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By Ronald L. Cocklin, Vivian Patz

Blasting techniques are becoming increasingly sophisticated as the need for improving mining efficiency grows. One of the areas of blasting that has never been fully exploited, due to a lack of a control and reliability, is the initiation of explosives. Expert Explosives have taken on the challenge to not only provide an initiation system that offers control and reliability, but also provide benefits that are critical to enhanced mining productivity. These benefits can only be delivered through the medium of electronics and computer controlled systems.

Jan 1, 1995

By Ettore Contestabile, Cameron Thomas

Implosive connectors such as XECONEXTn have been used extensively for joining electrical conductors. This implosive action of explosives has also been used in other forms of high-energy metal working with excellent results. However, the inherent blast energy of these units can cause environmental side effects (especially airblast) which may restrict their use around inhabited areas.

Jan 1, 1994

By Nobel Insurance Service

[Executive Director’s note: ISEE is committed to continuing its efforts to ensure that blasters be made aware of the issue of migration of carbon monoxide resulting from blasting operations. In the July/August 2001 issue of the J o u rnal we printed excerpts from “Carbon Monoxide - The Silent Hazard,” an article from the Safety Update, published by Nobel Insurance Services. We also re minded readers of the text from the 17th edition of the ISEE Blasters Handbook in its section on trench blasting as follows: “...consideration must be given to the proper venting of gases generated from the blasting. Should those gases spread laterally rather than vent directly to the surface, the gases may travel underg round and finally vent well outside of the planned area. Such events may be caused by the strata, soil conditions or root systems, or existing and/or abandoned utilities or other man-made structures. In the worst situation, gases resulting from the detonation such as CO2, CO, and/or N Ox may travel through the strata and find their way into basements of nearby homes or businesses.” While incidents are rare, a number of cases in re c e n t years have resulted from outdoor blasting operations p roducing carbon monoxide gas that has migrated t h rough the earth and accumulated in nearby enclosed spaces. T h e re are steps that a blaster can take to be proactive in preventing incidents. These steps and studies of the occurrence have been expertly presented in several papers presented at ISEE conferences and included in the ISEE Conference Proceedings, available th rough the Blasters Library. In addition, Material Safety Data Sheets provided with explosives used in surf a c e blasting should provide additional information on gases p roduced by detonation. Below, we have reprinted the IME white paper, entitled “Fumes from Blasting Operations.” The paper underscores the unique set of circumstances that combine to contribute to high concentrations of CO measurements in underground, enclosed spaces following the detonation of explosive materials and provides recommendations to blasters

Jan 1, 2004

"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 'interactionbetween 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 focussedon the dependence of trajectory or natural deviation on the geological features of the rock mass being drilled."

Jan 1, 1996

By Eric Kelley

Having been retained as a legal expert for the fatality at the Canberra, Australia project, it made me aware of how good intended blasters profess to be implosion experts. Owners and contractors can be misled by these representations, seeing a video of Directionalized Structures constructed of reinforced concrete may be impressive to watch, but lack sound evidence of the true mechanics of an actual “implosion”; on steel structures more prevalently. If any well intended blaster comes to a determination that he can implode a structure, it should be not be construed he cannot. It should be well investigated that the specific blaster has verifiable experience. What happened in Australia reflects on all end users of explosives. I have heard a direct quote in our project in Alberta, “We don’t want to have what happened in Canberra”. Such a tragedy could have, and should have been avoided. Simple by using the “Right Tool for the Job”. We should sideline egos and economics. Would any competent blaster compromise his or her reputation, company or insurability? More importantly, have an honest conscience knowing that if the proper explosive is available, use it, don’t shortcut it. If possible expand the schedule. Better, yet, examine all avenues before the project, and last, cancel the project. A human life is our best asset and should not be compromised.

Jan 1, 1999

By O E. Jr Crenwelge

Frequency domain, single-charge vibration signatures are used to interpret the characteristics of explosive impulse excitation and ground vibration transmission. The effects of charge height, charge splitting, and different blasting agents are first discussed. Then the effects of rate of change with distance of overburden material properties and layer or surface geometries are illustrated.

Jan 1, 1988

By Harry Verakis, Thomas Lobb

Over the past decade, approximately 5.1 billion pounds of explosives were used annually, on average, in the United States. Most of the explosives were used by the mining industry. The coal mining industry was and still is the dominant user of explosives. About two-thirds of the explosives consumed was used in coal mining.

Jan 1, 2003

By Jack Elorenta

We often hear that, "Blasting was an art, but now blasting is now a science". 'Scientific' blasting implies that we have quantified and reproducible measurements of the feedstock and product of the blasting process. However, the industry's reluctance to adopt two key technologies, drill monitoring and optical size analyzers, sheds doubt on the claims of scientific blasting.

Jan 1, 2003

By S. Paul Singh

Rock is a heterogeneous medium, a fact often ignored during blast design. In reality, the rock mass characteristics have a controlling influence on the outcome of a blast. If the optimum blasting results are to be achieved over a range of rock mass conditions, it is prudent to understand the role played by the geological features of a rock mass in producing overbreak around the periphery of an excavation. The field work was performed in a drift located in a geologically dominant rock mass and also included observations and assessment of blast damage at several operating mines. The blast damage was estimated on the basis of the half cast factor. The effect of rock strength, rock quality designation, orientation , frequency and aperture of joints, number and thickness of layers and hydrogeological conditions on blast damage has been described.

Jan 1, 2000

By K B. Holm

This paper deals with the advances made at Syferfontein Colliery in the calculation and control of dragline methodology. The high capital outlay and operating cost of a dragline necessitates strict control of all aspects of the dragline operation. Before purchasing a dragline, a complete evaluation of all the parameters that can affect the viability, now and in the future, of the dragline operation needs to be completed. Such parameters as thickness of burden, material properties (swell), “castability”, pit width and pit length, etc. need to be considered.

Jan 1, 1994

By George D. Raitt

Anyone who has spent any time in and around the drilling and blasting profession knows that probably the most critical part is the drilling portion. A blasthole is nothing more than a cylindrical vehicle designed and strategically situated to hold and contain an explosive charge so that it can be detonated in the most efficient and optimum manner possible. It matters very little if the latest “State-of-the-Art” explosive or detonation system Is employed if the hole is poorly placed; i.e. excessive burden and spacing, sized incorrectly for desired results, insufficient in depth etc.. This is not to mention that the drilling phase is the most expensive, requiring sizeable initial outlays and upkeep. It’s also true that improper drilling can cause costs to skyrocket throughout the remainder of the work cycles such as excavating and hauling, crushing, screening and so on.

Jan 1, 1990

By A J. Rorke, U Chhika

"A series of tests was carried out on a dry blend of PPAN and LAN prills (LANFO). The objective of thetests was to determine detonation stability and VOD performance compared to ANFO. Heave andfragmentation results in the field were also evaluated visually. A number of factors were behind for.mulating this blend. A lower cost is combined with higher in-hole energies, but at slower reactionrates and lower peak borehole pressures. The resultant effect is improved heave characteristics andlower energy losses caused by inefficient crushing of the rock immediately around the borehole.The test results indicate that IANFO is ideally suited to blasting in softer midburden and overburdenrock types often encountered in coal strip mines."

Jan 1, 1995

By Robert B. Hopler

The hazards which naturally prevail in underground coal mines, always severe and unpredictable due to the loosely-consolidated strata in which coal is frequently found, are increased by the commonly-occurring combination of coal dust, methane, and explosives. It was recognized by the mid-nineteenth century that coal dust was the basic factor contributing to disastrous explosions killing hundreds of miners, and that the ignition of methane gas was often the source of the coal dust explosions. It was apparent that preventing the ignition of methane was a critical part of avoiding these disasters, and it was also apparent that one cause of such ignitions was the firing of explosives. In addition, it was found that dust explosions were often initiated by blown-out shots of explosives in the absence of methane.

Jan 1, 1996

By Brad Bulow

Blasting is an essentially violent process aimed to disrupt and loosen rock for productive excavation. Some dilution of any ore present is the inevitable result. This makes blasting a dirty word to most geologists, particularly in narrow vein gold mines. A 1% increase in gold recovery may be worth $1 M extra revenue to a large mine.

Jan 1, 2000

By Ruilin Yang

The following simple equations are frequently used within the blast vibration community;PPA f PPV v = 2p · , PPV f PPD d = 2p · ,a f PPV PPA 2p = , and v f PPD PPV 2p = where, PPA is the peak particle acceleration, PPV is the peak particle velocity, PPD is the peak particle displacement, and fa , fv , and fd are the frequency of the particle acceleration, particle velocity, and particle displacement vibration waveforms, respectively. Conceptually, the frequency should be selected to be the frequency of a simple sinusoidal wave that is used to approximate the blast vibration. In the literature, f is sometimes chosen as the dominant frequency (fdm) estimated from the Fast Fourier Transform (FFT) of the blast vibration wave, on other occasions, f is chosen to be the principal frequency (fpr) from the vibration cycle with the peak vibration amplitude.

Jan 1, 2012

By Mark William Withey

"Blasting safety in surface mining is a necessary industrial goal. Proper techniques and disciplinesexercised during the blasting process enhance the probability of achieving that goal.The blasting process is generally a series of repetitive steps performed by all blasting technicians.Because habits formed during this process influence safety, production and cost, proper habitsbecome compulsory."

Jan 1, 1995

The common approach of designing blasts on a trial and error basis is quickly coming to an end. When utilizing the full scale blast environment, trial and error can quickly become cost prohibitive and leaves much to be desired in terms of true blast diagnostics. In these situations testing is usually only continued until a perceived improvement is achieved and when the gross undesirables in blast results are removed. This does not preclude, however, that further improvements of up to 100% or more can not be obtained.

Jan 1, 1994

By Dale Preece, Stephen Chung

Blasting induced rock fragmentation is an art that has been developed and refined for hundred’s of years through blasting and recording the results. Good blasting fragmentation practices were thus developed through experience. However, this method requires a history that is typically developed in a mine over a number of years and sometimes at considerable expense. Quantification of fragmentation as a function of rock-mass characteristics and blast design is attractive. Developments towards this end have included semi-empirical methods as well as computer codes that explicitly treat shock wave transmission and the subsequent rock breakage. This paper will present predictions of fragmentation resulting from rock blasting using the computer code AUTODYN and a new state-of-the-art material model for brittle rock and concrete.

Jan 1, 2003

By Don Novotny, Dana Spencer

In this workshop our intent is quite simple; that is that we will introduce a relatively new technology that may have applications in blasting applications. This technology is the laser initiation of explosives. This workshop course is not intended to suggest ways in which specific blasting problems can be resolved. That is the purview of experts within each of your fields.

Jan 1, 1994

By Marlyn King, Kevin Peterson

Power Decks are voids created in the bottom of the borehole through the use of a suspended Super Plug. Explosive energy is started downward at initiation creating high pressures which find relief at the comers of the borehole cylinder in the bottom of the hole. This relief creates a horizontal break to the neighboring boreholes - the same effect as presplitting. This “presplit” represents a change of mass to.the explosive energy,and it is reflected upward in the more efficient form of tensile waves. This provides better use of the explosive energy than compression waves. This technique has created a new way of looking at the ways that explosive energy is transported through the rock mass.

Jan 1, 2002