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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 Thomas Leonard, Philip R. Berger, Bryan E. Papillon

Bardon Trimount Inc., a large producer of aggregate, crushed stone, and concrete, was experiencing significant public opposition to its five quarries in the Boston area. It was believed by the authors that this opposition could be significantly lessened if the total number of blasts per week were reduced. Although the blasting company at these quarries, Austin Powder Company, contended that this could easily and safely be accomplished by increasing the size of the blasts, regulations precluded this alternative by limiting the total amount of explosives that could be used per blast.

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 Brent Blanchard

Dallas/Fort Worth Airport recently took a major step in its fiveyear expansion project with the explosive demolition of the Hyatt Regency Hotel West. Built in 1965, the Hyatt Regency held the distinction of hosting five U.S. Presidents over the years and was reportedly one of the first hotels in the world to be built within an airport’s boundaries.

Jan 1, 2003

By G. R. Adhikari

Step 4: Selection of explosives and initiation system Various types of explosives are manufactured in India and a wide choice is available among them that include nitroglycerin based explosives, slurries, emulsions, ANFO (ammonium nitrate mixed with fuel oil) and heavy ANFO. The choice is also available between cartridged and bulk loading systems. In Indian mines, much importance is unduly given to the cost of explosives alone which is not conducive to optimization of blast design parameters. The concept of energy per meter of blasthole and the way in which the total explosive energy is partitioned between shock and heave is not considered in the prevailing practices. Besides, very little efforts are made to objectively evaluate the performance of explosives for a given site condition. Tailoring explosives is limited to changing the density of the bulk explosives. Cartridged explosives are still being extensively used in large operations where bulk explosives should be the preferred choice.

Jan 1, 2002

By John Dean Smith

In order to discuss problem solving techniques for the future. we must first review the past. This paper will discuss the drilling and blasting problems and techniques that were used by .Imax Coal in the past few years, tn those of today.

Jan 1, 1991

By Nick Lewis

Farce Mining of Texas is a surface coal mine located in Laredo, Texas. Farce mines and sells approximately 600,000 tons /year of bituminous coal. A map showing the location of Laredo is provided in Figure 1. As shown, Laredo is located on the border between the United States and Mexico. The mine property runs to the Rio Grande River, the border between the two countries. Farce pumps water from the Rio Grande for use in their coal preparation plant. Laredo’s climate is quite dry with annual rainfall averaging about 12” per year. Also, due to the southern location, Laredo is quite hot. It is common for the temperature to reach 100” F in March and maintain these temperatures through September.

Jan 1, 1994

By Pharis E. Williams

The ability to predict the performance of an explosive relies upon having a Reaction Rate Law and knowing its functional dependence upon various parameters of the explosive. In particular, emulsion explosives have a matrix cell size and may be sensitized with glass or plastic microballoons. The cell size dependence should. be very nearly the spherical grain burning dependence upon web that appears in the reaction rate laws for ball gun powder. The dependence of the reaction rate law upon the parameters of the sensitizing microballoons has been explored using hydrocode analysis of the pressure field produced by the collapse of a microballoon. This pressure field provides an increase in pressure in the vicinity of the microballoon which, in turn, increases the rate of reaction within this field and provides the energy release that must be achieved in order to have a steady state detonation for use as a blasting agent. Hydrocode analysis allows the determination of an approximate functional form for the reaction rate law which shows the dependence upon the size, type, and quantity of microballoons. This presentation includes the theoretical background and the determined functional form of the reaction rate law.

Jan 1, 1995

By Pertti Paavola, Hikki Rasanen

This paper describes a very exacting tunneling project. Planning and technical realization of this service and transportation tunnel was especially difficult as a matter of vibration control, because the tunnel is situated only a few meters under Maria Hospital, which is one of the most busiest hospitals in Helsinki. In this hospital there are many departments for bedpatients, research and treatment with high-tech equipment, operational surgery and a big laboratory. Besides access tunnels are situated near several apartment buildings. The functionality of the tunnel required the placement of the access tunnels to be straight towards these apartment buildings for which special care for blast induced air pressure had to be taken.

Jan 1, 1997

By Mark Svinkin

The purpose of this paper is to present an overview of recommended existing criteria of ground vibrations generated by blasting. It is shown that these criteria have limited liability because they were found for specific categories of structures. A new approach based on measurement of structure vibrations is suggested for assessment of damage in structures subjected to blasting vibrations. This approach provides the flexibility of implicitly considering a variety of soil-structure interaction and structure conditions. It is explained a new frequency-independent safe-level criterion of 51 mm/s (2 in/s) for the PPV of structural vibrations. Attention is brought to use seismographs properly calibrated for the required frequency range. Positive flexibility is demonstrated in assessment of structure and component of concern vibrations from blasting.

Jan 1, 2003

By John Haviland, Richard E. Danell

"BHP Australia Coat Pty Ltd (BHPAC) operates seven large open pit coal mines in the Bowen Basin ofCentral Queensland, Australia. These mines have operated for periods ranging from 16 to 37 years. All of these mines have dipping seams to varying degrees and are facing increasing overburden removal in an effort to maintain production. To ensure the economic viability of the operations, this increased level of overburden removal must ah.0 be conducted at lower unit costs."

Jan 1, 1995

By Richard Curtis

Optimum Colliery is presently experiencing a shortfall of stripping capacity in order to meet its production requirements. Due to the long dragline procurement times, several alternative stripping methods were evaluated in order to alleviate this shortfall in the interim period. Based on the experience gained at the mine. The writer will discuss some of the important factors which influence dragline performance and show how these factors may by used in a theoretical approach to analyse various dragline applications.

Jan 1, 1990

By Lance McAnuff

The year 2001 coincided with the forty-fifth year of blasting-control specialization by the author. Commencing with the construction of the Saint Lawrence Seaway System in 1956 and continuing until the present time this career has spanned one of the most progressive and exciting periods in the still relatively short history of commercial blasting. The paper touches upon a number of the more interesting projects with which the writer was involved during those early days, including the removal by explosives of “Ripple Rock” the infamous underwater hazard to shipping which at one time inhibited ocean traffic along the Inside Passage between Vancouver Island and the mainland of British Columbia, Canada’s most westerly province. Various assignments involving incidents from devastatingly ,tragic to comically absurd are described, along with personalities encountered along the away, most of them readily recognizable as giants in the field of explosives engineering. Various stages in the evolution of state-of-the-art explosive products, initiation systems vibration monitoring equipment and limiting criteria are compared and some of the effects these have had on safety and productivity during the last forty-five years are analyzed.

Jan 1, 2002

By David A. Bacca

Hydraulically powered submersible borehole dewatering pumps and emulsion/ANFO blends evolved at about the same time and for the same reasons. Mining operators needed safe, efficient dewatering systems and water resistant products.

Jan 1, 1994

By Kai Nielsen

The paper presents the results of several industrial and laboratory blasting, crushing and grinding tests and experiments investigating how blasting can influence the subsequent crushing and grinding operations. The paper also describes how these results can be used in order to optimize the entire comminution process from solid ore to a semifinished or marketable product. Two cases are presented, one looking at the processing of fine grained taconite ore, and the other discussing the processing of raw milling product for cement burning.

Jan 1, 1998

By Doug Bartley, Roy McKinstry, John Floyd

In March of 2001, Barrick Goldstrike became the first surface gold operation in North America to evaluate the advantages of electronic detonators. A detailed study was conducted to quantify the benefits of the use of electronic detonators to the downstream excavation, crushing and ore processing operations. The following methods were used to quantify blast performance:

Jan 1, 2003

By Wenbo Lu

A combined method is present in this paper in analysis the dynamic stability of rock slope under the loading of blast induced seismic, in which, by combining the dynamic load calculating method of quasi-static method with the load inputting method of dynamic finite element method, such factors as the decay of seismic wave along its way of propagation, the frequency. amplitude. the phase difference of seismic wave, etc., can all be taken into account in analysis of the dynamic stability of slope.

Jan 1, 1999

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

By C. Navalkar

Systematic drilling & blasting techniques are currently being viewed in the mining & construction industry as a correct 8z scientific approach for optimization process in rock excavation, as drill & blast costs usually represent major share in total cost of production and also the environmental impacts plays an important role in designing of the operations. Designing a blast is a complex planning task, which for optimization, includes deciding the bench geometry with respect to the rock properties & geology of the area, capacity of the excavators, choice of explosives & detonation method, tiring sequence, etc. Optimization of blast design needs a detailed comprehensive study of all the above intersecting elements. Preblast & Post blast surveys are required for further improvements in blast designs. However, the choice of blast design depends upon the the requisite blasting results opted for and the cost you are ready to pay for the same. The blasting operation, in general, also involves numerous side effects namely, ground vibrations, fly rocks, dust, noise & gas pollution, air blast effect etc. Again these effects can be made tolerable up to a certain extent depending upon the limitations of the environmental obligations as may be specified by the concerned authorities.

Jan 1, 2001

By S A. Steyn, P Terrett

Air decking has become a widely practised method internationally for modifying fragmentation results and providing cost savings from reduced explosive consumption. Duvha has been applying air deck technology to overburden and midburden blasting for a few years. A thorough evaluation of air decking at Duvha has been made by instrumenting a number of blasts and analysing costs from direct savings in reduced explosives costs to savings in improved dragline productivity.

Jan 1, 1995