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By Karl Kure, Anders M. Heltzen

Mixtures of prilled ANFO and 0,5 - 3 mm polystyrene balls are interesting substitutes to the tube charges or other types of reduced explosives or detonation fuses. Experiments have shown detonation ability even of a mixture of 95% bolt polystyrene balls and 5% ANFO. The gas and shock energy in the mixtures decrease proportional with the content of polystyrene. The detonation velocity shows higher values than expected for mixtures with more than 50% (vol.) ANFO.

Jan 1, 1980

By Timothy D. Stark

Blasters are usually strictly liable for injury or damage caused by flyrock (trespassory invasion) and blast-induced vibrations (non-trespassory invasion). The application of strict liability to non-trespassory invasions has resulted in significant litigation that has hampered the use of blasting and the blasting industry. Stark (2002) proposes that blasters should not be held strictly liable for non-trespassory invasions but should be liable only if their conduct is proven to be negligent. This change in legal standard was proposed because improvements in blasting technology over the last thirty years allow blasting to be conducted without substantial risk of harm to property and thus the amount of harm imposed by a blast can be related to the level of care exercised by the blaster. It is anticipated that negligence standard will reduce the amount of litigation because a plaintiff will have a greater burden to overcome. To facilitate the acceptance of negligence standard by a court of law, this paper illustrates the application of the negligence and strict tort liability frameworks using actual cases in which a decision was rendered. It is evident from these cases that some of the successful claims under the strict liability framework would not have been successful, and probably not litigated, under a negligence framework, which could result in substantial cost savings to the blasting industry and consumers.

Jan 1, 2004

By Mark Roberts

Automation, data analytics and optimisation are key trends in the mining industry. Doing more, and better, while expending less resources targets KPIs around efficiency and productivity. With the explosion of data, the next step is to develop an optimal level of processes and systems to harness this data to support value-in use decisions. Typically, significant amounts of resources and effort are invested to develop realistic simulation models. However, models are frequently not integrated with existing systems, and therefore are underutilised. When we consider the specialised process of blasting, integration with upstream and downstream processes is a significant driver to realise sustained improvements and value. The application of genetic algorithms and cloud computing to solving complex mining problems has advanced over the last 15 years, in particular with mine scheduling. Genetic algorithms are unique in that they support true multi-objective optimisation, utilising population-based methods to present trade-offs between multiple solutions. Secure in-cloud processing speeds up the processing, with results delivered in timeframes that are not feasible with desktop computing.

Feb 6, 2023

Blast performance is related to rock structure and strength, as well as to factors such as site geometry, drill patterns, explosives loading, firing sequences and delays.

Jan 1, 1986

By Jerry R. Wallace

Infrastructure improvements and industrial plant expansion and modernization often require rock blasting within 20 feet of existing structures. In many instances trenchlines must cross beneath existing in-serv1ce utility lines.

Jan 1, 1994

By Rowland Jones

This type of quarrying is very much different from that of established quarries in developed countries, demanding somewhat unorthodox techniques to produce the variety of materials required. The demands on the resourcefulness of-the quarrymaster can be very testing, and produces quite a different breed of individual than what is normally met in managerial status in quarries of developed nations.

Jan 1, 1977

By Tom Medak, Don H. Cranney, G Paul McKay, R Douglas Reid

Explosive initiated afterblast dust explosions can occur in high sulfide ore mines when the flame generated by the detonating explosives ignites the sulfide dust produced from the blast, from previous blasting, or from other mining activities. The dust explosion can be a devastating, self-propagating fireball that will damage or consume any flammable object in its path. Damage to ventilation tubing is a frequent occurrence. These explosions also produce large quantities of sulfur dioxide and other noxious gases that can take several hours to clear from the mine. Thus, these occurrences can result in substantial losses in productivity to the mine.

Jan 1, 1994

By Ruilin Lang

This paper presents an application of 3-D plots and non-linear regressions to define a sitespecific form of the charge weight scaled distance. The PPV (PPA) of single hole blasts is normally considered as a function of two independent variables - the charge weight and the distance. It is of great importance to obtain the relationship of the function accurately for a concerned site in terms of blast vibration analysis and modeling. However, in pre-computer time it was difficult to plot 3-D graphs. Consequently, a charge weight scaled distance was used to plot the PPV (or PPA) against the scaled distance as 2-D graphs. Blast vibration investigators use several forms of the charge weight scaled distances to plot data. We can exemplify them with the cube root of charge weight scaled distance, the square root of charge weight scaled distance, and other forms (Hossaini and Sen, 2004). Each of these scaled distances assumes relative contributions of the charge weight and the distance to the vibration attenuation. For example, the charge weight is assumed to have a less contribution to vibration in the cube root scaled distance than it is assumed in the square-root scaled distance. In reality, for different sites the relative contribution of the charge weight and the distance may be different and site-specific. This may explain that in some cases, the blast vibration data plots using these charge weight scaled distances are scattered. This could be largely due to the fact that the definition of the form of the charge weight scaled distance is not adequate for the particular site condition.

Jan 1, 2006

By R W. Givens

Comparison tests were performed on 6 emulsion concentrates, 3 microballoon sensitized emulsion concentrates, and 2 water gel concentrates from 8 different sources with ANFO used as a control standard. Variables measured include density, detonation, velocity, detonation pressure, calculated borehole pressure, viscosity, and lead cylinder deformation for blends of 15%, 30%, and 45% concentrate and AN/ANFO blends. Comparative results are presented for detonation velocity vs. deformation, and percentage of inherent air vs. deformation for these blends. It was hoped that these tests would serve as a tool to facilitate the comparison of different manufacturer's concentrates in AN/ANFO blends for equivalent performance characteristics and to help evaluate these products on an equal basis for bid solicitation purposes.

Jan 1, 1990

By Bryan Papillon, Karl Christopherson

In order to improve vibrations from quarry blasting, a new technique and timing pattern was established and applied to the particular geology. By shooting a single representative borehole one full second ahead of the production blast, a signature waveform can be isolated and analyzed. Multiple productionsignature blasts were performed. Encroaching residences require quarries to adjust their blasting techniques to reduce vibrations and raise frequencies. A signature hole inherently poses problems to quarries. Blasting one single hole from a production bench poses safety issues to wall stability; vibration issues to close neighbors; and budget issues to the quarry operator. Results showed that the new timing pattern reduced vibrations through timing optimization without a loss in quarry production. Therefore, this technique of vibration analysis employing a production-signature hole is successful in creating a timing pattern that meets the quarry’s goals.

Jan 1, 2008

By Cathy Aimone-Martin, Frank Achuff

The New Mexico Department of Transportation (NMDOT) and the Federal Highway Administration (FHWA) have let a contract to Sierra Blanca Constructors for a design / build contract along 38 miles US 70 in Lincoln County, New Mexico. The project will improve safety of travel along the corridor and facilitate the adopted economic development goals of the state. Proposed improvements include widening the existing highway from two lanes to four lanes, providing left turn lane options at selected locations, improving access for businesses and residences, aesthetically enhancing retaining walls, improving storm drainage and replacing the existing pavement with a 30 year mechanistic imperialistic perpetual pavement design. The US 70 Hondo Valley highway project is situated in a narrow valley with steep limestone walls, passes along a Scenic Byway and numerous historic ranching communities with structures that date back three centuries. The scope of work included requirements to monitor and mitigate blasting, noise, and vibrations. The contract was very presumptive with regard to blasting design and procedures. These included visual impact mitigation to treat and stabilize slope cuts, the Migratory Bird Treaty Act protecting roosting and nesting birds from airblast, and the protection of historic and cultural features such as acequias, wells, and structures. Public involvement affecting the rock blasting design has come from citizen task forces and committees concerned with highwall aesthetics and preserving the scenic byway and cultural resources. Constraints placed on the blasting program from agencies and the communities are often at odds. For instance, blasting must produce stable yet natural-looking walls to preserve aesthetics. Restrictions have been placed on pre-splitting and smooth-wall blasting yet safe slope are of the highest priority. This paper presents details of the design/build process undertaken by the contractors to conduct blast rock in an environmentally sensitive region. Blast designs consistent with good construction practices and used to comply with the many federal and state highway stipulations are described.

Jan 1, 2004

By Takeo Ueda, Masashi Nakano

We have developed a new blasting system remotely controlled by an electromagnetic firing method, which has proved advantageously applicable to sites where rapid tidal current or deep water may cause serious troubles in underwater blasting operation by a conventional method.

Jan 1, 1983

By Curtis G. Kremer, Jeffrey L. Brummert

Blue Circle Cement's Ravena, New York quarry mines approximately 6.7 million tons of limestone per year. Blasting occurs approximately twice a week on three separate benches. Shots average 60,000 tons but can range up to 140,000 tons. Ongoing scrutiny of the drilling and blasting program allows for maximum blast efficiency which results in lower overall mining and crushing costs. Close cooperation between management and explosives supplier assures Blue Circle Cement's objective, "To develop, implement, and continuously improve a measurable drilling and blasting system that will optimize the total mining and crushing costs while ensuring compliance to safety and maintaining or reducing the environmental impacts of blasting".

Jan 1, 1994

By Saeed Karimifard, Saman Nouranian, Shahram Tafazoli, Bahram Sameti, Frank Chu, Caitlin McKinnon, Tetiana Konstantynivska, Glen Turner

We propose a particle size analysis solution for haul trucks that does not impact current operational workflows. Using artificial intelligence (AI) and 3D imaging technology, our solution reliably localizes and identifies haul trucks as they drive by, then accurately calculates the particle size distribution of the visible material in each truck load. In this paper, we identify the challenges of designing and implementing the proposed solution and explain the strategies we employ to overcome these. We also discuss a method for boulder detection that leverages the existing deep learning architecture to significantly reduce crusher downtime caused by oversized rocks

Feb 1, 2020

This is the story of a blast - not a large blast by todays standards as it only involved a total of approximately 50 cubic yards of rock. Nor did this blast involve any new or revolutionary blasting technique or require involved analysis or the applications of rock mechanics theories. Instead, it was a blast that involved the tried-and-true principles of good blasting: precise alignment of blastholes; selection of explosives and detonators designed for the conditions encountered; extreme care in loading and hooking up and the use of several ingenious devices and techniques to achieve the proper loading and firing of the blast

Jan 1, 1976

By Robin L. Simmons

Mining in the Genesis open pit has been conducted above the active haulage and ventilation declines of the Deep Star underground mine. Production has continued in both mines. The Deep Star haulage and ventilation declines, the primary and secondary egresses respectively, had to remain open and safe for travel until the new haulage and ventilation accesses were completed. Eventually, the upper 350 feet in each decline will be removed. The declines are in relatively competent calc-silicate hornfels with several high-angle, northeast-striking, clay-filled or open-spaced fault zones that create localized areas of poor ground requiring steel sets. To maintain the integrity of the declines, blast-induced vibration levels and damage were monitored in both declines after each surface blast. Seven geophones were installed in the declines to monitor peak particle velocity and peak vibration frequency. These data helped design subsequent blasts and predict expected vibration and damage levels. Blast design modifications included reducing the pattern size, reducing the powder factor and limiting blasthole detonations per delay. While limiting blast-induced vibration, these blast design modifications had to allow effective surface mining to continue. Linear regression analysis of peak particle velocity and scaled distance was used to determine the scaled distance necessary to keep the peak particle velocity under 2 inches per second. To date, the new ventilation raise, which is also the secondary escapeway, has been established and safe conditions were maintained in the original ventilation decline. Data collection and conscientious blasting procedures continue above the haulage decline.

Jan 1, 1998

By Agus Setiabudi

East Pit Wira II Project in South Kalimantan, Indonesia with a radius of <500 meters (1,640 ft) from residential has about 454,168 tonnes of coal reserves, with a total remaining reserves of 3,369,383 tonnes (topography per end of June 2011). Thus, reserves may be lost as much as 13.48%. Therefore, it is needed to determine safe blasting technique which meets the Indonesian National Standards (SNI) No. 7571:2012 of vibration threshold, the maximum vibration of 3 mm/s (0.118 in/s) and air blast of 120 dB.

Jan 1, 2014

By Alan R. Cameron, Alastair C. Torrance

An explosives underwater test facility has been established and commissioned in the Hunter Valley, New South Wales, Australia which allows the measurement of the actual shock and gas energies of the explosive

Jan 1, 1990

By Sehoon Lee, Duhwoe Jung, Eunsu Cha, Kyeonghwan Jeong

This case study presents the effectiveness of underground rock blasting to facilitate the trench cut in the hard rock layer using a conventional trench cutter for the construction of a diaphragm wall. Rock blastings are pre-performed up to the scheduled depth and then the fragmented rocks can be easily cut using a conventional trench cutter. Two trial underground rock blastings have been performed and the effectiveness of pre-blasting is presented in terms of a cutting rate, a loss of cutter heads and an amount of overbreak. Based on the results obtained from the trial underground rock blastings, the following conclusions can be appropriate: 1) A pre-blasting of hard rock layer located in depth can help to overcome the limitation of the trench cut using a conventional trench cutter. If the hard rock layer is fragmented after blasting, the fragmented rocks can be easily cut using a conventional trench cutter, 2) The speed of cutting works was accelerated and the loss of cutter heads was significantly reduced in the sections where the blastings were applied prior to cutting. 3) The amount of overbreak, expressed in terms of the amount of poured concrete, can be reduced to some extent. However, the location of blast holes in the trench can also contribute to the amount of overbreak. The closer the location of blast holes to the edge of the trench, the more extensive fractured and cracked zone can be formed on the face of the trench. This can increase the amount of overbreak if the trench is left empty for a while.

Jan 1, 2000

By Clayton Thompson

Linear detonation wave generators (DWGs) shape a detonation wave so that every portion of the wavefront reaches the target “line” simultaneously. A projection-type linear DWG uses Gurney plate velocity predictions and Taylor deflection angle predictions to estimate the angle at which a thin projected flyer (typically metal) will impact a target. A mousetrap-style planar DWG consists of two projection-type linear DWGs working in succession to create a planar wave-front through shock initiation of each successive target explosive. The angle of deflection is critical to yielding a planar or linear wave profile. Gurney predictions, nominally accurate to within 10% of empirical results, may not yield ideal linear or planar detonation behavior when used with a grazing projection-type DWG, which typically requires accuracy within 2%. Simulations were conducted using AUTODYN hydro code to compare deflection angle prediction methods. Ranges of minimal error between Gurney and Taylor predictions and the results from the hydro code were determined, using PBX-9404-driven polyethylene flyers.

Jan 1, 2011