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By Dwayne Tannant, Jeffrey Loeb

Blasting techniques and protective measures exist that can mitigate risks associated with flyrock and the nuisance of vibration, and overpressure. However, these are often misused or not used because there are no prescriptive regulatory requirements and typically urban blasting guidelines do not exist. The relationship between the increasingly negative publicity that the urban blasting industry receives and the existing state of regulatory control on blasting in urban environments is presented.

Jan 1, 2012

By C H. Ryu

This paper presents a simplified two-dimensional numerical model of block fragmentation in a Jointed rock mass during the late or throw stage of a blast after wave effects have subsided. The model is based on the distinct element method. Examples illustrate the approach and allow for a comparison of effects of Joint patterns on fragmentation and resulting block motion.

Jan 1, 1986

By Winston Wilches B., Scott Scovira

This paper discusses recent changes to the emulsion blend blasting agent used at the Drummond Pribbenow Mine in Colombia, one of the world’s largest open pit coal mines, and the resulting improvements in rock breakage and excavator productivity. Based on field evaluations, the use of High Density Ammonium Nitrate (HDAN) can be effectively implemented in an emulsion blend blasting agent, yielding excellent results in terms of energy release, shelf life and velocity of detonation (VOD). Field evaluations showed that formulations using HDAN exceed the performance of the actual 50%/50% emulsion/ANFO blend using Porous Prill Ammonium Nitrate (PPAN). PPAN is conventionally used for emulsion blend manufacturing, with physical characteristics to facilitate sensitivity during the detonation process.

Jan 1, 2014

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 Albert van Niekerk, Mick Lownds

Overview of the UNI Tronic™ Electronic Blasting System

Jan 1, 2004

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 Edward J. Walter

Vibration control is affected by many factors which are difficult to isolate and evaluate. Occasionally a circumstance occurs in which one factor appears to predominate and its effects can be evaluated. Changing rock characteristic or lithologic variation is one of these factors or parameters. In a recent seismic monitoring project, lithologic variation in the form of hard lenses occurring suddenly and randomly in the rock to be excavated caused sudden and large increases in vibration level. Data are presented to illustrate these effects, and procedures used to control these effects are described.

Jan 1, 1981

By Owen Collins

In surface mining, designing patterns to reduce the probability of flyrock and optimizing fragmentation through powder factor calculations are important for safe, efficient blasts. The designed powder factor is established for the blast once parameters such as burden, spacing, stemming, and powder column height are determined. In practice, these parameters are usually constant throughout a production blast with row-to-row burden and spacing. However, challenges can arise with the introduction of an open face. Many variables could necessitate the adjustment of the face row to optimize blast results. Variables include drill accessibility, challenges with toes, overhangs, and geology. The approach is often, but not exclusively, determining how to keep a consistent powder factor from the open face through the body of the blast. However, the solutions used vary case-by-case and rarely are two blasts the same. Technology has improved the ability to deal with challenging face conditions. 3D modeling with the aid of drones allows the application of angled holes to be more effective and simpler. This is just one instance where technology has improved blast results. This paper will present solutions to challenging face conditions. Thoroughly analyzing instances where challenging open-face variables were met with an effective blast solution could help provide insight as to what yields consistent blast results.

Jan 26, 2026

By Erik Nygaard

During the last years, ammonium nitrate has been involved in several accidents worldwide. This have caused increased focus on security and safety issues and resulted in:• Revised Yara standards • Revised international standards for storage and transportation • Stricter regulations from national authorities in many countries.

Jan 1, 2008

By Sushil Bhandari

Presented here is the simplified process of fragmentation of homogeneous rocks by blasting based on experimental studies. Small scale single hole blasting experiments on jointed limestone are described. Results show that directions of joints overshadow the degree of fragmentation and also influence the remaining rock. The possible influence of joints on the process of fragmentation of non-homogeneous rock by blasting is also discussed.

Jan 1, 1983

By Thomas Leonard, Philip R. Berger, Bryan E. Papillon

Bardon Trimount Inc., a large producer of aggregate, crushed stone, and concrete, was experiencing significant public opposition to its five quarries in the Boston area. It was believed by the authors that this opposition could be significantly lessened if the total number of blasts per week were reduced. Although the blasting company at these quarries, Austin Powder Company, contended that this could easily and safely be accomplished by increasing the size of the blasts, regulations precluded this alternative by limiting the total amount of explosives that could be used per blast.

Jan 1, 1996

By Philip Barnhard, Lyman G. Bahr

By recording the arrival time of a pipe wall at evenly spaced intervals in a plane perpendicular to the pipe axis, application of the equations of motion permits calculation of the pressure of the explosive acting to accelerate the pipe wall. Data observed from various non-ideal explosives are presented, together with values of pressure to be expected from thermodynamic calculations.

Jan 1, 1981

By D T. Froedge

Before this study was started, literature was searched and cases of alleged water well damage were investigated. Occurrence of ground water in Appalachia is primarily in low yield, fractured, water table aquifers. Four test sites were chosen based on geographic and geologic diversity. Test wells were drilled at each site and base line data on water quality, static water level, and drawdown characteristics were obtained before surface mining commenced. Blast-induced ground vibrations were measured at the surface by the wells at levels up to 5.44 inches per second maximum resultant particle velocity. Measurements made at the bottom of wells indicated that vibrations were considerably attenuated at depths of 140 to 160 feet.

Jan 1, 1983

By Richard J. Mainiero, James Q. Wheeler, Lewis H. Kopera, Yael Miron, Solin S. W Kwak

The research reported here was part of an effort to evaluate the safety of a process to recover TNT from MK-9 depth bombs by the autoclave meltout process. In this process the depth bombs are heated to 121oC so that the TNT will melt and run into a vat. Unfortunately, asphalt lining the inside surface of the bomb also melts and flows out with the TNT. Prior to this study, it was not known what effect the asphalt contamination and the higher than normal process temperatures (121oC) would have on the sensitivity of the TNT.

Jan 1, 1996

By John P. Ashby

Production blasting is a process of destruction of rock masses in order that ore may be extracted. Many open pit operations are faced with the apparently conflicting requirements of providing large quantities of fragmented rock for the processing plant and of minimizing the amount of damage inflicted upon the surrounding pit slopes. A reasonable compromise between these two conflicting demands may often be found by means of simple engineering of production blasts.

Jan 1, 1980

By Leslie C. Taylor, Anthony L. Kee

Computational modeling of explosively loaded saturated sand on a suspended plate is an inherently complex problem. In this study a computational method is used to predict the dynamic pressure load/impulse from a buried charge. A fully coupled code modeling the explosive charge, sand and air with a Eulerian mesh and the plate structure with Lagrange elements, such as Gemini-Dyna, is an appropriate computational tool. In water-saturated sand, the loadings are soil and water-transmitted shock and bubble or blast effects depending on the depth and the charge size. The computations provide the capability to determine the total impulse load placed on a horizontal plate on or above the soil due to an explosion in the saturated sand for different burial depths in saturated sand and different plate stand off distances. The following test case will be presented: (a) 4.5 Kg (10 lbs) TNT, 10.16 cm (4 in) depth of burial to top of charge, and 20.32 cm (8 inch) stand off distance (Test 4).

Jan 1, 2005

By William Everett, Jack Eloranta

United Taconite is an iron ore mine operated by Cleveland-Cliffs Inc (Cliffs) located near Eveleth, Minnesota. The mine, originally known as Eveleth Taconite Mines, was purchased in December 2003 by Cliffs (70%) and Laiwu Steel (30%). The mine site, known as the Thunderbird Mine, produces taconite ore for delivery by rail to the company’s Fairlane plant, located approximately 10 miles to the south near Forbes, Minnesota. At the plant, the crude ore is ground, concentrated and processed into pellets for steel industry customers. Total pellet production capacity is about 5.4 million long tons (Ltons) per year.

Jan 1, 2006

By Y Omura

If dynamite is used in hot metal mines, it may be subject to decomposition, and the increase in nitroglycol vapour under the high temperatures causes bad headaches of workers. Also the explosives containing ammonium nitrate are very dangerous when mixed with sulfide ores at a high temperature!. Therefore we developed a heat-resistant water gel explosive which is safe to be handled at these hot metal mines.

Jan 1, 1983

By Lon D. Santis

This paper presents data and theorem to calculate the risk of experiencing undesirable lightning related events while blasting or while engaged in other lightning sensitive activities. The paper provides an overview of lightning hazards in blasting operations and a brief history of lightning related blasting accidents. Lightning continues to be the primary cause of premature initiations of explosives in mining; on average, over two such incidents are reported to the Mine Safety and Health Administration (MSHA) each year. The energy contained in lightning discharges and how this energy sets off explosives in mining is presented. Three categories of lightning warning methods: public media, lightning detectors, and atmospheric electrostatic field measurement are discussed. The remainder of the paper presents recently acquired data on the spatial characteristics of lightning development. This data is used to estimate the risk assumed by blasters under certain conditions. Risk estimations are made for electric and nonelectric blasting if persons are evacuated when cloud-to-ground (c-g) lightning approaches within a certain distance. For example, about 0.6% of all c-g lightning strikes have no other c-g lightning strikes within 25 miles in the previous 30 minutes. The paper shows that a typical blaster using nonelectric initiation in a high lightning density area with a 100% accurate lightning detector set to alarm at 25 miles would have a lightning caused unplanned detonation every 14,000 years.

Jan 1, 1998

By Raimo Vuolio

"Over the past 30 years, the Nordic countries have developed similar practices for estimating damage caused by rock blasting vibrations. However, over the last few years the risk of damage has sometimes been estimated by using international values, which have created unnecessary costs, since they are too conservative. This paper gives a proposal for Finnish blast vibration standards and a calculation model for the extent of the zones for building inspection, risk analysis, and vibration measurements. The international conclusion is that particle velocity is the best descriptor for limiting damage potential for structures. Over 900 000 vibration data recordings from 52971 blasts were collected for this paper during 1970-1989. They show that the most practical description is the vertical component of the peak particle velocity. As rock is a nonhomogeneous medium, it is hard to predict the need and scope of risk analyses, building inspection, and vibration measurements. As a large number of blasts were monitored for the recording of the peak particle velocity in several locations in Finland, and the data combined, it is possible to establish safe scaled distances for the calculation of the need and scope of risk analyses, building inspections, and vibration measurements."

Jan 1, 1991