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By Jorge Cárdenas, Alejandro Luna

In mining simulation for fragmentation results prediction is of utmost importance to study feasibility, ensure safety, and estimate the correct use of resources in drilling an explosive to meet requirements and avoid excessive usage. One critical case is fragmentation prediction, developed through models. Developing a fragmentation model in a mining unit aims to control blasting results to align theoretical and real data and improve correlation. Therefore, it is essential to collect post-blast fragmentation data, organize it, and systematically process it to develop a suitable model that meets variable requirements. Using a robust system of equations, this model should generate the required results with minimal variability between simulation and actual results. Additionally, this model must be adaptive to reduce this variability. Studying the most known and used models in mining resulted in our work correlating Cunningham 2006, Swebrec, and CZM models. Thus, the Simfrag model was created, presenting a robust foundation and combining the most notable advantages of the aforementioned models.

Jan 21, 2025

By D. S. Scovira, T. Gustavsson

Exiting WW2 (mid-1940s), the potential of nitrates (ammonium nitrate, calcium nitrate, sodium nitrate) and hydrogen peroxide for application as a commercial explosives for mining, construction, and other industrial purposes both became known. The technology stream advanced the development and uptake of nitrate based explosives to the point that they are the current global standard for blasting. Today, environmental issues are shaping the strategic agenda across various industries. Most global mineral resource, construction houses, and explosive manufacturers have publicly announced ESG carbon reduction commitments in support of COP26 Net Zero 2050. The mid-2010s saw a renewed interest in hydrogen peroxide explosives to eliminate NOx fume. Carbon reduction initiatives in the early 2020s provided additional impetus to investigate hydrogen peroxide based explosives for industrial use. Hypex Bio has recently pioneered the formulation, manufacture, and end-use delivery of a Hydrogen Peroxide Emulsion (HPE) on an industrial scale. The HPE is composed primarily of hydrogen peroxide (H2O2) plus a lesser amount of fuel and emulsifier phase. The base HPE is produced in a low energy intensity modular plant using industry proven mixing techniques. The base HPE is a white, highly viscous emulsion that is similar in consistency to base nitrate emulsions. To enable end blasting use, a mobile charging unit gases the base HPE to a detonable density. The HPE is compatible with current priming and initiation systems. Hydrogen peroxide explosives offer a significant reduction in total carbon emission as compared to nitrate based explosives. The production of ammonium nitrate (AN) emulsion is energy-intensive and not carbon neutral. Based on the EU Average and for the oxidizer phase only, 1 kg [2.2 lb] of AN emulsion emits 2.3 kg [5.1 lb] of CO2 as compared to the production of hydrogen peroxide emulsion that results in 0.23 kg [0.5 lb] of CO2. This is a difference of 90%. HPE contains no nitrates and does not generate post blast nitrous oxides (NOx). HPE generates no aqueous nitrate or ammonia pollution and is a solution to meeting increasingly regulated mine site water discharge limits. Hypex Bio recently conducted a successful underground HPE evaluation with a major mining company in Sweden. HPE blast designs were the same as those done with nitrate based emulsions. Rock breakage, advance, muck displacement, and excavator performance were equivalent. Ventilation and re-entry times were reduced. The mining company has expressed further interest in assessing HPE and is demonstrating industrial leadership by exploring this transformative explosive technology

Jan 1, 2024

By L. Trivino

Blast-induced damage criterion based on the peak particle velocity has worked reasonably well for estimating building damage. However, the same criterion cannot be used to estimate damage to rock and mine structures such as shaft and tunnel walls. It does not take into account the nature of seismic radiation pattern in the near-field, which is very different than what is obtained at far-off distances. To investigate this phenomenon, a systematic study has been carried out involving single-hole blasts and normal production blasts, with explosive source ranging from nearly point source charges to standard borehole sizes (6-7 m long explosive column), with charge weight varying from 0.5 kg to 30 kg. In the near-field, it is shown that, both P-wave and S-wave take a dominant position compared to the mainly surface waves measured in the far-field. These are shown to depend strongly not only on the length of the explosive column but also the way it is initiated in the borehole (i.e. direct vs. reverse initiation in the borehole) with respect to the target location. The seismic radiation patterns were recorded by high-frequency triaxial accelerometer stations grouted in the rock mass. This study describes the nature of seismic radiation in the near-field from long and short charges, the role of initiation direction and their effect on frequency with respect to sensor locations or target area of interest, and their implication in prediction of blast-induced damage in the near field.

Jan 1, 2009

By Dale Ramsey

During Phase IV of our Landfill Mine Stabilization project at a coal burning power generating station, it was determined that a coal barrier pillar separating two abandoned areas of the deep mine had to be breached prior to expansion of the ash disposal area. The proposed plan by the landfill design engineers involved using a high pressure jet cutting tool to cut a slot to allow water flow to an existing industrial waste water treatment facility. Our plan proposed using explosives to breach the pillar from the surface reducing earth disturbance in a high quality watershed while reducing the project cost and accelerating the project time schedule. Many issues surfaced with the proposed change of using explosives. There were a number of lessons learned from this case history and is the primary basis of this paper.

Jan 1, 2003

When a company has an effective hearing loss prevention program, everyone wins-the employers, the employees, and the safety and health professionals who implement the program. This guidebook is not about minimal programs that meet only the letter of the law. It is concerned with programs that are effective as well as efficient: those optimizing program elements that succeed in preventing hearing loss in a practical and cost effective manner.

Jan 1, 2006

By John Montgomery

This paper discusses the major changes to the Commissioners Rules and Regulations, Chapter 120-3-10 “Rules and Regulations for Explosives and Blasting Agents”; how the changes came about, and a summary of the status of the blasting industry in Georgia.

Jan 1, 2003

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 Denise de La Corte Bacci

The Brazilian Regulation NBR 9653 is a guide intended to evaluate mine and quarry blasting effects in urban areas. The first version, written in 1986 by the Committee of the Brazilian Associate of Technical Norms, is currently being revised. Current regulations specify a maximum PPV limit of 15 mm/s (0.59 in/s) without consideration of frequency or type of structures being protected. The present regulation is still a draft and it is not validated. Several different agencies and institutions have participated in the Committee such as the Environmental Agency from the State of São Paulo (CETESB), University of São Paulo (POLI-USP), University of Rio Grande do Sul (UFRGS), National Department of Mineral Resources (DNPM), Aggregate Industry (ANEPAC and SINDIPEDRAS), besides a number of industry representatives, explosives manufactures and independent consultants. The present regulation proposes to modify the limits of particle velocity and introduces new definitions and criteria for evaluation of vibrations, as well recommendations to address blast vibration complaints.

Jan 1, 2005

By Jack Eloranta

Optimization of blasting requires the comprehension of processes including drilling through milling. The author has previously considered the role of powder factor in relationship to downstream processing costs. Recent modeling done by Lownds provides improved prediction of fragmentation based on the distribution and level of blast energy. Many recent studies have indicated improved downstream costs due to higher powder factor. However, changes in powder factor are accompanied by changes in pattern. The purpose is to segregate the effects of higher powder factor from powder distribution. This paper will attempt to use typical Mesabi Range iron ore parameters and costs to illuminate the subject of total process optimization.

Jan 1, 2001

By Larry Schneider

In recent years, many individuals looking into the future of the blasting industry have predicted that the most likely next technological breakthrough would be the use of high precision, digitally controlled detonators. This seemed logical since not only was there much room for improvement in this area, but any significant improvement in delay timing could yield great benefits in productivity and control of adverse effects. And in fact, within the past two or three years, such electronic detonators have been introduced in the field by a number of different manufacturers. These systems are currently being used in many routine blasting operations around the world which are being closely watched and evaluated.

Jan 1, 2006

By Jim Breedlove, Stephen P. Case, Mike Fabio

To meet salt production needs over the remaining life of the Cayuga Mine at Lansing, New York, the Salt Division of Cargill, Inc. decided to build a new underground screening plant. The new plant required a chamber 50 feet wide by 250 feet long and nearly 70 feet high. On advice of their mining contractor, Dynatec Mining Company, the company chose an ingenious excavation method similar to sublevel stoping. This method eliminated the need for an access ramp, reduced equipment needs and excavation time substantially.

Jan 1, 1996

By Catherine T. Aimone-Martin, Meyers Joseph A.

A new strain-based criteria is being adopted for rock blasting in New York City (NYC). This criteria is based on several years of research involving vibration measurements of tall structures during blasting within several feet from buildings designated historic and Landmarked. This research has demonstrated that tall, heavy structures show little upper-structure vibratory response during hard-rock, urban blasting carried out in NYC. The Fire Department of New York City (FDNY) permits rock blasting and regulated limits for ground vibrations using the U.S. Bureau of Mines (USBM) safe blasting criteria. However, these regulations are often superseded by a 0.5 in/s (12.7 mm/s) limit imposed by the New York City Department of Buildings for historic and Landmarked buildings that are adjacent to the majority of blasting projects in the City. This onerous limit is often exceeded resulting in frequent stop work orders that increase the cost and time of rock excavation projects. The

Jan 1, 2019

By Steve Brace

Electronic detonators have been commercially available to the mining industry worldwide for over ten years. It is estimated that total cumulative global sales will have reached 25 million units by the time of the Conference in February 2004. This is below 0.2% of all detonator types sold during this period. Perhaps 20 million will have been used underground in South African gold, diamond and platinum mines. These will have been produced by South African companies, in South Africa for South African customers. Here efforts have met with greater success and in 2003 fully 5 million, or 3% of local detonators sold, could be of an electronic type. However, it is estimated that about US$7.00 (R50.00) has been expended on R & D, manufacturing facilities and marketing, for each unit so far sold. Large sums of money continue to be spent. Despite the apparent success in South Africa, is it justified? Electronic initiation systems have not produced significant technical benefits to the end-user underground nor corporate profits to the supplier. Some doubt they ever will (even from the large surface operations where the price per unit is much higher). A conclusion might be that they have failed. In 1998 Smit and Pistorius wrote a paper titled “Implications of the Dominant Design in Electronic Initiation Systems in the South African Mining Industry”. This ISEE paper seeks to summarise and review the conclusions of the earlier work. These were: that a dominant design had not yet emerged; the type of connector and the way in which detonators are connected and programmed would be a strong determinant influencing the development of a “winning” product; technical aspects rarely solely determine which becomes the dominant design (marketing, social and economic factors often have a strong influence); electronic initiation systems were an emerging technology for the underground gold mining industry in South Africa and because it was under severe cost pressure the mines would look to them to raise productivity and hence profits; finally, as a dominant design begins to emerge, one could expect a number of players to exit from the industry.

Jan 1, 2004

By C. Braun, C. Kennedy, P. Katsabanis

A series of small scale tests, simulating multi-hole blasts have been performed to establish the effect of delays on blast fragmentation. The blasts were performed in high quality granodiorite blocks, which were cut from stone prepared by dimensional stone quarry operations. The pattern used was equilateral triangular, with a distance of 10.2cm between boreholes, which had a diameter of 11mm, were loaded with detonating cord and the coupling medium was water. The delays used were achieved using different lengths of detonating cord for the cases of delays between 0 and 100 microseconds between holes and a sequential blasting machine firing seismic detonators for larger delays up to 4ms. All fragments were collected and screened. The experiments showed that the coarsest fragmentation was achieved with simultaneous initiation of all charges. Fragmentation became finer with delay time between holes up to 1ms between holes. The results show that in moderate to competent rock, similar to the granodiorite of the experiments, fragmentation optimization requires delays of few milliseconds per meter of burden. In view of the findings, which agree with previous published work, the current trend of selecting fast firing times for fragmentation optimization is questioned.

Jan 1, 2006

By Ayman Tawadrous

Cave mining offers a flexible technique to exploit large, low grade, deep ore bodies with low operating costs. It is typically done in either a top down approach; i.e. sublevel caving, or in a bottom up approach; i.e. block or panel caving, to extract ore bodies that may have been previously considered unfeasible to mine. Sublevel Cave (SLC) mining, in particular, is a cave mining method based upon the utilization of gravity of blasted ore while the overlying host rock fractures and caves under induced stresses and gravity. Thereby the caved waste originating from the overlying rock mass fills the temporary void created by ore extraction to achieve a controlled collapse of the roof.

Jan 1, 2015

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 Brulia

It has been said that the only thing that remains constant is change. After more than 33 years in the explosives industry, I do not take any exception to that adage. I have seen changes in people, changes in ownership of companies-both small and large, domestic and international; changes in products; changes in the way we use products; changes in the way we handle products; changes in regulations; and last, but not least, changes in our perceptions of threats to our industry.

Jan 1, 2008

By Gene Baker

A new Safety Library Publication (SLP), SLP-27, which is titled “Security in Manufacturing, Transportation, Storage and Use of Commercial Explosives” was recently released by the Institute of Makers of Explosives (IME). SLP-27 makes recommendations for both general security and enhanced security at explosives sites when security risk levels, declared by the Department of Homeland Security (DHS) using its Advisory System, have temporarily increased.

Jan 1, 2006

By Agne Rustan

The goal of this paper is to describe Fragblast 10 for those who did not have the opportunity to attend the Symposium and also give some examples of new research findings used in practise in some countries throughout the world. Also some entertainment events from the symposium are described.

Jan 1, 2013

By James A. Bachmann, Christopher J. Gray

On December 26, 1994, at 1:00 am, Santa Fe Pacific Gold's Twin Creeks Mine experienced a major highwall failure involving over 2.5 million tons. The resulting effects of this slide were thousands of ounces of gold that were now deferred and an unstable wall above which made mining the slough material unsafe.

Jan 1, 1996