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By John Horgan, Ethan Marcoux

Explosives have been used to demolish many unsafe structures around the world. However, it is unlikely any demolition job has ever involved destroying buildings already buried 40 feet (12 meters) into the world’s largest ice sheet. That is what happened to the original research station at the geographic South Pole, built back in the 1950s, following a series of discrete explosions between 2011 and 2013.

Jan 1, 2015

By Jeffrey Meissner, Mike Waldron, Charles Dowding

Most studies of crack response have focused on opening and closing of a crack in the plane of the wall in which the crack occurs. Crack movement also occurs perpendicular or normal to the plane of the wall. This paper will examine and compare the in-plane and out-of-plane (normal) response of cracks in two different residences near limestone quarries. In two locations, sensors that measure in-plane and normal displacement were installed side-by-side on the same crack, allowing direct comparison of the two modes of response. In a third location, a perpendicular pair of displacement sensors was installed in a corner of a room to observe the bidirectional response of the structure at a corner. Both long-term and dynamic data were recorded with the same sensors; temperature, humidity, and air over pressures were also recorded to compare blast and weather effects. Measurements show that ratios of out of plane to in plane response to dynamic events can vary. However, the ratios of out of plane (normal) response to vibratory events to that of climatological change is still as small as the ratio for in plane crack responses.

Jan 1, 2010

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 Catherine T. Aimone-Martin, Elena Oana Jacobs, Brent Meins

Accurate pressure measurements during underwater detonations are critical for the protection of structures and mitigating impacts to fish and marine mammals. Current guidelines that limit underwater pressures are based on past studies, many of which used sample rates of 48 and 65 kS/s (48,000 and 65,000 samples per second). These sample rates may be insufficient to accurately record high frequency, sharp rise time blast pressures. As such, pressure thresholds associated with fish and marine mammal injury or mortality may be underestimated, calling into question the pressure and sound pressure level guidelines that govern underwater blasting today.

Jan 1, 2019

By Douglas R. Burns

Complying with SARA-Title III and the Emergency Planning and Community Right-To-Know Act as a Non-Manufacturing Facility. As of August 23, 1988 non-manufacturing facilities storing end using chemicals which require MSDS (Materia1 Safety Data Sheets) must fi1e with SERC (State Emergency Response Commission), the LEPC (Loca1 Emergency Planning Commission), and the loca1 Fire Department a list or copies of all MSDS sheets with the Tier I and Tier II forms completed.

Jan 1, 1989

By B. Papilon

Dynamic pressures during blasting can affect performances of both electronic and non-electronic detonators. Boreholes can develop tremendous amount of pressures during blasting. The effect of such elevated pressure especially during electronic delay countdown is probably more acute in electronic detonators. Measuring the pressures during blasting can aid to understand the relationship between magnitude of the pressure developed and the multitude of blasting conditions.

Jan 1, 2013

By Richard J. Mainiero, Eric S. Weiss

This project investigates the behavior of blast waves from the detonation of high explosives in an underground mine. A series of explosive tests was conducted in the underground and surface facilities at the Bureau of Mines' Lake Lynn Laboratory to evaluate the potentially dangerous effects of blast waves produced by open shooting, blown out holes, or accidental detonations of explosives. Shots of C4 and TNT were fired at the dead end of a 6 ft high by 20ft wide entry, at the intersection of two entries, and on the surface. C4 and TNT were chosen for this research because they exhibit very consistent performance. Behavior of the blast wave was evaluated through recording of the pressure as a function of distance from the explosive detonation.

Jan 1, 1995

By M E. Hanson, K Chong, R H. Jacobson, S C. Way

To create conditions for economic rates of mineral recovery in a deep, hard rock mass, enhancement of naturally occurring permeability is necessary, and may be achieved through explosives detonated in boreholes. Previous theories of explosively created permeability are reviewed and found to relate permeability solely to the degree of fracturing, neglecting porosity. A theory is presented that includes both fracture density and porosity, and its results are applied, together with a knowledge of explosive behavior, to derive design parameters for in-situ mining.

Jan 1, 1983

By Per-Anders Persson

This chapter deals with the concepts of shock wave8 and detonation wavea together, because a detonation wave is really a shock wave, supported by the explosive reaction that the shock wave ignites and propagates as it travels through the explosive material. In the context of rock blasting, furthermore, there is justification for treating shock waves and detonation waves together, because the mechanical effect of the detonation in an explosive in a drillhole in rock is propagated and its effects are spread throughout the surrounding rock by means of a shock wave. The overall performance of an explosive in rock blasting or any other application is of course dependent on how much thermal energy is released in the chemical reaction that occurs when the material detonates, and on how much useful mechanical work the reaction products can do as they expand. A major portion of thii chapter deals with the prediction and measurement of explosive performance, a subject which is now still in a process of rapid development.

Jan 1, 1998

By Chuck Kliche, Bill Clements

This project involved the removal of the top of an old water supply reservoir tank for the City of Lead, SD by explosives. The general contract called for the removal of the concrete top without damaging the sides or floor of the reservoir. The option of a rock hammer was eliminated, due to the possibility of an unpredictable collapse damaging the sides or floor of the reservoir. Different blasting options were discussed between the primary contractor and the blasting contractor, along with the pros and cons of each. The primary contractor settled on the option of drilling the structure for blasting versus using shaped charges

Jan 1, 2007

By Carlos Campos Junior, Leonardo Soares Chaves, Raul Carretero Hoz, Renato Jacome Costa, Davi Bastos Martins de Oliveira

The Vale’s Serra Sul mine, also known as S11D project, is one of the world’s largest open pit iron ore mines, located in Brazil’s Amazon region. The mine produces around 90 Mt of high-quality iron ore annually. Its unique orebody enabled the S11D project to adopt a truckless mining system with In-Pit Crushing and Conveying (IPCCs) for ore exploitation and waste stripping. The IPCCs system requires crushing the waste, mainly composed by the jaspilite lithology, and is also conveyed to waste deposits several kilometers away from the mine. Due to Amazon’s environmental restrictions, the project was designed with preliminary geological knowledge, leading to the installation of primary crushers not designed for the hardest jaspilite, with uniaxial compressive strength (UCS) up to 500 MPa. This resulted in low waste crushing performance, affecting stripping ratio and threatening future production. A project was developed to improve the fragmentation of the jaspilite, allowing higher waste IPCC production, and reducing the risk to the production due to low performance of waste crushing and conveying. The first challenge was the independence of the geological and the geomechanical models, while only the geological model was considered in blast designs, the geomechanical model describes six waste groups of jaspilite classified according to their strength. A new geological model was then created to incorporate the geomechanical classification, allowing different blasting design according to the rock strength of the jaspilite. The blasting pattern on most compact jaspilite was reduced 27%, from 22m² to 16m² in 9 7/8” diameter holes, with a proposed theoretical reduction of 23% of the P80, from 326mm to 250mm. The second challenge was the implementation of the new design, as this pattern size and the high powder factor (2.9 kg/m3) were paradigms for such a large iron ore mine. The measured results have shown 25% reduction of the P80, the crushing rate was increased by 17% (230t/h), saving around $2.4 million annually in crushing and conveying system maintenance.

Jan 21, 2025

By C. Feliciano, M. Cavalcante

A large iron ore open pit mine in Brazil operates with reduced blast sizes, due to the imminence of red alerts in the rainy season and the proximity of plant and dam structures that demand control of the maximum load of fired explosives. Blasts are currently not allowed to remain loaded with explosives due to the risk of red alerts, limiting mine operations close to them. There is a need to increase the blast sizes, reducing the number of events required to obtain the planned mass and, consequently, the unproductive operating hours lost with mine evacuations. The WebGen™ wireless electronic initiation system is a technology for firing detonators via lowfrequency magnetic induction that propagates through the medium, without physical connection. A blast was carried out with 406 holes divided into 4 panels, aiming to validate the preloading technique with wireless detonators and its performance in safety and productivity. The absence of lead wires in the system eliminates the risk of interaction between vehicles and detonator cables in stemming and loading operations, which can result in unplanned detonation or misfire. By eliminating the need for a spotter, it reduces people's exposure to dust and the risk of human-machine interaction. Furthermore, it eliminates the risk of unplanned detonation caused by lightning strikes. The pre-loading technique with wireless detonators enables flexibility and efficiency in planning through temporary accesses over loaded areas. In the demonstration, driving over the loaded area was essential to avoid jams and excessive wear on equipment due to the narrow berm and very friable material. Another gain in productivity was optimizing operational stages, since detonators were programmed in parallel with loading, anticipating process stages, in addition to eliminating the need to connect detonators. Considering the average handling and savings in downtime due to the reduction of blasting events, a potential increase in movement of 49,000t (54,013 short tons) in 3 months was estimated, keeping the vibration results within the required limit. The trial with wireless detonators demonstrated the feasibility of carrying out blasts with preloaded panels, without restrictions on the number of panels or detonators, enabling vibration control, innovating mine planning and increasing safety and productivity

Jan 1, 2024

By Robert B. Hopler

Explosives have been important to the oil and gas industries since the very earliest days. The first wells of Pennsylvania and New York in the 1860’s were able to be brought back to productivity by the use of nitroglycerin after their porosity was lowered by the high para& content of their oil. Success in the use of seismic waves to locate enemy artillery in the First World War led to the use of explosives in the 1920’s for generating ground vibrations to locate geological structures favorable for the entrapment of oil. Explosives also find widespread use in the more conventional applications of well site preparation and pipeline construction. Explosives applications unique to the oil and gas industries include the jet perforating of casings and formations, fighting well fires, and cutting casing during well shut-in.

Jan 1, 1998

By B. Winterberg, C. Lewis, M. Starkel, C. Johnson

Non-electric systems, specifically shock tube, have become the pyrotechnic detonator of choice over electric due to their safety regarding accidental initiation from stray radio signals. Typically, the best practice when hooking up shock tube systems is to have direct contact to ensure initiation. When gaps are introduced to the explosives chain, there is potential for detonation to come to a halt. It is understood that direct coupling is required between the various elements in the explosive chain to ensure detonation. This holds true whether tying in non-electric detonators, loading holes in a mining related blast, or priming a block of C-4. Poor contact and gaps in the explosives chain can lead to detonators firing out sequence, leading to increased vibration, air overpressure, and other undesirable blast results. Furthering work conducted in previous experimentation, a new study was conducted at the Missouri University of Science and Technology’s Experimental Mine in Rolla, Missouri to observe the initiation potential of an air gap and fragmentation on non-electric shock tube. A series of small test blasts were conducted using 50 grain detonating cord and fragments from a blasting cap to initiate a non-electric shock tube across an air gap of varying distances. The data collected in the high-speed imagery was used to analyze the velocity of the pressure fronts and blasting cap fragments used to initiate non-electric shock tubes across an air gap. It was found that the shock tube was sensitive to 50 grain det cord at a 5cm (1.97in) distance while parallel and 10cm (3.94in) when perpendicular as well as sensitive to frag from the electric cap out to 2.4m (7.87ft).

Jan 1, 2024

By Sayantan Chakraborty, Kaushik Dey, SaKaushik Dey tyabrata Behera

Drilling and blasting is a popular excavation technique in the drift of underground mine. Faster completion of drift reduces the gestation period and thus longer blast pulls are attempted with longer drill holes. This compels the blasters to initiate higher charge quantity with higher confinements and ultimately results into blast-induced cracks beyond the desired periphery line of excavation. Assessment of the extent of these crack networks is difficult and often neglected. Near-field ground vibration models are often used as damage predictors (Dey, 2007, Yang et.al 1993, Holmberg et. Al 1979) but not necessarily deals with the positions of the cracks. Qualitative measurement of actual damage extent often measured using some geophysical tools, namely, P-wave velocity (Tezuka, 1995), seismic imaging (Dey, 2011), bore hole pressure monitoring (Brent and Smith, 1996), electrical resistivity (Grady and Kipp, 1993), GPR (Adams et.al, 1993) etc. Ground Penetrating Radar (GPR) is a similar geo-physical tool, which uses Electro-magnetic (EM) pulse for characterizing the medium. Similar to other geo-physical tools, GPR also comprises of a transmitter and one/multiple receivers to generate the EM pulse and receive the same after reflection/refraction from the medium(s) respectively. After its development in 1970s, GPR gained increased popularity due to its application in many important fields, namely, identification of buried objects, geological characterization, identification of geological disturbances etc. Thus, it is felt that GPR technique can be used to detect the invisible cracks inside the rockmass from the rock surface (wall and roof) itself. Understanding the same, field experimentations are carried out in an underground manganese mine in Central India, which operates on the ‘cut and fill’ method of mining at a depth of around 300m from the surface. Wedge cut blasting is carried out in the horizontal drifts of the mine using suitable blast design. A 1.6 GHz antenna was used for the GPR scanning, in which GPR transmitter transmits signals predominantly of the said frequencies. The signals get reflected back from any type of interfaces between materials in the target area, with different dielectric properties and is received by the receiver part of the ‘trans-receiver’ antenna and memorized in the Data Acquisition Unit (DAU). The data acquired is processed using a software. Ground vibration monitoring of the blasts are also carried out to develop a vibration predictor. The numerical analysis of near-field vibration predictor model results into the estimated vibration levels at the point of identified cracks. Introduction

Jan 1, 2019

By Dal Sun Kim, Michael K. McCarter

"Comminution (crushing and grinding) of rock materials is energy-intensive and expensive. Mucheffort has been directed to improve the efficiency of conventional milling practice, but relatively littleattention has been given to the potential benefits of blast-induced damage on comminution processes. To help assess this effect, research has been conducted at the IRECO Laboratory and the Generic Center for Comminution at the University of Utah. The objective of this research is to investigate the effect of shockinduced “crack-like” damage on rock properties and subsequent breakage efficiency for three petrologically different rock materials under laboratory conditions. In order to evaluate the effect of shockinduced damage, a quantitative measure of rock damage is needed. For this purpose, a scalar variable (0) is proposed."

Jan 1, 1993

By Frank Huber, Ed Fulop, Neil Singh, Ron Elliott, Blair Gohl, Lewis Clarke

This paper covers the successful application of explosive compaction technology for the densification of the foundation soils for the seismic upgrade of the Seymour Falls Dam, Vancouver, BC. The original earthfill embankment constructed during 1958 to 1961 was upgraded in 2004 to 2007 to withstand the effects of a maximum credible earthquake. This paper provides general background information on the theory of the explosive compaction of soils, history of use, geology of the site, project constraints, explosives selection, blast designs, instrumentation used, problems encountered and solutions implemented, and the results achieved.

Jan 1, 2009

By Andy Hudson, Stuart Brashear, David Lilly

Because of greatly increased timing accuracy, electronic detonator systems are a well-known and widely accepted major tool to control and reduce ground vibration. At a Southeastern quarry the authors found that the use of electronic detonators improved the reliability of the well known cubed root scaled distance equation for determining air blast. In addition, the authors noticed significant correlations between selected major peak particle velocity frequencies and air blast magnitudes. The major peak particle velocity frequency alone is a close approximation to air blast magnitudes. This relationship is not as significant or not always evident when standard pyrotechnic initiation systems are used.

Jan 1, 2009

By Ronald Joseph

Windows-based automated blast loading systems have long being conceptualised and never really taken off in the surface mining sector. However, with the introduction a windows-based automated blast loading and reporting system onto the Mobile Manufacturing Units (MMU’s) at Debswana Diamond Company operations in Botswana in August 2004, a project to automate blast loading (charging) and reporting ensued. This work was pioneered over three phases at Debswana’s Jwaneng Diamond Mine by African Explosives (Botswana) (Pty) Limited as part of the African Explosives Limited’s (AEL) integrated-mining (i-mining) concept. The first phase of the project involved the blast reporting system, at which time an average amount of explosives were loaded into all blastholes and all blast loading information was saved to a Microsoft Access 2000 database on the MMU computer. The second phase of the project, which ran until the end of the second quarter of 2008, involved manual blast plan loading and reporting system using flash disks, and the third phase which was installed and commissioned in the third quarter of 2008 and is currently operational at Debswana’s Jwaneng Mine, involves the automated blast loading and reporting system via Wireless Local Area Network (WLAN). This system is now routinely used to achieve operational and mining efficiency goals at the mine with respect to blasthole charging and blasting, and this paper briefly summarizes the status of this project at Jwaneng Diamond Mine where this technology is currently being monitored and also illustrates the positive mining impact that this innovation brings to the mining operation, both from an economic and efficiency perspective.

Jan 1, 2009

By Miquel Lamadrid, Changshow Sun, Chris Johnson

To reduce blasting overbreak and improve stope stability, several new blast designs were proposed for current and future stopes. Based on the analysis of the powder factor, and the extent of damage zone, the appropriate new blast design was selected. Excellent results were achieved from the new blast design. Comparing the new blast design with the old one, the largest of the overbreaks decreased more tan two times and average overbreak reduced more than two times. The new blast design is currently applied in all mining zones in Leeville underground mine.

Jan 1, 2008