Airblast-overpressure levels from confined underground production blasts by James J. Olson

Cover of: Airblast-overpressure levels from confined underground production blasts | James J. Olson

Published by U.S. Bureau of Mines in [Washington] .

Written in English

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  • Blast effect.,
  • Blasting.

Edition Notes

Bibliography: p. 23-24.

Book details

Statementby James J. Olson and Larry R. Fletcher.
Series[United States. Bureau of Mines] Report of investigations, 7574, Report of investigations (United States. Bureau of Mines) ;, 7574.
ContributionsFletcher, Larry R., joint author.
LC ClassificationsTN23 .U43 no. 7574, TN279 .U43 no. 7574
The Physical Object
Pagination24 p.
Number of Pages24
ID Numbers
Open LibraryOL5169000M
LC Control Number74616003

Download Airblast-overpressure levels from confined underground production blasts

The Bureau of Mines recorded and analyzed overpressure levels for three production blasts at the White Pine Copper Mine, upper Michigan, to obtain representative data from single-heading blasts in a long, straight haulageway and to estimate the damage potential inherent in production blasts fired in close proximity to underground structures.

Airblast-overpressure levels from confined underground production blasts / By James J. Olson, joint author. Larry R. Fletcher, Twin Cities Mining.

fined or poorly confined blasts that were dominated by acoustic energy in the audible range (20Hz to 20 kHz) and that could be measured by standard com­ mercial sound measuring systems. InSiskind and Summers (32) surveyed airblast noise from conventional quarry blasting, using instruments with a.

At each of the sites, an airblast overpressure microphone was positioned approximately 1m above ground level. Blast data used for modelling The blast data used for establishing site laws is based on the measurements of ground vibration and airblast overpressure taken on three days.

The informationAuthor: Cedric Roberts. The stress on a structure from a dB overpressure produced by a blast is roughly equivalent to the stress produced by a 25 mph wind. The wind isn’t as noticeable as the air overpressure due to its slow rate of pressure change and the correspondingly minor or nonexistent rattling.

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Air Vibration Predictor helps in assessing Air vibration levels in the area surrounding the blast. The predictors support and improve compliance with blasting related planning conditions and contribute to improve blast performance and blast design. The basic characteristics of the shots (the powder factor is not available for blasts in quarry A and is not given), the predicted peak overpressure and the relative prediction errors calculated with Eq.

(11) are shown in Table 6. The absolute value of these errors is ranged from % to %, with mean of %.Cited by: Understanding Blast Vibration and Airblast, their Causes, and their Damage Potential Author: Wesley L.

Bender This document was originally presented at the Spring and Fall workshops of the Golden West Chapter of the International Society of Explosives Engineers and has been updated and revised to include new Size: KB.

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European Commission only some milliseconds and it results in the production of very high temperatures and pressures. During detonation the hot gases that are produced expand in. Theory of blast waves shows that all other blast wave parameters are can be expressed as functions of overpressure.

Formulas below are for blast wave in air at standard ambient conditions: Velocity of shock front (in m/sec, overpressure dP is in atm): Velocity of gas behind shock front (in m/sec, overpressure dP is in atm).

Environmental Blast Management Plan Document Owner Issue Number Date Next Review Date Page Environmental Advisor 00 25/07/ 25/07/ 4 of 54 1. Introduction Background This Blast Management Plan (BMP) forms part of a series of Environmental Management Plans for the Vale Integra Size: 2MB.

In ALOHA, an overpressure Level of Concern (LOC) is a threshold level of pressure from a blast wave, usually the pressure above which a hazard may exist.

When you run a vapor cloud explosion scenario in ALOHA, overpressure is the hazard that is modeled. (ALOHA does not model the threat from hazardous fragments.

audible. Elevated airblast levels are generated when explosive energy in the form gases escape from the detonating blast holes. Energy escapes either through the top stemming or through fractures in the rock along the face or at the ground surface.

Airblast Airblast radiates outward from the blast site in all directions and can travel long. center of a blast that exceeded a peak SPL of dB. None of the soldiers were wearing hearing protection at the time of the accident. The reported locations of the five individuals regard-ing the epicenter of the blast are illustrated in Figure 1.

Exposure levels from the blast esti-mated from a computer model at the ArmyFile Size: KB. Air-blast effects on civil structures. an underground magazine are confined so that the blast wave follows a restricted flow path to the portal.

one end were scaled to standard sea level. Blast overpressure time history curves were recorded by center pressure gauge. Empirical prediction on the peak blast overpressure is based on UFC [12].Based on the comparison between the experimental and empirical blast pressure-time histories as shown in Fig.

it is generally concluded that empirical method can give reasonable overpressure. Figure 1: Blast wave propagation Blast Loading and Blast Effects on Structures – An Overview T. Ngo, P. Mendis, A. Gupta & J. Ramsay The University of Melbourne, Australia ABSTRACT: The use of vehicle bombs to attack city centers has been a feature of campaigns by terrorist or-ganizations around the by: Airblast-overpressure levels from confined underground production blasts / ([Washington, D.C.]: U.S.

Bureau of Mines, []), by James J. Olson, Larry R. Fletcher, Twin Cities Mining Research Center (U.S.), and United States. Bureau of Mines (page images at HathiTrust). This work is concerned with the internal air blast resulting from firing a mm Howitzer gun in a closed test range.

The range is about meters long and has a typical cross-section of 5x6 meters. Various openings in the range are closed by steel doors. Additional Physical Format: Online version: Olson, James J. Airblast-overpressure levels from confined underground production blasts.


Abstract. Eight flush mount pressure sensors were used in a series of 3 test sequences to measure air overpressure produced by a firecracker. Overpressure was recorded at a. Airblast Overpressure Although unusual, blasting generated air waves can reach a level where they can damage buildings.

NYSDOL (12 NYCRR 61) specifies limits for airblast levels at buildings in the vicinity of blasting operations. Air waves not at a level sufficient to cause damage can disturb individuals, resulting in complaints.

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Air Blast Overpressure Although unusual, blasting generated air waves can reach a level where they can damage buildings. Air waves not at a level sufficient to cause damage can disturb individuals, resulting in complaints. Factors that affect air blast overpressure include topography, blast design, and atmospheric conditions.

noise levels are within the EPP Noise LA1 acoustic quality objectives of 45 dB(A) (day/evening) and 40 dB(A) (night). Blasting Blasted is anticipated to occur once a month.

Any blasting would occur in a fully confined blast hole, minimising the potential for excessive blast overpressure. Assuming blasting could occur anywhere. Duties of ventilation officer - underground Ventilation log book Ventilation system defects to be rectified Exposure standards Control of atmospheric contaminants Air in underground workplaces Air temperature Air sources Ventilating fans and equipment Control of air distribution undergroundFile Size: KB.

mechanics of blasting and air-blast - its concept and control while blasting Air-blast Monitoring - Placement of the microphone relative. attributable to air blast can take various pressure wave and collapsed com-forms. For example, the blast may de- pletely. Light structures and residences ftect structural steel frames, collapse were totally demolished by blast and roofs, dish-in walls, shatter panels, and subsequently destroyed by fire.

Indus-break Size: 8MB. simple, reliable method to predict low-level detona-tion overpressures and impulses as a function of dis-tance and charge weight from routine underground production blasting. Such methodology can aid in the design of air-blast resistant and economical ven-tilation control structures used for coursing fresh airFile Size: KB.

the release of the gases is a violent event that results in a high level of fly rock, shock waves and a high overpressure which produces a destructive concussion effect especially in confined spaces such as are found in underground mines.

In contrast, a tailored Nxburst™ charge produces an optimal pressurization of the hole, which results in. This information sheet provides basic information on conducting a workplace transport risk assessment.

Confined Spaces; COVID Children's Book 'Stay Safe on the Farm with Jessy' Young & Elderly on Farms. Children on Farms. @article{osti_, title = {BLAST LOADING AND RESPONSE OF UNDERGROUND CONCRETE-ARCH PROTECTIVE STRUCTURES}, author = {Flathau, W.J. and Breckenridge, R.A. and Wiehle, C.K.}, abstractNote = {Four reinforced-concrete arch structures, with the top of arch crown 4 ft below ground surface, were exposed at high overpressure ranges from.

Blasting Limit Guidelines v 4 Underground Mines Many of the risks that are of particular concern for surface blasting outside the day period are reduced for blasting in underground mines.

The risks of flyrock or excessairblast are essentially eliminated for underground blasts and there is usually no riskof unauthorised public entry to File Size: KB. The atmosphere underground is limited and confined, and is thus readily reduced to a sub-standard (or even dangerous) condition if contaminants (e.g.

gases, dusts, fumes) produced in the course of operations are not controlled, safely extracted or diluted to acceptable levels. Ventilation is used to extract and dilute contaminants.

Burden = x production blast burden (B) Uncharged length at top = 10 x D Powder factor = kg per square metre of face Do not stem holes. Fire all holes on the same delay, or in groups of ≥ 5 holes Smooth Blasting Spacing = 15 x Hole diameter (hard rock) 20 x Hole diameter (soft rock) Burden = x Spacing.

An extensive blast monitoring program has been carried out to study explosive performance and the effectiveness of blast designs in production blasts in a deep underground mine. Comprehensive monitoring of blasting vibrations through multi-station high-capacity, high-frequency accelerometers, and borehole deformation history have been the main.

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The company states that the PRO Range is as innovative as it is tough, being designed for carriers in the and tonne weight range. The production blast is performed in sub-vertical blastholes drilled in fan-shaped pattern referred to as SLC production rings.

The blast is done under confined conditions, which means that there is material in front of the burden to be blasted (either ore and/or waste rock).

The result of the confined blast is highly influenced by the Cited by: 3. The Bureau of Mines recorded particle accelerations in the mine roof produced by three types of explosives in the Pilot Knob Pellet Co.

mine, Pilot Knob, Mo. Examined were the effectiveness of cube root, square root, and two-thirds power scaling in grouping the underground blast vibration data, and the effects of mine geometry, rock type, explosive type, and charge size on blast vibration levels.The Blast Gauge® System is not intended to diagnose or treat the blast victim's first responder may use the Blast Gauge® System data to characterize the blast overpressure and acceleration the subject sustained during an explosion but will rely on standard diagnostic protocols to drive treatment of the subject’s injuries.overpressure (ō′vər-prĕsh′ər) n.

1. A transient air pressure, such as the shock wave from an explosion, that is greater than the surrounding atmospheric pressure. 2. Geology Pore or subsurface pressure that exceeds normal hydrostatic pressure at a given depth. tr.v. overpressured, overpressuring, overpressures To cause.

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