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By H Fukui, K Ichikawa, K Aikou, E Suzuki

An electronic delay detonator (EDD) consisting of a digital-base electronic delay module and a conventional instantaneous detonator module, designed for series connections with a special adjustable-output blasting machine, is described and shown to provide a delay time accuracy some four to twelve times higher than that of pyrotechnic millisecond and decisecond delay detonators, together with the other performance characteristics necessary for practical use. Also described is a blasting design system which allows effective reduction of ground and air vibration, through the use of EDDs with optimum delay times as determined by accurate computer simulation based on wave form and other data obtained from an on-site single-shot test blast.

Jan 1, 1989

By Mark S. Stagg, David E. Siskind

Five major environmental effects of rock blasting are ground vibrations, airblast, flyrock, dust and fumes. What makes them "environmental" as opposed to occupational health and safety issues is that their impacts are felt off the mine, quarry or construction site. For some impacts, safe zones are defined through experience, flyrock being a good example. Flyrock at a mine can be 1) rock thrown beyond the blast area or expected hazard zone, 2) rock thrown beyond the permit area, or 3) rock thrown more than 1/2 the distance to the nearest non-mine structure (OSM rule for surface coal mines). Rock throw of less than the "flyrock" range is then a safety issue.

Jan 1, 1997

By Otto E. Jr Crenwelge, Timothy A. Peterson

We have developed a site-specific method for analysis, prediction, and control of ground vibrations induced by overburden blasting operations in surface coal mines. Field tests conducted at R&F Coal Company have verified our approach for obtaining signatures of the overburden vibration characteristics at locations of interest near the mine, selecting the optimum excitation frequency for minimizing vibrations, measuring and synthesizing multiple-charge excitation signals for minimizing vibration amplitude and duration and controlling frequency, accurately predicting the multiple-charge vibration response in both the time and frequency domains, and accurately controlling the blast detonation to achieve the predicted vibration control. Initial field studies also indicate that by minimizing the vibrational energy radiated from the blast zone, and by optimizing the number of charges detonated per delay period as allowed by this technique, more effective use of the explosive energy is obtained within the blast zone itself for improving overburden fragmentation, swell, and cast. In all of the phases of this technique, including actual blast detonation, personal computer hardware and software have been verified for use in either field or office environments.

Jan 1, 1986

By Martin L. Smith, Robert L. Hautala

The objective of blast optimization can be approached either in a qualitative sense of designing a blast which will be "trouble free", or quantitatively in the sense of minimizing overall mining costs. Blast design simulators and fragmentation models have become an accepted tool in blasting over the last decade. Numeric simulators are very useful for solving quantitative problems, but are limited in their ability to address more qualitative problems such as post-blast bench condition. Also, current blasting models are limited by the complexity of site-specific blasting and are not functionally suited to mathematical optimization. As a result a great deal of expertise is still needed in optimizing a blast. The following describes the application of an expert system approach to integrating both a symbolic model of the expertise of the blasting engineer for attaining a trouble free blast, and a numeric optimization model relating fragmentation to unit operations from drilling to grinding. Research into this application of a coupled modeling approach to blast design is being carried out to develop a modeling methodology which will provide a suboptimal design for qualitative design goals as well as minimizing blast related costs.

Jan 1, 1991

By C. Mick Lownds, Dale S. Preece, Ali Bhuiyan

FDM (Fracture Density Model) is a three-dimensional mechanistic model of blast induced rock fragmentation. FDM uses several computational mechanics algorithms to simulate the effect of blasting in different rock types. Earlier, FDM was successfully exercised to simulate 29 small scale shots from the United States Bureau of Mines (USBM), and 6 full-scale bench blasts at the Bararp dimensional stone quarry in Sweden. Excellent agreement was obtained for those shots, and the results were documented in earlier publications. One of the drawbacks of previous ver- sions of FDM was its inability to predict the fines, specifically in Bararp quarry simulations. Ac- curate predictions of fines can be very useful in reducing energy consumptions during down- stream comminution processes and improve the mine-mill operation efficiencies. In this paper, we propose a newer algorithm that can predict the fines as well as the coarse fragments in Bararp with reasonable accuracy. The model was also applied to an open-pit Copper mine with heavily jointed rocks, and it produced very good fragmentation predictions for the full range of fragment sizes. Comparisons with the sieved fragmentation data (for both Bararp stone quarry and the open- pit Copper mines) show great potential for this updated version of FDM in modeling the entire range of fragment size distributions in mining and quarrying applications.

Feb 6, 2023

By D. Johansson, C. San Miguel, U. Stenman, N. Petropoulos

Blasting is a commonly utilized method in civil engineering projects and mining operations. Ammonium nitrate-based (AN-based) explosives are the most efficient explosives today in terms of handling and performance. However, a side effect is the production of gases. The reduction of these gases plays an important role in the safety and environmental aspects in the working place. Therefore, optimizing the recipes of explosives is vital for minimizing the environmental impact and increasing performance. The aim of the project is to provide results and recommendations on the use of emulsion commercial explosives to support the Swedish mining industry and tunnel-contractors as well as the explosives manufactures. The approach was to test various recipes of civil emulsion explosives to investigate the generation of toxic fumes (CO, CO2, NO, NO2 and NOx) during their detonation. To further increase the knowledge of the influence of different additives, ammonium nitrate prills were added in various percentages. The experimental configuration consisted of magnetite mortar cylindrical specimens with a 50 mm borehole at their center, filled with emulsion explosive. Several tests with different emulsion compositions regarding ammonium nitrate additives (10%, 20%, 25%, 30% and 35%) were carried out in a blasting chamber. The measurement equipment was composed of a flue gas analyzer. The instrument was meticulously cleaned after every test, as well as before and during the tests due to condensation (high humidity and dust) at the inlet of the instrument. The emulsion was manually sensitized with microballons and pumped into the cylinders to ensure lack of bubbles, which could introduce inhomogeneities. The acquired gas concentration data was complemented with temperature, humidity, and VoD measurements. The results showed a linear increase of nitrogen gases as the percentage of ammonium nitrate prills increased. On the other hand, carbon gases had a relatively low coefficient of determination. The VoD data showed a behavior that can be described with a simple quadratic equation.

Jan 1, 2024

By G J. Kulbieda

The Empire Mine initiated production in 1963. Since then the unit operations of drilling and blasting have evolved continually in order to meet the increased mining requirements demanded by plant expansions in 1968, 1973 and 1980. Additionally, advance mine planning has become an integral part of proper pit development and is necessary to insure uniform blending of the distinct ore horizons contained within the mine area. Blasting practices have been modified to facilitate the autogenous grinding system utilized at Empire and pioneered in the Iron Ore Industry. Technical innovations in the explosives industry, as well as, progress regarding on site blast engineering methods have substantially increased the use of ammonium nitrate explosives and helped to establish efficient charging procedures. In addition, the recent introduction and use of ammonium nitrate fueled with nitropropane and methanol indicates that it is a viable substitute for aluminized ANFO.

Jan 1, 1981

By Ashwani Jain, D K. Soni

Compressive strength of rocks is often required by mining engineers and quarrying authorities for blasting operations. Uniaxial compressive strength of rocks can be predicted with reasonable accuracy with the help of point load strength tests which can be easily conducted at site by the field staff, simultaneously as the cores are recovered from drilling operations. A number of diametral point load tests and uniaxial compressive strength tests have been conducted on the specimens of different rock types under air dried, and saturated condition as well to study the effect of ground water saturation on strength. It has been observed that due to saturation uniaxial compressive strength and point load strength get reduced to a maximum of 32 and 29 per cent respectively. It has also been observed that uniaxial strength is sixteen times the point load strength in air dried as well as saturated condition. However, this factor used for calculating uniaxial compressive strength may be reduced to a lower value for the safety of miners in field blasting operations.

Jan 1, 1994

By Paul Worsey, Gillian Worsey

Description of Project:The basic blasting class underground lab at the Missouri S&T experimental mine in Rolla, o., shows the students how to drill, set up, load, and shoot a shot underground. In this case the shot was part of a new ramp to a second level.

Jan 1, 2014

By Julio Cesar Barbosa de Freitas, Rafael Gonçalves Araujo, Túlio Soares, Jair Koppe, Augusto Ferraz Ribeiro, Pedro Barreto Garcia

This study thesis was motivated by the fact that it is of fundamental importance for open pit mining that the slopes initially have a geometry in accordance with what is proposed in the mining planning. This occurs because an inconsistency in this design can impact the operational safety and economic solutions of the mining project. These consequences can be explained by the fact that rock blasting close to mining limits requires specific study due to the attention required. Because, when this operation is not carried out properly, the mining plan in the mine may not be respected and may create risks to the operation due to the presence of unstable blocks on the slopes (Mackenzie). In this sense, Mackenzie (2004) cites pre-split, trim blasting and buffer as commonly used explosive blasting techniques that aim to limit damage beyond the projected wall. Therefore, Enaex Brazil realized the need to better understand the pre-split method. To do this, it is necessary to understand how the energy released during detonation is perpetuated in the rock mass when this technique is used and when it is absent. Thus, this analysis is based on a seismic study that allows the creation of vibration attenuation laws and an elementary wave damage model, which allows the local characterization of the rock. With this model it is possible to relate the peak levels of vibration during blasting and the extent of damage, but a critical level of vibration (PPVc) and its relationship with the Uniaxial Comprehension Resistance (UCS) are also defined for the start of fracturing and its level (McKenzie et al, 1995). And, mainly, this work aims to address a way to measure the pre-split filter potential by comparing the attenuation law with and without pre-split, ultimately knowing whether this finishing blasting is being effective, to understand the pre-split filter capacity.

Jan 21, 2025

By S S. Kahlon

India is a large and growth market for explosives and accessories, which has dramatically changed from complete import dependence to self sufficiency, and now has an exportable surplus. The largest single user is coal mining which is continuing to show a healthy growth with opencast mining becoming increasingly dominant. The explosives industry has kept pace with mining and today all the well renowned explosives technologies of the world are available in the country. While slurry explosives are popular in large diameter, NG based explosives continue to be preferrred in small diameter usage. Emulsion explosives have had a good market response. ANFO usage is limited due to local reasons. As the mine size is increasing, the demand for bulk-on-site explosives is growing. Prices of explosives and accessories are cheap compared to international levels. The user industry is mainly Government owned mines whose profitability is not satisfactory. Explosives industry is over licensed in terms of manufacturing capacity, which is likely to put pressure on the viability of some of the explosives manufacturing units. Scope exists for optimization of blasting parameters through the use of computerized blasting models. The explosives industry is faced with new challenges and opportunities.

Jan 1, 1987

By Gloria Contreras

The study aims to optimize the density of holes per tunnel section. The energy distribution, the one with the highest density, is used in the center of the diagram and is distributed homogeneously towards the contours with the lowest energies up to the contours to produce a perimeter control.

Feb 1, 2020

By Thomas E. Lobb, Harry C. Verakis

Significant progress has been made in the reduction of serious injuries and fatalities resulting from mine blasting operations. Despite the progress, injuries and fatalities continue to occur. A leading cause of injuries and fatalities from blasting continues to be inadequate blast area security. Even though significant improvements in technology have been made, insuring adequate blast area security remains a challenge and requires constant vigilance. The advances in technology have created safer blasting products and have improved productivity and economics by enabling large, more efficient and effective blasts. However, as blasts grow larger in size, the complexity of adequately securing the blast area increases even more. Periodically the basic fundamentals involved in blasting safety should be reviewed, particularly for securing a blast site regardless of the size of the planned blast. Factors such as flyrock and toxic fumes must be taken into account to insure the safety of persons and property from the results of a blast. This paper examines the factors related to injuries due to inadequate blasting shelters and blast area security, and identifies mitigation techniques. The key concepts are: (a) accurate determination of the bounds of the blast area, (b) clearing employees from the blast area, (c) effective access control, (d) use of adequate blasting shelters, (e) efficient communications, and (f) training. Fundamentals are reviewed with an emphasis on analyzing task elements and identifying root causes for selected blasting accidents. Mitigating techniques are presented along with discussions and examples.

Jan 1, 2005

By L. Muñoz, L. Steffen, W. Vilas

The emission of particulate material is one of the several parameters related to environmental control in mining operations near communities. Blasting is an event that generates and leaves a large amount of dust in suspension, which can cause discomfort to communities, generating complaints that can compromise the operational continuity of the mine. The proper management of these environmental impacts is a key factor to ensure a good relationship with the neighborhoods, making a responsible mining in harmony with the environment, giving sustainability to the mining business in the medium and long term. The main goal of this work is to present different techniques and technologies applied in a large-scale open pit mine in Brazil, with operations close to a community, to minimize the emissions of particulate material into the atmosphere. For this, different technical solutions were implemented. First, a non-conventional blasting technique was introduced that incorporates special charging and timing configurations, generating a first upper layer that serves as a blanket to contain a second, higher-energy lower layer. An optimal stemming was also defined in order to minimize ejections and maximize cratering, using the scaled depth of burial theory as well as video and fragmentation analysis. In addition, changes were made in the timing between decks (to guarantee a minimum time between layers) and between holes (changing the initiation point opposite to the free face). Finally, additional measures such as humidification of the bench, use of a wind vane to identify wind direction and the construction of a physical barrier between the mine and the community were implemented as additional mitigation measures. By applying the above techniques together, in some specific zones of the mine, it was possible to considerably reduce the ejections generated by blasting versus conventional blasting without the above measures, which was demonstrated in the field with dual blasts trials. Additionally, it was possible to achieve a vibration reduction in the community of ~30%. This work demonstrates how, by applying these technical solutions, it was possible to minimize the dust and vibrations generated by blasting allowing this operation to do sustainable mining

Jan 1, 2024

By C. K. McKenzie

Presents outline of flyrock model and a field procedure to validate predictions of maximum projection distance. Field results are presented from 13 field tests with two different hole diameters.

Feb 1, 2020

By Eric C. Gerst

"In this current era of soft commodity and coal prices the mining industry is turning towards optimizingall levels of production to reduce operating costs. Part of this trend includes the automation of miningmachines. As the first tier of the mining process blast hole drill automation offers benefits through the entire value stream from drill bench to material processing."

Jan 1, 2017

By Orica Chile, Orica Brasil, Orica Brasil Victor Morais, Kinross Paracatu Leopoldo Muñoz, Kinross Paracatu Luis Marinho, Gubio Barsottini, Orica Brasil José Vergara, Lucas Steffen, Orica Brasil Washington Vilas

In drill and blast activities, it has been a challenge to sculpt walls accordingly to what has been designed in state-of-art mining design software. Obviously, the perfection of making neat and smooth walls – using aggressive sources of energy, like explosives – are time-and-money consumable and, sometimes, even unnecessary. But undoubtedly, it is vital to guarantee solid walls, safe operations environment, beyond to avoid ore losses and pit constraints caused by poor rock breakage on detonation. Kinross Gold Corporation owns the biggest Brazilian Gold Mine, located in Minas Gerais state. Morro do Ouro mine has reached over 30 years of operation, and due its mature age, the complex has developed its pits, becoming them deeper and surrounded by high walls.

Feb 6, 2023

By Selamawit Asfaw, Mohamad Sharif

In recent years, the use of modal analysis has increased to include many different aspects of the construction industry. Computer modal analysis can be used in determining the dynamic properties of a structure by mathematical equations and knowledge of the structure’s physical properties. This technique can now be used to predict the level of vibration induced by blasting on adjacent structures. Ground vibration induced by buried explosives is a major concern for contractors when excavating near utility pipelines such as gas and water lines. The size limitations placed on easements causes the necessity of additional utility lines to be placed in close proximity to existing lines. Through the development of computer models of the pipe, stress analysis can be performed prior to blasting. Based on the calculated dynamic properties (natural frequencies and modal shapes) and the maximum allowable displacements and stress levels (which are established by the pipe manufacturer) the allowable maximum charge weight per delay can be selected for the blast. The selected maximum charge weight per delay will ensure that the resulting pipe peak particle velocity level is within 95% confidence. This means, statistically, there exists a 95% probability that the actual pipe peak particle velocity would be less than the predicted value. The pipe is then instrumented with vibration measuring sensors to ensure that vibration levels are within the allowable maximum pipe strength. In conclusion, this technique can assist the engineers and blasters, to establish the proper blast design. It allows for safe and efficient installation of additional utility lines adjacent to existing lines. This technique can also be applied to predict the structural response to blasting induced vibration for a variety of complex structures. A detailed explanation of this technique, as well as an example of application including formulas used for this technique will be provided in this paper.

Jan 1, 2000

By John C. Adams, Darrel D. Porter

After conventional drill and shoot methods were determined to be unfeasible due the fractured nature of the ground, a "coyote" blast was designed to produce 250,000 tons of rock from Rhone-Poulenc's Maiden Rock silica pit located near Butte, MT. This paper will cover the design and excavation of the explosive drifts, the placement and priming of 190,000 pounds of explosives, and the backfilling of the drift to provide confinement of the charges.

Jan 1, 1993

By G G. Paine, C V. B Cunningham, G Harries

The companies of the ICI Explosives Group have successfully used a wide variety of internal computer codes including BOBCAT, KUZ-RAM, ICRAX, XPLODE, BLEND, 3CRACK, MICBLAST, DETON, etc. In recent years the extensive experiences across ICI have been combined into a single compatible model engineered to worldwide technical service and customer needs for the prediction and assessment of blast results.

Jan 1, 1987