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By William Reisz

Over the years as surface mining operations have become more sophisticated, angle drilling has become a more popular blast design technique, especially in areas where overburden and stripping ratios have increased. Another method of blast design is the staggered pattern, which greatly improves explosives distribution within the blast. While both methods present some engineering challenges, this paper will discuss how the two methods can be combined to enhance fragmentation, improve cast percentage, drill production ratios and highwall control. A practical engineering approach will be presented as well as a discussion on the discipline required to maintain a quality blasting plan.

Jan 1, 2002

By Reynold N. Hoover

The bombing of the Murrah Federal Building in Oklahoma City, Oklahoma, on April 19, 1995, has once again renewed public debate surrounding the availability and use of explosives in the United States. In the past, Congressional review of explosives regulation has generally followed tragic events such as the bombing of Pan American World Airways Flight 103 over Lockerbie, Scotland on December 21, 1988; the February 26, 1993, bombing of the World Trade Center in New York City; and the delivery of six package bombs to members of one family in several western New York communities, killing five people, on December 23, 1993.

Jan 1, 1996

By Raymond Chenier

British Columbia (BC) is Canada’s most western province. The landscape in BC is amongst the most beautiful and pristine in the world. Along with its beauty come vast mountain ranges, coastal rain forests, swamplands, deep river valleys, and almost every type of landscape imaginable. These all have, or at one time had, logging roads constructed. Some of these areas should never have had roads constructed due to poor drainage and unstable slopes, but some of the roads could be considered engineering masterpieces. To navigate a vehicle the size of an off-road logging truck down the side of a mountain with an 80°h side slope or greater can be a hair-raising experience. Not to mention coastal rains and/or high elevation blizzards. These factors collectively make logging BC’s most hazardous occupation. People are seriously hurt, sometimes even killed everyday.

Jan 1, 2001

By Kyle Ott, Bernard Daly, Syed Haq, Douglas Anderson, Parsons Brinckerhoff

Drill and blast was determined to be the most cost-effective means of excavating the Raw Water Tunnel (RWT) for the Croton Water Treatment Plant in the Bronx, New York City. One of the major issues confronting project designers was the potential impact of blast vibrations on a major City Distribution Tunnel (CDT). The proposed path of the RWT would cross less than 30 meters (100 feet) above the CDT, which was built in 1917. Discussions with New York City Department of Environmental Protection led to vibration criteria on the CDT of 51 mm/sec (2 in/sec) peak particle velocity as an alert level, and 38 mm/sec (1.5 in/sec) as a review level.

Jan 1, 2012

By John Dean Smith

"In many operations the two most overlooked aspects in the drilling and blasting process is theblast optimization and explosive selection. Often times we find a blast design that seems to work andproduce acceptable results and will use this cut afier cut, even years. When in reality one should never become complacent and should be constantly looking for ways to improve the drilling and blasting operation."

Jan 1, 1995

By Henry S. McDevitt

External Shock Mitigation (ESM) is being studied as a possible means of retrofitting existing buried structures to provide additional protection from ground shock. As part of this study, two tests were conducted on four ESM models and a control structure. The test articles were placed at a carrnon distance and subjected to the ground motions created by a buried explosive charge consisting of 2,ODO pounds of nitranethane (NM). Adequate instrumentation data were obtained to assess the response of the four ESM models. The assessment relied heavily on direct comparison of horizontal motions measured in the models, with similar measurements in the control structure. From the tests, it was observed that peak accelerations were reduced by a factor of 5 by the ESM. However, the particle velocities and displacements were not significantly affected by theEIS.

Jan 1, 1997

By Ron Glowe

This paper shows the potential of a new computer model, using the Glowe-Tech (GT) Tonnage Analyzer program to compare drilling and blasting results. This model uses the crushers and conveyors as measuring tools in aggregate quarries in the USA and Canada. All data is collected using commercially available kilowatt transducers and an analog input/output automation module. There are two areas of measurement used to compare results. The first area is the tonnage moved by key conveyors to show the split in products produced and the actual rate of production. If belt scale readings are not available then the Glowe-Tech Tonnage Analyzer can be used to convert kilowatts from the conveyor motor to tonnage. The second is the tons of rock crushed per kilowatt hour of energy consumption by the primary and secondary (optional) crushers. This modeling process works best if blasts are mucked and crushed in sequence. There are many other variables such as crusher types, crusher settings, screen sizing and actual geology in the pit that can influence the results, however if variables can be standardized then definite trends can be seen when comparing drilling and blasting results

Jan 1, 2005

By Jack Eloranta

This paper documents the relationship between material handling and processing coete compared to blasting cost. The old adage, "The cheapest crushing is done in the pit", appears accurate in this c!ase study. Comparison of the accumulated cost of: powder, selected wear materials and electricity; indicate a strong. inverse correlation with powder factor (lbe powder/long ton of rock). In this case, the increased powder cost is more than offset by electrical savings alone.

Jan 1, 1995

By Sadettin Bagdatli, Ali Kahriman, Umit Ozer, Alper Celtikci, Yucel Karakus

Due to population growth and rapid urbanization in Turkey, the need for the construction of residential units, transportation and infrastructure facilities has become increasingly more pressing. Since rock units encountered in the surface and underground in the construction of the subway, infrastructure and housing facilities, it is a necessity to use blast excavation methods. In recent years, large housing construction projects have been carried out especially in Turkish metropolitan areas, involving foundation excavations giving rise to great amounts of earthmoving. Since rock units encountered during foundation excavations are usually hard and solid, excavation with conventional machinery proves to be inadequate and unproductive, hence the necessity for the application of blasting technology.

Jan 1, 2014

By B Mohanty, M Alam, F Gauthuer

A series of eleven full-scale production blasts has been earned out in a limestone quarry to study the effect of delay interval and its precision on overall blasting performance. The quarry employed ANFO and cartridged aluminized emulsion in 75 mm diameter boreholes with 2.6 m burden and 2.9 m spacing on a 6.7 m bench. Both V-cut and echelon designs were studied. The types of detonators tested were regular short period electric detonators with expanding delay intervals, a more precise pyrotechnic-based electric detonator (EXADET) with a fixed (25 ms) delay interval, and the ultra-high precision electronic delay detonator (EDD) with constant (but site-selectable) delay interval. The various techniques employed to assess the blast results are described, and the performance of the three types of detonators compared. The use of both EXADET and EDD lead to improved blast results in echelon design. Of the three delay intervals (25 ms, 38 ms, and 50 ms) studied, the best results were obtained with EDD with a 38 ms delay interval, which translates into a delay of 38 ms/m of effective burden. The results also show the need for modification of current V-cut delay designs to derive full benefits from these high precision detonators.

Jan 1, 1991

By L C. Taylor, H U. Lesiste

This paper describes a method for estimating the density distribution in the soil cap as a function of distance from its top at the time of impact with the target. It provides an estimate of the density distribution in the soil on the center line of the soil cap at the time of target impact for a single depth of burial of the charge and two heights of target and shows that, for the heights of target and the depth of burial considered, the thickness of the soil cap first increases from the in situ value and then decreases. The distribution of soil density along the centerline of the soil cap changes significantly with distance from its original position. These results can be used for validating hydro-code computations and the soil models used in the computations.

Jan 1, 2011

By Patrice Favreau

In 1990 the Noranda Technology Centre commenced a project to develop an interactive three-dimensional blast design system using a commerical computer-aided drafting and design package (CADD). The objective was to alleviate the blast engineer from the tedious and time consuming blast layout and design functions normally done by hand. This would allow more time for optimizing blast designs through assessing multiple options. Since several blast design software "tools" already existed at Noranda, the need arose to integrate all the applications into one overall system that shared one common database. The result is BLASTCAD.

Jan 1, 1992

By Wade A. Narin, James K. Mitchell

Hydroblasting is considered a distinct soil improvement technique from explosive compaction, though the blast designs for the two techniques are similar. Hydroblasting is a three step process developed for densifying unsaturated, collapsible soils, especially loess. The required steps are: prewetting the soil to an adequate saturation, placing and detonating the explosive charges, and consolidating the soil (squeezing the water out of the pore spaces between the soil particles under gravity) to a denser state.

Jan 1, 1995

By Patrick D. McLaughlin

Crater blasting techniques have had relatively little application in the surface mining industry. This is not surprising, considering the geometry required to efficiently use cratering. The more widely known blasting operations that employ some form of cratering are listed below.

Jan 1, 1992

By Wilfrid Comeau

While researching for a theme lecture (Comeau, 1993l) on: 'The Mechanics and Physics Explosives', the author of Energy Transfer in Rock Fragmentaion by was confronted with many conflicting concepts regarding: the current explosive rock fragmentation theories, the physical principles governing energy transfers, the mechanical properties of rocks, and observations and data from full scale rock blasting.

Jan 1, 1995

By Paul Worsey, Dave McCool, Ryan Freeman, Chris Wolters, Rick Hines, John Bowles

Carroll Cave, located in Camden County, in south central Missouri, is one of the most significant caves in Missouri with over 12 miles of mapped passages and over 100 known but unmapped side passages. In the early 1990’s there was a breakdown of the originally excellent landowner/caver relations as the ownership of the only known entrance moved to a new generation and grottos squabbled for control. Subsequently the current owner of the natural cave entrance refused to grant anyone permission to enter.

Jan 1, 2003

By A R. Cameron

"The number of commercial explosive products available to the mining industry has been steadilyincreasing and associated with this there has been an increase in the range of characteristics or properties of them. This has lead to increased difficulties in selecting the most appropriate explosive for a particular blasting situation. Techniques are available that can be used to evaluate and compare the characteristics of explosives under a range of conditions. Also, the techniques are used to assess the variability in the characteristics between batches."

Jan 1, 1994

By Sandra Penttinen

To assist blasting professionals with the creation, documentation, and appropriate methodology to standardize the data collection of the pre and post blast investigation process. Penttinen Associates will present a logical non-technical presentation focusing on: Why pre-blast surveys SAVE How to prepare for pre-blast inspections What to do in preparation of pre-blast inspections The creation of an industry standard all-inclusive pre-blast document Establishing pre-blast inspection operational standards Preserving the data.

Jan 1, 2001

By Ken Cross

This paper aims to demonstrate that explosives organizations and workers have a legal, moral and financial duty to be able to demonstrate their competence when required, and how that may be achieved at any level from explosives storekeeper to senior explosives engineer on a major project. The concept of competence is outlined, as are the benefits to members of staff, management and the organization, particularly in a regulatory regime that includes competence management as a key performance indicator.

Jan 1, 2013

By Curtis G. Kremer

"New explosives initiation systems continue to be developed as new technologies make advancements possible. Due to recent initiator developments, explosives users now have the most reliable, accurate, safest and easy to use systems ever offered. Three initiation systems recentlyintroduced which offer significant improvement over standard electric and nonelectric initiation systems include Magnadet, EXEL high-strength shock tube, and Redundant two-Dath surface delay systems. These three systems will be discussed zn cecail with rmpiasis on their functioning, safety characteristics, ani specific application areas."

Jan 1, 1991