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By D T. Froedge

With successive generations of the Iso-Seismic System, we are acquiring more and more information about the actual behavior of blast induced ground, and airborne vibration, as it propagates through the environment. Some of the original “truths” that have been long accepted may have to be \revised.

Jan 1, 1995

By P Bellairs

The Hamersley Province is located 1000km to the North of Perth the Capital City of Western Australia and is of major economic significance due to the mining of extensive deposits of Haematitic Iron Ore for both domestic and export use. A small but significant proportion of the waste associated with these deposits presents problems due to its ability to spontaneously combust and react with explosives resulting in premature detonations.

Jan 1, 1996

By V. Wetzig

In the past, various investigations have been carried out at the Hagerbach Experimental Gallery under accurately reproducible conditions, in order to determine the emissions emanating from blasting operations. Comparative investigations proved that the composition of the blast fumes is influenced by the choice of different explosives. It also emerged that the use of emulsion explosives leads to significantly lower concentrations of harmful substances in the blast fumes. Further investigations concerned the residues and reaction products from the explosive process which are left in the debris. Eluate tests on representative samples of debris were used to determine the concentrations of nitrate, nitrite and ammonium in the debris.

Jan 1, 2001

By Valeri Mitkov

Studena Quarry is one of the main suppliers of inert materials for concretes production in Sofia. It is characterized by massif heterogeneity in density and fissuration. Failure to take into consideration this fact during the planning of the blasting works recently had unsatisfying results in their carrying out – obtaining of materials with too small dimensions or high percentage of outsize material. Series of test blasting were carried out to find the relations for calculation of the main parameters of the drilling and blasting works. The blasting network was enlarged to 6 x 6 m, the diameter of the shot-boreholes was changed from 110 to 152 mm, the stem of the boreholes was significantly reduced and the relative consumption of blasting agents as a whole was reduced to 0,37 ?g/m3.

Jan 1, 2010

By B Mohanty, Y C. Lizotte

Optimization of blast fragmentation in underground hardrock mining requires analysis of its effects on loading and haulage equipment, together with the downstream materials handling system, with the objective of minimizing total mine operating costs. A methodology is reported which has been developed to quantify the actual fragmentation and equipment performance in the field. This is data which has seldom been practicable to capture nor received serious attention in mines. Based upon the experience gained in underground studies, a prototype standard is proposed which aims to summarize the pertinent data, collection and analysis for fragmentation assessment. This relates to parameters of direct measure, such as mean size and distribution, as well as muckpile and work environment. The paper concludes by defining the impact of fragmentation on the loading and downstream handling system.

Jan 1, 1991

By Wang Xuguang, Tian Ruigi, Xiong Shangbin, Xiong Daiyu

Combining action features of explosive shock with those of natural lignocellulosic biomass structure, we have successfully developed a new explosive shock dilatation and separation technique for pretreatment of natural lignocellulosic materials in the laboratory. Based on a brief introduction to the technical background and experimental procedure of this new method, some preliminary experimental results are given and discussed: the scanning electron microscope (SEM) qualitative observation results show that for treated natural lignocellulosic sample such as corn cob etc., their length of fibre bundle shortens, fibre bundle arrange disorders, biomass appearance and structure of samples largely change to be dilatation and loose state. The dilute acid hydrolysis quantitative measure results show that for treated samples, the overall yield of the reducing sugar largely increases, hydrolysis rate of corn cob sample is over 80%, rate and speed of hydrolysis are increased by times.

Jan 1, 1998

By Lee B. Paterson

Mining Engineers throughout the world have an appreciation for the importance of the role of the Blasthole Drill in one of the primary elements of the mining process. This paper highlights areas that could influence the overall cost effectiveness of that process of breaking rock and the associated downstream mining and ore recovery activities - and how the drill is designed and configured to meet that challenge. Factors influencing drill productivity and overall cost effectiveness are addressed, particularly regarding the benefits which are not necessarily reflected in the drilling process and therefore more difficult to quantify. This paper explores some of the downstream benefits of what we do to the drilling process.

Jan 1, 2000

By John Brown

Let’s talk about things that you, the driIl boss, the pit boss and the driller can do to eliminate the trend in drilling related accidents that have come to plague our industry in recent years. My paper will focus on reaI issues, problems and solutions that will affect our everyday outlook and attitudes about our jobs and lives. There are some real hard facts we must address if we are going to reverse this terrible killing trend.

Jan 1, 2000

By Mats Keisu, Bengt Niklasson

The Sofia project has increased the level of knowledge and technique within tunnelling, drifting and contour blasting.

Jan 1, 1992

Blasthole deviation is a frequent, well documented and undesirable occurrence in mining operations. It is caused by the drill string mechanics, operating variables and the interaction between the drill bit and the rock mass characteristics. It is composed of three distinct components: collaring or marking error, alignment error and trajectory deviation. This study has focussed on the dependence of trajectory or natural deviation on the geological features of the rock mass being drilled.

Jan 1, 1996

By Ray Jambakhsh, Gabrielle Bourget

In the summer of 1998, Ontario Hydro awarded a contract to demolish an obsolete and inefficient chimney by blasting. The Ontario Hydro Thunder Bay Thermal Generating Station (T.G.S.), is a fully operational hydro thermal generating station located in Thunder Bay, Ontario, Canada. The Chimney was a 356 ft (108 m) high freestanding structure constructed of reinforced concrete with a brick liner. Falling the chimney required careful planning due to the highly sensitive structures and equipment which surrounded it. Damage either sustained to the existing systems through ground vibrations or direct contact would have resulted in expensive power outage and/or lost production. The role of Explotech Engineering Ltd. on this project was to provide and evaluation of the proposed demolition procedure, defme the predicted and maximum seismic vibrations at sensitive structures including underground services, conduct pre-blast / post-blast inspections and recommend various safety precautions. The general contractor for the project, LeBrun Northern Contracting Ltd., of Thunder Bay, Ontario was responsible for all site preparations and post-blast clean up. All demolition blasting calculations and operations were conducted by Dykon demolition experts from Tulsa, Oklahoma. On September 13, 1999, the chimney was successfully demolished. Extensive analysis of the vibration records and visual post-blast inspections of the surrounding structures concluded that the demolition event induced no damage to any of the Ontario Hydro facilities.

Jan 1, 2000

By Stuart Brashear, Lee Schettler

The effect of water on several ANFO/emulsion blend ratios are documented by both physical observations and analytical testing to demonstrate the effect even small quantities of water can have on water resistant blends.

Jan 1, 1996

By Detnet Solutions

1. “Daisy-Chain” concept The term “daisy-chain” stems from the fact that when the HotShot? detonators are connected there is a chain or electrical path for electrical current to flow from detonator A to detonator B, detonator B to detonator C etc until the path is terminated by an electrical means. The “daisy-chain” concept has long been used in electronic detonator systems, historically used in Expert Explosives’ ExEx 1000 5/6 wire system and currently in use in African Explosives Limited (AEL’s) Electrodet? electronic detonator system and has been adopted as the basis upon which the “auto-programmability” of the HotShot? electronic detonator system functions. HotShot? Detonators are connected to each other in a string, completing a “daisy chain”, and during the auto-detection mode of the control equipment, it is possible for the equipment to determine the order of hookup of the detonators as well as map the entire blast layout. The auxiliary components (Row Controllers & Branch Controllers) assist the control equipment in mapping the entire blast by indicating different points on the blast, i.e. The inflection point of a row of blast holes on a closed chevron timing pattern, the beginning of row of blast holes on open chevron timing pattern and extra blast holes or extra blast rows.

Jan 1, 2004

In the office, on the wall to the right of my desk is a large map of the world. Some people stick pins in maps like this to show where they’ve been. If I did that my map would be a mess and look like a pin cushion. I was so fortunate to have been able to see how people live and blast in other parts of this beautiful planet. We l l , maybe some parts weren’t so beautiful and maybe some parts that were beautiful were hell holes for those living t h e re . Every time I re t u rn to the good old US of A, I say a small prayer in thanks for having been born and raised in a land of freedom and plenty. So many places and people have not been so blessed.

Jan 1, 2004

By Gary Kahn

The knowledge of how and when your explosives go off can help you make intelligent decisions regarding future application of explosives thus removing some of the black magic associated with blasting. The net result will be intelligently set-up shots with timing, explosive charges, and placement more accurately done. Lower operational costs can be achieved when the correct combinations are applied.

Jan 1, 1989

I was lucky to land a job in the powder business. I was looking for some way to support my wife and first child to be when I saw an ad in the Hercules magazine, “Explosives Engineer” for technical representatives. I answered the ad in hopes that a geologist might find something else to do besides sit oil wells or “doodlebug” for oil. Both of these occupations I had tried and while the money was good the life was a bit erratic. The Army also wasn’t made for a guy who asked too many questions although my two plus years in uniform were interesting and in a few cases fun.

Jan 1, 2004

By D. Swanson

Cold Detonation Physics (CDP) is a patented new field of explosives and the name for the explosive that is produced when non-toxic dry ice (frozen carbon dioxide) is combined with powdered metals such as magnesium and aluminum, which are non-toxic and nitrogen-free. The explosive is detonator-sensitive and detonates according to the rapid reduction of carbon dioxide back to carbon, which produces solids comprised mainly of metal oxides and about 5% carbon. CDP was determined to produce a maximum of 300 liters of carbon dioxide per kilogram (4.81 ft3 /lb) and about 1.5 liters of carbon monoxide per kilogram (0.024 ft3 /lb). Both these figures shift according to metal content where higher metal produces less gases. According to theoretical modelling, the relationship between static pressure and metal content was determined to be an inverse parabolic curve with optimum pressure at 25% to 31% metal, depending on the type/s of metal/s used. Velocity of Detonation (VOD) was determined by measuring light at the wavefront with fiber-optic cable inserted into a series of holes drilled into the side of a 3-inch diameter (76 mm) schedule 40 steel pipe containing the mixture. The highest VOD was observed at 25% magnesium and measured between 2,500 to 4,500 m/s (8202 to 14,764 ft/s) when initiated by a 454-gram (1-pound) booster and an electric detonator. A 25% 50:50 alloy of magnesium and aluminum sample shot at a higher velocity than magnesium, according to how the alloy generated smaller pieces of shrapnel when compared with shrapnel from a magnesium test. CDP, using 25% alloy, was tested for blasting limestone by drilling 3.5-inch holes (89 mm) and inserting a 3-inch x 4-foot cardboard tube (76 mm x 1.22 m) with the mixture, packed to a density of 0.62 g/cm3 . The blast was initiated with an electric detonator, behaved like ANFO with more energy and fractured rock sufficiently across the entire length of the borehole. Seismic analysis determined that CDP produces lower ground vibrations than traditional explosives.

Jan 1, 2024

I had the opportunity recently to visit a magazine site of a major explosives company. It was fun to see the storage areas again and it was really interesting to see one of the old magazines that probably dated back before my time. Now that’s an old one. As son Tom says, “When Dad was young the Dead Sea was just sick.” While the magazine has been upgraded with a modern lock to match today’s standards it still has the old tumbler lock that is opened with the large bronze key. Those old tumbler locks were just about standard on magazines years ago. Those bronze keys were heavy and would make a good display item today or maybe a substitute for a blackjack. I don’t think the old locks would stop the modern criminal but then in those days we were all less sophisticated. And maybe I shouldn’t say this but honesty was a bit more prevalent then. Maybe ‘cause old fashioned police brutality still prevailed.

Jan 1, 2004

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan, Umit Ozer, Ertugrul Kaya, Kagan Ozdemir

The results of bench blasting on quarries, have important influences on the performance of subsequent mining activities such as loading, hauling, crushing, grinding etc., and the total costs of that mine. Drilling and blasting is an important step in mine producing chain and its results such as fragmentation, muckpile shape and looseness, dilution, damage and rock softening effect the efficiency of downstream processes. Within the scope of this study, the three different hydraulic excavators’ working performances have been studied considering the particle size distribution after bench lasting at a quarry in Istanbul Turkey. Five shots have been realized on the quarry and average particle size of muckpile after each shot were assessed by digital image analysis method. Bucket loading times have been measured by stopwatch study after five shots. Excavator bucket loading times were also estimated by bucket loading time estimation formula which was published in ISEE 2007 Conference, Ozdemir et al. 2007. Estimated and measured times have been statistically analyzed and the accuracy rate of formula has been determined for five events.

Jan 1, 2008

By Ed Clah, Catherine Aimone-Martin

The vibration response of a 30 in. diameter high-pressure (845 psi) natural gas pipeline to 11 coal mine blasts was measured. The X-52 steel pipeline was buried 7 ft. below the ground surface. Ground and pipeline motions in terms of velocities were recorded on the pipeline, in the ground adjacent to the pipeline, and near the ground surface directly above the pipeline. These data were used to estimate the maximum stresses and strains in the pipeline occurring during the blasts. Pipeline standoff distances varied from 264 ft. to 3720 ft. Two blast hole layouts and timing schemes were used. One represented highly confined blasts to limit movement of the shot overburden that generated high ground motions at the pipeline. The second represented patterns that provided greater relief and lower the ground velocities at the pipeline.

Jan 1, 2003