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By T Duff

This paper describes results from small scale tests conducted to determine the distribution of pressure on target plates when subjected to loading due to the detonation of a buried mine in various media. The tests are conducted by using saturated sand, dry sand, and water as the loading media. Different stand-off distances are investigated. Kolsky bars and pressure sensors are used to determine the free-field pressure - time profile of the output of the charge at any location on the vehicle bottom. For verification of the pressure results at certain distances, the specific impulse measured by utilizing different size round plates are employed. In order to investigate the loading mechanisms, high speed cameras are applied. The small-scale test results can be scaled to full scale by using verified scaling laws.

Jan 1, 2014

By Ron Woolf, Corry Goumans

With increasing traffic volumes experienced thro u g hout North America, a common goal for Highway officials is to keep traffic flowing as much as possible and to keep disruptions to the flow to a minimum. Our experience throughout the US and Canada has shown that all Departments of Transportation are under extreme pressure from the private sector to keep highways open for various reasons, convenience and revenue being the most common. For example, on Highway 99, from Vancouver, BC to the Whistler resort area, local merchants, homeowners and ski hill operators exert extreme pressure on the Ministry of Transportation to keep the highway open, and in Pennsylvania, the Turnpike Commission requires traffic to flow on a continual basis. Loss of revenue in these two cases is the main impetus to keep the traffic moving.

Jan 1, 2003

By Johan Hawinkel

This paper explores the journey through time of technology in the civil explosives market to provide testing, measurement, analysis and control tools. This ultimately leads to better decision-making, ensures full accountability of the decision maker and uses the same technology to review decisions for process improvement, in the settlement of disputes or for the investigation of incidents. Additionally, the paper discusses the application and integration of electronic and digital technology in explosives and initiation systems as engineering controls for blasting associated risks.

Feb 1, 2020

By C. Yi, D. Johansson, C. San Miguel, M. Wimmer

Sublevel caving (SLC) is a mass mining method based upon the utilization of gravity flow of blasted ore and caved waste rock. Production blasting has significant impact on the efficiency and productivity of SLC output, affecting material fragmentation, flow and recovery. Misfires could occur during blasting in SLC, which results in the loss of explosives and poor fragmentation. Usually, the blastholes are top-initiated with redundant lower primers set at + 25 ms as a precaution. If the top primers fail, the lower primers may initiate the explosive, which will induce out-of-sequence delays that can influence fragmentation and gravity flow. This work investigated the impact of misfires and out-ofsequence delays on fragmentation and gravity flow through numerical simulations using a coupled finite element and discrete element method. Different scenarios of misfires and out-of-sequence delays were studied, and the fragment size distribution was obtained to evaluate the blasting performance. The material flow behaviour was investigated to assess the gravity flow process. The results indicated that misfires significantly affect the fragmentation and the gravity flow process while the effects of out-of-sequence delays are not so significant for the investigated cases

Jan 1, 2024

By Rodney Pinksen, Remi Proulx

The IOC Mining and Operations Departments expressed an interest in reducing the amount of oversize material (>1.0 m x 1.0 m x 1.0 m; 39 inches x 39 inches x 39 inches) being produced and its subsequent downstream effects including in-pit sorting and reduction, damage to mobile equipment, and significant delays in the loading pockets and the primary crushers. To achieve this goal an oversize reduction project was undertaken by the mine and to date has significantly improved upon baseline measures.

Jan 1, 2011

By Roger G. Sprague

With the passing of time, changing marketplaces and years of hard service, coupled with new machines, increased productivity, rapidly improving technology, equipment which used to be the latest in modern mining have now slipped into obsolence. Mining companies need reliable, productive equipment in order to compete in today's market. In Western coal mining, as coal seams become deeper, older equipment must be replaced with that which can do the job more efficiently.

Jan 1, 1998

By Davey Bickford, Johan Hawinkel

Blasting and the use of civil explosives are a critical step in the mining process. Good decisions provide significant downstream benefits and create a safe and sustainable working environment, while poor decision making and judgement can have catastrophic consequences on workers safety, critical infrastructure or the security of the general public. An ever-tightening regulatory framework increasingly exposes manufacturers, transport companies and mining companies to the consequences of breaches resulting from erroneous or ill-informed decisions. In this context, new capabilities are required providing all actors in the explosive supply chain with tools to make better informed decisions allowing the individual to own up to his or her decision. Additionally, the traditional risk-control approach in the explosive supply chain up until usage and waste elimination, through administrative control procedures and processes, is becoming increasingly inadequate. In this era of digitalisation and automation, technology will play a pivotal role in ensuring safety and security in storage, transport and usage of civil explosives using the latest advances in electronics, communication technology and information technology. This paper explores the journey through time of technology in the civil explosives market to provide testing, measurement, analysis and control tools. This ultimately leads to better decision-making, ensures full accountability of the decision maker and uses the same technology to review decisions for process improvement, in the settlement of disputes or for the investigation of incidents. Additionally, the paper discusses the application and integration of electronic and digital technology in explosives and initiation systems as engineering controls for blasting associated risks. Finally, this paper reviews two practical cases of technology integration for risk management and improved decision making; the use of integrated GPS technology in initiation systems as an engineering control in the blast evacuation process and the use of RFID technology in explosive tracking from cradle to grave.

By L. Wilson, M. Kotzel, T. Pienaar

An empirical equation is presented for the maximum airblast from unconfined charges. This has been tested at a number of sites and with charges ranging from 0.1kg to 311kg. The equation is developed to predict community response to potential explosive test range sites and the testing has added to our knowledge of the effectiveness of mitigating measures. The first site had 10m to 15m high walls that were intended to ameliorate the airblast. These walls functioned to a limited extent and reduced the airblast levels by 2dB to 5dB. The airblast was affected somewhat by topography. Noise levels at the nearest residences exceeded 130dB for charges larger than 1kg, whereas the vibration levels were very small. Formal complaints were received where the airblast level exceeded 128dB as per conventional expectations. Pedestrians and pets in the suburbs were startled by the blasts, emphasizing that the community response is much more sensitive to noise and airblast than vibration levels. The maximum airblast levels were too high for this site to be used on a regular basis. At another site, the airblast levels were significantly increased downwind by up to 10dB due to a moderate wind. A third site, at a quarry, produced unconfined airblast levels beneath the derived limits, but are much higher than the normal quarry blasting. By involving community forums there were no complaints, possibly due to desensitization by the normal blasting activities. The study has highlighted new areas for research in understanding the effect of noise, air blast and vibration on the low cost and informal housing typical in South Africa

Jan 1, 2011

By Enver Alan

This Research & Development (R&D) study was conducted in the field of applied blasting engineering in Ethiopia, within the AKH Railway Project, which was built in Girena, within the boundaries of the province of Mersa, in the Basalt Quarry at km 346, Ashangi Formation, occured in Eocene geological time in the aphanitic trachibasalt.

Feb 1, 2020

By Raj K. Rajamani, Solomon A. Tucker, Michael K. McCarter

"In a study aimed at exploring possible improvements in operating performance at an Open Pit Copper (OPC) mine in the western U.S., the impact of blast energy changes on crushing performance was evaluated. OPC feeds its 3-stage crushing plant in 12-hour-day shifts with skarn ore from three domains: Pit_B (B), Pit_S Low-Grade (SLG) and Pit_S High-Grade (SHG), in the blending ratio 1:1:1 (B/SLG/SHG). Thecrushed product is fed to a 2-stage ball mill circuit. "

Jan 1, 2017

By Stephen Mansfield

In metalliferous mining operations, subdrill is that portion of the blast hole that is drilled below the target grade elevation, and in most cases loaded with explosives. Its primary aim is to enable efficient excavation down to the target floor level. Subdrill is often described as being expensive and that excessive subdrill should be avoided, as it can result in damage to the subsequent floor, lead to difficult drilling conditions and higher vibration levels. As a result, many operations aim to apply the bare minimum amount of subdrill in order to excavate to the target floor

Feb 1, 2020

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 Darío Innamorati, Jorge Oliva

Cerro Vanguardia is a known gold and silver deposit located in the province of Santa Cruz, Argentina. The mine has been in operation since 1998 and is thought to be one of the most important mines in Patagonia. More than 102 epithermal quartz veins have been identified in the area, with variable lengths, thicknesses, orientations and dips that constitute what is possibly one of the most extensive outcropping vein systems on earth. Veins are vertical and have variable depth. For this reason, the deposit is currently mined with a variety of extraction methods. This operation is made up of more than 60 open pits and 20 underground access ramps to exploit the deepest high grade narrow veins. This study is focused on the combination of underground exploitation with open pit blasting. That is, those production stopes in the upper levels of underground mines and their interaction with the damage levels in the final slope of open pit mines, as well as in the study of the impact of the generation of vibrations from the blasting of open pit mines and their influence on underground mines. Considering the current stage of the mine, after 20 years of operation, Cerro Vanguardia faces the need to mine deeper deposits in the face of increasing costs and declining grades. For this reason, it is essential to study the interaction of these exploitations. From a personnel safety point of view, this interaction must be well coordinated so as not to affect people and equipment. Likewise, the generation of vibrations due to blasting must be studied, which would produce new cracks, potentially generating overbreak and dilution. The main objective of this study is to determine the possible causes and influences of the blasting interaction in open pit and underground mines, seeking an optimization of the blasting process and a safety standard for personnel and equipment. To achieve these goals, this study includes a vibration monitoring plan to analyze the charge performance and determine rock constants. With the use of specialized software, damage modelling and simulations are used to determine values of damage in order to reduce overbreak. In addition, this plan contemplates the estimation of flyrock in blasting where underground work is connected to the surface, determining safety distances when carrying out a blast.

Jan 21, 2025

By B Mohanty, A Siamaki, K Esmaeili

Large scale open pit mining and quarrying operations dictate safe and reliable pit wall stability. The current approach of employing the particle velocity-scaled charge distance approach to estimate and minimize damage to residential structures is considered inadequate to protect rock slopes. This study utilizes close-in blasting vibration data as input to an advanced 2D numerical code to study its applicability to serve as a predictive tool in terms of blast-induced rock slope failure. Two tri-axial accelerometer stations, consisting of high-frequency and high-amplitude (20 kHz, 100g) sensors, located within ~100m of the blast, but at two different bench levels, were used to monitor production blasts in a limestone quarry. The production blast consisted of double-decked explosive loads in 125 mm (5 in) diameter holes, with an inter-deck delay of 42 ms, and each deck consisting of 130 kg (285 lb) of emulsion explosive. The blasting vibration data obtained at the two bench levels were critically analyzed, and the vibration results served as input to the numerical model consisting of a single rock block with a 45 degree persistent joint plane but with specified strength properties, significantly different from that of the intact rock. The model was able to characterise progressive accumulation of damage in the form of microcracks along the joint surface as a function of the relatively low vibration load from successive explosive decks. The results showed that such a numerical model can serve as a very good diagnostic and predictive tool, when backed up by careful vibration monitoring and further supported by detailed slope monitoring.

Jan 1, 2017

By Randall Wheeler

In early 2008 we were asked by a quarry to become involved in a conflict with a pipeline company concerning blasting near one of their underground high pressure gas lines. The pipeline company, without the quarry’s knowledge, had sought and obtained a temporary restraining order against the quarry forbidding them from blasting near the pipeline.

Jan 1, 2011

By William Reisz

Many different types of drills coming in a wide range of sizes and configurations are used in the blasting industry today. While each system may have its own unique attributes and capabilities, it may hold its own perils as well. This article will focus primarily on hazards that are mutual to most every type of drilling system.

Jan 1, 2013

By O. Rielo, A. Pascoal, P. Katsabanis

The dynamic parameters of two different granites have been obtained using Hopkinson bar experiments. One series of experiments were conducted using a Hopkinson pressure bar apparatus with an explosive source to provide the compressional wave. This wave would travel along the granite bar and would be reflected at the free end. Strains were obtained along the bar to examine the process. Using relatively long bars of rock, approximately 300mm long and 18mm in diameter, the separation of the compressive and the reflected tensile pulses was possible. If the net tension exceeds the strength of the material, spalling is witnessed. By properly selecting attenuation materials and explosive sources, single spalls were created, making results easier to interpret. Numerical modelling enabled the calculation of the propagation of the stress wave along the bar and its reflection at the free end. Knowing the location of the spalls, critical stress levels for rock failure under tension were obtained. Dynamic tensile strengths were also obtained, at different strain rates, using a Split Hopkinson Bar Apparatus. The results provide a measure of the increase of the dynamic strength at high strain rates, relevant to blasting applications. They are useful for the calibration of blasting models and the characterization of rocks for blast modelling, but also provide answers to the basic question of what is the rock strength for blasting applications.

Jan 1, 2011

By Joshua Hofman, Braden Lusk, Erin Morris

Explosions in urban environments, whether of accidental or malicious cause, often result in extensive injuries, loss of life, and property damage. The ability to predict the damage inflicted by these events is highly sought after; in order to predict damage, the behavior of blast waves within these environments must be quantified and understood. Urban constructs such as buildings and roadway intersections affect the natural propagation of a blast wave, intensifying or rarefying the wave depending on their arrangement.

Jan 1, 2012

By Randall Head

The drilling at the Taum Sauk Reservoir was a unique compilation of the latest technology and everyday common sense. This site is comprised of rhyolite, which is 30 times harder than limestone in comparison. Using some of the most state of the art drills, coupled with GPS guidance, angular drilling systems, and an ordinary piece of string, some of the most amazing drilling feats were accomplished. By constructing the new dam on top of a mountain that had been blasted once before nearly 50 years ago treacherous conditions for the drills and crew were a challenge. The drills had to be flown in by cranes to get to their locations, where they then drilled anywhere from 2.5 to 6 inch (6.4 to 15.2 cm) holes at angles up to 24.4 degrees. Custom drill bits were designed by the drilling crew to tackle feats such as drilling holes up to 120 feet (36.6 m) deep. A main challenge was the shape of the reservoir, as it is not in a straight line, but rather round, so no technological way was readily available to use to drill. Common sense came in and an ordinary piece of string was used to aide in drilling the hole. A revolutionary step was that our drill was used to core our own samples. By using our own equipment, we were able to complete this task for one-third of the cost of having a third party contractor obtain the core samples. On this unmatched jobsite, it has been established that technology has come a long way, but when all else fails, a piece of string will do just fine.

Jan 1, 2010

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