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By Jack Eloranta

Proper selection of stemming has a profound effect on blast performance. This paper describes several methods of evaluating stemming performance in 16-inch blastholes. Tests are done on stemming ranging in size from nominal 1/4" crushed rock up to railroad ballast size rock (2 1/2" > diameter < 3/4"). Concrete plugs (both pre-cast and poured) are evaluated as well as air decking.

Jan 1, 1994

By Feng Shuyu Yang Nianhua

According to the results of high speed photography tests, particle velocity measurement tests and the digital calculation with TP2 software, the shape of shock wave, the declined laws of the shock wave propagation speed and the peak particle velocity are described and analyzed in detail. New viewpoints about the theories of blasting fragmentation based on analysis of the progressive pictures of the fracture region are given. The formula for calculating the depth of fracture regions is established on the basis of the new viewpoints.

Jan 1, 1997

By Michael Wieland

Three laboratory tests were developed for rating the wave-impact ruggedness of cap-sensitive explosives that are used for blasting in underground coal mines. Destructible pipe fixtures, called simulators, reproduce the shock wave or rift compression registered during the cross-hole wave interactions. The rift-compression fixture was modified to render quasi-static desensitization, when utilized with a remote air supply. Waves that were recorded near charge explosions show narrow pulses resembling underwater shock waves, followed by wide, weak humps, called rift compressions.

Jan 1, 1996

By Michael S. Wieland

This report discusses the U.S. Bureau of Mines research regarding the desensitization and malfunction of cap-sensitive explosives deployed in underground coal mines. Delay blasting in underground coal generates severe shock waves and rifting forces that fracture and heave coal. These dynamic interactions can damage other charges still remaining in the delay pattern. The debilitating impacts precipitate degrees of reduced charge performance ranging from misfires to weak detonations or out-of-sequence firings. Damaged charges react poorly, perform less useful work, and/or generate atypical fumes with higher toxicity.

Jan 1, 1993

By Dale L. Ramsey

Blasters in the field for years have been faced with the task of plotting blast locations for future reference and calculating scaled distances or seismograph placement from maps,aerial photo's etc.'With the constellation fully operational, GPS provides a satellite signal transmitted to a ground receiver which will display the desired coordinate positioning worldwide, 24 hours a day in any kind of weather conditions. There are a variety of GPS receivers available with varying levels of accuracy. The field trials of a handheld navigational quality instrument for plotting blast and seismograph locations along with other necessary industry related data is the basis of this paper.

Jan 1, 1994

By Clarence Zink

Aside from the mechanical properties and process of actual rock breakage, rotary drill bit performance is affected by several “post breakage” items: cuttings size, flushing air pressure, flushing air volume, cuttings load, drill hole geometry, etc. We all recognize that more efficient drilling creates bigger cuttings, more air pressure cleans the hole bottom better, more air clears the cuttings from the hole, and a better hole geometry allows cuttings to escape with a minimum of “regrind”.

Jan 1, 2006

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

By Dale Ramsey

Located in the Chestnut Ridge Mountains of Southwestern Pennsylvania, the Casparis mine named for the founder Kenneth Casparis operated from 1916 until the early 1950. producing crushed stone for construction and railroad ballast. The rock was transported by aerial buckets to a railroad tipple nearly 1000’ (304.80 meters) below the mine. The mine property is now owned by the Pennsylvania Game Commission and is located in the Loyalhanna limestone seam with 4 primary entries that are approximately 40’ (12.19 meters) high by 30’ (9.14 meters) wide and extend over 2 miles (3.22 kilometers) into the mountain.

Jan 1, 2006

By Hu Wenjun

This paper changes the section of copper of copper to aluminum adapter bar into aluminum plate covered one face or double face with copper coat, and changes the conductor material of knife switch, fuse box, plug and socket into steel plate covered one face or double face with copper plate, and manufactures the composite (two layers or three layers) metal plates by means of explosion welding with the plates installed horizontally. Introduced in this paper are the blasting designing technique, manufacturing process and the electrical performances of the explosion bonded products. Besides, this paper presents the designing and manufacturing technique of cumulative charges and their time detonating units for cutting off the retired nuclear submarine pipes. Experiments on cutting off the stainless steel pipes by cumulative flow and on the time detonation are made. Keywords: explosive welding, electric, explosion bonded products, retired nuclear installation; pipe; blasting cutting; cumulative charge; time detonation

Jan 1, 2000

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 Otto E. Jr Crenwelge, Timothy A. Peterson

We have developed a site-specific method for analysis, prediction, and control of ground vibrations induced by overburden blasting operations in surface coal mines. Field tests conducted at R&F Coal Company have verified our approach for obtaining signatures of the overburden vibration characteristics at locations of interest near the mine, selecting the optimum excitation frequency for minimizing vibrations, measuring and synthesizing multiple-charge excitation signals for minimizing vibration amplitude and duration and controlling frequency, accurately predicting the multiple-charge vibration response in both the time and frequency domains, and accurately controlling the blast detonation to achieve the predicted vibration control. Initial field studies also indicate that by minimizing the vibrational energy radiated from the blast zone, and by optimizing the number of charges detonated per delay period as allowed by this technique, more effective use of the explosive energy is obtained within the blast zone itself for improving overburden fragmentation, swell, and cast. In all of the phases of this technique, including actual blast detonation, personal computer hardware and software have been verified for use in either field or office environments.

Jan 1, 1986

By Detlef Sulzer, Winfried Rosenstock

"At the end of this century a great breakthrough in the field of blasting technology is finally going tobecome reality. That, in the true sense of the word, is the long expected and desired “HighTechnology Blasting”. So far trials have been carried out in Australia, Africa and Europe with remarkable results, that have been predicted by the authors. As a result, significant reductions of explosives and drilling expenditure are emerging for the future."

Jan 1, 1999

By William F. Skully

An effective explosives storage program involves selection of a storage site, checking zoning and special permit requirements, acquisition of the storage site land, determining correct layout for required storage units, selection of storage units, construction of storage area, obtaining licenses and permits, and storage site operation.

Jan 1, 1976

By Paul D. Dupree

This paper discusses the drilling and blasting techniques used in blast casting at a large western coal stripping operation.

Jan 1, 1986

By J Lyall Workman, Peter N. Calder

Flyrock can be a serious hazard associated with blasting. Many surface blasting accidents involving injury result from excessive flyrock beyond the protected blast zone. Numerous cases of equipment damage at the mine, quarry or construction site have resulted from flyrock. Fragments propelled beyond the property limits of the operation have also caused injury and damage.

Jan 1, 1994

By Ronald L. Sanders

The prevailing view of the coal mining industry by government officials is: "Tell everyone you're coming - Don't let anyone know you're there - And remove all evidence you have ever been there". Now the irony is that the government inspectors are just enforcing the law. The coal mine operators seem more interested in genuine reclamation than the inspectors.

Jan 1, 1979

By Qingshou Chen, Gongbo Li, Hengqian Ran

A method for safe fracture of rock, concrete and other brittle solid material using dynamic water pressure by explosion is provided. The propagation of the pressure is studied with Allievi water hammer theory. Wave equation and velocity formulas of the pressure propagation are shown. The dynamic water pressure is tested in the lab. The propagation of the pressure is simulated by MMIC-2D. The results of fracturing rock in the lab and on a quarry are presented.

Jan 1, 2000

By Donald D. Eilers, Pharis E. Williams, Thomas O. McKnown

The Continuous Reflectometry for Radius vs. Time Experiment (CORRTEX) system was developed by the Los Alamos National Laboratory for determining the energy released in a nuclear explosion by measuring the position of its shock front as a function of time. The CORRTEX system, fielding techniques, and the methods and software for data reduction and analysis were developed over a 15 year period with hundreds of measurements made on nuclear tests and high explosive experiments. CORRTEX is a compact, portable, fast-sampling, microprocessor-controlled system, based on time domain reflectometry, requiring only a 24 volt power source and a sensing element. Only the sensing element (a length of 50 ohm coaxial cable) is expended during the detonation.

Jan 1, 1995

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 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 as 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