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By David E. Siskind

In the early 1980's, the Bureau of Mines published four reports of structural response and damage from surface mine blasting, vibration monitoring, and analysis methods. These findings replaced simpler and less restrictive Bureau criteria dating back to 1962 for ground vibration and 1943 for airblast.

Jan 1, 1991

By David Leidel

A revolution in hydrocarbon well completions within the last thirty years has enabled drillers to tap the resources of known gas plays in an economically viable manner and deliver to market natural gas supplies for industrial, transportation and domestic use without the importation of liquefied natural gas from verseas. An added benefit has been the convenient location of one of these gas plays, the Marcellus Shale, in the Northeastern states strategically close to a major natural gas market, namely the cities and towns of the New England and Mid-Atlantic states. As a sidelight, the development of the tight gas reservoirs and their subsequent production has created thousands of jobs in an otherwise lackluster economy.

Jan 1, 2014

By John Brulia, Grant ODell

The AIRDEK blasting method has recently been introduced as an overbreak control blasting technique. This paper discusses the use of a modified AIRDEK blasting method for use in open-face blasting to make cap stone riprap (6-20 ton size) at the Clinton Point quarry of New York Trap Rock Corporation, Lone Star Industries.

Jan 1, 1990

By Sehoon Lee, Duhwoe Jung, Eunsu Cha, Kyeonghwan Jeong

This case study presents the effectiveness of underground rock blasting to facilitate the trench cut in the hard rock layer using a conventional trench cutter for the construction of a diaphragm wall. Rock blastings are pre-performed up to the scheduled depth and then the fragmented rocks can be easily cut using a conventional trench cutter. Two trial underground rock blastings have been performed and the effectiveness of pre-blasting is presented in terms of a cutting rate, a loss of cutter heads and an amount of overbreak. Based on the results obtained from the trial underground rock blastings, the following conclusions can be appropriate: 1) A pre-blasting of hard rock layer located in depth can help to overcome the limitation of the trench cut using a conventional trench cutter. If the hard rock layer is fragmented after blasting, the fragmented rocks can be easily cut using a conventional trench cutter, 2) The speed of cutting works was accelerated and the loss of cutter heads was significantly reduced in the sections where the blastings were applied prior to cutting. 3) The amount of overbreak, expressed in terms of the amount of poured concrete, can be reduced to some extent. However, the location of blast holes in the trench can also contribute to the amount of overbreak. The closer the location of blast holes to the edge of the trench, the more extensive fractured and cracked zone can be formed on the face of the trench. This can increase the amount of overbreak if the trench is left empty for a while.

Jan 1, 2000

By David E. Siskind

In the period 1989 to 1994, the U.S. Bureau of Mines assisted the Office of Surface Mining, Reclamation and Enforcement (OSM) in studying a high-complaint situation near an active surface coal mine. As part of a review for its project report, the Bureau had to address issues on the adequacy of the safe blasting criteria and analysis procedures in its 1980 report RI 8507, Structure Response and Damage Produced by Ground Vibration From Surface Mine Blasting.

Jan 1, 1996

By Tapan Goswami, Brent Geoff

Mining multiple steeply sloping coal seams introduces challenges in terms of safety and productivity. Work on steeply sloping surfaces for the processes of bench preparation, mark-out, drilling, loading and blast tie-up, coal cleaning and recovery is inherently hazardous. Furthermore, a large number of mining cycles is usually necessary, as small rounds are required and each layer is separately drilled, loaded, blasted and excavated. This exposes personnel and machines to additional risks and also incurs higher unit costs of mining as machine productivity is reduced. A case study is presented of a mine in New South Wales, Australia where three coal seams are separated by layers of inter-burden rock. Due to the unfavourable sloping nature of the coal seams the conventional practice was to drill and blast each layer separately.

Jan 1, 2010

By Robert A. Cummings, Francis S. Kendorski, Charles H. Dowding

During the summer of 1980, a field project was carried out to determine the stability of the beautiful and dramatic natural limestone pinnacles (locally termed "Hoodoos") at Bryce Canyon National Park, Utah, when subjected to ground motions and airblasts resulting from proposed strip coal mine blasting. The concern arose from environmental considerations associated with the proposed development of a large coal strip mine which would approach within 4 miles of the park. The pinnacles range up to 150 ft in height and are quite slender, producing a fragile appearance. The remoteness and ruggedness of the area required a field camp, and 4-wheel drive vehicles, helicopters, and snowcats for support. Portable magazines were necessary to store the more than 7 tons of blasting agents and explosives required. In conducting the blasting, great attention was paid to environmental impacts. In the field, a target pinnacle was selected and instrumented with mechanical strain gages, and research seismographs that required helicopter placement.

Jan 1, 1982

By Michael Ostrowski

While the words “explosives” and “blasting” cause insurers to become apprehensive, skilled contractors using modern techniques under controlled conditions rarely cause serious damage or injury. However, blasting operations frequently result in complaints and, consequently, insurance claims. The purpose of this bulletin is to inform construction project participants of some of the measures which may be taken to reduce losses arising from blasting operations.

Jan 1, 2003

By Ronald Ticona, Anaani Huaman, Andrea Lucero

Mine-to-mill optimization begins with a clear understanding and ongoing assessment of blasting, crushing, and grinding operations. Modification of blasting practices to optimize feed size can increase a mine’s throughput. However, this is only an initial step. To optimize the entire process and fully utilize downstream equipment, fragmentation must be measured at critical points along the size reduction circuit

Jan 1, 2019

By Takeo Ueda, Masashi Nakano

We have developed a new blasting system remotely controlled by an electromagnetic firing method, which has proved advantageously applicable to sites where rapid tidal current or deep water may cause serious troubles in underwater blasting operation by a conventional method.

Jan 1, 1983

By Alejandro Rosario, Ricardo González

The restrictions imposed by the Brazilian environmental legislation regarding natural caves lead to a block of substantial amount of mineral reserves. Mining activities can released caves, as long as the company ensures that the activities will not cause any damage to them, requiring profound and time-consuming studies. Since the use of explosives in the mine are potential sources of some damage to any structures, it leads to a deep need for controlling the rock blasting activities. In this context, the maximum charge per delay used in operations close to cave regions must follow some internal blasting assumptions that have been developed during specific tests and mining activities. By the seed wave technique, it is possible to determine the behavior of a seismic wave, which travels through a rock mass and it is generated by blasting a known explosive charge. This technique has proved to be an effective tool because it is able to accurately include the physical characteristics of the rock and different lithologies. This paper discusses about modelling blasting induced vibrations in order to improve caves protection, which surround the mining operations.

Jan 1, 2019

By H. S. Venkatesh, G. Gopinath, R. Balachander, G. C. Naveen

Punatsangchu Hydroelectric Project Authority is constructing 1020 MW underground hydroelectric project in Bhutan. The project envisages construction of concrete dam, Desilting Chamber, Head Race Tunnel, Power House Complex and Tail Race Tunnel. Tunneling is one of the major activity in any underground projects as they are driven for multiple activities. By and large the tunnels are a major part of connecting networks from surface to caverns/underground working sites. Many tunnels in hydropower project are part of water conducting systems and one such important tunnel is the Tail Race Tunnel in this project and had to be excavated in thinly foliated rockmass conditions by D&B method.

Feb 1, 2020

By John Brulia

It has been said that the only thing that remains constant is change. After more than 33 years in the explosives industry, I do not take any exception to that adage. I have seen changes in people, changes in ownership of companies-both small and large, domestic and international; changes in products; changes in the way we use products; changes in the way we handle products; changes in regulations; and last, but not least, changes in our perceptions of threats to our industry.

Jan 1, 2008

By Robert Hopler

RBH Note: At the time of this price list the handwriting was already on the wall regarding the ultimate breakup of the company under the Sherman Anti-Trust Act. The brand names Atlas and Hercules, noted on page 3 of this pricelist, would become the names of the new companies created from du Pont.

Jan 1, 2012

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 Gour Sen, Peter Bellairs

Blasting conducted in rock temperatures greater than or equal to 55°C (13 1 “F) and / or in rock containing sulphide minerals and their oxidation products can result in unplanned detonations. Blasting practices involving the identification of the affected areas together with the use of speciality explosive products and rigorous attention to quality control are required to safely blast in these types of environments. Sulphide dust explosions occur in some underground mines where the primary blast results in a secondary explosion of the sulphide rock dust which propagates some distance from the primary blast area. This phenomena results in considerable damage and the generation of significant volumes of toxic gasses delaying re-entry to the affected area of the mine thereby increasing both costs and safety concerns. The exothermic reaction between ammonium nitrate based explosives and rock types containing partially oxidised sulphides have resulted in numerous high risk blasting incidents. These reactions can occur at ambient temperatures and often result in premature detonations / deflagrations causing a great deal of consternation at the affected minesite resulting in lost production and considerable expenditure to solve the problem. Rock masses at elevated temperatures can also result in unplanned detonations unless appropriate precautions are taken. This paper discusses each of these hazards, cites some case studies and details appropriate generic safe and efficient blasting techniques for each of the above applications using appropriately formulated explosive products.

Jan 1, 2000

By A K. Raina, P B. Chourdhury

Flyrock is the unwanted throw of rock fragments to excessive distances in opencast blasting. The incidence is relative in nature incorporating the distance of objects of concern like structures within and outside the mine, equipment within the mine & near the blast and persons within and off the mine. Several attempts to predict and defi ne fl yrock made worldwide could not address the problem since the phenomenon is not a regular feature in blasting. This probabilistic nature of fl yrock allows for risk calculation. CIMFR, India developed a Factor of Safety based risk criterion (10, 14) for evaluation of throw/ fl yrock in opencast mines that incorporates all the above in terms of distance and allowable limit of throw – which in turn determines the risk. The criterion provides the blaster a tool for mathematical evaluation of fl yrock risk in terms of a Factor of Safety and threat ratio (defi ned for the 1st time), thereby enhancing confidence when blasting. The method is easy to use and has been applied to several mines in India and the results are signifi cant. This paper details the evolution of the concept and its application in three limestone mines of India and the results obtained. The application of the method for defi ning a fl exible danger zone is also discussed.

Jan 1, 2008

By Roger Keller, Jason Ryan

A number of studies have evaluated excavation methods for the construction of subsurface facilities for a potential deep geologic repository for the disposal of nuclear waste at Yucca Mountain, NV. Many of these studies suggest that where TBM (tunnel boring machine) methods are not applicable and alternative mechanical excavation methods can not efficiently excavate harder rock drill and blast methods may be the most efficient means of excavation. However, a number of concerns regarding drill and blast applications have been raised in these evaluations, most notably the affects of blasting on the surrounding perimeter, as isolation of the waste by the natural barrier of the surrounding rock is a key element in the concept of a deep geologic repository.

Jan 1, 2001

By Robert Lee, Pertti Paavola

Automated vibration monitoring and web-based data distribution has proven itself on the largest single construction project ever undertaken in Finland. The excavation for the Kamppi Center Project in the center of Helsinki was completed in November of 2003 and involved the removal of over 200,000 m3 (260,000 yd3) of rock and over 1,700 individual blasts. A system was installed, incorporating 37 discrete monitoring points located throughout an underlying metro station, and other surrounding underground and surface facilities. After every blast, vibration data was automatically transferred from the monitoring network to a server database. Stakeholders were able to access and review vibration reports on a password-protected website within 90 seconds of each blast. This allowed engineers to verify that recorded levels were in compliance with established limits, before proceeding with subsequent blasts. The data was also imported into a semi-automated Scaled Distance tool for analysis using linear regression techniques. This was used to determine, and adjust for trends in blast-induced vibration.Copyright

Jan 1, 2004

By Enver Alan

In this study of applied explosives engineering the blasting applications are evaluated, which were carried out for research and development purposes at Yenisahra Station tunnels in Kartal Formation which was built with the aim of solving İstanbul's transportation problem within the framework of the Kadıköy-Kartal Metro Project. Twenty-four shots were made by using explosives in 60 blastholes that were drilled in the tunnel faces, which were located between and outside of two different faults. S

Feb 1, 2020