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By Agung Wibowo

The incident of Ammonium Nitrate explosion in Beirut on August 4, 2020, became a wake-up call to Ammonium Nitrate stakeholders for mining and construction regarding the deadly risks associated with explosives management. This is a very expensive a lesson learned for all parties involved in the storage of explosives.

Feb 1, 2020

By O Omidi

Selection of delay times to optimize fragmentation has been a controversial topic among researchers and blasting practitioners. This paper reviews previous experimental information and presents the results of new tests conducted in small blocks constructed using a commercial grout. The effect of the delay on the average fragment size, coarse fragmentation and uniformity of fragmentation is discussed. Fragmentation was coarser at extremely short or extremely long delays, while a fairly constant average size was obtained at a variety of intermediate delays. Uniformity, defined as the slope of the fragmentation distribution through the average fragment size, was poor at short and very long delays and relatively constant at the intermediate delays. Some tests attempted to minimize the effect of gas penetration by lining the boreholes with copper tubes. When this was the case average fragmentation changed marginally, while uniformity was significantly affected by delay and was typically smaller than in the unlined tests.

Jan 1, 2014

By Jack Eloranta

"Unwanted, dynamic interaction of adjacent blastholes is a well-recognized phenomenon. Timingschemes and products are selected to minimize adverse effects. Large diameter, surface blasting is less prone to dead pressing and other disruptions which commonly plague underground and construction blasters. However, several lines of evidence suggest that fragmentation may be compromised as a result of powder column disruption in large diameter shooting as well."

Jan 1, 2016

By Robert Hopler

BH Note: This price list stresses the point that the number six strength cap should be used with all high explosives. It’s interesting that duPont chose to continue to supply the lesser strength caps – but lowered the price of the #5 or #6 to be closer to that of the #4 and #3. There were imports of the lower strength caps at the time that had to be competed against, hence the price reductions. Another interesting point on this price list is the noting on the “Red Cross Explosives” page that these explosives reduce the danger incurred during the operation of thawing. As noted many times in these articles, this problem was not to be solved for about another 16 years or so.

Jan 1, 2011

By Pedro C. Carneiro, Luiz G. I. Maciel

"This article presents data of advance and excavation rates in tunnelling works, and how theseactivities interact with the duration and cost of a contract. These key parameters, after analysis andsynthesis, will be used in coming works to ensure the evolution and adaptation of the method created by the Norwegian University of Science and Technology - the NTNU Method - to Brazilianconditions, which will be reflected in the duration and cost of underground drill and blast tunnellingworks."

Jan 1, 2016

By Henry P. Jr Van Ormer

During any blast hole operation the first choice to be made is hole size - it seems simple, just calculate all the factors, spacing, burden, depth, rock characteristics, powder factor, etc. and you have it - Hole Size. But we all know that it is not that easy - the "hole size" is part of a system and many other situations can have great impact on the optimum production Blast Hole Size - such as crusher characteristics, hauling capability, mucking capability and - Drilling Capability!

Jan 1, 1983

By Ayman Tawadrous, Hendrik Botha, Simon St J Tose

The early miners and their mules always had the challenge of transporting unstable dynamite underground. The modern pumpable explosives, whilst far safer, still present a major logistics challenge for the mobile charging units (MCU). The challenge today is the efficient explosive delivery into declines, ramps, and vertical shafts, often requiring the MCUs to travel excess distances up and down to surface to re-load. Alternatively, the management of cassettes or ISO containers is utilized to deliver the pumpable base emulsion to the MCUs at the working face. Additionally, local laws and regulations regarding shaft clearance further compound the task and result in pausing other operations in the shaft or decline or ramp until the completion of the explosive transport. This paper examines the research & development challenges of dropping base emulsion down a vertical pipe to depths in excess of 1000 m (3280 ft.), either to an underground storage or directly into the MCU, depending on the depth. The boreholes (with pipes) are drilled in close proximity to the underground work areas. The paper also discusses the rheology of the emulsion within these vertical pipes as well as the economic benefits of such an innovative system. The learnings gained from this work, along with examples demonstrating the significant reduction in MCU travel and the safety benefits, are presented for the industry to consider moving forward.

Jan 21, 2025

By Mick Fritz, Gregory Poole

Construction blasting is always challenging when in close proximity to existing structures, but when you are next to a landmark like Sanford Stadium at the University of Georgia it can get intense. Blasting on this project was performed less than 100 feet from students studying in their dorms at Reed Hall. Some shots are only a few feet from the columns on the stadium that hold up the sky boxes where meetings were being held while blasting was being performed. If a shot goes vertical the rocks would go through the floor of the sky boxes.

Jan 1, 2011

By J P. Tidman

The demand for more data on the detonation properties of commercial explosives grows as blasting becomes a more exact science. Proper use of this information by blasting engineers depends on the appreciation of the assumptions and limitations inherent in calculating energies and pressures of explosives. The strength of an explosive is usually a calculated energy value derived from a model of the explosive. The model may be simple or complex, depending on the thermo-hydrodynamic assumptions made. The calculated energy and pressures of commercial explosives are sensitive to assumptions about their reaction products. The equation of state describing the reaction product gases, the treatment of solid reaction products (e.g. reacted calcium and sodium nitrate and aluminum) and the reaction time are examined to show the variability of calculated results as a result of different assumptions. These same models of explosives also serve to explain phenomena of explosives such as the effect of charge diameter on V.O.D. (and strength) and decoupled explosives.

Jan 1, 1981

By Mick Fritz, Ryan Gilmore

The Center for Disease Control [CDC] is in the midst of a twenty year project, part of which includes demolishing existing buildings and erecting taller, more modern structures within the same foundation foot print. Controlled Blasting Inc, a large and experienced construction drilling and blasting company in Metro Atlanta, was contracted to provide the drilling and blasting for the new building foundations. Working on a construction site, in this type of environment, creates many challenges for the drilling and blasting crews.

Jan 1, 2008

By Jon Hurt, Brent Meins, David Vardiman

"Two test blasts were conducted at the Sanford Underground Research Facility to establish optimum blast designs and to limit blast effects on existing research rooms and equipment in preparation for the largest deep underground excavation in North America. Located on the 4850 Level (4,850 ft below the surface)at the former Homestake Mine in Lead, SD, this excavation is part of the U.S. Department of Energy’sLong-Baseline Neutrino Facility that will house particle detectors for the international Deep Underground Neutrino Experiment hosted by Fermilab. A large array of seismographs was deployedthroughout the 4850 Level to measure ground vibrations and airblast pressures in tunnel drifts and in lab spaces."

Jan 1, 2017

By Robert Hopler

209. Nitro-glycerine is produced by the action of nitric and sulphuric acids on glycerine, and is a heavy liquid of oily appearance, of specific gravity about 1•6, varying from colourless when quite pure to a yellow or brownish yellow. It is of a very sweet taste, and without odour, and is an active poison. Mere handling of it will in most persons induce sickness and headache. It explodes when heated to about 360° F. or from shock, but in small quantities it ignites and burns with some difficulty by the mere contact of flame.

Jan 1, 2011

By Tom Snyder, John Brulia

"The U. S. commercial explosives industry annually transports thousands of tons of hazardous materials (HM) in the form of explosives, oxidizers, and combustible liquids by highway in truck-tractor/trailer combinations and straight trucks, including pickups. Managing risk during transportation is every commercial explosives industry motor carrier’s number one job."

Jan 1, 2014

By R. Ranjan

Stanstead granite has been investigated with respect to its dynamic compressive strength and its strain-rate dependency. A standard Split-Hopkinson Pressure Bar (SHPB) apparatus has been employed to generate strain rates of up to ~500/s through high-velocity impact. The diameters of the test samples were 19 mm, and tested under impact velocities up to ~20m/s. It is found that even within this limited range of strain rates, the dynamic compressive strength for the granite showed nearly a 100% increase in value compared to those obtained under static loading conditions (e.g. compressive strength of 394 MPa at a strain-rate of 600/s, compared to 215 MPa obtained under static loading). The details of the test are described in terms of incident, reflected and transmitted stress pulses, along with means to achieve stress equilibrium in the test samples under dynamic loading conditions. The advantage and drawback of the use of ‘pulse shaping’ techniques to achieve dynamic stress equilibrium are also detailed.

Jan 1, 2010

By Thomas E. Ricketts

An important part of underground mine planning and operations involves the reclamation of working areas after blasting before the mining cycle can continue. This is especially true for mining that must use large blasting operations in the vicinity of extensive underground workings. In an effort to develop a rational procedure for estimating mine damage produced by blasting, underground rock fall has been assessed for a large-scale blasting operation in oil shale. The amount of mine damage has been quantified in terms of manshifts of effort required to reclaim underground working areas after blasting. This has been further broken down into the three main phases of reclamation, i.e., scaling and excavation, rockbolting, and miscellaneous repairs on ventilation, utilities, etc. Different types of openings have also been assessed including level tunnels, incline drifts and rooms. The effect of repeated blasting on mine damage has also been documented with initial blasts producing more damage than subsequent blasts.

Jan 1, 1988

By D T. Froedge

This paper is a presentation of a coyote shot at the Oriskany Sand Quarry of the Pennsylvania Glass Sand Corporation, Berkeley Springs, West Virginia.

Jan 1, 1982

By James Rowland, Richard Mainiero

When most people think of explosives transport they think of a hazardous operation. We all know that we aren’t allowed to transport explosives through tunnels and are discouraged from traveling through heavily populated areas. Popular opinion suggests that explosives transport is a very risky operation. The authors decided to look into this a little more thoroughly and found just the opposite to be true.

Jan 1, 2008

By Brian Stump, Chris Hayward

Blasting operations at one copper mine are studied in detail to examine the relation between blast design parameters and near-shot, in-mine, and regional seismic and acoustic observations. Five observational experiments, namely collection of blast design data, near source recordings, GPS synchronized video, near mine recordings and distant regional observations were performed during one week in August. A variety of seismic and infrasound instruments were installed near the shot, on the perimeter of the open pit mine, and at several locations up to 500 km distant. Time tagged video recordings were taken of several shots. Three shots were used in the preliminary analysis, a 350,000 lb pattern with long delays, a 60,000 lb pattern with short delays, and a 256,000 lb pattern with short delays. Maximum peak-to-peak amplitudes of the seismic signals in the mine are not a simple function of the total size of the shot, but are related to the pattern timing. Peak pressures have a less clear relation to peak pressure but match the relative amplitudes of spectra modeled from the pattern design. The predicted spectrum based upon a simple impulse model fits the observed spectrum for ground acceleration measured near the pattern and explains why in this case a pattern of 60,000 lb results in the same seismic disturbance as the 350,000 lb pattern.

Jan 1, 2002

By Goran Lande, Bernt Larsson, Dennis Clark

The effects of vibrations on close surroundings has been studied in Europe and the United States extensively in the past three to four years due to the ever increasing demands of environmental control. Therefore, "routine measurements" or "standard vibration consulting services" are being carried out by numerous firms with widely different qualifications.

Jan 1, 1983

By D J. McLane, J T. Rathbun, B T. Lusk

The dynamics of explosive detonations are understood, however recreating a real-world, full scale scenario is costly. The use of a shock-tunnel allows testing to be done on a smaller scale, with the simulated effect of a large explosion. Analyzing explosive waveforms using this method can greatly reduce cost in testing blast resistant products, such as anti-terrorism devices, mine safety products, and military equipment. The purpose of this paper is to better the understanding of how the waveform characteristics resulting from an explosive detonated within a shock-tunnel differ from those in an open-air arena test. The variables of comparison between an open-air arena test and those conducted within a shock tunnel are peak pressure, impulse, shock wave velocity, and cross sectional shape of the shock front. Understanding how these variables differ, tests utilizing a shock tunnel can be conducted with a higher degree of accuracy and repeatability.

Jan 1, 2013