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By J S. Brower

Disposing of the AMDP-1, Jackup drilling rig in the Arabian Gulf.

Jan 1, 1978

By Albert van Niekerk, Mick Lownds

Overview of the UNI Tronic™ Electronic Blasting System

Jan 1, 2004

By Alday B. Andrews

A computer program called Seiswise that predicts the character and intensity of ground vibration generated by surface blasting operations was developed and field tested. The program uses the time histories of one or more pilot shots in combination with various initiation sequences to construct synthetic seismograms which are examined to select designs that will produce low levels of ground vibration.

Jan 1, 1990

By J R. Brinkmann

The South African gold mining industry presently uses four different types of explosives in stope blasting. There is general agreement that the type of explosive has considerable effect on Important blasting results such as the degree of rock fragmentation, the intensity of damage to surrounding rock, and the success of break-out at the toe of the hole.

Jan 1, 1989

By Robert B. Hopler

Hercules Incorporated has developed and introduced a totally new non-electric delay blasting cap system which utilizes a low energy gas detonation to activate the caps. Unlike any other initiation system, there is no hole-to-hole connection other than empty plastic tubing until the blast is to be set off. Only at that time, when all personnel and equipment are in the clear, is the special gas mixture introduced through the tubing. The actual time of firing is completely under the control of the operator, by pressing the fire button on the blasting machine.

Jan 1, 1977

By Mark S. Stagg, Stephen A. Rholl

The firing times of millisecond-delayed initiators are random variables that exhibit varying degrees of scatter. This scatter can cause crowding and overlap of adjacent delay periods, which results in adverse effects on safety, fragmentation, and blasting vibrations.

Jan 1, 1988

By T Weaver, R Dick, R Sivakumar, C T. Aimone

A series of small-scale crater tests were performed in concrete and sand in an effort to understand the cratering process in large-scale field blasts. The surface orientation of these tests varied from flat to a 30° slope. In comparison to previous crater experiments in competent oil shale, the crater tests in concrete produced craters similar to those in oil shale after scaling the measurements for differences in the mass of explosives among the experiments. Material strengths and the degree of brittleness had a significant effect on the size and shape of the crater. The small-scale sand tests resulted in some crater features that were similar to large explosive tests in alluvium and soil.

Jan 1, 1986

By Andrew P. Ritter, Douglas A. Anderson, Stephen R. Winzer

We have adopted a unified approach to blast design. Based on earlier research, we chose minimum relief of 3.4 ms/ft between holes in a row and 8.6 ms/ft between echelons to produce good fragmentation. A model has been created which generates the expected ground vibration frequencies from a particular delay pattern. Within the relief guidelines, blast designs have been created to shift the expected frequencies of the ground vibration above the resonant range of residential structures. A programmable sequential blasting machine was used to delay circuits. An extensive three-month seismic monitoring program determined that this approach is successful. From data collected for over a year, we have determined that crusher throughput is up about 10%, frequency modification has been largely successful, peak particle velocities have generally gone down by a factor of 2, and neighbor complaints have decreased drastically.

Jan 1, 1982

By Virgil J. Stachura, Calvin L. Cumerlato

The Bureau of Mines conducted a series of tests to develop a blasting method that would reduce overbreak and rockfall hazards at a limestone quarry in northeastern Wisconsin. Reductions in overbreak were achieved by shortening the main explosive column and reducing the explosive load in shortened stemming zones in shotholes which were to form the highwalls. Two blasthole diameters, 3 and 4 inches, were used with 7 by 7 foot and 9 by 12 foot burdens and spacings respectively. ANFO, Comsol 300, or PowerAN were used in the body of the shots and Gelmax or 40 pct extra dynamite cartridges were used in the reduced load zones. Smoother highwalls were visually apparent, however further analysis by seismic refraction techniques were performed as an aid to studying overbreak within the rock mass.

Jan 1, 1989

By Leslie Taylor, Kevin Genson

This paper reports on an experimental study of the effect that bottom shaping might have on the impulse delivered to a light armored vehicle due to a buried mine detonating beneath the center of it. The study was restricted to explosives buried in saturated sand and three parameters were varied within the study: bottom angle (0 degrees to 21 degrees), depth of burial of the explosive (1.02 mm to 12.7 mm), and stand off distance (0 mm to 38.1 mm). Six hundred and thirty six milligrams of explosive was used as the explosive load. It has been shown in previously published work [1,2] that Hopkinson scaling works well for the determination of impulse loading on a semi-rigid target plates. Therefore in terms of a full scale test using 4.54 Kilograms of explosive the parameters investigated would cover a DOB of from 19.56 mm to 243.84 mm and a Stand off distance from 0 to 734.06 millimeters. These values nicely cover those of interest to the Marines with regard to the AAV (amphibious assault vehicle). Four angles were investigated at all DOB’s and Stand off distances – 0 degrees, 7 degrees, 13 degrees, and 20 degrees. The results show that reduction in impulse delivered to the target is achieved with an angled bottom on the target plate with a major reduction occurring before the 13 degree angle is reached. Hence vehicles with quite modest bottom angles could help greatly in load reduction with very little loss in utility.

Jan 1, 2008

By Brian Wingfield, Rick Givens, Greg Williams

Many technological advancements have been made in explosive products and applications over the last 15 years resulting in productivity and cost gains. However, the application of total energy (engine horsepower) in the majority of rotary drilling technology, has remained virtually unchanged over that period. While advancements have been made in components, efficiency, and types of hydraulic systems used on drills, the application of current hydraulic technology to improve drilling productivity has not been interactive with end users.

Jan 1, 1996

By Selwyn Pearton

Pumpable emulsion explosives have been available to surface and underground massive mining operations for decades and through their unique properties offer significant advantages through improved safety, reliability and performance. Despite their advantageous properties, the benefits of pumpable emulsions have been unavailable to narrow reef mining operations due to the void in technology necessary for their successful implementation within the challenging environment. Despite efforts to promote and enhance the safety and performance of bulk emulsions for narrow reef stoping, little research has been undertaken to advance the pump technologies required for their implementation. This has resulted in a gap in knowledge and technology and as a consequence the successful implementation of a pumpable emulsion system has consistently eluded the narrow reef environment.

Jan 1, 2015

By John L. Floyd

The use of explosive energy to displace overburden or waste material can provide substantial savings to operations which normally rely on mechanical means for material removal. To optimize the available explosive energy, it is important to quantify the rock's response to the type of explosive and explosive accessories used. During a blast, rock breakage and movement occur so rapidly that the naked eye cannot detect the details of the fragmentation process. A relatively high speed motion picture camera (500 frames per second) can provide the extended time base needed to analyze in detail the site-specific rock response to the explosive detonation. The data of importance to blast casting that can be quantified from these films includes initial face movement, trajectory of rock, and differential face velocities of the material shot. In addition, the ground swell velocities, stemming confinement, and stemming ejection velocity can be determined. The performance of explosive products and delay element accuracy can also be ascertained. The use of high speed motion picture photography and analysis can reduce the number of field trials necessary to maximize explosive performance and increase the benefit provided by blast casting, and in turn, lower production costs. This paper will discuss the methods used for data accumulation and analysis. In addition, three field studies conducted at three separate mining operations will be presented.

Jan 1, 1988

By Andrew F. McKown

Overbreak and damage to rock walls at the perimeter of rock excavation can lead to safety problems due to rock falls and additional costs due to a] extra mucking, b] extra concrete or shotcrete to backfill overbreak, c] additional rock reinforcement, d] additional water inflow and e] additional maintenance of rock walls. To minimize these undesirable effects, there are several perimeter control techniques available (i.e. line drilling, cushion blasting, pre-splitting, smooth blasting, and fracture control blasting) which control perimeter hole spacing, burden and loading to provide a smooth, stable excavation contour. Conventional perimeter control loading and hole spacing is satisfactory for massive, homogeneous formations, but when blasting in weathered or fractured rock closer spacing and very light loading is required.

Jan 1, 1984

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 S. Huang, K. Xia

The down-stream size reduction processes such as crushing, grinding and milling, represent major expenditure of energy. The present study is aimed at linking the fragmentation characteristics of the rock feed in a crusher with the physical and mechanical properties of the rock and the energy expended in the process. This is done through a modified Hopkinson Pressure bar apparatus, where both the impact velocity and energy input can be carefully controlled. A single layer of rock particles of very narrow feed size range (9 mm - 12 mm) and occupying a fixed volume in a chamber is impacted by means of a striker. The resulting fragment size distribution is determined for two different rock types (e.g. a granite and a limestone), involving single and multiple impacts, with all other experimental parameters remaining constant. The progressive reduction in overall product size and detailed fragment size distribution curves are obtained through sieve analysis, for specified number of impacts. The resulting fragment size distribution is analyzed in the light two distribution functions, Rosin-Rammler and Swebrec.

Jan 1, 2015

This paper describes the circuit simulations based on SPICE of the SDI Electronic Detonator System at the system level. SDI is launching the Electronic Detonator System with a robust serial protocol exhibiting great ease in field usability and deployment. Programmable delay time with increment of 1 ms up to 10s is possible. Bus length of up to 2 km containing 1600 detonators can be utilized. This system was analyzed using SPICE simulations and an Excel-based firing model spreadsheet. The effects of wire diameter, resistivity, detonator leakage characteristics, blasting array topology (lumped, linearly distributed or branched) were simulated using the firing model. Such spreadsheet is instrumental in determining the blasting topology of any given detonator number and bus wire diameter or resistivity. Initial simulation results were interactively coupled back into making the serial protocol more robust during typical mining conditions.

Jan 1, 2006

By Carlos Pañura, Michael Geldres, Alejandro Rojas

In this current era of production in large volumes of surface mining, which demands the realization of large-scale blasting, the mining industry must deal with the impact of the vibrations generated by the detonations that are carried out daily in the mines. In this context, the need arises to minimize and control the impact produced by vibrations by determining the interference times of each generated vibration waveform. The vibration waves are produced by the detonation of the explosive charges of each blasthole, analyzing the vibration waves produced by each blasthole, allow us to determine the optimal time between the detonation of each blasthole to reduce the vibrations of the production shot. Once the optimal time is found, it is possible also, to predict the vibration of the production shot (considering times and sequences) using predictive models. The waveform recorded includes information regarding the particle velocity and the dominant frequencies of the vibration. To determine the time between holes, a graph was constructed with the values of the vector Sum VPP (m / s) vs Time between blastholes (s), once the time between blastholes “t” was found, the simulation of the output sequences continued in such a way that, by adding the single waves generated by the blasthole, it gave us a record of vibrations with the lowest level of vibrations.

By Andrea Brickey, Ethan Marcoux

The South Dakota School of Mines and Technology (SD Mines), located in Rapid City, South Dakota, is one of only a few universities in the United States that offer a Bachelor of Science in Mining Engineering. The Department of Mining Engineering and Management (MEM) at SD Mines teaches courses that introduce students to concepts related to mining, including a course covering explosives engineering. Students are taught the basics of explosives theory and application in the mining and construction industry through a series of lectures and assignments. With limited field experience, many students find some topics difficult; these include: flyrock, ground vibration, timing, and others. Some US mining schools have an experimental mine in which they can simulate field conditions and conduct hands-on training, but not all universities have such facilities. For those without, teaching certain concepts can be more challenging in a pure classroom environment. To counteract the lack of an experimental mine, the mining department at SD Mines implemented Paradigm (Version 18.4.4984.0; McKenzie, 2017) a computerbased blast modeling software to improve the learning environment.

Jan 1, 2019

By Martin Langenderfer, Sergii Chertopalov, Catherine Johnson, Vadym Mochalin, William Fahrenholtz

The high temperature and high pressure of an explosive detonation can be used for the production of nanomaterials. The controlled detonation of explosive compositions along with the collection and characterization of reaction products encompasses a process known as detonation synthesis. The primary advantage of the method of detonation synthesis is the possibility for producing monocrystalline nanoparticles with diameters of less than 10 nm. In order to successfully synthesize nanomaterials via the detonation process, it is necessary that the explosive detonation is conducted in a sealed environment. This environment when pulled to a vacuum or purged with inert gas such as argon will reduce the oxidation of detonation reaction products. Detonation synthesis testing is currently being conducted in a 1.8 cubic meters (m3) (64.3 cubic feet (ft3)) ellipsoidal pressure vessel consisting of two interlocking half shells. The testing involves the controlled detonation of cast mixtures of Cyclotrimethylene-trinitramine (RDX) and 2,4,6-Trinitrotoluene (TNT) in conjunction with siliceous compounds to produce nanocrystalline diamond and silicon carbide. Alternative detonation environments including the presence of a cooling medium such as water or dry ice to absorb residual, post detonation, thermal energy and enhance the stability of the materials being produced have improved yield. Modifications to the explosive charge composition have an effect on the type and quantity of materials that can be produced. Doping of explosive charges with various organic and inorganic compounds has shown promise in the synthesis of materials that are difficult or uneconomical to produce through other methods. This paper outlines the process development of detonation synthesis facilities. Preparation of the pressure vessel to create a suitable detonation environment for the production of nanomaterials is examined. Formulation of explosive charge compositions and considerations involving test charge initiation are discussed in detail. Experimental results and analysis from initial testing as well as plans for future research are also evaluated.

Jan 1, 2018