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By Eduardo Lozano, Vilem Petr

The use of explosives bring countless benefits to our everyday lives in areas such as mining, oil and gas exploration, demolition or avalanche control. However, because of the potential destructive power of explosives, strict safety procedures must be an integral part of any explosives operation. The goal of this paper is to provide a solution against the hazards which unfortunately accompany the use of explosives. For this reason, a blast shield is specifically designed and tested for protecting personnel against these unpredictable effects. This document will develop a complete analysis answering the following questions: what are the potential hazards from an air blast; what are their effects; and how can we be protected against them. In order to answer these questions, theoretical, analytical, and numerical calculations are performed. Finally, a full blast shield prototype is tested under blasting conditions proving its effectiveness as a safety device while explosives are used.

Jan 1, 2015

By D. Fry, S. Hunsaker

Ammonium nitrate in explosives and sulfides in reactive ground have the potential to react at ambient and elevated temperatures resulting in premature detonations. The Australasian Explosives Industry Safety Group (AEISG) published, in 2006, a Code of Practice1 for elevated temperature and reactive ground. This paper reviews the chemistry, general reactivity of various ground types, elevated temperature hazards, and testing protocols contained in the code, that are industry best practices for managing ammonium nitrate-based explosives in elevated temperature and reactive ground conditions. In addition to reviewing the 5th edition AEISG Code of Practice, data is presented validating the recommended sampling guidelines within the code. Dyno Nobel has been screening reactive ground samples and performing sleep time testing since the code of practice was first released. Test results demonstrate the effects of samples that are allowed to oxidize before testing and are shown to be subsequently less reactive and not representative of the actual hazards facing mining blasting operations. Results also show that for a given reactive ground sample, reaction times decrease with increasing temperature. Data also quantify the delay in reaction time given by inhibited products. These results emphasize the importance of proper sampling and preparation of samples to accurately characterize elevated temperature and reactive ground hazards. They also demonstrate the efficacy of inhibited products in managing these hazards

Jan 1, 2024

By Jason Baird, Philip Mulligan

This report details the preliminary calculations governing the underwater collapse of an oil pipe via explosive lensing. An explosive lens changes the detonation wave produced by an explosive by changing the geometric conditions of the explosive (Zukas and Walters, 1998). Multiple lenses can be focused on a central location, generating a series of precise detonation waves collapsing in on a specific point. This report will assume a spherical-shaped, single explosive charge and explain how the authors determined the explosive charge size needed to seal a metal pipe while focusing on one explosive charge acting on part of the pipe. Future calculations will analyze the combination of multiple explosive charges acting on the pipe as a whole.

Jan 1, 2013

By Benjamín Cebrián, David Flores, María Rocha Gil

This document shows the evolution of drilling and blast digitization process, savings and trends in a mine, using new technologies that creates business opportunities and general improvement of D&B process.

Feb 1, 2020

By S. Behera, K. Dey

This paper presents a methodology for finite element (FE) modelling to analyse the total deformation of rockmass under blast-load, with a focus on predicting backbreak that may occur during surface blasting operations. Backbreak can result from improper use of explosive energy, leading to damage beyond the excavation zone and jeopardizing operational safety and productivity. The paper highlights the impacts of backbreak on bench stability, excavator operation, drilling operation, flyrock generation, and improper fragmentation and boulder formation in surface blasting. However, prior estimation of extent of rock breakage zone can provide an idea to formulate the blast design to control the backbreak. While vibration-based prediction models are commonly used to estimate backbreak, they require physical blasting experimentation. To overcome this limitation, the paper describes the development of a FE model using ANSYS Explicit dynamics, which simulates rock blasting and calculates the total deformation of the rockmass. The rockmass deformation is modelled using Drucker-Prager (D-P) strength model with the Jones-Wilkins-Lee (JWL) equation of state for the explosives. The accuracy of the FE model is evaluated through physical experiments, and the results are compared with the vibration models. The FE model demonstrates close proximity to physical observations as well as vibration model result in predicting backbreak, thereby offering a promising alternative to vibration-based prediction models. The primary objective of the study is to predict the response of the insitu rockmass to explosive blast loading and determine the effective rock breakage zone.

Jan 1, 2024

By Benjamin Cebrián, María Gil, David Flores

In many occasions during the Mining operation life, blasting engineers find different and controversial results of fragmentation, dilution or wall control for the same geotechnical domain and blast design (pattern and explosive charge). Most of the times, the difference between same blast designs is not measured, not controlled. Once a blast designed is defined, the most important part of the process after that is the implementation of every step of the blast on site. Almost nobody is measuring it, controlling it, but just controlling implementation is possible to relate blast design with results in a consistent way, to optimize the full process of D&B. Controlling implementation not only per event but also to check and change trends and decision-making is paramount for optimization and saving millions of extra costs every year. The lack of resources and the hardness to manage all the info created every day in a blast make this process very tough and difficult to maintain in long term. The use of new technologies on site and software that allows a best, more consistent and continuous control of blast implementation have been proved to be the key for optimizations and cost saving. This document shows the evolution of drilling and blast digitization process, savings and trends in a mine, using new technologies that creates business opportunities and general improvement of D&B process.

By Alastair Torrance, Gary Cavanough

Over the past two years a research project has been performed on reactive and hot ground. A key finding is that host materials including carbonates and coal are inhibitors to the reaction of sulphide and nitrates. The mechanism of this inhibition is pH buffering and isolating the surface of sulphide from reactants. It has been identified that acidity is a key driver of the reaction with a pH of 2 required for a reactivity event. A series of decomposition experiments confirmed that reactive and hot ground are essentially the same phenomenon with the heating produced either by the reaction of sulphide with nitrates or an external heat source. The results indicate that the key driver of detonation in reactive ground is energy and heat released from the acid induced reaction of sulphide and nitrate with no indications of sulphide being a catalyst or contributor to detonation apart from being a heat source. There must be sufficient sulphide and thermal insulation to provide and retain enough heat for detonation to occur. A pathway to detonation is postulated whereby the heat travels upwards and results in evaporation of water in the explosive. When the temperature reaches approximately 200°C (400°F) the ammonium nitrate starts to decompose, decreasing the mass of the reacting species. The material in the top layers has reduced density and specific heat hence the temperature of the top region rapidly increases up to >1000°C (1800°F) and may initiate detonation. Field tests on loaded blast holes support this proposed mechanism. Case studies are presented whereby the research findings are used to provide an analysis of historical reactive ground events.

Jan 21, 2025

By L. Muñoz, L. Steffen, J. Alarcón, W. Vilas

Today, mining operations close to communities face increasing challenges, especially in their drilling and blasting operations. Proper management of environmental impacts is important to guarantee their license to operate and to provide sustainability to the mining business in the long term. Blasting is an event that generates impacts such as vibrations, noise (airblast), projections (flyrocks), ejection of dust and fumes (when there is a deficient detonation of the explosive). If any of these variables exceed the established regulations, sanctions can be generated and even lead to stop mining operations. The goal of this work is to present a review of different techniques, concepts, technologies, simulation software and monitoring / control tools to minimize the environmental impact generated by blasting. For which, a case study of a big scale open pit mine in Brazil with operations close to a community will be presented. An adequate management model, combined with good operational practices, the use of new technologies, enable a safe operation without incidents with the communities. In this way, building trust with neighbours, maintaining the license to operate, and helping mining industry to mobilize resources essential for progress in a sustainable way

Jan 1, 2024

By J. Silva, M. Kotraba, F. Pontanilla

Blasting is the application of highly complex science that, in some cases, could be viewed as an art. Many variables are involved in a blast, including geology, pattern design, timing and firing sequence, and explosives selection. Assuming that better results can be achieved by only increasing the powder factor is inaccurate. The Drill-to-Mill (D2M) concept has been in the mining industry for over two decades. The D2M approach is commonly viewed in an oversimplified manner, assuming that by simply increasing drilling and the amount of explosives used (both of which add operational costs), the downstream value will be created. An optimized D2M initiative should combine the smart application of explosives at the beginning of the mining process, matching the dynamic properties of the rock to the explosive selected to improve the efficiency of the energy created by the explosive to the rock mass being blasted, and to bring benefits to the mining operation across the entire mining and processing value-chain. This paper reviews the principles behind matching the shock impedance of the rock and the explosive and compares the traditional use of explosives versus the smart application for two hypothetical blasts.

Jan 1, 2024

By Lifeng Li, Jhon Silva-Castro

"Signature Hole Technique is one method to assess the vibration waveform of a production blast.Methematically, it is the convolution between a prior measured waveform of a single blast hole (signature) and a given time delay sequence (comb function). Being an advantage, the inverse operation of convolution, known as deconvolution, can be used to estimate the signature."

Jan 1, 2017

By Luis Huaroc, Augusto Sotomayor, Erick Rodriguez, Paulo Fernández, José Ricaldi, Luis Alejandro

The application of the Kuz-Ram model for the prediction of fragmentation is used worldwide, in Coimolache Mine it was used to determine blast domains and optimize the process by obtaining drilling patterns that meet a required X80 and reducing the uncertainty of drilling.

Feb 1, 2020

By Jeff Wachendorf

As the title "Cast Blasting Around Town" implies, this paper details the starting of a cast blasting program in and around the town of Colstrip, Montana. As strip ratios have increased, the need to adapt and find solutions to provide coal at a reasonable cost to the captive power plants has risen. Colstrip, Montana has a long history of coal mining which dates back to the early 1920's when Foley Brothers began supplying coal strictly for powering locomotive engines. Early mining days starting in the 1920's and the progression up through the 1970's when mine mouth power plants were built will be discussed. To accomplish the desired results, early mining techniques included steam and electric powered equipment as well as a lot of actual horse power.

Jan 1, 2009

By John A. Franklin, Tom C. Palangio, Norbert H. Maerz

No blast evaluation is complete without fragmentation measurements which until now were inaccurate, costly, time consuming and created delays in production. “WipFrag.s”is a fully automated PC based fragmentation analysis system that uses digital photo analysis techniques to measure broken rock. Fragmentation can be measured in minutes using compact videocameras for image acquisition. Even subtle changes in rack quality can be detected providing the information necessary for pattern optimization, explosives evaluation, timing selection, benchmarking and blast model validation.

Jan 1, 1995

By Zhiwei Jiao, Ziqing Guo, Mushen Wang, Yueda Fang, Qiuming Tang

In order to achieve anti-terrorism, production safety, better explosive performance, lower cost, and environment protection, we developed HMS (emulsification in borehole).Long-process PM (plant-mixed) and SM (site-mixed) emulsion trucks are reviewed and compared to a new type of short-process HM (hole-mixed) truck for onsite emulsion manufacturing. The short-process HM truck has demonstrated many advantages over its PM and SM counterparts in areas such as process safety and security, energy efficiency and environmental impacts: 1) No emulsion matrix is manufactured in the plant, transported on public roads, or even present on the surfaces of blasting job sites. Such characteristics are certainly beneficial in eliminating risks of the product being diverted and used by unlawful players; 2) This short-process involves "micro-fluid control to form super oil phase-rich" in tubular emulsification process, making it intrinsically safe; 3) There is basically no residual matrix left in the truck or on the job site to clean up, which greatly reduces environmental impact of the process; 4) Comparing with typical PM and SM trucks, the HM truck has eliminated the needs of many power equipment and critical pump pressure for turbulent flow forming a static emulsification with super oil phase -rich is only 0.2Mpa. These is therefore quite energy efficient.

Feb 1, 2020

By Tom Treleaven

The success of any blast is dependent on the accuracy of the blast design and the field controls used on the shot. This point cannot be over emphasized because when the geometry is not measured and/or field controls are not properly implemented, it can often have devastating effects on the final blast results. Thus drilling accuracy, tiont row burden control, explosive confinement, energy distribution, explosive selection, timing and structural geology become critical parameters in the design of successful blasts. Understanding the actual dynamics of the blast and why certain results were achieved is the fast step in optimizing a blast design. As stated by R. Frank Chiappetta, “Of all the blast monitoring systems available today, high speed videography still remains as the best stand alone instrumentation system for blast diagnostics.” Over the past years I have analyzed hundreds of blasts using either high-speed lowcams (500 frames per second) cameras or standard digital (30 frames per second). These analyses confirm, without a doubt, that shot geometry, in combination with structural geology, is the most important factor in overall blast results. Drilling accuracy is the single most important component in efficient blasting. Having equal mass associated with an equivalent energy is the basis in which blasts are designed. When drilling inaccuracy or borehole deviation occurs, not only is the energy unevenly distributed, but the basis of all design calculations becomes invalid. Over the past several years, quarry and mining operations have employed the use of boretracking measuring devices to measure borehole deviation and hole toe locations. In cases of operations using top hammer drills, it was discovered that the amount of deviation was significant and far greater than they believed they had. Set up error, improper drilling techniques and bit wear were some of the contributing factors. Through video anaysis of boretracked blasts, blast results were directly linked to drilling ..accuracy. The comparisons here took into account blast design, energy factors and hole sequencing.

Jan 1, 2000

By Trevor Howie, Mal Edwards

"Thiess Contractors Pty Ltd. designed and operate the Mt Owen Mine in the Hunter Valley of NewSouth Wales, Australia on behalf of the owners of the mine, BHP Coal Pty Ltd. The mine is a multiseam open cut coal operation. Mining by Thiess commenced in September 1996 following thecompletion of the coal preparation plant. The location of the mine is shown below on Figure Al."

Jan 1, 1997

By Winfried Rosenstock, Carlos Orlandi

Along the Pacific West coast of Latin America there are several large operations of metal mining activities. To mention only a few: Chuquicamata in Northern Chile moving daily approximately one million t of copper ore and waste, Cerro Verde near Arequipa in Peru, or lanaccocia. Apart from the coal deposits in north-east Columbia it is mainly to deal with metal-mining, which has due to geographical reasons relatively high cash-cost. This sector of mining is traditionally severely depending on the world-market.There are reasons to believe that the world-market will remain on a low price level and some analysts predict that in general the price-level will continue on low basis for the next decade. The cash-cost factor becomes therefore even more important as it already is. The goldprice development during the year 1999 illuminates that market changes can quickly lead to a severe crisis which forces the shutdown of mines with cash-costs close to or above the present market price per ounce. The breakdown of the cash-cost shows, however, that there are ways to overcome even the crisis like it struck the low-grade open pit goldmines around the world. Especially hitherto the “Electronic Option” is the only solution as the possible reduction using advanced technology based on the application of electronic detonating systems and newly developed special ignition procedures. The electronic option will lead to tremendous cost reductions similar to the results of research operations Thiess Contractors, Brisbane, Australia have carried out in Australia in 1998 and 1999. The electronic option allows a comprehensive integration of side effects of the blasting process which in the past could not have been achieved so far. Electronic initiation can achieve secondary effects which have an additional and positive impact on the level of costs. Appropriate application can enhance the production of material which will reduce the primary crusher costs or even make a primary crusher operation obsolete.

Jan 1, 2000

By M. Ganster, H. Krenn

The mission of the project is the fast and cost-effective rehabilitation of decommissioned lignite mining and coal upgrading facilities. This is necessary to ensure the successful future utilization of these sites. On the one hand, for founding new industrial and commercial facilities and on the other hand for touristic activities.

Jan 1, 2013

By Dan L'Heureux, Joe Haid, Stephen H. Chung

Most coal deposits in Western Canada involve steeply dipping multiple seams. An efficient way to recover coal seams would be to drill through the seams and blast both the overlying and underlying waste material in one shot without disrupting the coal seams while fragmenting the waste rock for easy removal. This requires special blasting techniques as reported by Chung and Jorgenson in 1985.

Jan 1, 1998

AQUILA Mining Systems Ltd., designs, develops and delivers systems for measurement, analysis, simulation, control and automation to the mining, construction and petroleum industries. The objective of current efforts by AQUILA is the continued development and refinement of computerbased systems and techniques to automatically process monitored performance data from surface blasthole drills and mining shovels, and the management and coordination of these pieces of equipment by GPS (Global Positioning Systems).

Jan 1, 1994