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By Thierry Bernard

Since the signature hole method principle has been described in the 80's, there has always been a lot of controversy about it. The theory is easy to understand but when it comes to apply it for predicting vibration level, optimizing timing to reduce PPV or shifting frequencies, it’s not always working as expected. Simulations show waveforms that don't make any sense or predictions that are far away from actual results.

Jan 1, 2012

By Barbara Rutter, Shonn Kevin McNeil

"This study discusses how a prototype was built to measure the sonic velocity in powdered explosives.The sonic velocity of an explosive is a benchmark to determine if the explosive deflagrates or detonates;however, little work has been done to determine this value for powdered explosives. This paperdiscusses the results of the initial prototyping tests where two known mediums, air and water, were used for validation. The prototype did record the sonic velocity within the known velocity ranges of air and water; however, a few depths did not fall into this range. This prototype could be used for testinggranular materials."

Jan 1, 2017

By Robert Hopler

A detonator is a copper tube about a quarter of an inch in diameter and an inch and a half long, closed at one end and containing in the closed end a small charge of fulminate of mercury, which has been found to be the best explosive for detonating dynamite. The fulminate charge is a very powerful explosive very sensitive to friction, lows or heat and very poisonous. When exploded it has an intense local action, shattering things in its immediate vicinity, but not extending very far away from the explosion. This kind of detonator is intended to be exploded by a spark from burning fuse.

Jan 1, 2014

By O. Cermak, F. Degonld

Although 3D fragmentation analysis is a relatively new technology, it is rapidly gaining popularity among mid-sized mining operations and quarries. The results provided by this technology are adequate, but like other picture analytic methods, it mainly focuses on the surface of the muck-pile. These results are incomplete or incorrect as falling rocks and boulders from the stemming zone are constantly influencing the muck-pile surface. This obstacle can be overcome by collecting a large amount of data and analyzing it over time. However, this is not always an ideal solution, as companies prefer to receive results immediately after the blast to make resource allocation decisions, production planning, and plan for the next blast. Over the past year and a half, we have conducted a study on various muck-pile fragmentation analysis results from 3D modeling in Central Europe, comparing the results between the surface and inside of the muck-pile. By analyzing multiple shot results, we were able to determine the percentage difference between the top and inside fragment sizes and calculate the range of correction coefficients for different rock types. Applying these coefficients to a single muck-pile surface fragmentation analysis allows us to determine the actual fragment sizes inside the muck-pile. This enables us to make informed decisions regarding loading, hauling, material mixing, and proper crushing or milling. By overcoming the limitation of surface-based analysis, we can now accurately evaluate blast performance, which leads to better processes optimization and increase efficiency. As 3D fragmentation analysis becomes more widespread, we expect to see even more benefits for the mining and quarrying industry

Jan 1, 2024

By Thierry Bernard

It was in the 1980s that USBM published one of the first regulations to protect constructions from the effects of vibrations caused by mine blasts. Several countries have made their own regulations or recommendations since then with vibration limits that are often lower. However, on many sites, operators choose vibration limits that are lower than those of the existing standards, in order to limit the number of complaints received. The real question is how can we know what level of vibration is susceptible to create or worsen an existing crack in a construction. MCM, to the north of Quebec, is working a deposit on the periphery of the town of Malartic. Within the scope of its environmental monitoring programme, together with the joint monitoring committee, MCM has equipped four sample houses for over 18 months, in order to learn if there is a relationship between the evolution of damage to existing constructions and the seismic levels of vibrations created by mine blasts. The publication presents the results of this unique study that has analyzed millions of measurements (seismic, extensometric, and temperature) to define what relationship exists between the levels of vibration and the movement of cracks. Some surprising results versus some published previously (see ref) might change our perception of the subject.

Jan 1, 2018

By Ravi Sahu, Brad Gyngell, Oktai Radzhabov

Design machine learning approach to simulate the process of muckpile throw distribution before blasting.

Feb 1, 2020

By D. Scott Scovira, Thomas Gustavsson

The potential of hydrogen peroxide explosives was introduced to Thomas Gustavsson and Robert Håkland by Dr Miguel Araos through his development of hydrogen peroxide gel compositions (HPG). In 2020, Thomas and Robert developed a concept project with Boliden Minerals and received Swedish government funding to evaluate HPG technology in a mine environment. The project showed HPG reacted violently with mine mineralization and concluded that HPGs did not offer a commercial solution due to safety concerns. Thomas and Robert engaged with Stefan Nilsson to develop hydrogen peroxide emulsion (HPE) compositions and the process techniques to manufacture them. In 2021, laboratory work produced a promising low carbon intensity, nitrate free, ammonia free, emulsion formulation based on industrial grade hydrogen peroxide and a fuel-emulsifier phase. Design and construction of an HPE pilot plant and underground charging unit commenced. The manufacture of hydrogen peroxide emulsion shares several similarities with the production of nitrate-based emulsions in that the plant is a facility to blend a strong oxidizer solution with a liquid fuel phase into a finished emulsion. A key differentiator between HPE and nitrate-based emulsion is that the manufacture of HPE is a cold production technology in that neither the oxidizer phase (HP) nor the fuel-emulsifier phase requires high temperature heating to prepare raw materials. A successful proof-of-concept HPE evaluation ran from April 2022 to October 2022 at Boliden’s Kankberg underground mine in Sweden. This evaluation demonstrated HPE technology's safety, performance, production, handling, and indicative environmental benefits.

Jan 21, 2025

By Dr. Paul Worsey, Dr. Calvin Konya, Dr. Anthony Konya

Development of methods to calculate presplit blasthole pressures through simplified models, namely the Empirical Model and the Detonation Pressure Model. These models can be used with variations in explosive type and diameter, along with borehole diameter. All models have been validated with test data and shown to have minimal error.

Feb 1, 2020

By Michael Wieland

The thrust of this report is to overcome some of the technical deficiency in the scientific methodology that correlates the work output during a charge explosion to the resulting toxic fumes. Thermodynamic work-principle models yield (undissipated) shock and heave results for shooting underwater and in rock stratum with related toxic fumes. Underwater circumstances yield reliable test data for the work process, though questionable or no fume results. Work-output measurements in rock shots remain difficult if not intractable, though some fume reports exist. Underground tests with thick-wall metal pipe bombs yield consistent toxic fumes trapped within the test chamber. The work output, rendered as fragment kinetic energy, can be inferred from the well-tested theory of R. W. Gurney, originally designed for military ordinance. Therefore a work-principle model for cylindrical pipe bombs was developed to predict fragmentation work output and reaction-zone fumes, permitting the double comparisons to reported and inferred results.

Jan 1, 2010

By Robert Hopler

THE work that is being done by the Government to reduce the dangers of mining was brought out strikingly in the First National Mine-Safety Demonstration which occurred at Pittsburgh, Pa., on October 30th and 31st, under the auspices of the United States Bureau of Mines with the assistance of the American National Red Cross Society and the Pittsburgh Coal Operators’ Association.

Jan 1, 2012

By Steve Brace

Electronic detonators have been commercially available to the mining industry worldwide for over ten years. It is estimated that total cumulative global sales will have reached 25 million units by the time of the Conference in February 2004. This is below 0.2% of all detonator types sold during this period. Perhaps 20 million will have been used underground in South African gold, diamond and platinum mines. These will have been produced by South African companies, in South Africa for South African customers. Here efforts have met with greater success and in 2003 fully 5 million, or 3% of local detonators sold, could be of an electronic type. However, it is estimated that about US$7.00 (R50.00) has been expended on R & D, manufacturing facilities and marketing, for each unit so far sold. Large sums of money continue to be spent. Despite the apparent success in South Africa, is it justified? Electronic initiation systems have not produced significant technical benefits to the end-user underground nor corporate profits to the supplier. Some doubt they ever will (even from the large surface operations where the price per unit is much higher). A conclusion might be that they have failed. In 1998 Smit and Pistorius wrote a paper titled “Implications of the Dominant Design in Electronic Initiation Systems in the South African Mining Industry”. This ISEE paper seeks to summarise and review the conclusions of the earlier work. These were: that a dominant design had not yet emerged; the type of connector and the way in which detonators are connected and programmed would be a strong determinant influencing the development of a “winning” product; technical aspects rarely solely determine which becomes the dominant design (marketing, social and economic factors often have a strong influence); electronic initiation systems were an emerging technology for the underground gold mining industry in South Africa and because it was under severe cost pressure the mines would look to them to raise productivity and hence profits; finally, as a dominant design begins to emerge, one could expect a number of players to exit from the industry.

Jan 1, 2004

By Randall M. Wheeler

Pre-blast surveys are used to document the condition of a structure prior to the commencement of blasting activities. They provide the best means of determining the pre-existence of visible cracking and deterioration in a structure before blasting is initiated. A small investment in a good pre-blast survey, coupled with good public relations, could mean a large cost savings for a company in the future.

Jan 1, 1992

By Jeon Jeon, Yong-Kun Choi, Chung-In Lee, Yong-Hun Jong, Hag-Soo Kim

In this study, a computer program to design tunnel blasting pattern has been developed. The program consists of two parts; one is for tunnel blasting pattern design and the other is for blasting modeling to estimate the peak particle velocity, the distribution of fragmentation and the excavation damage zone. We modified the design method of tunnel blasting pattern suggested by Langefors because it provided undesirable pattern in blasting practices such as considerably large center cut and too large burden for Vcut as drilling length increased. As a result, the burden and spacing were reduced to practically appropriate amounts. In addition, the correlation between rock mass rate, RMR, and rock constant in blasting, c, was analyzed based on the data collected from twenty three tests of tunnel blasting. It was concluded that the correlation between them was fairly good enough to be applied in cut design. In order to check the validity of the modified methods and their practical applicability, test blasting was carried out at two different tunnel construction sites in Korea. The results were satisfactory in that the average rate of advance was 90% and the overbreak did not cause additional support. Futhermore, the developed program is capable of estimating peak particle velocity by using (a) the existing vibration equations, (b) the vibration equation obtained by test blasting to check out the practical applicability of the designed blasting pattern. Feedback is implemented into the program to adjust the designed blasting pattern and control the vibration.

Jan 1, 2005

By Christopher Laughton

A new underground laboratory is under construction at the recently closed Homestake Gold Mine, Lead South Dakota, United States of America. The Deep Underground Science and Engineering Laboratory is designed to meet the needs of an international group of scientists and engineers interested in conducting fundamental and applied research at depth in the Earth’s crust.

Jan 1, 2011

By Anders Lagerkvist, Agne Rustan, Tommy Edeskar

Landfills containing house hold waste produces methane gas during its decomposition. This gas can be recovered and used for heating purposes or as fuel for vehicles. Gas drainage pipes are installed in the landfill and connected to a central suction point. Methane gas is produced over several years until the slots in the drainage pipes are clogged by black mud. And the bottom of the vertical drainage pipe are filled with mud and water. The hypothesis tested in this paper is if blasting in the drainage pipes could activate the production and flow of methane. In the first part of the paper we have studied what maximum linear charge concentration could be used in different size of PE-pipes place vertical on surface and surrounded by air. The results show that the maximum linear charge concentration for single blasts varied between 5-10 g/m, depending on the diameter of the pipe (90, 100 and 160 mm). Maximum charge concentration for the repeated blast varied between 2-5 g/m. In the second part of the paper we study what maximum linear charge concentration could be used in situ for full scale blasting tests in a special prepared test area which later on was dug out after the blastings. Up to 40 g/m could be used without damaging the top of the 160 mm diameter pipes. The increase in methane flow was so low so it could not be measured c4.5 m3/h. The conclusion therefore is that the stimulation of methane flow by explosives is not enough.

Jan 1, 2000

By Charles Zdazinsky

Many blasting applications in the mining industry demand that the hard rock being blasted remains structurally competent. For example, pre-splitting is a common technique to reduce fracturing, and operators of dimension stone quarries use this blasting method to eliminate overbreak. When pre-split design parameters are not applied correctly, there will be a redistribution of stresses within the rock, resulting in Blast Induced Rock Damage (BID). Advances in geophysical technology are enabling blast technicians to monitor BID and then use the results to correctly design their blasts.

Jan 1, 2011

By D. Swanson

Cold Detonation Physics (CDP) is a patented new field of explosives and the name for the explosive that is produced when non-toxic dry ice (frozen carbon dioxide) is combined with powdered metals such as magnesium and aluminum, which are non-toxic and nitrogen-free. The explosive is detonator-sensitive and detonates according to the rapid reduction of carbon dioxide back to carbon, which produces solids comprised mainly of metal oxides and about 5% carbon. CDP was determined to produce a maximum of 300 liters of carbon dioxide per kilogram (4.81 ft3 /lb) and about 1.5 liters of carbon monoxide per kilogram (0.024 ft3 /lb). Both these figures shift according to metal content where higher metal produces less gases. According to theoretical modelling, the relationship between static pressure and metal content was determined to be an inverse parabolic curve with optimum pressure at 25% to 31% metal, depending on the type/s of metal/s used. Velocity of Detonation (VOD) was determined by measuring light at the wavefront with fiber-optic cable inserted into a series of holes drilled into the side of a 3-inch diameter (76 mm) schedule 40 steel pipe containing the mixture. The highest VOD was observed at 25% magnesium and measured between 2,500 to 4,500 m/s (8202 to 14,764 ft/s) when initiated by a 454-gram (1-pound) booster and an electric detonator. A 25% 50:50 alloy of magnesium and aluminum sample shot at a higher velocity than magnesium, according to how the alloy generated smaller pieces of shrapnel when compared with shrapnel from a magnesium test. CDP, using 25% alloy, was tested for blasting limestone by drilling 3.5-inch holes (89 mm) and inserting a 3-inch x 4-foot cardboard tube (76 mm x 1.22 m) with the mixture, packed to a density of 0.62 g/cm3 . The blast was initiated with an electric detonator, behaved like ANFO with more energy and fractured rock sufficiently across the entire length of the borehole. Seismic analysis determined that CDP produces lower ground vibrations than traditional explosives.

Jan 1, 2024

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 Robert Jacob Cefalo

In 2019, the Bingham Canyon Mine, owned by Rio Tinto Kennecott Utah Copper Company, mined through the active underground that dewaters the pit. The active underground required the limitation of vibrations to avoid catastrophic damage or damage that would require work to the shotcrete and additional roof support. The surface design of the current sector was mined next to and through portions of the active underground.

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