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By Richard J. Mainiero, T S. Bajpayee

The U.S. Bureau of Mines (Bureau) has conducted research to evaluate the firing accuracy of electric delay detonators used in surface blasting operations. Over four billion pounds of explosives and blasting agents are used every year in surface blasting in coal, metal and non-metal mines. In a typical large-scale surface blast, several thousand pounds of explosives are fired in a timed sequence using delay detonators. The delayed firing of explosive charges allows time for the fragmented rock to move out before the next charge is fired.

Jan 1, 1990

By R Holmberg, C Sjoberg, B Larsson

This paper describes the excavation of an underground naphta storage facility at Stenungsund in Sweden. The main purpose with this paper is to give an overall view of how the excavation was carried out and in what type of bedrock the storage was built. Emphasis has been done to highlight the importance of using cautious blasting to avoid blast damage in the remaining rock. Attempts has also been done in order to evaluate what the degree of Swedish cautious blasting has meant for the rock support costs during the construction period.

Jan 1, 1984

By James Ballard, Charles H. Dowding

Recent Office of Surface Mining regulations have called for pre-blast surveys of residences within one-half mile of blasting. Unless lighting effects and the multiple origins of cracks are recognized, hurried (lowest bid price) pre-blast surveys may be more harmful than beneficial. Unrecorded, but pre-existent, cracks can be noticed by homeowners during blasting under special lighting conditions. This paper discusses important factors to note during pre-blast surveys, presents data collection forms and discusses the importance of photographic technique in recording cracks (both present and previously patched).

Jan 1, 1979

By M. Gebhardt, J. Johnson, S. Rosenthal

The use of presplitting applications in an underground mine setting is a method of reducing overbreak in the rib and back when blasting occurs. Presplitting performed at the Underground Mine Education Center (UMEC) on Montana Technological University’s campus in Butte, Montana showed a dramatic decrease in the amount of overbreak incurred in the blasting process. Application of the presplitting technique occurred after presplitting presentations at ISEE in San Antonio. Presplit testing consisted of drilling perimeter holes closer together than production holes and loading perimeter holes with a combination of specialized presplit explosive and packaged emulsion with electronic detonator initiation. The ideology was to shoot the perimeter row first, to create a fracture around the perimeter, so when the main production round is shot there is less shock exerted on the surrounding walls due to the pre-fractured perimeter rock. For the test performed, the back ended up with 83% of total holes resulting in half barrels representing a remarkable result. The right rib ended up with one half barrel visible before muck was removed while the left rib did not have any half barrels visible due to a clay seam being in very close vicinity to the perimeter row. The first test blast was a great start encouraging future work on presplitting applications in the UMEC. Additional testing will continue with different combinations of perimeter hole spacing, the addition of a buffer row along the ribs, and varying loading techniques to determine the most effective presplit method for the rock type of the UMEC. Detailed test results and loading configurations will be provided in the paper.

Jan 1, 2024

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 Christodoulos Xiouris, Ali Reza, James Karnesky

A rocket parachute signal flare is often used to signal a maritime emergency. In the general operation of these devices, a solid rocket motor propels a metal body to an altitude of approximately 1000 ft (305 m). At the end of the rocket motor, a propelling charge drives a signal flare and parachute out of the metal body and ignites the flare, which then burns for approximately 40 seconds as it falls to earth. In this paper, we describe an engineering investigation of an accidental ignition of a rocket parachute signal flare, which caused injury to the user. T

Feb 1, 2020

By Phil N. Bradbury

"During a routine belt tightening of all cost centers, the management at the Martin County Coal Surface Mines, located in Martin County Kentucky felt that a thorough investigation of the drilling and blasting program could possibly pinpoint areas where the cost could be cut without sacrificing production. Upon close inspection of the drill benches it was noted that the actual layout of burden,spacing and stemming varied a bit from the actual blast design that the management had outlined for the blasters. This paper will outline the method of reducing the drilling and blasting cost at the Martin County Coal Operation."

Jan 1, 1986

By Marlyn G. King, Robert L. Martin

Blasting activities in all four pits at Thunder Basin Coal's Black Thunder Mine are focused on cast blasting. With widths varying from 190 feet to 265 feet and bench heights varying from 90 feet to 175 feet, casting efficiencies vary with different geometry's. For example, the percent cast to final in the 200 foot pit is on the average higher than the 270 foot pit. The powder factors are somewhat higher in the narrower pits, thus increasing the cost of blasting. This leads to a very detailed look at the actual benefit of cast blasting and the associated cost of these benefits.

Jan 1, 1995

By John F. Mitchell

Large production blasts involving many series in parallel have long been a source of complication. When speed and accuracy are most necessary in blast preparation an efficient and precise method of wiring is required. After loading a large number of holes and being pressured for time, due to lack of daylight, equipment shutdown, etc., an effective hook-up plan can eliminate many last minute problems. It is the intention of this paper to offer a simplified wiring proceedure which when employed can save precious time and encourage efficient and economical utilization of blasting personnel and material.

Jan 1, 1976

By Karl E. Burgher

Accidental explosions occur throughout the world. They can happen at chemical plants, fireworks plants, grain depots, or as a result of collisions involving volatile or hazardous chemicals. It is interesting, as we know as blasters, that we can take two very harmless products and mix them under certain conditions and produce a violent explosion. It is often very difficult for the investigator to determine the magnitudes of blasts after the fact. However, an estimate must be made to settle vibration and airblast damage claims. The blasting consultant or technical representative is often called upon to act as an expert to mitigate these claims.

Jan 1, 1993

By S B. Richardson, N T. Moxon, A C. Torrance

In many mining situations the energy released by an explosive is far too high and results in over fragmentation and excessive damage to the surrounding strata. Laboratory experiments have demonstrated that the shock energy of an explosive can be significantly reduced by surrounding it with an attenuating material such as a foam. The effect of this reduction in shock energy on fragmentation has been determined using model materials. A four fold reduction in the amount of minus 8mm material relative to an air decoupled charge of the same weight was obtained for a foam attenuator.

Jan 1, 1989

By Chang-Ha Ryu, Hyung Yang, Hyung-Sik Yang

Ground vibration by rock blasting causes many environmental problems to adjacent structures and human bodies. Growing concerns have been given to the effects of dynamic loading induced by blasting works near safety-related structure like nuclear power plant, hospital, broadcasting station, research institute and tish farm, etc. In order to ensure the safety, rational safe criterion should be established. It requires development of a model to predict the design parameters through more systematic measurement and analysis. Primary estimation by adequate model with general parameters will be very useful for safe design and understanding the possible hazards in advance.

Jan 1, 2001

By Bill Runner, James T. Ludwiczak

During the last few years, there has been a flood of local, state, and Federal government regulations concerning blasting. Many of the laws and regulations were written by individuals who know little about explosives, the purpose of blasting, or blasting vibration and damage. I feel that the special interest groups responsible for some of these regulations are not trying to regulate blasting, but to stop it completely by unreasonable, non-flexible, regulations. The most recent being the Office of Surface Mining regulations that are already spreading to the quarry industry and will, no doubt, spread to all blasting involving disturbance of the surface.

Jan 1, 1979

By Mike McGill, Stephen Chung, Dale S. Preece

Cast blasting can be designed to utilize explosive energy effectively and economically for coal mining operations to remove overburden material. The more overburden removed by explosives, the less blasted material there is left to be transported with mechanical equipment, such as draglines and trucks. In order to optimize the percentage of rock that is cast, a higher powder factor than normal is required plus an initiation technique designed to produce a much greater degree of horizontal muck movement. This is a significant change from normal blasting practice where fine fragmentation and sufficient muck movement were the prime requirements to permit efficient excavation.

Jan 1, 1994

By Jeff Wachendorf

As the title implies, this paper details the start of a cast blasting and the design flexibility required to satisfy different parameters encountered on a large coal mine employing cast blasting as the program has grown and evolved around the town of Colstrip, Montana. As strip ratios have increased, the need to adapt and find solutions to provide coal at a reasonable cost to the mine mouth power plants has risen. Colstrip, Montana has a long history of coal mining which dates back to the early 1920s when Foley Brothers began supplying coal strictly for powering locomotive engines.

Jan 1, 2015

By Donald H. Matthews

The Society of Explosives Engineers is an international organization of over four hundred members involved in the explosives industry, with most members being active in the United States. The regulations imposed by regulatory agencies on the explosives industry have drastic effects far beyond the industry. Since explosives are used in mining, manufacturing, construction, entertainment, and art, all phases of man's activities, including fundamental needs for survival, are affected by how efficient the industry uses explosives. We, as members of SEE, must be sincerely concerned with both the quantity and quality of government regulation, and this paper spells out some of the problems caused by regulations and offers a solution.

Jan 1, 1980

By Thomas M. Keevin, Gregory L. Hempen

Natural resource agencies, under various regulatory authorities, are challenged with permitting underwater explosive use while at the same time protecting aquatic resources. Deciding on whether or not to allow use of explosives requires striking a balance between development and aquatic resource protection. A company's goal in underwater explosive use is to select methods that are both expedient and cost effective. Use of explosives is often the best alternative for engineering reasons or economic considerations. Over and above legal requirements, indiscriminate destruction of fish and other aquatic resources is not in a company's best interests because of concerns relating to public image, as well as the need to secure future contracts.

Jan 1, 1995

By P. D. Katsabanish

Air decking applications are examined using numerical modelling and the AutodynTM code. The mechanism of damage is illustrated and discussed. Air decking is shown to provide advantages over stemming when powder factor is maintained. The current effort does not support reduction of the explosives column in favour of air decking. In a similar fashion, bottom hole air decking increases fracturing in the area of the air deck, compared to when the same volume is occupied by inert materials; however air decking does not appear to reduce the requirement for subdrilling. The apparent discrepancy between the numerical results and some field observations reported in the literature is discussed.

Jan 1, 2005

By Andre Pinsonnault, Francois Lefebvre, Yves Newman

In 1989, Les Entreprises Kiewit Ltee signed a C$32 million contract with the Societe d'energie de la Baie James, on behalf of HydroQuebec, to excavate the intake and tailrace channels for a second powerhouse at the LO-2A James Bay hydroelectric project. The multistage contract included removing three marine rock plugs. The first plug was blasted in April 1990. It was a 43 yards wide, triangular shaped wedge that projected into 18 yards of water. Located at the mouth of the intake channel, it contained over 72,000 yd3 of rock, more than twice the 30,000 yd3 found in most rock plugs.

Jan 1, 1991

By Courtney Vallejo, Rafiqul Tarefder

This study examines the effects of small scale airblast experiments on cohesive soils and the resulting ground vibrations and crater geometries. Relationships for ground vibration attenuation with soil depth and distance from the blast source were developed. The study is part of a broader research topic of understanding the vulnerability of earthen embankment dams to blast loading. Many earthen embankment dams in the United States were constructed more than fifty years ago and were not designed to withstand high-stress loading such as blast loading. These structures may be susceptible to failure and it is important to describe the response of the earthen dam during a blast event.

Jan 1, 2013