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By Vitor Barcelos, Eduardo Elói, Gabriella Vaz, Davi Oliveira, Leandro Silveira

Following a routine production blast at Vale S.A.'s Itabira Mine in the Quadrilátero Ferrífero region of Minas Gerais, Brazil, nearby residents registered complaints about blast-induced vibrations. Analysis of the blast footage revealed that multiple blastholes were detonated simultaneously, resulting in a higher-than-expected charge per delay, ground vibration and cratering even though the electronic delay timing was configured correctly. Subsequent blasts within the mine's soft schist region confirmed the occurrence of sympathetic detonation. Mitigating or eliminating this phenomenon is critical for the mine's operation. Two dynamic pressure tests were conducted using carbon resistors together with typical VOD monitor maintaining the standard booster, electronic detonator, and a blend of 70% emulsion with 30% ammonium nitrate explosive. The tests involved increasing the distance between the central hole (detonated first) and the four surrounding holes in a five-hole sequence. Unfortunately, sympathetic detonation occurred in all these tests. To address this issue, a new explosive with a lower density and detonation velocity was tested. This approach proved promising, as no sympathetic detonation occurred. By leveraging the data obtained from this study, engineers can now identify situations at risk of sympathetic detonation and implement preventive measures, such as selecting the appropriate explosive and recommending safe minimum burden and spacing settings as well as confinement level for each blast while maintaining the desired level of rock fragmentation.

Jan 21, 2025

By Frederick B. Kuhnow

Harmonic energetic delamination of T2 building is being considered for demolition at a formerly known atomic lab. The T2 building is within a containment structure that is under a negative pressure of -49 Pa (-0.2 inches of WC) so that no remaining radioactive material is leaked out. The T2 containment enclosure is a portal frame-type system that spans east/west over 35.05 m (114’-11 7/8”) and spaced 2.9 m (9’-6”) apart. The west side of the portal frames is supported by a 64 cm (2’-1”)thick concrete wall which is backfilled to the west and open to the T2 basement to the east. The east side of the portal frames is supported by a 61 cm (2’-0”) thick concrete wall that is backfilled to the east and open to the tank farm vaults to the west. A concrete slab-type footing supports both the east and west walls. Transverse walls provide lateral support for the walls as part of the original design. The west wall has an elevated slab that provides further stiffening of the concrete wall between the transverse walls.

Jan 1, 2017

By S B. Richardson, D Mead, N T. Moxon

The use of air-decks to reduce explosive costs has become very topical in recent years. The majority of the research in this area has been arried out between the Soviet Union where reductions in explosive consumption of between 10-30% have been claimed with apparent benefits being gained in both fragmentation and movement. Work carried out by the University of Maryland using thick plexiglass blocks has supported these findings and indicated that air-decks in measetbe duration of action of the shock wave on the surrounding material by a factor of 2 to 5 (see Figure 1). Although the fracture network resulting from this mechanism is not as intense as that produced adjacent to the explosive charge it does appear to act over a larger volume of material. Although the mechanism attributed to air-decking has been studied in some detail the effect of this mechanism on the size distribution of material produced during a blast does not appear tot have attracted much attention.

Jan 1, 1991

By Tyler Rockley, Cara Rosen

Blasting at a granite quarry in eastern Maryland produces elevated air blast readings that can fall into the cautionary zone for the state of Maryland environmental regulations on a semi-regular basis. When designing blast patterns in this quarry, challenging geology creates rough and uneven blast faces that can be difficult to capture with 2D laser profiling fully. Utilizing several methods known to manage high air blast results like pattern adjustments, decking, and timing changes have not achieved consistent outcomes.

Feb 1, 2020

By J. P. Remi Proulx, Areli Rodriguez, Ruilin Yang

Historically, presplitting has been considered effective in reducing the impact of blast vibrations on highwalls. However, it remains a debated topic: how significantly can it protect highwalls, and is it worth the cost and effort to implement presplit blasting techniques? In hard rock, presplit blasting can leave half-barrels on the highwalls, clearly demonstrating its usefulness. However, in a fractured rock mass, the half-barrels from presplit blasting may not appear in most cases, leading to questions about its role in protecting highwalls. Previous studies in the literature used geophones to measure blast vibrations at far distances and could not ascertain the significant benefit of presplit blasting in reducing the impact of blast vibrations on highwalls. Additionally, no studies in the literature address the role of presplitting in alleviating blasting-released gas pressure that could penetrate joints and open new fractures in highwalls. Yang & Proulx (2019) and Yang et al. (2022) using near-field blast vibration monitoring of signature hole blasts have revealed that the peak particle velocity (PPV) of blast vibrations at a scaled distance of 1 m/kg^0.5 can be reduced by 50% or more for presplit-filtered vibrations. These results have been confirmed for both hard rock and fractured ground. In addition to summarizing the reduction in blast vibrations due to presplitting for both hard rock and a fractured rock mass, this paper demonstrates the relief of subsequent blasting gases after the detonation of blastholes. This is shown through video recordings of gas ejections from a row of empty previously fired presplit blastholes located 6 to 9 meters away from the detonation edge or final buffer row of a blasthole pattern. The results clearly show that presplitting not only lowers blast vibration PPV’s but also reduces the entry of the gases produced by the detonation process into rock fractures and or open joints.

Jan 21, 2025

By Jason Baird, Braden Lusk, Dominique Nolan, Allen Stults

Conical shaped charges have been used to penetrate rock for many years now. Examinations have been made looking at shaped charge liner geometry, material, and standoff, as well as explosive composition, confinement and initiation. Most of the testing conducted towards penetration rather than cratering has fallen within the realm of the petroleum industry and as such been confined to specific rock types, with test apparatus that include simulated down hole (subterranean) environments. The testing conducted within this experimentation is conducted at ground level, in small scale samples, using a single standoff, against multiple rock types. The data collected from that testing is examined here and relationships between physical properties of the rock and the liner are analyzed. The analysis of that data raises the possibility of a relationship that may lead to new empirical methods of penetration prediction in rock.

Jan 1, 2012

By Huang Daguang, Paulo Couceiro, Juan Navarro

Mining is typically conducted through a set of interdependent unit-operations, which commonly include drilling, blasting, digging and hauling, in order to deliver the required ore material into the comminution circuit and to remove waste rock with minimum impact in the operation. In such complex environment, the identification of critical paths, and respective interfaces between different unit-operations, are necessary to determine a sustainable long-term operational program. Facing this challenge, adaptive cost optimization strategies are required to increase productivity and revenue while minimizing potential environmental impacts. Since the overall mining efficiency can be strongly impacted by blasting outcomes, an operating method based on the searching of the ideal blast design is required in order to minimize the mine total cost of ownership. The implementation of a consistent continuous improvement program requires specific care in terms of design, control and execution of the different stages of blasting. For that, the application of the most advanced technologies for rock characterization, based on drill monitoring systems, and smart explosive products, allows the improvement and control of blast results by adapting the explosive energy distribution to the rock condition, so as to optimize the performance of downstream stages such as digging, hauling and comminution. This paper describes the application of a heuristic optimization approach, where blast parameters are used as decision variables to evaluate the potential impact of several blasting scenarios on subsequent unit operations, under the continuous ability of modelling, measuring and calibrating operational performances along of the mine cycle.

Feb 6, 2023

By Douglas Bartley

As the economy continues to slowly recover, our industry continues to finds ways to increase productivity while being forced to cut costs. The drilling and blasting process is the starting point of any aggregate or mining process. Many people refer to it as the “Primary Crusher” as it will always be more efficient to crush rock with explosives energy than it will be mechanical energy. It is the more efficient use of this energy that is addressed in this paper.

Jan 1, 2012

By Alan Diaz Butron, Eng. Thierry Bernard

"In tunnel blasting the most challenging objective is definitively obtaining the maximum advanceassociated to a minimum overbreak. Achieving 100% of advance with no overbreak is the targetchallenge by Chavimochic Consortium. Chavimochic Special Project is an irrigation system that extends throughout much of the coast of the La Libertad Region, on the north coast of Peru. In 2012, it began management for construction of the third and last stage of CHAVIMOCHIC to irrigate lands of Chicama Valley, North of Trujillo. This project of 13 Km (8 mi) of various tunnels, it's a combination of technology and daily optimization by experienced people, which allow to accomplish the objective. Achieving this advance with no overbreak provide a huge saving on time. This paper describes the method, technology used, and the results obtained on more than 600 blasts done with conventional initiation system on the first 3 km (1.86 mi)."

Jan 1, 2017

By Shadrack Nuamah, Erik Westman, Bright Afum, Jesse Addy

Rock fragmentation is the most critical aspect of hard rock production blasting due to its significant impact on drilling and blasting costs and the economics of subsequent loading, hauling, and crushing operations. This study analyzes current cost trends in the drill and blast operations of an anonymous open pit gold mine and proposes cost-effective drill and blast geometric parameters. The investigation focused on one operational pit with provided design parameters for two shots, shot 1 and shot 2. Existing blast parameters and two additional proposed sets of geometric parameters were evaluated using the Kuz-Ram and Chung and Katsabanis fragmentation models to estimate mean fragment sizes. The results indicated that the proposed blast parameters produced estimated mean fragment sizes within the mine’s desired range (not exceeding 45 cm). Additionally, the explosive energy was utilized efficiently per in-situ material blasted. The proposed parameters increased the estimated total volume of in-situ material fragmented by approximately 14% for both Shot 1 and Shot 2 compared to the current parameters. Furthermore, adopting the proposed blast parameters could lead to significant cost savings. The evaluated total drill and blast cost savings were approximately 11% for Shot 1 and 12% for Shot 2. These savings stem from the increased efficiency and effectiveness of the blast operations, highlighting the potential for substantial economic benefits. This study demonstrates that optimizing blast geometric parameters will allow open-pit mines to achieve desired fragmentation, utilize explosive energy more effectively, and realize considerable cost savings in drill and blast operations.

Jan 21, 2025

By Manuel Gutierrez, Roberto Gomez, Juan Aravena, Johan Gjoevad

The use of explosives in mining operations is a process that involves the search for an ideal explosive for the type of geological condition of the mineral to be extracted. For the explosives present on the market the majority are based on Ammonium Nitrate. This as it is an ideal balance of high energy efficiency achieved with low development of gas emission. The manufacturing and loading operation of the explosive requires multiple process stages and different raw materials, which, if is not correctly supervised and controlled may cause the development of harmful gases or, in the worst case, even toxic gases. The majority of mining operations are located at remote locations without the presence of communities, and hence individuals, which could be affected by emission of the harmful or even toxic gases. In these operations the protection is mainly to protect the employees of the operation. However, if the operation is located near communities, the effect of these gases becomes a serious problem. The communities' perception of post-blasting gases, according to interviews carried out in this project, describes these as smells of black gunpowder, damp soil with a volatile permanence and medium intensity, sometimes a stinking tone is added. The legislation in Chile that controls the exposure of “workers” to different gases is Supreme Decree 594, 2019 (Decreto Supremo 594). Currently the Chilean Ministry of Environment and Sernageomin (Servicio Nacional de Geología y Minería) are taking actions to reform and strengthen oversight, seeking through a short law to provide more tools to the government to decentralize decisions in case of non-compliance with the decree. This paper describes the development and implementation of a permanent and remote gas monitoring system, considering the reasons for choosing the gases to be included in the equipment, the types of sensors and their capabilities, the way to verify in the field the correct functioning of the technology throughout the project, and finally how the data collected in the field is meeting the government's expectations in terms of permanent and online reportability. Additionally, it addresses the continuity of gas monitoring in the community that will disappear in the short term due to the expansion of mining operations, thereby ensuring the protection of both workers and affected communities.

Jan 21, 2025

By Adrian J. Moore, Alan B. Richards

Responsible blasting requires that rock throw be controlled to ensure that no danger will result to people and property. This paper describes the development and testing of empirical field calibrated formulae that can be used to evaluate rock throw, provide an early warning of when reduced burden will endanger people and property, and prevent flyrock incidents. Inputs to the formulae are charge mass, burden or stemming height, and a site constant that lies within a general range that can be tightened by site calibration. The output is the distance that rock will be thrown, and this ‘design your own flyrock’ quantification can be used to establish both safe clearance distances, and the critical range of burdens and stemming heights where the situation changes rapidly from safe to hazardous. Examples are given of the use of the model to control flyrock in open-pit mining and quarry operations, in situations which are controlled by both burden and stemming height.

Jan 1, 2004

By M. Gonçalves Peixoto da Silva, E. Rodrigo Carvalho Souza Siqueira

Mining in narrow veins is commonly applied for precious metals, generally carried out to extract gold in underground mines, due to the ore occurrence on narrow veins, mainly up to 2-meter large. The current work presents the implementation of the methodology in a zinc mine located in the state of Minas Gerais in Brazil. The Vazante Mine through the years has always carried out mining on stopes with a thickness larger than 3,5 meters, but nowadays due to the need to reduce the waste planned in its blocks, as well as increase the useful life of mine, mining has been implemented in blocks that are less than two meters. Given this, the challenge is to be able to carry out blasts that does not exceed the operational dilution required and does not generate an impact on recovery, as working with extremely heterogeneous stopes. This study seeks to correlate the main characteristics of stopes and its relationship with the results obtained in the execution of those blasts. Also, it proposes an analysis between the empirical data, and existing theoretical references, creating ideal mining parameters, such as minimum thickness, maximum height, and optimum timing in the blast plan. One of the main challenges for carrying out this mining method is the control of operational dilution, generally pointed out as the biggest difficulty for companies that adopt this methodology, due to the thickness of those stopes, any displacement can make it unfeasible, thus the technical level on carrying out the drilling and loading of these blocks must be impeccable, an understanding of the structural geology of the site is also essential for dilution control. The outcome will be a set of ideal parameters and mining methodology to guarantee the success in execution of these blocks, thus bringing a financial benefit to the company.

Jan 21, 2025

By Kia Riihioja, Mike Higgins

A major difference between electronic and pyrotechnic detonators is that, in almost all but the simplest of blast layouts, computer software is required to plan a blast using electronic detonators. While it may be possible to program delay times without software, using only the manufacturer’s control hardware, the full potential of electronic detonators can only be realized through software. Until recently, the only software available has been provided by the suppliers of the electronic detonators. These usually have just enough features to create a hole layout and to assign times to the detonators in the holes. The software is also able to communicate only with the manufacturer’s detonators. This means that the client may be compelled to change several parts of the blasting process when a different delay system is adopted, from design through to implementation and reporting, even though these may be sub-optimal at the client’s mine. While many authors have demonstrated improvements in blasting outcomes using electronic detonators, very few have discussed how the delay times were calculated. Where the calculations are discussed, it is also obvious that the delay times must be monitored and re-evaluated as conditions in the mine change. For example, the principles of superposition and scaled distance, burden relief and energy cooperation between holes should be checked constantly for different locations within the mine, changes in rock properties, or even for differences between design and actual hole positions. The most common methods in blast design software to calculate delay times are inter-hole interval, relief contour and direct editing. Although they are simple in concept, they can result in fundamental errors if they are not applied correctly. The software for electronic blast designs should be capable of not just a timing calculation, but also of showing, to some degree, the impact and interaction of the calculated times.

Jan 1, 2004

By M. Ganster

Austria’s biggest supplier of oil and gas, transports gas through the West Austria Gasline for domestic consumption. In addition, the OMV also works as gas carrier and ensures the transit into neighbouring countries.

Jan 1, 2010

By William Gates, Gabe McClain, Thomas Pallua, Joe Schrank

The Tennessee Capitol Corridor connects the Cordell Hull Building (CHB) to the State Capitol, which isa 232-foot-by-124-foot (71 x 38 m) structure in Nashville that includes porticoes built from local massive limestone. This connection was affected by the Capitol Connector Pedestrian Tunnel (CCPT) project, which is part of the overall Cordell Hull State Office Building and Central Services Demolition, New Construction and Renovation Project (Cordell Hull Renovation Project). To construct this connection, the two existing elevator shafts and a new emergency stairwell in the State Capitol were extended down to anew lobby area—the elevators by about 50 feet (15.2 m) and the stairwell by about 60 feet (18.3 m). This lobby was connected to the CHB by a 435-foot-long (133 m) pedestrian tunnel. It was predicted that most of the tunnel would be excavated in a relatively strong limestone; therefore, considering the project features and constraints, drill-and-blast techniques were selected as the primary excavation method. Because of restrictions on blasting in urban areas and, more importantly, the proximity of this construction to national historic landmarks, blasting operations were extensively monitored to measure and correlate ground vibrations as peak particle velocity (PPV), frequency, and strain—these being the major factors that would impact the surrounding buildings. As a result, copious amounts of data were gathered and interpreted within a short time to estimate blasting parameters and optimize the subsequent blast rounds. To calculate the ground response factor, the scaled distance of each shot was compared to the ground vibration as PPV, generating a subsequent regression curve with an R2value of about 0.7. Using the best fit curve equation, the estimated ground response factor was about 150 for the best fit line. Other than some cases with relatively high (> 2 in./sec [51 mm/sec]) recorded PPV values, the blasting operation was successfully conducted as planned and the observed strain on the monitored buildings was very low, mainly within ±2 με (0.0002% elongation). (In general, the recorded PPV was lower than 2 in./sec at frequencies of more than 50 Hz.). The strain gauges at key locations (cold joints and old fractures) in the Capitol and on other critical structures demonstrated strain was insignificant in relationship to ground vibrations from the blasting operations. The apparently small vibration-induced strains were related to the massive limestone construction of the Capitol and ancillary buildings, as the induced strain plus the existing strain did not exceed the critical strain of the massive structures.

By Tom Watts

Bulk Security Best Practices

Jan 1, 2006

By J. P. Remi Proulx, Juan Camilo Gonzalez T., Winston B. Wilches

Alabama USA based Drummond Ltd. operates two open pit mines in the Cesar Coal Basin of Northern Colombia. The mines produce a combined total of over 25 million tons (22.7 Mt) of thermal coal per year which is transported by rail to Puerto Drummond, a direct ship loading facility, where it is exported to over 15 countries. The company has proven and probable reserves in excess of one billion tons of thermal coal.

Jan 1, 2015

By D. S. Preece, S. Silling, A. Bhuiyan, C. M. Lownds

GEM (Geologic Element Motion) is a Discrete Element Method (DEM) capability for blast-induced heave simulation with a very fast computational algorithm that can efficiently treat many different element shapes by utilizing alternating arcs and lines. GEM calculates rock motion from a knowledge of the gas pressure moving the elements. This requires an expression for the pressure vs volume, or the adiabat, of the explosion product gases. This work uses an analytical expression for the adiabat derived from the explosive’s properties. The effect of the explosive detonation pressure in crushing an annulus of rock, and setting up a shock wave, is termed Brisance. GEM incorporates a working hypothesis for the deleterious effect of Brisance on subsequent rock motion.

Jan 1, 2024

By Deepesh Yadav, B. S. Choudhary

Underwater drilling and blasting is conducted for deepening of sea channels for port berths, lake or reservoirs for water supply etc. so that rock dredging becomes easier. During this process there are several associated unwanted effects having potential to cause damage to surrounding structures and the environment, flora and fauna. Though all these ill effects can’t be completely eliminated but adopting controlled blasting techniques can minimize these to tolerable levels. It is recognized that ground vibrations resulting from rock blasting below water near dam may endanger the safety of earthen dams. Therefore, controlled blasting technique was used to ensure the safety of dam and its efficacy was established by monitoring of blast vibrations. The usage of small quantity of explosives confined in blast holes, non-electrical delay detonators and initiating each hole with a separate delay helped to minimize the ground vibration effects on surrounding structures.

Jan 1, 2018