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By Dale Preece, Mike Stern, Steve Piercey, Ayman Tawadrous, GC Zhao

The McArthur River uranium mine in Saskatchewan, Canada is the world’s largest high-grade uranium mine. It has employed a freeze-wall system consisting of multiple freeze pipes to control the large quantities of water encountered during mining.

Jan 1, 2011

By Toby Forney, Joshua Schoonover

In typical surface quarry operations, productivity and efficiency related to pit development begin with drilling and blasting efforts. By embedding technology within drilling and blasting operations, blast results can be tailored to benefit the quarry by driving continuous improvement of production. This technical paper will focus on the continuous improvement efforts at a cement limestone quarry in Maryland and how those efforts have impacted mining production, safety, and efficiency with the application of specific blasting technologies.

Feb 6, 2023

By Christopher Jon Preston, Troy Williams, Daniel Roy

There has been significant progress made with narrow vein gold mines in which a second option for crushing has begun to attract attention. To ensure the profitability of a mine that has based its economics on the absence of a crusher station, more than just best blasting practices are required. Using a blasting operation itself as a primary crusher would undoubtedly save enormous capital costs as well as eliminate some of the costs of crushing ore with the result that considerable savings might be realized. The challenge would be to define the conditions necessary to make this type of operation feasible by providing consistent blasting methods that result in a significant paradigm shift with respect to both blasting and current underground crushing methods. A break model has been developed and applied as a technique in designing blasting patterns based on a unit charge blasting geometry and stress reflection from free faces. There are four components to this model and these are 1) unit charge, 2) thermodynamic/energy, 3) stress reflection, and 4) radial break. Some important changes in timing between holes and rows based on rock properties and the percentage of burden moved were also used. On-site testing at a narrow vein gold mine in Quebec Canada, provided measured parameters for the model. No underground crusher was planned - relying only on the fragmentation profile generated by ring blasting. The specification for muck was that the fragmentation profile needed to be 100% < 400 mm (16 in) with no overbreak - with dilution less

Jan 1, 2019

By Thomas M. Keevin, Gregory L. Hempen

A user-friendly model for environmental effects from underwater explosions is presently available. The model by Munday et al. (1986) is effective for determining fish mortality radii from underwater shooting. The IBLAST program (Coastline Environmental Services 1986) from this model includes estimates for both borehole-loaded explosives for demolition or rock removal purposes and midwater shots. Midwater shots may be used for fish population assessments or some seismic surveys. The program produces approximate mortality distances for planning purposes. IBLAST does have serious shortcomings of which users should be aware.

Jan 1, 1995

By Chris Vagasky

On July 10, 1926, lightning struck at Picatinny Arsenal, New Jersey, and caused the explosion of at least 600,000 pounds (272,000 kilograms) of ammunition, resulting in more than $600 million (2015 dollars) in damage, the destruction of 200 buildings, and 22 deaths. Fortunately, there has not been a major incident involving lightning and explosives in the US in some time, though lightning has destroyed fuel storage tanks in recent years, including in North Dakota, Texas, and Ohio. Lightning poses a significant hazard to the explosives industry. Carrying high currents and temperature, lightning can cause explosives to detonate, start fires near storage facilities, and injure or kill operators.

Jan 1, 2017

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 David Porter, Nathan Rouse

The implementation of presplit perimeter control in underground mining as a method to decrease dilution yields positive benefits throughout the current and future mining cycles. A case study to understand the benefits of reducing overbreak and underbreak in a cut and fill mining cycle was performed to quantify the reduction in backbreak. The study was performed in a control section of the mine where a presplit perimeter control design was utilized for a length of heading. This control heading was then compared to the existing standard blasting design within the same mining zone. The comparison included multiple aspects of the mining advance including overbreak, dilution of waste, dilution of Cemented Rock Fill, bolt counts, and cycle times. Once mining in the control section was completed and mining commenced in adjacent headings, blast damage due to blast design could be quantified.

Feb 6, 2023

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 Anderson da Cunha Meireles, Pedro Garcia, Ernst Young, Leandro Coelho, Carlos Eduardo Soares Feliciano, Key Fonseca de Lima

Rock blasting is a crucial technique employed in mining construction and quarrying industries to fragment large rocks into smaller, more manageable pieces. However, it often generates ground vibrations that can pose significant challenges. This study explores the application of Conformal Prediction (CP) in the context of rock blasting to develop predictive models that estimate blasting-induced vibrations and quantify the associated uncertainties. Various machine learning models were integrated within the CP framework using MAPIE and CREPES libraries. The results demonstrated the effectiveness of CP in providing statistically reliable prediction intervals, making it particularly useful for applications where the stakes of underestimating uncertainty can be high.

Jan 21, 2025

By Finn Ouchterlony, José A. Sanchidrián

"A model for fragmentation in bench blasting that originates from dimensional analysis of fragmentation in asteroid collisions is presented. Percentiles of the size distribution are obtained in the basic model as the product of a rock strength-to-explosive energy ratio, a bench shape factor, a scale factor or characteristic size and a percentage passing-related factor. The parameters of the model are fitted to 169 bench blasts in different sites and rock types, bench geometries and delay times, for which thefragmentation of the muckpile was obtained by sieving. The basic model is found to significantlyimprove with an additional factor describing the rock mass structure in terms of the spacing and orientation of discontinuities, and another one describing the delay between successive contiguous shots; the latter is conveniently formulated as a function of the P-wave velocity and the holes spacing. The rock strength property chosen is the strain energy at rupture that, together with the explosive energy density in the rock (or energy powder factor), forms a combined rock strength/explosive energy nondimensionalfactor. The model, called xP-frag, is applicable from 5 to 100 percentile fragment sizes, with all parameters determined from the fits significant to a 0.05 level. The expected error of the prediction is below 25 % at any percentile. These errors are half to one third of the errors expected with the best prediction models available to date."

Jan 1, 2017

By Tony Rorke, Sydney Thabethe

A large overburden blast was carried out at Douglas Colliery, Middelburg Mine Services, close to a national road in South Africa. The road is a busy route between Witbank and Bethal and damage to the road could not be risked. The section of road next to the blast was particularly prone to damage, because it had been mined out on its eastern flank, and the large blast was to take place on its western flank. There were thus three potential damage risks: 1. Fly rock damage to the road surface 2. Vibration damage to the road substrate 3. Damage caused by bulk displacement of the block supporting the road into the void on the mined out side. This paper presents the design and blasting methods used to control the blast and avoid these three risks. Electronic delay detonators were used in multi-decked holes. Signature data were used to determine the blast timing to make sure that delays were used that would provide destructive interference. The timing direction and sequence was decided using wave interference patterns to direct repeated shocks away from the road. The precise detonators and the odelling capability allowed effective control of the blast vibration result. Each hole was charged with two explosive decks separated by a deck of aggregate to limit the charge mass fired per delay and thus limit the reaction forces acting towards the unsupported road. The vibration and blast results are presented in the paper, together with the design that was applied. Details are provided on how the blast was charged and primed. The detonators that were used are described and the timing design is presented.Copyright © 2004 International Society of Explosives Engineers 2004G Volume 1 - Blasting Next to an Unsupported Road Using Electronic Detonators 1 of 13 It is concluded that damage risk to nearby structures can be effectively controlled using electronic delay detonators, provided the appropriate modelling is applied to obtain the most effective delay periods.

Jan 1, 2004

By Scott King, Norm Patterson, Ruilin Yang

The multiple blasthole fragmentation (MBF) model developed by Orica models the contributions from multiple blastholes to fragmentation at any given point in the rock and simulates a production blast with the actual geometry of the blasted overburden and free faces, explosive loading, multiple decking, and delay timing of each explosive charge. The model has been successfully applied to several open pit mines and quarries around the world, including Canada and the United States. The peak particle velocity (PPV) induced in the rock from the explosive detonation is used in the MBF model as the key parameter relating to the size distribution of the rock fragmentation. Relating the PPV to the rock fragmentation is based on earlier work relating the particle velocity to the dynamic strain in rock. A recent publication further revealed that the PPV is related to the maximum relative displacement that induces three dimensional strain at a point in the rock. The model can explicitly model most of the blast design parameters including explosive properties.

Jan 1, 2018

By Frederick B. Kuhnow

Harmonic energetic delamination a building is being considered for demolition at a formerly known atomic power lab. The building is within a containment structure under a negative pressure, so that no radioactive material is leaked out to the environment. A new approach was developed to make this work possible.

Feb 1, 2020

By John Norman

This paper will cover blasting techniques that are applicable to underground and other rescue that involves removing obstacles and breaking rock in close proximity to rescuers and subjects.

Feb 1, 2020

By Ravi Sahu, Ankit Jha, Sudarshan Rajagopal, Purushotham Tukkaraja

Geologic structures are one of the crucial parameters in blast design. Structural geology and rock properties influence drilling patterns, blast layout, and initiation systems. A comprehensive understanding of structural characteristics is essential to achieve the desired blasting objectives. This paper aims to identify geologic features in a bench using images obtained from the drone.

Feb 1, 2020

By Joseph A. Meyers

NYC has always been a high-profile target for both foreign and domestic terrorists. Explosives have always been the go-to tool for terrorists to bring about serious physical injury, death, and property damage in our society. Today with the anti-police movement gaining traction in the United States and anarchists groups using homemade explosives against law enforcement and municipalities, it is the responsibility of the explosives industry to ensure that every explosive product on a blasting site is secure. We must prevent the theft of these energetic materials used on projects and sold by vendors so they are not used by these terrorists. We have learned many lessons here in NYC which began with the theft of explosives used for blasting projects in NYC to supply the IRA (Irish Republican Army) 50 years ago. The liability is too significant to take short cuts in securing energetic materials. Over the years through cooperation with all agencies and the industry we in NYC have developed certain proven protocol and procedures we would like to share with the industry. An efficient and effective security plan for the logistic movement of explosives, as well as for the blast site is imperative to keeping the good name of the industry from negative repercussions and possible additional bureaucratic oversight of an industry that is highly regulated and still recovering from the pandemic. Communication, security assessments and transparency with all stakeholders and the Authority Having Jurisdiction (AHJ) will greatly improve the overall security for the blasting project. This SOP (standard operating procedure) will allow the AHJ to become a proactive partner in the security of the blasting project. If the AHJ is not a law enforcement agency, the law enforcement agency specialty unit must be notified and included in all phases of the project. The security for a blasting project with AHJ and law enforcement input starts at the inception of the project when the memorandum of understanding (MOU) is obtained, and involves the AHJ through all steps of the approval process. This includes threat assessments on new and existing structures. SME’s (Subject Matter Experts) must be present at all stages. The blasting industry and regulators must work collaboratively to improve safety, security, and create a dialogue with law enforcement and the AHJ. Relationships are built through trust, teamwork, transparency, and communication and greatly improve the safety of our great country.

Jan 21, 2025

By Neal Lee

Often the effects of wet boreholes are not taken into consideration when designing a blasting program to exhibit a certain amount of explosive energy per unit of rock such as design by powder factor, expressed in lbs./bcy (pounds explosives per bank cubic yard) or kg/bcm (kilograms per cubic meter), often the effects of wet holes are not considered. This paper examines different methods of loading wet holes and the effects they have on actual explosive quantities/unit of rock. In particular, we are looking at the amount of water trapped within the explosive column (bulk loading from the collar), or the annular space left void of explosives product around and between cartridges (wet-bags) with many of the current wet hole loading methods in use. We will focus on the effect this has on actual powder factor relative to “as designed” dry hole loading values, as well as the effect on performance of the explosives.

Jan 1, 2011

By Perry Sisk

In order to protect nearby structures during a blasting project, a peak particle velocity limit is often stipulated by a government agency or the owner of a particular structure. At the start of a blasting project, a preliminary estimate for the minimum scaled distance is often determined using a vibration prediction equation before any site-specific data have been obtained. Reasonably conservative assumptions are typically made for the unknown input variables in the vibration prediction equation until site-specific blasting data have been obtained and evaluated. Although this approach is prudent, it provides no assurance that the peak particle velocity values generated during the initial phase of the project will be below the specified limit.

Jan 1, 2013

By J. Eloranta

"Previous work indicated that the annual per-capita consumption of raw aggregate material averages about 10 tons; half of which is produced by blasting. Given a population of approximately 320 million in the United States alone, this amounts to 1.6 billion tons of blasted material annually. It was also estimated that up to 20% of the blasted material in aggregate operations is smaller than 6.35 mm (1/4inch) in size. Thus, about 320 million tons (i.e. 1 ton per capita) of byproduct is produced annually and sold at significantly lower prices or potentially discarded in waste dumps."

Jan 1, 2017

By Charles R. Barnhart

The Nitrogen Dioxide Cloud: After one year of testing it can be stated that we do know and understand a great deal about why the nitrogen dioxide formation is exacerbated in cast blasting. Picture 1 is an example of how concentrated the NOx can be from a cast blast. It has long been felt that 300 or more milliseconds of timing needs to be put between each row of detonations to allow the rock a maximum time of flight so the cast percentage is high. Our experiments have found that higher cast percentages can make with timing between 150 to 200 milliseconds between rows. Picture 2 show a definite improvement in nitrogen dioxide concentration and most of that was the result of shooting a previously shot end of the cast pattern that had not been dug, thus no confinement of the powder columns.

Jan 1, 2004