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By Tom Snyder, John Brulia

"The U. S. commercial explosives industry annually transports thousands of tons of hazardous materials (HM) in the form of explosives, oxidizers, and combustible liquids by highway in truck-tractor/trailer combinations and straight trucks, including pickups. Managing risk during transportation is every commercial explosives industry motor carrier’s number one job."

Jan 1, 2014

By Raúl Carretero de la Hoz, Leonardo Soares Chaves, João Paulo Soares Toneli, Francisco Felipe da Silva Dantas, Marcos Peres Lopes, Marcus Vinicius da Silva Gonçalves

The mining activity results in environmental impact and thus requires the adoption of techniques to minimize its effects. The rock blasting process is required to break up and move the rock enabling the haulage of the material, however, it might also cause undesirable effects such as flyrock, overbreak, excessive ground vibration or air-blast at the neighboring communities and damage to civil or geological structures located nearby. The Serra Sul mine, commonly referred to as S11D project, has obligations to preserve two natural tropical montane lakes and several maximum relevance natural cavities whose legal preservation radius represents constraints to the mine development and operation. Controlling measures are undertaken to ensure preservation of the cavities, especially during rock blasting stage, with limitations of the maximum instantaneous charge (MIC) and ground vibration control. The demand for high productivity and the large areas with hundreds of blastholes to charge are challenging factors to the charge control. This work presents the development and field application of a map for limiting explosive charges in the rock blasting process at the Serra Sul mine, used for the definition of maximum charges according to the blast location, ensuring the preservation and compliance with the defined ground vibration limits for each cavity. The map is applied at the mine for every blast and when there is a charge constraint, the map helps to define the areas with different charging profiles in the field contributing to higher charging productivity.

Jan 21, 2025

By Finn Ouchterlony

"Recently detailed fragmentation data from blasts fired with electronic delay detonators (EDDs) in the Red Dog mine in Alaska were presented. They include a comparison with pyrotechnic detonators fordifferent in-­-row delays in a standard pattern and EDDs in an expanded pattern. Fragmentation was measured on the belt after the primary crusher. The Rosin-­-Rammler function (RR, two parameters) was used to describe the crusher product. This was combined with the JK SimMet crusher model and the CZM blast model (Crushed Zone Model, three to five parameters) to estimate a reasonable crusher feed (muck pile fragmentation or run of mine, ROM) for each fitted product. In this way the effect of delay timing and electronic detonators on the median fragment size x50 and uniformity coefficient n for both crusher product and the blasted rock was determined. "

Jan 1, 2012

By Sunil Vytla, Akash Adhikari, Purushotham Tukkaraja

Blasting operations produces gases and fumes that may be toxic or non-toxic in nature. A detonation of commercial explosives such as ANFO, emulsion, and dynamite would ideally produce only nontoxic products such as steam (H2O), carbon dioxide (CO2) and nitrogen (N2). However, in the real world, the detonation of explosives produces toxic products such as nitrogen dioxide (NO2), nitric oxide (NO) and carbon monoxide (CO). The focus of this study is the blast fumes entrapped in the muckpile. Fume clearance and workplace re-entry time studies performed in the past have overlooked the toxic gases entrapped in the muckpile. Studies show that as much as 60% to 70% of the fumes or gases produced during blasting underground can remain entrapped in the adjacent rock mass or in the muckpile. The toxic fumes trapped inside the muckpile are slowly released and could be fully uncovered during the mucking process. Exposure to these gases or fumes is hazardous to mine workers. In this study, author have analyzed the nature of fume flow, i.e. accurately predicting where and how the fumes flow after an underground development/tunnel blast. This will help in determining i) precise re-entry times for the workers ii) rate and direction of the fume flow. Computational Fluid Dynamics (CFD), a mathematical simulation technique that predicts fluid dynamics phenomena is used for this purpose. CFD is preferred over physical models because it is inexpensive, once the accuracy is established, a wide range of scenarios can be simulated quickly, and the toxic gas flow patterns through underground openings can be analyzed efficiently. For this study, CFD is performed using SC/Tetra software owned by MSC software company.

By Dennys Huaman, Carlos Rojas

Using the Levenberg-Marquardt algorithm to reparametrize the Kuz-Ram original model equation of the mean characteristic size and assess the errors of both models and their comparisson using different statistics measures like chi-squared or relative error with the usage of the Monte-Carlo algorithm.

Feb 1, 2020

By Clara Godoy, Álvaro Dapía, Paulo Couceiro, Pablo Segarra, José Ángel Sanchidrián, Juan Navarro

This paper applies geostatistical tools in Measure While Drilling (MWD) data to estimate the probability distribution of values in all the points of the studied domain in order to assess the continuity of rock classes between boreholes. The analyses carried out by Ghosh et al. (2018) and Navarro et al. (2019) have been used as starting point of this work to classify the geotechnical rock condition in four classes: solid rock, fractured rock, cave- in rock and cavity. From it, an application for the geotechnical rock condition of orebodies have been developed, aiming at characterizing the rock before the charging the holes to minimize unexpected rock conditions and to address issues associated with charging and blasting operations. Such problems are closely related with non-optimal rock fragmentation after blasting.

Feb 1, 2020

By Henry P. Jr Van Ormer

During any blast hole operation the first choice to be made is hole size - it seems simple, just calculate all the factors, spacing, burden, depth, rock characteristics, powder factor, etc. and you have it - Hole Size. But we all know that it is not that easy - the "hole size" is part of a system and many other situations can have great impact on the optimum production Blast Hole Size - such as crusher characteristics, hauling capability, mucking capability and - Drilling Capability!

Jan 1, 1983

By Richard J. Mainiero, Michael S. Wieland, Harry C. Verakis

The Bureau of Mines, U.S. Department of the Interior, has been conducting research on delay blasting in underground coal mines in support of the efforts of Mine Safety and Health Administration (MSHA), U.S. Department of Labor, to revise coal mine blasting regulations. Part of the research centered on developing an understanding of the factors that lead to misfires of permissible explosives. Research was conducted to determine whether frequency of misfires was related to borehole spacing. For a wide variety of permissible explosives, misfires were observed for about 50 X of the holes at 45-cm (18-in) spacing. Misfires were also observed for 60-cm (24-in) spacing, but the frequency of misfires was much lower than observed for the 45-cm (18-in) spacing. The Bureau has recommended that hole spacings of less than 60 cm (24 in) be prohibited.

Jan 1, 1986

By Xu Tianrui, Jin Xiang, Pen Dianhua

Based on the results of research or investigation, this paper describes the causes of and countermeasures for unexpected accidents, such as premature, postponed or spontaneous explosions in blasting practices in China.

Jan 1, 1996

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 John W. Brown

The purpose of this paper is to describe different methods of evaluating the performance of your current rotary blast hole drills. To properly evaluate a drill rig's performance you should include a competent driller, mechanic, rotary bit technician and a technician representing the manufacturer of the drill.

Jan 1, 1998

By D. Lee Petersen, Travis Davidsavor

The 2003-2004 expansion of a Duluth medical center required rock blasting adjacent to the existing structures, a Mn/DOT retaining wall and other urban structures. This case history describes the methods of a blast damage assessment, based on blast parameters, excavation locations, and critical vibration receptors (including surgical suites, a linear accelerator and a major retaining wall). The assessment concluded that blast vibrations could be controlled, by limiting charge weight, to eliminate impact at the critical receptors. Prior to construction, we conducted preconstruction surveys on structures susceptible to vibration damage. During construction, we reviewed submittals, observed test blasts, reviewed blasting logs and monitored blasting vibrations. Up to 13 seismographs were used simultaneously. Close coordination with medical center operations personnel was necessary to prevent impacts to critical medical procedures. Measured vibrations were clustered around the predicted values, and attenuated at the predicted rate. High-frequency blast induced ground vibrations induced low-frequency vibration of an adjacent MnDOT retaining wall. Medical center structures were observed to significantly attenuate the ground-borne vibrations. This paper was first published in the Proceedings of the 56th Annual Geotechnical Engineering Conference, 2008, at the University of Minnesota.

Jan 1, 2010

By R. F. Favreau, Favreau Patrice

"The economy profits from the rock excavated in mines and quarries and the excavations required for the construction of roads and buildings. However such excavations are achieved by blasting withexplosives, and explosions create fly rock and vibrations which in some cases may throw rock far intoinhabited regions and may vibrate buildings excessively in these regions. Society, however, no longeraccepts that their quality of life be disturbed by the risks of fly rock or the perturbation of vibrations.Thus it is important to know how to design blasts that do not cause excessive fly rock or vibrations, and to understand why sometimes a blast does create excessive vibration or fly rock. An article presented at the 2015 ISEE (reference 1) explains how unacceptable vibrations can be avoided, while the present article explains why dangerous fly rock occurs and how it can be avoided. The article shows by rigorous calculations with the blast simulator Blaspa that long range fly rock can be due to short collar or short burden, but mainly it explains how inadequate blasting that allows the floor to rise can cause even further reaching fly rock, a situation not usually recognized by most blasters."

Jan 1, 2016

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 David N/A Doucet, Colter N/A Angell, William N/A Joa, Kyle N/A Wagner, Catherine N/A Johnson, Marty N/A Langenderfer

The Kingery-Bulmash (K-B) equations are a widely accepted means of predicting air-blast parameters from surface explosive detonations. The parameters predicted from these calculations include incident and reflected pressure, time of arrival, shock front velocity, incident impulse, reflected impulse, and positive phase duration. K-B calculations are based on curve fitting of experimental data and can be used to predict air-blast parameters for explosive weights from less than 1 kg (2.2 pounds) up to 400,000 kg (440.9 US Tons), and ranges of 0.05 to 40 meters (1.9 inches to 131.2 feet). The K-B equations can also determine the parameters for multiple explosive types using scaled distances and relative equivalency to TNT. An experiment was designed to demonstrate if the measured results for incident pressure, time of arrival, shock front velocity, incident impulse, and positive phase duration equal the expected results reported for the detonation of a small quantity of explosive determined by the K-B Calculator. Three surface-detonated 300-gram (0.66 pound) hemispherical charges of Composition C-4 were observed via high-speed imaging and hydrostatic pressure monitoring. The hydrostatic pressure generated from each charge was measured via piezoelectric pressure transducers at a scaled distance of 10 from the charge epicenter, and at elevations of 0.30, 0.61, and 1.22 meters (1, 2, and 4 feet) above ground level. Variances in experimental values from the K-B predicted values were recorded for each measured blast parameter. Time of arrival, which was redundantly confirmed through high-speed imaging analysis and hydrostatic pressure monitoring, showed the highest deviation from the predicted values at more than double the K-B predicted value. This report compares the observed blast parameters from the test series with the expected blast parameters from the Kingery-Bulmash Blast Parameter Calculator. Differences between the experimental and predicted values are reconciled through analysis and discussion of testing conditions, instrumentation setup, and scaling methods.

Jan 1, 2019

By Harry Verakis, Thomas Lobb

This paper is a summary and an update of the underground mine blasting accident investigations and studies previously conducted by the Mine Safety and Health Administration (MSHA) and the former US. Bureau of Mines. 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. In 2000, about 5.7 billion pounds of explosives were produced in the USA. The mining industry consumed the greatest portion of explosives manufactured for blasting with about 67 percent used for coal mining. Metal and nonmetal mining operations account for about 23 percent of the use of explosives. The use of permissible explosives in underground coal mines continues to decline (3,373,069 pounds for 2000).

Jan 1, 2002

By A. Andrades, E. Arias, Y. Pizarro, J. Alarcón

Division Ministro Hales - Codelco (DMH) is located at 2600 meters above sea level, 10 km north of the city of Calama, Antofagasta region, Chile. In operation since 2010, it corresponds to a porphyry copper deposit that is exploited by the open pit mining method. The ore is mainly composed of sulfides, which is concentrated by comminution processes such as crushing, SAG milling and ball milling to liberate the mineral particles, and then separated from the waste (concentrate) in flotation stages, including a concentrate regrinding stage. Reports from the DMH processing plant area have identified a decrease in fine copper recovery, with the first hypothesis being the high percentage of ultrafine particles (% <45µm) in the flotation feed. Due to the above, DMH & Orica decided to carry out activities to identify the controllable variables that can impact the generation of low size particles in ore and adjust them to reduce the percentage of fine material generation, with special focus on the Drilling and Blasting processes. Based on the data provided by DMH, we evaluated what could be integrated to make an analysis. The different attributes associated with the ore and their effect on copper recovery were evaluated. In parallel, at the mine, a fragmentation measurement campaign was carried out at the loading faces and granulometric analysis of the drill cuttings. Once the correlations between the attributes and copper recovery were identified, hypotheses were established and reviewed with the Drilling & Blasting, Geotechnical, Geology and Process Plant areas. With the validations of the hypotheses and the results of the in-mine (cutting) measurements, we proceeded to review the criteria for the classification of Blastable Geotechnical Units and their associated D&B designs. Using software and the Crush Zone Model (CZM) tool, which considers rock and rock mass parameters, scenarios for various D&B design proposals were simulated with the objective of reducing the generation of ultrafine particles from the blasting process. Next steps include trial blasting with the D&B design recommendations, which will require follow-up to the flotation process to identify the impact on the reduction of ultrafine material from blasting.

Jan 1, 2024

By Francisco Sena Leite, Vincius Miranda, PhD Machado Leite, PhD Pinto, Raquel Carvalhinha, Alexandre Julio, Dorival de Carvalho

Rock blasting, in particularly the drilling process, is one of the first processes in the stage of rock fragmentation and plays a fundamental role by influencing all the following stages. Given its importance, some proposals to optimize this process have been presented over the last few years. These proposals, while having different approaches, aim (in a large part) to minimize the costs of drilling and blasting respecting the limits of fragmentation required by primary crushing. Reviewing some recent articles leads us to an enriching experience, since the authors of these articles clearly model the problem, but do not address the mathematical solution of these models, which in turn, given their non-linear nature, have no directly and easy solution. Simple and even robust optimizers present in the market show different results and often do not converge to a single solution. To address this problem, an adapted gradient heuristicbased model was developed to try to find optimum values. Heuristics search for values of stemming, subdrilling, burden and spacing that minimize the costs of blasting and drilling. This search, which by the nature of the heuristic moves the solution in the direction of the gradient with maximum decrease to find optimal solution, found values that in turn, when compared with values presented by market solutions not only equaled them as, in some situations, even improved the proposed solution. The algorithm was tested and validated on the field, and although the results have already been presented in papers published in the last year by the authors of this paper, it is now presented with its mathematical formulation and comparison with the other solutions. This approach is expected to be able to improve (and even demystify) the process of pattern expansion and be the basis for future work in the continuation of the optimization process.

Jan 1, 2019

By Lazar Kricak, Vladislav Kecojevic, Dragan Bogunovic

In spite of many advantages explosives have, their usage may cause environmental problem such as seismic vibration. One of the solutions to this particular problem may be application of an artificial screen as a barrier to the seismic wave path. This paper presents the results of experimental research on the artificial screen concept, its characteristics and role in attenuation of seismic effects generated by blasting. More than 1,500 laboratory measurements were conducted with different combinations of screen sizes, positions of the screen to blasting source, and intensities of blasting impulses. The results of the study show a significant reduction of generated vibrations by employment of artificial screens.

Jan 1, 2007

By Adrian Moore, Bryan Goodwin, David Fales, David Lam

This paper describes the development of blasting protocols used to successfully create a 450m long blast fractured permeable trench in a basalt aquifer up to 20m thick, at a petrochemical facility in Australia, to enable the remediation of contaminated groundwater.

Jan 1, 2011