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By Steve Dillingham

Here in the United States, as well as around the world, pose a daily dilemma - to wash or not to wash. Let’s face it, all trucks, especially our industry work horses - bulk trucks - get dirty. We all know that these units can be very expensive and washing them keeps your business investment looking new, improves public relations, fuels company pride, and facilitates equipment safety and preventative maintenance inspections.

Jan 1, 2001

By Tristan Worsey, Nathan Rouse

Florida legislature allocated funding for the Florida State Fire Marshal to review the applicability of the United States Bureau of Mines (USBM) Report of Investigations (RI) 8507 blast vibration limits with respect to Florida and its soils. The study also discusses whether the current blasting vibration limits set by statute are still appropriate, including a review of measured vibration amplitudes and frequencies, structure responses, and theoretical analyses of material strength and strains.

Jan 1, 2019

By Bob Turnbull

The dictionary definition of calibration is: to determine by measurement or comparison with a standard, the corre c t value for each scale reading on a device.1 As a consultant or blast contractor, you assess risk every day. But, have you considered the importance of, and the risks associated with the calibration of your seismograph and the accuracy that is p rovided? Can your calibration pro v i d e r back you up in times of trouble and provide documented evidence that the equipment was functioning within specification? Can their calibration pro c e d u res withstand independent scrutiny and be shown to be traceable to a National Standards for accuracy of measurement? These are important documents that in court provide tremendous support that blasting and monitoring activities are conducted professionally and competently.

Jan 1, 2004

By Martti Hagfors, Mervi Hokkanen

The Finnish Defence Forces has destroyed obsolete and spoiled ammunition in open surface mass detonations at Hukkakero fell, in municipality of Kittilä, in Lapland since 1988. The de-struction method was learned from Sweden in 1987. The disposal camp is organized every au-tumn and it lasts four to six weeks. A gross weight of an average charge varies from 150 to 250 tons and the net weight of explosives from 15 to 25 tons. As a booster there have been used 2 to 3 tons of emulsion explosives. The explosives mainly consist of trinitrotoluene (TNT) containing smaller a mounts of amatol and hexotol. The Finnish Defence Forces Tech-nical Research Centre (PVTT) has studied the environmental effects of these mass detona-tions since they began in 1988.

Jan 1, 2011

By Keith Pucalik

Understanding Vibrations fr om Blasting focuses on explaining blast vibrations and their effects on people and homes while keeping an eye on the importance of the use and significance of explosives in our daily lives. Unlike many predecessors, this film will help blasting pro f e s s i o nals explain blast vibrations and address many of the layman’s most fre q u e n t l y asked questions. The film can be used in pubic hearings, given to homeowners during preblast surveys, or played at educational seminars for professionals. The film can also be used after blasting has begun and residents have already experienced vibration events.

Jan 1, 2004

By Dale Preece, Stephen Chung, Qian Liu

Stoping is one of the widely adapted methods in underground mining. In this method, fanned or parallel holes are often drilled from a top sill down to a sub- level in the ore zone and blasted ring by ring into a stope for excavation. At Brunswick Mine of Canada, this technique has been used daily in conducting production blasts. However, when mining into the West Ore Zone, it has been identified strategically that a mass stope blast, involving the blasting of rock from the 3-sub level down to the 1-sub level, should be considered to ensure the safe operation and regaining of access to the trapped main ore zone. The challenge of this mass blast lies in the control of ground vibration and precise timing for blasting 800 holes drilled in six blocks from three different levels within 6.5 seconds, to allow sufficient void to be created in each level for the muck moving in order from the upper to the lower levels without bridging. This paper describes stope blast simulations using a discrete element computer code for modeling blast-induced rock displacement in conjunction with a precision electronic programmable delay timing system for various stope geometries including a drop raise blast at the start of the mass blast. The modeling concept is also described in the paper.

Jan 1, 2003

By P J. Dailey, S L. Burchell, R F. Chiappetta

In recent years, high-speed motion picture photography has become a powerful diagnostic tool and technique to study, analyze, evaluate, and aid in blast designs. Production blasting, typically lasting less than two seconds, requires an extended time base for observation and clarification of short-lived phenomena. Information obtained from high-speed photographic analysis is categorized into two main groups.

Jan 1, 1989

By David Reddick

The mining industry is in the midst of dramatic change. Mining activities are moving from industrialized first world countries (Canada, Australia, and the United States) to the third world. This shift is occurring due to depleted reserves, tough environmental standards, and expensive labor in traditional mining countries. During a recent trip to South Africa, I was asked, owing to my educational background in economics and an international involvement in drilling and blasting, what changes could be anticipated in third world blasting practices as labor costs increase. It is from that beginning that this presentation has evolved.

Jan 1, 1997

By William G. Szymczak

A set of experiments were conducted at the Aberdeen Proving Grounds [1] in which explosive charges were buried in saturated sand beneath a suspended rigid platform. The goal of these experiments was to measure the dependence of the impulse transmitted to the platform on the standoff distance and the charge burial depth. Simulations of these experiments were performed using the BUB2D axi-symmetric code using a frictional-cohesive visco-plastic model to describe the response of the saturated sand. This code solves a constrained set of conservation laws in which the liquid region (in this case saturated sand) is assumed incompressible. The explosion is initialized as a high pressure gas bubble (void) within the fluid. Comparisons of the simulations to the experiments are presented together with a study of the physical phenomenology associated with the loading process. In particular, it is shown that the force imparted to the platform is a combination of the impact of the sand on top of the explosion gas bubble and the pressure of the bubble as it expands before venting into the atmosphere. Under certain conditions, when the platform standoff is sufficiently small and the platform is sufficiently large, the bubble can over-expand before venting and pull the platform downward. This phenomenon was studied further through carefully measured and photographed small-scale experiments performed at the University of Maryland [2]. The small-scale experiments provide additional important validation benchmarks for our model.

Jan 1, 2005

By Benedicto Hadad Cintra

In an inflationary environment the need for reduced cost is a daily concern of all industries. The Du Pont do Brasil "Expanded Pattern" method has proven to be an extremely effective means of reducing costs in mining, quarrying and construction operations. Over the past years much emphasis was placed on rectangular drilling patterns where the burdens are less than the spacing. The Expanded Pattern method combining rectangular and staggered patterns, was implemented in 1971 in Brazil after extensive trials in close collaboration with numerous explosives users and Du Pont do Brasil Technical Services Engineers. The best multiple row spacing-to-burden ratio (S/B) was demonstrated to be in the 2 to 5 range and the effective spacing to burden ratio (Se/Be) was found to vary from 5 to 11. These ratios are for the interior of the blast pattern and do not hold true along the front row of holes. Geological rock properties, hole diameter and inclination, explosives energy and loading density, explosives characteristics, blast pattern geometry, bench height and delay patterns along with type and size of digging, hauling and crushing equipment must all be evaluated for each and every operation. The integration of these interrelated parameters, together with sound blasting practices are the basis for the Expanded Pattern method. Color slides and documented case histories will be presented.

Jan 1, 1985

By Eric Dussell

Commercial or industrial explosives are mechanically-mixed, fuel-oxidizer composites which exhibit varying degrees of non-ideal behavior. Non-ideality results from a relatively slow and state-insensitive reaction rate (Lee, 1990) and is characterized by C-J pressures, velocities or expansion isentropes significantly lower than those expected from equilibrium, steady-state calculations such as Tiger or BKW (Mader, 1979). This departure results from significant amounts of explosive material which remain unreacted at the sonic point. Energy released by continued combustion within the emergent supersonic region downstream of the sonic point, constrained by local sound speed, cannot flow to the shock front and do work on it. The significant amount of this ‘late energy” and its slow time rate of release must be considered in any blast performance model.

Jan 1, 1997

By Matt Slezak, Tristan Worsey, Nathan Rouse, Kyle Hall

As everyone knows, blasters are required to file blast reports of every blast for regulatory purposes. To this day, the authors see many handwritten blast reports. Handwritten blast reports are notorious for containing errors or omissions. This is not because the blaster intends to misreport information. It is because blasters have many tasks to complete in a day, are sometimes in a rush, and could accidentally miscalculate data, omit items, or record incorrect data. In most cases, blasters do not suffer consequences to these errors because blast reports are seldom reviewed in detail. In some cases, such as when a blasting operation undergoes some sort of litigation process, the reports are reviewed in detail and the blaster is ultimately held responsible. If the reports contain errors, the blaster can be fined, have his/her license revoked, or worse. Electronic blast reporting and centralized data management can help reduce or eliminate the potential for accidental blast reporting errors to occur. This paper presents many ways that electronic blast reporting can reduce or eliminate blast reporting errors, decrease time and extra costs spent reporting, and improve efficiencies in the field and the office.

Jan 1, 2018

By Thierry Bernard

For many years now electronic initiation has brought the time parameter to the centre of blast designs forever. Although this parameter existed before the era of electronic detonators, Blasting engineers or blasters could not directly handle it; technology imposed it. Only discrete values were available. Today, the fact that we can choose any detonation time for an explosive charge questions the viability of most of the rules applied for blast design. Thus, the very famous charge per delay method, that enables a level of vibration to be forecast at a given distance (“Chapot’s law”), is no longer necessarily valid when using electronic initiation. Therefore, it must be approached in a totally different manner. The KUZ-RAM formula, that allows fragmentation to be forecast, is also subject to the same distortion. The aim of this article is to show how the calculation laws used for blast design are influenced by the time parameter (sequence) and how we can efficiently make the most of this, in particular for vibrations. Copyright ©

Jan 1, 2005

By Calvin Konya, Anthony Konya

State and Federal construction specifications require the Blasting Contractor to prepare a Master Blasting Plan which is reviewed by the Owner’s Representative. The Master Blasting Plan requires the Contractor to submit the design of a typical blast. Most blasting specifications also require the Blasting Contractor to submit Daily Blasting Plans. The Master Blasting Plan and the Daily Blasting Plan require that the Blasting Contractor also submit the types and quantities of explosives and initiators used. The specifications also request that the Blasting Contractor submit the pounds of explosive used per delay for both production and presplit blasts. The Blasting Contractor may also be required to predict the anticipated ground vibration and air overpressure levels for the proposed blasts. There are equations that can be used to predict the ground vibration. There are also equations that can be used to predict the air overpressure levels. The data for these equations were primarily derived from quarry and surface coal mine and some construction blasts. Data from major construction projects were analyzed in this study to determine new air overpressure propagation equations for construction blasting. These new prediction equations compare calculated results analyzed from field data with other existing air overpressure prediction equations. Production blasting air overpressure values are also compared to air overpressure from presplitting

Jan 1, 2015

By Tristan Worsey, Nathan Rouse

The Florida legislature allocated funding for the Florida State Fire Marshal (FSFM) to review the applicability of the United States Bureau of Mines (USBM) Report of Investigations (RI) 8507 blast vibration limits with respect to Florida and its soils. The study also discusses whether the current blasting vibration limits set by statute are still appropriate, including a review of measured vibration amplitudes and frequencies, structure responses, and theoretical analyses of material strength and strains.

Jan 1, 2019

By Michael Olmsted

Inspection of boreholes prior to blasting can result in cost reductions as well as increases in efficiency and safety. Until recently, borehole inspection was performed in two manners. For simple inspections, a flashlight was used to view the upper part of the hole. More thorough inspections were performed with long tool strings developed for oil field applications. Borehole inspection tools developed specifically for mining and blasting applications have now been developed. Video Cameras developed for borehole inspection have been in service for several years. Now measurement tools are available, developed specifically for mining.

Jan 1, 2000

By Charles Barnhart

This paper is a discussion of the causes of deflagration in cast blasting and a description of a project intended to demonstrate how changes in six critical parameters contribute to the deflagration chemical reaction. Control of these parameters is key to solving the nitrogen dioxide “orange smoke” problem. Preliminary results of an investigation into the development of a technology addressing the problem of atmospheric releases of nitrogen dioxide during cast blasting in surface mine operations are described. The project is funded by a $600,000 Small Business Innovative Research grant from the National Science Foundation and an $80,000 Abandoned Coal Mine Land Reclamation Program grant from the state of Wyoming. The presentation will address the measures required to control the blast chemical reaction so that it does not produce nitrogen dioxide through deflagration. Experimental blast data will be focused on a new shaped charge detonation system designed to instantaneously bring the powder column to maximum velocity of detonation (VOD), thus insuring efficient detonation of the entire colulnn.

Jan 1, 2003

By Steven A. Mathe, Seokbin Lim

Current analytical models can accurately predict the final velocity of explosively driven flyers and can somewhat predict the acceleration profile, but do little to address the deformation of the flyers. Explosive systems such as linear shaped charges and explosively formed projectiles, which can be described as multiple interacting explosively driven flyers, often involve interactions between the flyers that occur much before the flyers reach their predicted final velocity. In this regime, it is important to accurately understand both the acceleration profile and the deformation profile of the flyers, as both significantly affect the functioning of the explosive systems. Previous work proposed an analytical model to meet this need. As the expanding gas cloud of detonation products drives the flyers, rarefactions impinge upon the gas cloud from around the flyer edges, which produces a pressure difference across the back face of the flyer leading to deformation of the flyer. Previous research condensed the effects of the rarefactions into a single term, the pressure release ratio, ?, which was calculated based on hydrocode simulations of a block of explosive only and an assumption of isentropic expansion. This work intends to determine the value of ? for different explosive compounds. The results of this analysis were compared to hydrocode simulations of an open-faced sandwich configuration explosive/flyer system with an average accuracy of 15% across the tested compounds.

Jan 1, 2015

By Douglas Rudenko

Have you ever had a neighbor complain about a blast one day, but says the next day’s blast was better, even though the Peak Particle Velocity (PPV) increased? How about neighbors that complain about a small trimming shot, but don’t complain about a big production shot? Have you ever reduced the pounds/delay and gotten more complaints? Mine operators are often bewildered when trying to correlate blast design parameters to homeowner complaints.

Jan 1, 2002

By Thierry Bernard, Jean Marc Laboz

This paper explains why and how integration of EIS (Electronic Initiation System) with dedicated software tools can increase benefits to blasters and at the same time simplify the design of blast sequence

Jan 1, 2000