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By Carlos Agreda

A general review of the comminution theory and also the general differential equation of the comminution are described, analyzed and discussed in order to be applied to rock blasting. Some size distribution functions are reviewed and discussed to determine which of them represents better the cumulative low size distribution F(x) as a function of the nominal particle size (x), for the rock blasting fragmentation. Based on the mathematical comminution model before presented a formula to calculate the burden (B) is developed and discussed.

Jan 1, 1994

By Sam Taoum, Omar Riahi

Few tools allow for accurately tracking ore dilution after blasting. Existing methods often rely on data analysis or linear interpolation of velocity, which can be imprecise and less effective in varied geological settings. A promising alternative is the use of numerical simulations, which involve complex mathematical calculations incorporating real physical data about explosives and geological characteristics. These simulations can model blast-induced fragmentation and subsequent ore dilution with greater accuracy, providing detailed insights into blast dynamics by considering factors such as explosive type, blast pattern, and rock properties. Numerical simulations integrate data from sources like seismic sensors, blast monitoring equipment, and geological surveys, offering a holistic view that single-method approaches cannot match. By simulating different scenarios, mines can predict the outcomes of various blasting strategies, optimize blast designs to minimize ore dilution, and maximize recovery. Advanced numerical simulations enhance the prediction of fragmentation distribution and size post-blast, crucial for effective dilution control and maximizing ore recovery rates.

Jan 21, 2025

By Thomas Barkley

Mining tradition holds that a parallel round underground can not be any deeper than it’s smallest face dimension. ln other words, a mine using a 12’ (3.7 m) high by 24’ (7.3 m) wide room and pillar mine, the deepest pull that can be achieved is plus or minus 12’ (3.7 m). After experience with decking of rounds in a 12’ (3.7 m) diameter shaft to achieve more than 12’ (3.7 m) advance per round, the concept of deepening the pull on horizontal parallel rounds seemed to be a feasible concept. Tests were conducted in a conventional room and pillar metal mine with a round size of 12’ (3.7 m) high by 24’(7.3 m) wide. Standard rounds were drilled with a 16’ (4.9 m) steel as parallel rounds to an average depth of 14.5’ (4.4 m). The average depth of pull on these rounds was about 13’ (4.0 m). Using the available drilling equipment, 20’ (6.1 m) drill steel was used to drill holes to an average depth of 18’ (5.5 m). Five rounds were drilled and shot with a resulting aven$e pull of 16.2’ (4.9 m) or 90 % of drilled depth. Rounds were designed with decked bum cuts to maximize depth of pull in the cut area An innovative method of de&mining drilling accuraq was used to estimate it’s effect on depth of pull in the rounds. This method used a standard automatic 35-mm camera and scaling to determine the average drill deviation for many of the holes in the rounds.

Jan 1, 2000

By Dale S. Preece, Lee M. Taylor

Computer simulation of the physics involved in conventional rock blasting can be split into two phases; transient stress wave propagation and rock motion. Because the two phases involve totally different mechanisms and time scales, they must be numerically modeled with two different computer programs. The first phase is usually modeled with a finite element or finite difference code which treats the rock ss a continuum and simulates the transient stress wave and subsequent fragmentation of the rock. The second phase is usually modeled with a distinct element technique where the rock mass after fragmentation is no longer treated as a continuum but as a finite number of distinct particles that interact with each other through collision mechanics.

Jan 1, 1989

By Gregory S. Parker

The explosives community has seen tremendous technological advances during the past several decades. When this industry was in it's infancy and even past, Powder Monkey's defied the odds by relying on daring and cunning to unleash the power contained in nitroglycerin and black powder. Unlike the manufactured improvements, there has been little in professional evolution amongst the blasting fraternity unless provoked (for the most part) by the government. It is the intent of this author to advance the cause of an industry wide training and certification program, uniform in nature and broad-based enough to be voluntary, giving states whose outstanding programs are already in place, the opportunity to provide input. In creating this type of atmosphere, grandfathering, reciprocity and accessibility would be paramount. With ISEE taking a firm leadership role during the inception and NICET's involvement in the administration, the idea postulated here is intended to spark interest and debate, bringing the inception of such a program to the forefront.

Jan 1, 1995

By J. Schoonover, A. Moore

In the explosives industry, individuals face a multitude of hazards while working in mines, quarries, and construction sites. Safety becomes an ever-present driver as companies attempt to control costs, promote quality service and products, and grow business all while ensuring employees return home safely every day. One of the most challenging hazards that threatens the goal of absolute safety is flyrock. Ensuring that a blast does not result in rock leaving the blast area, thereby creating a danger for personnel in the vicinity, can be complicated due to the multitude of factors. Shot design, geology, operational procedures/techniques, explosive products, security plans, communication methods, and drilling practices can all adversely affect the safety of individuals helping execute a blast through an increased risk of flyrock. Flyrock can also pose a major threat to the public and other non-blasting personnel in proximity. Like many other industries encountering various challenging hazards, the explosives industry has recently adopted innovative technologies to help mitigate the risk of complex hazards such as flyrock. Specific applications of Unmanned Aerial Vehicles (UAVs), commonly referred to as drones, employed in the explosives industry can help reduce the likelihood and severity of a flyrock incident. This paper explores a case study and theories of how the integration of drone technology within blast security plans, mine planning, blast design, design auditing, and blast area clearance procedures can help to decrease the risk of a flyrock event through the provision of data and information previously unavailable. Multiple opportunities exist during a blasting operation to gather data using drone technology. It is these data-gathering opportunities that can be leveraged to be maximally equipped for the mitigation of flyrock. Better data from drones can be sourced and used in security plans and clearance measures as well as utilized during mine planning and blast design. Increases in the quality and quantity of information during these crucial steps of blasting has proven to be an effective way to increase the peace of mind for explosive end users. This peace of mind, along with design flexibility and adherence to performance, is why the integration and utilization of drone technology is key for effective flyrock risk reduction

Jan 1, 2024

By Michael S. Wieland

Underground coal-mine explosives (permissibles) can be substantially degraded by the underground stress waves from the explosion of neighboring borehole charges. This cross-borehole interaction generally yields the worst receptor (impacted) charge performance when the borehole separations are too close. For explosives which recover, the receptor degradation is worst when the delay until firing is small. Except for a poor quality muck pile or unreacted cartridge fragments, degraded charge malfunctions of this type are difficult to detect in coal-mine delay blasting. A simulator which reproduces the underground wave/receptor charge interaction and special underwater donor/receptor tests were utilized to study this transient desensitization problem. Test results revealed reductions in receptor energy output, delayed transitions into detonation, inferior reaction rates, or sympathetic reaction responses from the impaction. Tests on detonators showed reduced tip-strength, abnormal functioning times, or sympathetic firing as a result of transient impaction. The cross-borehole desensitization and sympathetic reaction response problems warrant concern because they are logical mechanisms for raising the risk of hazardous mining conditions, including blown-out shots, flyrock, charge deflagration, and methane/coal dust ignitions.

Jan 1, 1987

By Charles B. Ingram, Neil E. Gehrig

The development of water gel explosive products has been the single most important development in explosive research and development since the invention of nitroglycerine and dyne-mite many years ago. m e Explosives Department of Gulf Oil Chemicals Company has been engaged in the research, development, manufacturing an marketing of slurry explosives and blasting materials for over twenty years. Explosive research and development is being carried out at the Jayhawk Technical Laboratory and the Underwater Testing Facility near Pittsburg, Kansas. There are fourteen manufacturing facilities geographically located around the country to serve the mining, quarrying, and construction industries with a complete line of explosives, blasting agents, and accessories. This paper discusses the Gulf slurry products, their properties, and uses.

Jan 1, 1977

Bloomfield Collieries Rix’s Creek Mine is an open cut coal operation located in the Hunter Valley region of Australia. The mine produces approximately 1.1 mt of saleable product per year and routinely employs cast-blasting practices for its unique dragline-truck overburden excavation method.

Jan 1, 2006

By Sterling Ziegler, Kameron Ray

Mining operations at a Wyoming coal mine were progressing to within 300 feet (91 meters) of a high pressure natural gas pipeline. Vibration levels from cast blasting were at a point at which standard designs would exceed permitted limits and could potentially damage the pipeline. Without a confident vibration model, mining would be unable to continue in the pit rendering an entire cut of otherwise mineable coal sterile. To safely blast in the area, linear superposition seedwave analysis techniques were attempted to be used to create a model that could accurately predict the vibration at the pipeline. Four signature holes were fired individually. The four signature waveforms were monitored at eight discrete locations to create thirty-two vibration data points. Two of the monitors were equipped with triggers enabling the calculation of p-wave velocity.

Jan 1, 2018

By Richard W. Watson, Julius Roth

The Bureau of Mines has recently completed a contract study of the hazards associated with surface mining.! Part of this effort involved an analysis of surface mining accidents associated with blasting activities. For this purpose, 71 reports of accidents investigated by the Bureau of Mines or the Mining Enforcement and Safety Administration (MESA), covering the period from 1962 to 1976, were collected and analyzed. In addition, blasting accident frequencies for the period 1973-1976 were extracted from the central computer files maintained by the Health and Safety Analysis Center (HSAC) in Denver, Colorado. This paper presents a preview of the findings, which are treated in more detail in the final report.

Jan 1, 1978

By D K. Joyce, B Mohanty

"A variety of initiation modes are currently in use. This includes initiation by single ormultiple detonators and boosters, by detonating cords of varying strengths, and bycombinations of cords and boosters. A lack of clear understanding of the role of initiationon detonation characteristics often leads to under-utilization of the explosives system inblasting. This paper reviews the current practice of initiation in packaged and bulkexplosive products. It illustrates the effect of various types of initiation on energy releasecharacteristics in emulsion and ANFO, through calibrated underwater energy tests. Itcompares energy release under end-inidadon against side-inidadon condition for variousinitiator strengths. The effect of confinement on these characteristics has also beeninvestigated. It is shown that side-initiadon by detonating cord results, in most cases, insignificant degradation of detonation properties. This study also provides guidelines forselecting the optimum mode of initiation for various blasting situations."

Jan 1, 1993

By Walter Jr Duke

The security of explosive materials is a vital concern to every mine, quarry and contractor engaged in blasting. Proper construction of magazines and sufficient locking mechanisms are the fundamental means of maintaining secure storage. The object of this paper is to review the proper methods of construction of storage facilities for explosives as defined by the Alcohol, Tobacco, and Firearms regulations. Subpart K subsection 55.208 and the Institute of Makers of Explosives recommendations.

Jan 1, 1991

By Janos Foldesi, Calvin J. Konya

The determination of the number of primers necessary to efficiently initiate an explosive column charge is essential to good blasting. If the number of primer is insufficient, the total energy stored in the main charge will not be released. On the other hand, the use of too many primers will be counterproductive and raise the blasting cost. Tests were conducted by the authors to determine the correct priming procedure for a basalt quarry. This paper describes the results of those tests.

Jan 1, 1976

By Martin Chenoweth

The Metropolitan Water District of Southern California (MWD) is undertaking one of the nations largest water management projects. The Eastside Reservoir Project is being built to insure a supply of water to Southern California in the event of earthquake damage to the aqueducts supplying the region. An 800,000-acre-ft lake will result from the three dams, closing off the valley between two parallel ridges. The single largest contract of the project, the West Dam, was awarded to the joint venture of Atkinson Construction Co., Washington Construction Co. (Morrison Knudsen Co.), and HB Zachry Co. Over 50 million bank cubic yards of rock must be drilled and shot on this contract alone. AWZ relies on the TechBASE database management system for documenting drilling and blasting. The database format of TechBASE allows all production parameters to be linked to the location of the activity. This allows parameters such as drill penetration or boulder production to be analyzed for geologic trends that can either be exploited or dealt with. Shot locations are stored as 3D polygons in a polygon table. Production and cost data are stored in flat tables. Shot names are unique and link the polygon table to the flat table. This allows typical database queries to be made by date, location, cost or any production parameter. The output from these queries can be presented in table, graph and as map formats. The map output is particularly helpful in quantifying geologic conditions and blast performance. The ability to transform the data into information has been very helpful. The ability to present this information graphically has been invaluable.

Jan 1, 2000

By J P. F Warkentin, A W. Bauer

Recently, significant improvements have been made in both blast design methods and blasting accessories. The introduction of extremely accurate blast delays now allows proper implementation of advanced blast designs. Thus the onus for future blasting improvements has moved from blast design to the need for ensuring that explosives quality is of the highest order. One measurement commonly used to assess explosive performance is the velocity of detonation (VOD).

Jan 1, 1991

By Y. Hirosaki, H. Hamashima, Y. Itoh Kato, S. Tanaka

The emulsion explosives show non- ideal detonation behavior, and its detonation velocity can be controled by selecting the size and adjusting the quantity of voids involved. To establish the technology to control the detonation characteristics of the emulsion explosives, some experiments have been carried out using resin balloons of five different sizes ranged from O.OSmm to 2.42mm in the average diameter. Detonation velocities of the emulsion explosives containing resin balloons of different size and quantity were determined for the charge diameter of 20-50mm. The detonation velocity at infinite charge diameter was compared with calculated ideal detonation velocity. The emulsion explosives containing large (0.5mm or larger) balloons showed big discrepancy between the measured and calculated detonation velocities, and the fraction of ammonium nitrate reacted in the reaction zone was estimated to be significantly low. It was shown that the reaction zone length was proportional to the size of voids involved. The critical charge diameter was determined for the emulsion explosives containing different resin balloons at the various explosive densities. It is large for the emulsion explosives containing large voids, and it was shown that the critical diameter is proportional to the distance between the void surfaces, not to the void spacing, the distance between the centers of the voids. The reaction rate of the bulk emulsion matrix seems to be the major factor that affects the critical diameter than the specific surface of voids. Good relationship between the critical diameter and the reaction zone length was observed.

Jan 1, 2000

By Michael S. Wieland

This report discusses measurement techniques utilized in and trend results obtained from research on delay blasting malfunctions in underground coal shots at the U.S. Bureau of Mines. Charge malfunctions occur during delay blasting in underground or surface mines, rendering the explosive operations more hazardous and less productive. Modern instrumentation techniques reveal several types of reduced charge performance, resulting from cross-hole interactions. Two receptor (wave-target) charge malfunctions were detected in fourteen shots that were undeniable. There were other receptor charges that exhibited under-performance by registering out-of-tolerance or noticeably reduced detonation rates. Delay blasting generates tremendous shock waves and rifting forces that fracture and heave the surrounding stratum and unfortunately damage remaining unfired charges. This report contains two graphs, representing roughly 1% of total records, that show donor (wave-source) charge shock waves and rift (reaction-to-heave) compressions. These debilitating wave impacts precipitate modes of reduced charge performance ranging from weak detonations or misfires to sympathetic detonations. As recognized from previous research, impaired charges react poorly, perform less useful work, and yield fumes with atypical higher toxicity.

Jan 1, 1995

By Wang Xuguang Shen Yingfeng

Structure is the main aspect affecting the performance of emulsion explosive. Calculation of such structure parameters as osmosis pressure, interface area per unit volume etc. must be helpful to the understanding of the structure of emulsion explosive. This paper has solved the Laplace-Young Equation for simplified monodisperse emulsion system by Galerkin method, and gained the relationship between mean curvature, contact angle, volume fraction, fractional film area and interface area per unit volume. The paper also presents a new expression of osmosis pressure at non zero contact angle.

Jan 1, 1998

By Paul E. Thompson

Current magazine regulations are designed to avoid injury or property damage caused by accidental detonation as well as to store explosives securely. The primary emphasis appears to be the avoidance of unintended detonation or in the event such detonation occurs, the avoidance of damage to surrounding property. Adherence to these regulations largely serves the purpose intended but has caused difficulty in magazine sitting in built up areas. To the extent that magazine siting is too heavily restricted, other more significant dangers such as storage of explosives in more dangerous and less secure places may be encouraged. In summary, the regulations have served rural magazine locations well but may need further study for urban settings.

Jan 1, 1990