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By Cesar Guerra, Alejandro Rojas, Dr. Jhon Silva, Luis Velasquez

The ANN method is applied to predict the P_80 size in one open pit gold mine in Peru. The ANN was implemented in Matlab programming language, and the results from the ANN are compared with data obtained using photo-fragmentation analysis software.

Feb 1, 2020

By Tom Snyder, John Brulia

Part I is the first of a series of articles by the authors on hazardous materials (HM) transportation safety and compliance for shippers and carriers who offer and transport commercial explosives in commerce on public highways in the U.S.

Jan 1, 2014

By Robert Hopler

HUDSON MAXIM A Noted Inventor of High Explosives ALTHOUGH the subject of the present sketch has been a tireless worker in many fields of activity, his name is best known in connection with his work in the development of high explosives and their application to modern ordnance

Jan 1, 2012

By X. Gumede

A model is being developed to quantify the benefits for mining houses resulting from the reduction in greenhouse gas and energy consumption by the application of innovative blast designs in addition to direct financial benefits throughout the mine to mill value chain. The conversion from shock tube initiation systems to electronics and some changes to powder factor measured on an open pit mine had previously been used to show significant improvement on blast outputs. Benefits were realised on drilling, blasting, loading, hauling and beneficiation. Quantification of the relationship between powder factor and reduced greenhouse gasses is investigated in this study. The study has highlighted new data that must be recorded and hence some assumptions were made as to fuel consumption and the energy in crushing was obtained from the Bond work equation. The mine to mill projects in an open pit platinum mine and a quarry produced energy savings and reduced greenhouse gas emissions associated with the careful application of explosives and blast innovations. The less fines project showed an increased carbon footprint. The model provides a new insight into how project feasibility should be decided based on economic and environmental viability.

Jan 1, 2012

By S. Geerts, J Davidson

The purpose of the experiment was to determine detonation characteristics of various improvised explosives. The test consisted of detonating a pipe filled with an explosive compound inside of a plywood arena. The pipe will be located in the center of the arena to ensure even distribution on the witness panels. Details on pipe dimensions, weights of the pipe and explosive, and the density were recorded prior to testing for use in the model calculations. The same size pipes were used throughout to minimize the variables inherent in testing. The plywood witness panels will capture the fragments so that penetration data was obtained, primarily the surface area of impact and depth of penetration. Through the use of the penetration data in conjunction with a mathematical model the original fragment velocity was determined. The mathematical model was developed to measure lethality of fragments from explosives and was modified to determine the original fragment velocity instead. From this model other variables such as the Gurney velocity were calculated. This test was done with an explosive compound that was commonly found, and numerous improvised compounds. In order to guarantee accurate data all of the explosives used for testing were cap sensitive, to eliminate the need for a booster charge which would introduce many unknown variables. The one common explosive compound that was used was C-4 which has known data in order to show accuracy of the model and calculations. The other 5 compounds chosen will not have this data as they will primarily be improvised mixtures.

Jan 1, 2011

By O. Rielo, A. Pascoal, P. Katsabanis

The dynamic parameters of two different granites have been obtained using Hopkinson bar experiments. One series of experiments were conducted using a Hopkinson pressure bar apparatus with an explosive source to provide the compressional wave. This wave would travel along the granite bar and would be reflected at the free end. Strains were obtained along the bar to examine the process. Using relatively long bars of rock, approximately 300mm long and 18mm in diameter, the separation of the compressive and the reflected tensile pulses was possible. If the net tension exceeds the strength of the material, spalling is witnessed. By properly selecting attenuation materials and explosive sources, single spalls were created, making results easier to interpret. Numerical modelling enabled the calculation of the propagation of the stress wave along the bar and its reflection at the free end. Knowing the location of the spalls, critical stress levels for rock failure under tension were obtained. Dynamic tensile strengths were also obtained, at different strain rates, using a Split Hopkinson Bar Apparatus. The results provide a measure of the increase of the dynamic strength at high strain rates, relevant to blasting applications. They are useful for the calibration of blasting models and the characterization of rocks for blast modelling, but also provide answers to the basic question of what is the rock strength for blasting applications.

Jan 1, 2011

By Lon Santis

This paper analyzes 110 serious accidents that occurred during the use of commercial explosives in mining, construction, and other industries since 1992. Data from the Mine Safety and Health Administration (MSHA), the Institute of Makers of Explosives (IME) members’ reports, and media reports were used. Only accidents that resulted in a fatality, significant lost work time, or injury to the public were considered in this analysis. The accident data were analyzed for trends in frequency, type of industry, cause, type of individual harmed, and geographical region. Although the data showed that explosives accidents are decreasing in frequency, still, 29 people were killed and 134 injured. Eightyfive of the accidents occurred in mining, 17 occurred in construction, and 8 occurred in other industries including oil recovery, seismic exploration, agriculture, logging, boiler cleaning, and avalanche blasting. As other studies have shown, flyrock and failure of blast area security caused over half of the accidents. Mishandling, misfires, or fumes caused just over one-third of the accidents. Lightning and drilling into explosives were responsible for the remainder of accidents.

Jan 1, 2003

By Ajoy Singh

A study was conducted to investigate the damage potential to underground multi-seam openings caused due to vibration generated by open-pit coal mine blasting. The objective was to recommend optimal explosives weight per delay to be detonated in open-pit blasts to ensure the safety and stability of underground openings. Sixteen blasts with varying charge weights and initiation sequences were conducted at Samleshawari open-pit mine and eighty four blast vibration data were recorded in the Hingir Rampur underground colliery in India. Analysis of vibration data showed that roof of the underground openings vibrated with higher amplitude of vibration compared to pillars and floors. The amplifications of vibration in the roof at the junction were upto 4.3 times the pillar vibration. It was observed that coal chips detached from roof when the peak particle velocity reached 131 mm/s or high. The vibration magnitude recorded was higher in upper seams openings than in below seam openings. Rapid attenuation of vibration was recorded in below-seam openings at similar locations. Appropriate particle-charge weight-distance equations were established to calculate the safe explosive weight per delay to be detonated in open-pit mine for safety of multi-seams workings of underground mine. The support for the galleries and junctions were further modified for the working seams to ensure greater safety.erground Coal Mine

Jan 1, 2012

By Panagiotis (Takis) Katsabanis, Lyall Workman, Jack Eloranta

The reduction of metallic ores to concentrate consumes a great deal of electrical energy. In the past two decades, a number of case studies have demonstrated a beneficial relationship between powder factor and grindability. However, changes in mill performance cannot be attributed to changes in feed size alone. Blasting energy and the distribution of that energy appears to affect subsequent comminution beyond crushing. This experience has prompted researchers to attempt to duplicate and quantify the mechanisms involved. To date, published reports indicate a measure of success. However, the blast engineer and the mill engineer still lack the tools and basic understanding necessary for full drill to mill optimization.

Jan 1, 2015

By Gregory Hempen, Thomas Keevin, Russell Wilcox, William Wild

The Department of Defense Strategic Environmental Research & Development Program (SERDP) awarded funding for evaluation of procedures to mitigate peak pressures and energy flux density in the water column from ordnance being detonated on the ocean floor. The research purpose was to conduct scaled testing to resolve whether a theoretically-viable covering technology was operationally effective in reducing blast effects and the impacts of shrapnel. An additional objective was testing effectiveness of this method for hard-bottom units (rock or coral) and (unconsolidated) sediment substrate.

Jan 1, 2011

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 Tapan Goswami

The main objective of the blasting phase in a coal mining operation is to maximise the coal recovery. However, coal loss due to blasting is a serious problem. The Australian Coal Association Research Programme (ACARP) reported in 2011 that in Australia one in every ten coal mines is completely wasted due to such losses. Coal is either lost in the spoil, largely due to the blasting operation or becomes diluted and cannot be recovered entirely. The major coal loss mechanisms include losses from the coal seam roof, the floor, the front edge and from dilution. Coal damage and loss mechanisms during cast blasting that have been observed by various authors include: •Excessive cast dragging the coal edge in the cast direction. Movements of this nature are oftenassociated with the formation of trenches. •Spatial movement of overburden where rock shears and moves in a plane above the coal seam,which damages and dilutes the coal. •Rock falling over the coal during the blast often producing indentations in the exposed coal. •The inappropriate use of bulk and initiating explosives that often results in coal damage. •Insufficient stand-off distances from the coal. The Australian coal mining industry has gone a long way towards addressing the coal loss issues since 2011: almost all operations now deploy touch-coal drilling and sporadically use gamma logging for loading overburden. A study was conducted to compare the effectiveness of touch-coal information in which some touch-coal blastholes were drilled on a fixed or random pattern. In another study, some blastholes were drilled to the touch-coal, gamma-logged and mapped to determine stand-off distances. It was found that the coal roof surface created by gamma-logged holes was the most effective option for minimising coal loss. As a result, a variable stand-off distance was found to be the key to minimising losses. This paper discusses the importance of coal mapping, the rock properties of the roof and floor interface of the coal seam, and the significance of loading and initiating designs in minimising coal damage. Furthermore, the importance of using electronic initiators cannot be emphasised enough. This paper also discusses how a cast blast can be initiated from many locations by mitigating geological abnormalities and thereby avoiding spatial movement of rock shearing in a plane above the coal seam.

By Tapan Goswami

This paper discusses the importance of coal mapping, the rock properties of the roof and floor interface of the coal seam, and the significance of loading and initiating designs in minimising coal damage. Furthermore, the importance of using electronic initiators cannot be emphasised enough. This paper also discusses how a cast blast can be initiated from many locations by mitigating geological abnormalities and thereby avoiding spatial movement of rock shearing in a plane above the coal seam.

Feb 1, 2020

By Michael Twomey, Alastair Torrance, Alan Twomey

Low density explosives have been available in various forms for nearly 20 years. These initially consisted of various diluted forms of ANFO formulated to slow the rate of reaction. One such product that was developed was a blend of ammonium nitrate and rubber. This product uses a coarse fuel provided by granulated rubber to slow the reaction rate of the explosive rather than being a diluted form of ANFO. There has always been a technical difficulty in blending two dissimilar materials without subsequent segregation.

Jan 1, 2011

By F. Schott, M. James, G. May, E. Baker, C. Johnson, R. Bauer

Explosive demolition typically utilizes cutting charges to sever columns, detonating cord to time charges and provide an initiation path, and dynamite as a kicker charge. The kicker charges of dynamite are used to “move” columns out of alignment, causing collapse. Demolition projects involving dynamite can pose significant health and safety risks to workers and the public. Nitroglycerin in dynamite can cause dizziness, fainting, and other health problems. Moreover, dynamite placed directly on columns can result in fragmentation and cutoffs, preventing other charges from being initiated and resulting in incomplete demolition. Fragmentation can occur from columns and travel significant distances from the initiation point, sometimes reaching hundreds of meters away. This fragmentation can pose serious dangers to anyone in the vicinity, including workers and members of the public, as the debris can cause severe injuries and property damage. The force and velocity of the fragmented material can be unpredictable and difficult to control, making it important to take proper safety precautions and consider alternative demolition methods that minimize the risk of fragmentation. Previous work concluded that casing charges in water showed that a reduced dynamite charge mass could still successfully kick the charge out of alignment. This study aims to investigate the use of Pentolite boosters in water-cased charges as a safer alternative to dynamite-based demolition. The research involved testing various amounts of dynamite and pentolite boosters in water to compare their effectiveness in moving a hanging W-beam, which swung freely like a ballistic pendulum. Water-cased charges consistently move the column at a higher velocity than the traditional dynamite charge placed directly on the column. The method of water-casing increased the area of impact and impulse felt by the column, improving demolition efficiency when compared to traditional demolition methods as found in previous studies. Pentolite water-cased charges moved the column at 7.8 meters/second (m/s) while the dynamite water charge moved the column at 5.9 m/s. The increased strength and explosive properties of the pentolite contributed to this increase in velocity. This study showed that it is feasible to remove dynamite from demolition projects by utilizing pentolite boosters and that when considering safety, explosive properties, and effectiveness, pentolite boosters can be cost effective as well.

Jan 1, 2024

By Agung Wibowo

The incident of Ammonium Nitrate explosion in Beirut on August 4, 2020, became a wake-up call to Ammonium Nitrate stakeholders for mining and construction regarding the deadly risks associated with explosives management. This is a very expensive a lesson learned for all parties involved in the storage of explosives.

Feb 1, 2020

By Stewart A. Silling, C. Mick Lownds, Dale S. Preece, Ali Bhuiyan

GEM (Geologic Element Motion) is a Distinct Element Method (DEM) for modeling blast-induced heave. It was developed with a very fast computational algorithm that efficiently treats many different element shapes utilizing alternating arcs and lines to create GEM elements. The GEM computational technique has been previously documented so only a summary will be included in this paper. New features of GEM are the ability to define the size of the rounded corner radius as well the length of the sides for quadrilateral and hexahedral elements. Circles can be created from a quadrilateral element with zero length sides and four arcs. An additional new GEM feature is energy partitioning between brisance and heave. This physics-based partitioning is essential for accurate modeling of blast results over a wide range of rock and explosive types. It accurately defines the volumetric, pressure and energy state of the explosive gases in a blasthole following detonation. Rock mechanical properties and explosive characteristics are included in the calculations. Example simulations provide comparison of the GEM predicted heave for two different classes of explosive. A GEM simulation utilizing hexahedral elements is compared with previous modeling incorporating circular elements.

Feb 6, 2023

By Ph. D. Favreau, Favreau Patrice B. Eng, R. F.

Geology is important in mining by helping to identify the rocks which contain sufficient valuable ore to justify their excavation. Geologists give a geological name to each rock type, so geology is a player in blasting; when a blaster has successfully blasted rock of a given geological name at a former site, and he later has to blast rock at another site whose rock has the same geological name, then his first trial often is the same method as he used at the former site, since the geological name of the rock is the same

Jan 1, 2019

By Claudio Lechuga, Carlos Scherpenisse, Juan Rafael Otaiza

From the analysis of drilling process, Block Model information, drilling pattern data and expected fragmentation targets; GBlast® software optimizes the explosive charge design in order to standardize the particle size of each blast.

Feb 1, 2020

By William Nicoll

Those who use electric detonators in firing blasts will be interested in a new electrical testing instrument known as the ‘Blasters’ Friend’, recently devised by the New York Blasting Supply Co. of New York. Owing to the necessarily delicate construction of the platinum wire bridge in the shell of a detonator, it frequently happens that it becomes broken or disconnected; thus destroying the circuit and rendering the detonator worthless. In many cases, misfires and premature explosions are caused by defective detonators. Heretofore, to detect the deficiencies of a detonator before using has been an impossibility, owing to the absence of a testing instrument adapted to the purpose.

Jan 1, 2010