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By Dieter Froelich, Giles Turcotte

In the near future, Bong Mining Company (BMC) will start mining a new deposit known as Zaweah II which is a narrow iron orebody requiring multiple row blasts with the bench floor as a free face. This called for the development of a new blasting technique. The article delineates the problem and its restrictions related to blasting. It also describes the approach which was taken for developing this new blasting technique which is essentially an application of the cratering theory with near spherical charges. Basic crater tests were conducted using various combinations of hole sizes, explosive strengths and delay patterns. From the results obtained, several alternatives were considered for production blasts and the most promising ones were evaluated.

Jan 1, 1980

By Lon Santis

This paper describes several applications of quantitative risk assessment in the management of commercial explosives operations. The Institute of Makers of Explosives’ (IME) quantitative risk assessment software modeling program IMESAFR was used for this analysis. Modeled activities include the unloading of a ship at port, locating a safe haven, and dealing with encroachment on a manufacturing facility. The layout of actual explosives sites were used for the analysis. The risk of fatality is analyzed and shown it can be used to make informed operational decisions for each activity. A study of the risks to individuals from activities involving commercial explosives compared to individual risks from other daily activities or exposures is also presented.

Jan 1, 2008

By David Kosnik

This paper describes the technology and methods deployed in the continuous autonomous remote monitoring of cracks in interior and exterior walls of a residence near a limestone quarry. The objective is to quantitatively compare crack response due to blast-induced ground motion to that induced by diurnal temperature changes, weather fronts, occupant activity, and other phenomena. The remote monitoring and communication technology developed to obtain and disseminate crack response data for this study may provide the means to mitigate the effect of public concerns about potential impacts of ground vibrations inherent in construction and production of raw materials; it is critical to address these concerns because subsequent litigation may result in delays and increased costs.

Jan 1, 2009

By Jennifer Paukula, Steven Lindsay, S. Joon Kim

String loading is the placement of a bead or ‘string’ of emulsion along the lower edge of a development drill hole. The loading hose extraction rate controls the amount of emulsion placed in each drill hole. This allows a controlled distribution of explosive energy throughout the development round. Center holes are loaded using the slowest extraction rate causing the majority of the explosive energy to be placed in the center of the round. The loading hose is extracted successively faster for the buffer and perimeter holes causing less explosive energy to be placed near the edge of the blast. This causes less damage to the rock mass that remains in place after the development blast.

Jan 1, 2012

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 Corry Goumans

The job location is at Bear Lake Hydro Project located north of the town of Sechelt, British Columbia, Canada

Jan 1, 2013

By Lon Santis, David Leidel, John Tatom, Meredith Hardwick

This paper describes the development and methodology of the Institute of Makers of Explosives’ Safety Analysis for Risk (IMESAFR), a risk analysis software program for commercial explosives operations. IME is a nonprofit safety and security association devoted to the safe and secure manufacture, transportation, storage, and use or disposal of commercial explosives in the US and Canada since 1913. The software methodology’s basis is the U.S. Department of Defense Risk Based Explosives Safety Criteria Team’s Safety Assessment for Explosives Risk (SAFER) software. A diverse group of industry and government experts contributed to modifications to SAFER that reflect commercial operations. IMESAFR is intended to supplement the American Table of Distances (ATD) and offer standardized methods of managing risk from a wide variety of commercial explosives operations where the ATD does not apply. The modifications made to SAFER primarily involved the addition of commercial activities and potential explosives sites (PES). A review of commercial explosives accidents and operations over the last 20 years served as the basis for establishing probability of event values. An industry survey of commercial PES types in the U.S. and Canada was conducted to identify and address critical differences in commercial structures as compared to the military structures in SAFER. The paper concludes with discussion of the potential uses for quantitative risk analysis (QRA) and a description of other explosion effects software

Jan 1, 2007

By R. Bitmead, R Barker, A. Drake

The opencut coal mine is located about 50 km west of Brisbane, the capital city of Queensland in Australia and produces about 140 000 tonnes per annum of high grade steaming coal utilising a small team (ten) of personnel to mine remnants of the Aberdare and Bluff seams left by previous underground mining. This, in itself, is not remarkable except that one of the seams has commenced spontaneously cornbusting resulting in temperatures in excess of 55’C commonly being encountered with portions of the p’it being wreathed in steam. To extend mine life, the mine required a blasting system that would: . Safely blast in temperatures below 100°C . Significantly reduce overall unit costs . Not increase the current vibration impacts on nearby housing . Not increase flyrock.

Jan 1, 2002

By P. D. Lightfoot, C. Badeen, R. Turcotte, D. E. C. Jones

Following localized (i.e. hot-spot) ignition, there is a minimum pressure required for combustion to propagate in water-based commercial explosives. The latter is usually referred to as the ‘Minimum Burning Pressure’ (MBP) of the explosive. In the present work, both an apparatus based on hot-wire ignition and an associated methodology were developed to measure the MBP of water-based explosives. It was demonstrated that the MBP constitutes a sharp pressure threshold below which the probability of inducing sustained burning in these explosives becomes very small. It was found that each emulsion explosive tested has a distinct MBP value, which depends critically on its formulation. It appears that this test may offer a firm basis for the classification of emulsion explosives for regulatory purposes.

Jan 1, 2004

By Pierre Mousset-Jones, Geraint W. Harris, Robert Karlin, Jaak Daemen

In order to minimize the ore dilution induced by blast movement in surface mines it is necessary to quantify such movement. This will make it possible to more accurately locate the grade boundaries on the surface of a blasted rockpile prior to excavation. This paper describes the development and testing of a method to accurately measure the direction and magnitude of sub-surface blast movement. The technique involves the use of magnetic "radiometry, using a cesium vapor "radiometer and real-time differentially corrected, GPS system, to locate the post-blast position of magnetically enhanced target objects, whose pre-blast locations are known, without disturbance of the blasted rock. The objective is to design an accurate and efficient technique which can be integrated into a mines production cycle.

Jan 1, 1997

In situ, most Taconite is heavily pre-fractured; because of the high cost of comminution of taconite, maximum fracture of pre-existing blocks is desirable. Sustained borehole pressure plays a significant role in fragmentation, especially by penetrating pre-existing fractures. The distribution of explosive-induced energy in the burden in three dimensions was calculated. Data on the comminution of single particles was used, with the distribution of energies and the distribution of pre-existing block sizes, to calculate fragmentation for a case study. The calculation agreed well with the measured fragmentation. Sequential comminution events are much more efficient than single ones, and enhanced fragmentation may be possible with alternative blasting practices. Some important factors in the dependence of comminution on energy input are discussed.

Jan 1, 1995

This paper presents a brief discussion of three case histories to illustrate several aspects of the question of blasting in or immediately adjacent to concrete. The results demonstrate a need to make dramatic upward revisions in previous criteria, whether it be the standard particle velocity criteria or damage response spectra bounds, - especially those which include conservative upper limits of constant acceleration for the high-frequency portion of the spectrum. It is demonstrated, also, that conventional off-the-shelf blast-monitoring instruments are not capable of monitoring small blasts at close range. Both the frequencies and the levels of effect are beyond the range of such instruments. These case histories suggest further that there is a need to review the applicability of certain wellknown equations of elasticity.

Jan 1, 1980

By Michael S. Wieland

The work-principle method was developed for theoretically resolving toxic fumes from non-ideal charge formulations. The whole description of a wanted process refers to macroscopic changes resulting from removing and imposing constraints that work one at a time to chronologically render trajectory terminal (key) states. The trajectory resolution utilizes a thermodynamic quasi-potential or negative work function, and numeric results require some appropriate standard thermodynamic (equilibrium) reaction code TDRC. The underlying method is unable to restrict reactions, tailor the work output or resolve states within the trajectory transitions, so the trajectory terminology is used somewhat figuratively. The work-principle model has the working fluid (reaction material) interacting with a tremendous reservoir (chamber air and walls), while forecasting the work performed upon a mechanical agent.

Jan 1, 1998

By Jim Daly

The word “Enron” has taken on a totally different meaning since its leaders were caught juggling the books, President Clinton’s reputation was destroyed not by what he did but by how he tried to cover it up, Martha Stewart spent time in prison for not being honest. Our society is tolerant of mistakes we humans make but has become very critical about what we do following those mistakes. The blasting industry is in a similar position. We have all heard the stories of the tree stump that came down through someone’s roof, of the windows that were broken, of the casualties that occurred when a blast was not properly guarded. What was done following these incidents? In the mind of the public, not enough.

Jan 1, 2007

By James G. Stuart, Tassilo N. Baur

We will discuss the kind of procedure that we use to predict the no-fire (for safety) and all-fire (for reliability) current levels for any given type electric detonator. The basic idea is to expose several detonators to different levels of electric current, so we can estimate the probability of firing as a function of current. We call this a statistical firing test. But what about the uncertainty in measuring the current? Suppose we are not quite sure what stimulus level we apply? This is the question that we will consider here. This relates to both safety and reliability. Surprisingly enough, we will find that some uncertainty in measuring the levels during our statistical firing test improves our long-term safety and reliability

Jan 1, 2019

By Andrew F. McKown

Overbreak and damage to rock walls at the perimeter of rock excavation can lead to safety problems due to rock falls and additional costs due to a] extra mucking, b] extra concrete or shotcrete to backfill overbreak, c] additional rock reinforcement, d] additional water inflow and e] additional maintenance of rock walls. To minimize these undesirable effects, there are several perimeter control techniques available (i.e. line drilling, cushion blasting, pre-splitting, smooth blasting, and fracture control blasting) which control perimeter hole spacing, burden and loading to provide a smooth, stable excavation contour. Conventional perimeter control loading and hole spacing is satisfactory for massive, homogeneous formations, but when blasting in weathered or fractured rock closer spacing and very light loading is required.

Jan 1, 1984

By James C. Irvine

Meramec Mining Company's Pea Ridge underground mine is presently involved in a large scale pillar recovery program and has made use of both rotary and down-the-hole drills for large diameter blastholes. Groups of pillars have been blasted with water gels in massive blasts which have broken in excess of one million tons of ore per blast. An outgrowth of the pillar recovery program is the combination of rotary and down-the-hole drills to develop vertical "raises" between mine levels. This paper outlines the Pea Ridge procedure for pillar blasting including the use of non-electric caps. Techniques and loading rates are discussed, and safeguards against blasting damage which were developed as a result of the program are presented.

Jan 1, 1976

By W. Reisz

Blast area security is the responsibility of everyone involved in the blasting operation and goes well beyond simply controlling access by unauthorized personnel.

Jan 1, 2009

By D T. Froedge

This paper is a presentation of a coyote shot at the Oriskany Sand Quarry of the Pennsylvania Glass Sand Corporation, Berkeley Springs, West Virginia.

Jan 1, 1982

By Harry Verakis, Thomas Lobb

In the past decade, approximately 5 billion pounds of explosives were used annually in the United States. Most of this quantity of explosives was used by the mining industry and coal mining was the dominant application for explosives. Considering the large amount of explosives used, the accident safety record for the mining industry has improved significantly over the past two decades. Blasting accidents are usually a small percentage of the total number of mining accidents. However, blasting accidents continue to occur and the severity of these accidents is disproportionately high with respect to other types of mining accidents. This paper is a summary and an update of the surface mine blasting accident investigations and studies conducted previously by the Mine Safety and Health Administration (MSHA) and the former U.S. Bureau of Mines.

Jan 1, 2001