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By K Ramachandra Rao

Joints, fractures and other structural defects bring anisotropic character Into a rock mass. Conventional methods of blast design In a rock mass consisting phyllites, mica schist etc., which are characterised by the presence of closely spaced, nearly vertical planar Joints, result In formation of large slabs which cannot be handled by the excavation and loading equipment without resorting to secondary blasting. Frequent secondary blasting Is not only expensive but also, Is a source of environmental hazard. Interruption of production cycles frequently, leads to uneconomical mining. This problem could be minimised by designing blasts which produce forces whose components along and across the joints/fracture planes Is lust sufficient to break the rock mass In both directions. Rock mass strength can be assessed from field and Laboratory tests. Projecting structural features with respect to bench orientation on a stereoplot helps In assessing magnitude and direction of force vectors required to fragment the rock mass to the desired size range.

Jan 1, 1995

By Valerie A. Rhodes, Catherine T. Aimone

Often blast damage litigation involves structural damage which clearly is not blast related. The fact that structures are observed to be damaged when blasting has taken place in the near vicinity of these structures does not necessarily mean that the damage was caused by blasting. If careful blasting and seismograph records were kept by the blaster which decisively indicate damage is not blast related, then other causes of structural damage need to be assessed. These include problematic soil characteristics and long-term changes in climate or subsurface soil moisture. This paper presents the evaluation process required to investigate soil problems leading to damage often attributed to blasting.

Jan 1, 1991

By Katherine L. Heineken, Timothy J. Tope, Kim David Murphy

One method for small arms disposal is the use of a deactivation furnace or explosive waste incinerator. There are numerous hurdles a facility typically encounters to get the furnace or incinerator fully operational and permitted. For example, one Department of Defense installation was in the permitting process 7 years, which included numerous facility upgrades and modifications. This paper will discuss the technical approach for proactively addressing permitting issues and requirements and will identify potential pitfalls to avoid as well as ways to reduce costs. For example, when determining the waste profile, the facility should forecast its treatment needs (taking into account the net explosive weight limits of the furnace/incinerator) and then classify the wastes into "chemical families" based on the type and composition of the wastes. One waste from each family should then be selected for potential inclusion in the trial burn. Modeling the waste disposal can help to narrow down the number of wastes requiring characterization during a trial burn, as well as the number of analyses.

Jan 1, 1997

By I. Petropouleas, J. Croll, R. Bassett

A programme of tests on controlled internal explosions to a class of circular reinforced concrete columns, has allowed the relationships between the blast energy and the extent of local damage to be understood. These tests have also demonstrated the important additional effects on the damage levels of preexisting axial loads.

Jan 1, 2006

By Mike McGill, Steven P. Case, Mark Spaulding

The General Crushed Stone Company at Doswell VA. decided to open a new pit to expand their reserves. The elevation of the property was 136 feet above the present primary crusher. The project required driving twin tunnels under the highway to access the primary crusher from the new property. A shaft was needed to pass blasted rock to the tunnel elevation where it's loaded and hauled to the primary crusher. In addition, a ventilation shaft was required to provide adequate airflow. Dynatec Mining Contractors Inc. Lakewood Colorado was subcontracted to handle the tunnel and shaft development.

Jan 1, 1993

Casting design for bench blasting in surface coal mines is a new focus and a fairly recent success. This study aims at the development of a mathematical model to predict the throw of overburden material based on geological conditions of a bench and charges in blast holes. The procedure, derived on the basis of blasting theories and dynamics of the multiple-particle system, explores the mechanisms of casting rocks into pits. Implementing the model with a computer program is a part of the study. The computer program will supply quantitative data for evaluation. It serves the purposes of verification for the model and, hopefully, field applications.

Jan 1, 1988

By A Gene Riggs

The Cerrejon Coal Project in Colombia, South America is one of the largest coal mines in the world. The mine is located in northeastern Colombia on the La Guajira penninsula. The area is in a remote valley 132 miles east of the city of Barranquilla.

Jan 1, 1984

By Lawrence C. K Hu

The release of load mechanism during rock breakage by explosives was founded by Dr. T. N. Hagan & published at the Sixth International Colloquium on Gasdynamics of Explosions and Reactive Systems Stockholm, Sweden, 1977.

Jan 1, 1995

By Rodger Andrews

High cost - low productivity mining methods at the Homestake Mine forced the need for a new and safer means of ore extraction. Vertical Crater Retreat (VCR) was introduced in 1978 and accounts for over 50% of the underground mine production today. Many advantages can be attributed to this form of "bulk mining"; including steady production, decreased labor costs, and the ability to mine bulk stopes in the lower portion of the mine. However, safety and high productivity are the two major advantages. This paper will deal specifically with crater blasting and the application of mass blasting techniques in Vertical Crater Retreat slopes.

Jan 1, 1988

By Juan Carlos Vasquez, Romel Villanueva

We present the results of our field research on the variation of the density of the gassed explosives and their influence on the blasting results in the Peruvian mines: Yanacocha, Toquepala and Antamina. Currently, 90% of Peruvian mines uses gassed explosives, for their economic and technical benefits. But new practices and design criteria have had to be adopted, and the most important a careful control of the in-hole density, whose variation in the depth of the hole strongly affects the detonation process.

Feb 1, 2020

By Karl E. Burger

Recently an experiment was completed at the Golden Sunlight Mine, a property owned by Placer Dome Inc. of Vancouver, British Columbia, to measure the Body Waves entering their highwall created by blasting. The purpose of the study was to assess the damaging effects of blasting on the highwall, in order to further slope stability. Stress and Strain experienced in the earth that is created as a result of blasting can be determined by knowing several important pieces of information. These include the compressional and shear wave particle velocities initiated by blasting, the Body Wave travel velocities in both the shear and longitudinal direction, and the densities of the rock in question. A series of equations based on wave theory can then be used to determine the stress and strain affecting the highwalls. The Blasting Engineer can then use this information to design blasts that create peak particle velocities less than levels that maintain the integrity of the highwalls. This paper first discusses the experiment used to measure the Body Wave velocities. It then traces through the subsequent calculations necessary to generate the information needed by the Blasting Engineers, the Mining Engineers, the Geological Engineers, and the Geophysicists to design blasts and develop open pit plans to alleviate unstable highwall conditions.

Jan 1, 1989

By Joe Strobbe, Kevin Joe

The U.S. Bureau of Reclamation awarded PCL Civil Constructors the project to build a new visitor's center and parking lot structure at the Hoover Dam. The excavations for these structures present many blast design challenges. The visitor center, a 30 foot deep excavation was blasted in the Nevada side of the canyon wall, 600 feet above the existing power plant. This excavation also included a through-cut underneath the existing road that carries the traffic over the Dam between Nevada and Arizona.

Jan 1, 1993

By Floyd W. Crump

New technology in video equipment, such as Super Video Tapes, Super Video Camera Recorders equipped with high speed electronic shutters, and VCR's with editing capabilities make it possible to resolve high speed events to still frames with an event elapsed time of 17 milliseconds (ms). This is far from the 2 ms resolution available with a High Speed 16 mm Film Camera such as the LOCAM at its maximum 500 frame persecond speed, but is adequate for many field blast evaluations.

Jan 1, 1991

By Jianjun Tang, Wenjuan Bai

This paper presents a new method of formulation design for multi-component composite explosives. Based on the thermochemistry of the detonation process, the mathematic model of formulation design is established by optimization mathematics. Using the heat of detonation as target functions and taking the constraint conditions such as oxygen balance and costs etc into consideration, this model can provide an optimal solution quickly by means of personal computer. Using this method, the calculation and the simulation tests for a series of constituent sets and various constraint conditions can be conducted easily. In this way, the optimal formulation for the explosive can be determined, on the basis of the maximum heat of detonation and the lower cost.

Jan 1, 1997

By Anderson Meireles, Vladimir Carrasco, Carlos Feliciano

Adopting new technology in drill and blast requires a structured implementation process, as it represents a significant change in a traditionally conservative industry. It involves addressing initially unknown implications. As the problem is not yet acutely felt, developing a market strategy must be approached from the customer’s perspective, considering how the product can optimize their activities or enhance flexibility. To achieve this, it is essential to have a comprehensive understanding of the context of the customers identified in the deployment process pipeline. This paper discusses aspects of introducing wireless initiation technology - the initiation of primers through a magnetic field without physical connections - in Brazil. Additionally, it presents a case study of the application of a structured process of sales with purpose in an underground mine. By identifying key opportunities that were highly profitable for the client, the necessary awareness was created, leading them to recognize the technology as an enabler for exploring their mineral deposits in a new way which allowed a successful change management process. Based on the applicable technique, a preloading project was developed to maintain inaccessible areas with high-grade precharged with the area loaded with wireless primers acting as a temporary pillar and controlling dilution throughout the orebody. Once the excavation of the stope was completed, the pillar was successfully blasted and the material - once considered lost in the original plan as a rib pillar - was recovered after serving its structural function. Through this method, the metallic recovery of the stope increased without dilution losses. Demonstrating economic viability and stablishing the previously unknown technology as a strategic tool for optimizing stope recovery.

Jan 21, 2025

By Charles G. Wade

In the ensuing years nitroglycerin-based dynamites will continually be replaced by water-based explosives. Until recently, the choice of a high explosive water-based product was limited to some type of water gel. Now, there is another choice. New emulsions are available having several degrees of sensitivity over a wide range of diameters. This paper discusses the properties of these new emulsions, e.g., physical and thermochemical; the relationship between diameter and explosive properties; and the effects of aluminum on total energy. There is also discussion of some of the unique properties of emulsions, their advantages, and how they differ from water gels.

Jan 1, 1978

By Nan Lee, Stephen H. Chung, Peter Lienberger

INCO Limited's Thompson Open Pit has researched extensively into improved blasting techniques towards increased productivity as well as optimum pit wall protection. Blasting with excessive amounts of explosives near the pit wall can induce severe back-break, new cracks and opening-up of existing joints in the wall. These ill effects can reduce the wall slope stability and restrict mining activities.

Jan 1, 1992

By Rene A. "Moose" Morin, Craig Copping

Innovative concepts in drilling and blast design have been used to remove deteriorated concrete and have enabled contractors to reduce costs and time on St. Lawrence Seaway rehabilitation projects. Time is of the essence on these contracts since the Seaway system is only available for this work during the winter freeze up. Unique electrical sequential initiation systems and specially modified drilling equipment have been used to accurately remove a narrow slice from the 83 foot high lock walls. These new methods successfully reduced demolition time, minimized overbreak and adhered to strict vibration limits.

Jan 1, 1986

By G G. Paine, C V. B Cunningham, G Harries

The companies of the ICI Explosives Group have successfully used a wide variety of internal computer codes including BOBCAT, KUZ-RAM, ICRAX, XPLODE, BLEND, 3CRACK, MICBLAST, DETON, etc. In recent years the extensive experiences across ICI have been combined into a single compatible model engineered to worldwide technical service and customer needs for the prediction and assessment of blast results.

Jan 1, 1987

By Cathy Aimone-Martin

The City of Henderson, Nevada is experiencing extraordinary population growth. Some residential development requires blasting to be conducted at close proximities to high-value houses. Blastingrelated concerns voiced by the community residents include dust, noise, fears of damage to residences, and claims of insufficient controls exercised by the blasters. Residents perceive geological conditions are adverse to the protection of structures at the current vibration regulatory limit of 0.5 in/s. Airblast limits are 120 dB. Vibrations felt within structures leave home owners with the perception that damage is taking place. New cracks appearing in homes at distances far from the blasting are being blamed on blasting.

Jan 1, 2007