increase in the value of the mean particle size and index of uniformity of the fragmented rock. Looseness and angle of repose affect the fill factor and the digging cycle time of a loader and in turn the productivity of the equipment. Moisture content affects the angle of repose as well as the stickiness of the material to the loader’s bucket. It was observed that the angle of repose increased with the increase in the mean particle size and the moisture content of the muck. It was also found that the bucket full factor and rate of scooping decrease with the increase in the values of mean particle size and index of uniformity. This was also conformed during fieldwork that bucket fill factor decreases with the increase in the mean particle size as well as the index of uniformity.

Jan 1, 2005

By Lauren Shields

This paper discusses the application of current fragmentation models for underground blasting, establishes a conceptual fragmentation model for underground operations, and discusses the applicability of the mine-to-mill approach for underground blasting. Additionally, this paper also discusses selected case studies where the mine-to-mill approach is applied to underground mining operations.

Feb 1, 2020

By Julia Creasey, Natalie Hodgson, Claire Ward, Craig Davies, Helen Sarginson

"Emulsion explosive producers are attempting to lower the cost of emulsion production by using lowquality ammonium nitrate in emulsion formulations. Low quality ammonium nitrate contains additivessuch as anti-caking agents and crystal modifiers which contaminate the emulsions causing instability. This presents a need for an effective emulsifier that will maintain emulsion stability under thesechallenging conditions."

Jan 1, 2017

By Jung-Hoon Ryu, Chang-Ha Ryu, Byung Hee Choi, Yang-Kyun Kim

Control of overbreak in tunnel blasting is one of the key factors affecting the construction expenses as well as safety. Overbreak causes an increase in the cost of construction by requiring an additional amount of shotcrete. In addition, blast damage to the final rock face may cause instability and rock fall hazards. For these reasons, controlled blasting is an indispensable routine in tunnel excavation in order to get a smooth face and to reduce damage to the final wall. We have experienced a very poor quality of excavation depending on the tunneling sites although a similar design of controlled blasting technique was applied. Field experiments over 40 rounds were carried out to investigate the cause of the poor results in tunnel blasting. In this paper, discussed are the parameters affecting the overbreak and some findings from the field experiments. Overbreak could be controlled considerably by adjusting some parameters before the efforts of developing a new blasting method.

Jan 1, 2004

By S. Evans, J. Phillips-White, D. Morton

The partnership between Orica and MMG at the Dugald River Zinc mine in Australia has led to the first global field trials and deployment of Orica’s Subtek™ 4D™ (hereafter referred to as 4D) Bulk Systems underground bulk emulsion blasting technology. This technology offers advantages over conventional bulk explosives by extending the range of energy and length of explosive column that can be charged in underground production. 4D gives blast designers energy options between Relative Bulk Strength (RBS) 50 - 150, delivered uniformly along the entire column in most blasthole conditions along with the ability to instantaneously modify the energy within an individual blasthole. During Phases 1 – 3 of the project from October 2022 to January 2023, over 57 tonnes of the 4D Underground emulsion were loaded in 17 stopes. The primary objectives of this phase were to reduce hanging wall dilution and improve stope recovery. While drilling and other parameters remained unchanged, the energy selection was tailored for specific situations, guided by a revision to the site's drill and blast standard. The design used low energy (RBS 50 - 70) in holes adjacent to the hanging wall and high energy (RBS 130 - 150) where stope recovery had historically been challenging, such as at the toes of long downholes. Initial results of the project focused on five stopes selected for their similarity to those used for the baseline data set. Although the 4D data set was small, the post-blast scans indicated favourable results for recovery and dilution. This suggests that selecting and delivering bulk explosive with tailored energy levels can improve stope performance.

Jan 1, 2024

By Aiden Carey, Jim Kennedy

During December 2007, Lake Cowal Gold Mine located in New South Wales, Australia experienced a significant pit wall failure. The wall failure resulted in the deposition of a large quantity of saprolite consisting largely of clays and lake bed sediments to the bottom of the Phase 1 open pit mine. This wall failure ultimately buried two loaded blast patterns.

Jan 1, 2011

By Ben Barrett

Dangerous goods, known as hazardous materials in the USA, are subject to special controls during transport to ensure the safety of the public. Dangerous goods are divided into nine classes, and Class 1 is devoted to explosives. Unlike storage or manufacturing, explosive transportation crosses the political boundaries of localities and nations, and its regulation must be centrally managed to avoid duplicate costs of complying with multiple regulations. Additionally, the transport of dangerous goods occurs by four different modes – highway, rail, vessel and air. While each mode has differences which must be addressed, the fundamental principles of classification, packaging, hazard communication and documentation remain the same. When a shipment travels by multiple modes and across borders, consistent regulations become paramount to cost efficiency. This is a common occurrence in the growing global economy.

Jan 1, 2010

By Michael Wieland

Delay blasting in underground coal generates shock waves and rifting forces that damage charges remaining in the blast pattern. Damaged charges detonate poorly, raise fume toxicity and reduce coal breakage. Such circumstances could be prevented by using explosives resistant to cross-hole interaction damage. The design of rugged explosives is fraught with contradictory requirements, but tradeoffs related to hard-particle size characteristics prove useful. Hard particles, related voids or trapped bubbles represent reaction nucleation centers which strongly influence the performance of coal mine explosives.

Jan 1, 1992

By Ray Heater, Qian Liu, Alan Bauer

The channel effect is a phenomenon that takes place with decoupling explosive charges; an air shock wave propagating ahead of the detonation wave in the annular space around the explosive charge compresses the charge so that the process of detonation is modified and even stopped. For commercial explosives, such as AN/FO slurries and emulsions, the channel effect causes partial detonation under certain conditions. To simulate and evaluate the phenomenon, a hydrodynamic model was developed based on the assumption that the pre-shock wave is produced by Mach reflection at the tube walls. Based on instrumented experimental studies with the above explosives in diameters ranging from 25 to 90 mm in pipe sizes ranging from 35 to 127 mm, it has been possible to demonstrate that a criterion for failure based on a critical impulse concept fits the experimental data well. Critical impulse values for the various explosives tested are presented along with the necessary correlations between charge and borehole diameter required to produce this.

Jan 1, 1988

By Bilegt Batbold, Bayu Saputra, Chris Batten

The ability to fire multiple blasts simultaneously can provide significant benefits to any open pit mining operation. Reduced blast-related downtime by reducing blast events can increase equipment utilization and maximize material movement. Significant sequencing benefits can also be delivered, associated with reduced equipment relocation. This paper describes the work completed in partnership between Orica and Oyu Tolgoi to successfully demonstrate that combined production-trim and midsplit blasting could be implemented successfully while successfully managing the risk of increased damage to the final walls. The paper details the methodology used to assess key performance measures linked to final wall damage and compares the performance between the following blasting methods. • Free face trim blasting vs. combined production-trim blasting • Presplit blasting vs. midsplit blasting. The results of the initial trial blasts are presented, along with the method agreed by the key site stakeholders for ongoing application. The method used to keep the risk of final wall damage to an acceptable level is explained, along with the benefits delivered to Oyu Tolgoi operations associated with the initial 12 months of application.

Jan 21, 2025

By Steven Townend, Don Wadden

In today's global economy the need to stay competitive is essential for commercial survival and growth. To this end Inco is committed to continuous improvement in its operations. Various aspects of the mining process have been examined to find ways of improvement.

Jan 1, 1994