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By K. Ram Chandar, Vedala Rama Sastry

Fragmentation and muck pile profile together play an important role in optimizing the excavation costs for given geo-mining conditions. Initiation system is one of the vital parameters influencing the fragmentation and muck pile throw (profile). An attempt is made through this paper to study the characteristics of muck pile produced in addition to fragmentation. Two new parameters namely “throwburden ratio” and “muck pile ratio” are proposed for assessing fragmentation and movement of material. Field investigations were carried out in a limestone mine in southern India with shock tube and detonating cord initiation, using four initiation patterns, keeping other parameters like burden, spacing,delay timing etc. same.

Jan 1, 2008

By H Y. Fang, H Sutherland, R M. Koerner

Due to the increased number of complaints by property owners to blasting related industries an apparent need for a clearer understanding of blasting-related damage is needed. We feel that direct structural crack monitoring during such blasts is the appropriate measurement technique. Instrumentation and interpretation of results for taking such measurements are described in this paper. Typical results from blasting and other environmental effects are also described which can eventually be related to Fracture Mechanics principles in the hope of clarifying such disputes in an equitable manner.

Jan 1, 1976

By David Harrison, Edward J. Walter, Meitra Ferek

A pre-blast survey can be a great tool in the prevention of blasting complaints and subsequent damage claims. In today's highly competitive industry, we are always looking for ways to become more cost effective. This paper investigates the importance of pre-blast surveys not just for regulatory compliance, but as an overall long term cost cutting and public relations tool.

Jan 1, 1995

By D T. Froedge, Michael J. Nutting

A system consisting of an unlimited number of biaxial geophones that measure peak particle velocity and frequency has been developed and utilized at surface mines, quarries and construction sites. An ability to accurately measure ground vibrations completely surrounding a blast and to construct a vibration topograph has facilitated the study of blast design parameters and geologic factors on the resulting generation and propagation of the vibrations.

Jan 1, 1990

By Wang Xuguang, Kang Tingzhang, Zhang Xiaozhi, Wang Guoli, Li Ziqianga

Emulsion powder and granule explosive is produced through airflow fluidization technology by using W/O emulsion. Maintaining the microstructure of W/O emulsion, it has the advantages of both emulsion explosives, such as good water-resistance and detonation properties and powder explosives, such as low cost and east handling. The basic theory of emulsion powder and granular explosive, choices of constituents and formulation, technology for preparation, equipment and relevant parameters, product property as well as technology for safe use have been illustrated in this essay. Based on the above illustration, related factors influencing property and use result have been analyzed.

Jan 1, 2000

By Henry P. Jr Van Ormer

During any blast hole operation the first choice to be made is hole size - it seems simple, just calculate all the factors, spacing, burden, depth, rock characteristics, powder factor, etc. and you have it - Hole Size. But we all know that it is not that easy - the "hole size" is part of a system and many other situations can have great impact on the optimum production Blast Hole Size - such as crusher characteristics, hauling capability, mucking capability and - Drilling Capability!

Jan 1, 1983

It has been common practice for many years to predict and control underwater blasting effects on the basis of certain simplified theories related to the pressures generated by underwater detonations. Unfortunately, two of the most commonly applied concepts in many instances do not provide an accurate modeling of typical field conditions nor the potential for damage. One of these concepts is that the damage potential is related directly to the peak pressure generated by an underwater detonation, without regard to the time history of the pressure pulse. This belief has led to the widespread use of air bubble curtains to reduce peak pressures, without considering the effect that air curtains have on the time history of the pressure pulse. At times, this procedure can be unwise. The other concept is based on the premise that pressure pulses in solids (such as rock) will always be transmitted to nearby water bodies in agreement with the theories of the transmission of plane waves across normal (perpendicular) boundaries. In reality, such conditions are quite rare.

Jan 1, 1985

By David Lilly

The introduction of electronic caps with significantly more precise timing is forcing an examination into the practical effects of timing precision upon vibration, air blast, fragmentation and crusher productivity. These investigations have produced suggestions that techniques using multiple delays of the same period with conventional detonators might approximate electronic high precision.

Jan 1, 2006

By Douglas Anderson

In the early 1980s, a method for controlling blast vibrations other than by modifying the Scaled Distance came into use. Research studies had indicated that blast vibration could be simulated by detonating a signature hole with the vibration monitored at critical locations, and then using a computer to superpose the waveforms with varying delays. By choosing delay times that create destructive interference at frequencies that are favored by the local geology, the “ringing” vibration that excites structural elements in houses and annoys neighbors could be reduced.

Jan 1, 2008

By Farshad Rashidi Nejad, Ali Asgari, Sanaz Norouzi

Blasting is known as the first step of rock breakage in mines. An indication of the importance of blasting is that more than 1 billion kg (2.2 billion lb) of explosives are used annually in Australia and 3 billion kg (6.6 billion lb) in the United States for rock breakage, more than 85% of which is used in the mining industry. The notion that blasting, as the first step of comminution, plays a significant role in crushing and grinding energy consumption is not an unfounded thinking. It can be noted that the comminution electrical energy consumption decreases in these ways: First, if the feed size to the primary crusher is decreased, less energy will be required to crush the ore to the same product size. Second, a decrease in work index (Wi) related to additional macro fracturing and micro fracturing within individual fragments.

Jan 1, 2015

By Peter Bellairs

It is generally expected that drilling and blasting be a routine part of a mining process where the blastholes are drilled, left for a period of time and then primed, loaded with explosive, stemmed and then detonated via an appropriate surface initiation system. The occurrence of a premature detonation(s) therefore results in a great deal of consternation and disruption to the mining operation.

Jan 1, 1997

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 C. T. Aimone-Martin, V. L. Rosenhaim

The response of two structures to blast-induced ground vibrations were evaluated and compared in order to quantify the impact of different blasting operations, hard rock and soft rock blasting, upon the structures movements. The first instrumented structure was a residential type, located in the operational area of a coal mine, were blasting is conducted in soft rocks, such as siltstone and coal, with compressive strength ranging from 20 to 50 MPa. Blasting is characterized by low benches, with hole lengths averaging 5.5 m (18 ft) and low powder factors, 140 to 210 g/m3 (0.236 to 0.354 lb/yd3), resulting in very little horizontal movement of the rock during the blast. The second structure was a commercial building, located in a basalt quarry (compressive strength between 109 and 180 MPa), where blasting is conducted in 12 m (39.4 ft) benches with powder factors ranging from 200 to 350 g/m3 (0.337 to 0.590 lb/yd3). Velocity sensors were placed on the structure walls to measure wall displacements and calculate blast-induced strains in the walls, and these results were compared with the driving ground excitations. The calculated strains were compared with the limits of rupture of the cement grout used as mortar between bricks and as wall coating, considered to be the weakest material in the structure composition. The blast-induced response of existing cracks in the structures were also measured using displacement gages and compared to the daily influence of weather fluctuations, such as changes in temperature and humidity, on crack movement. The results show that for the same levels of ground motions the structures present different movement, resulting in distinct levels of induced strains on the walls depending on the geology. The influence of long-term temperature and humidity variations on crack movements on both structures is very similar, during the same seasons of the year. Crack response to long-term weather changes is 2.5 to 3.5 times greater than blast influences.

Jan 1, 2015

By Jerome S. Brower

Quadrex-L is a two component liquid explosive which was developed by J. S. Brower & Associates, Inc. to facilitate handling and shipping, and use in unique applications, while emphasizing safety. It may be advantageously used for all explosive applications. Quadrex-L can be introduced into a preinstalled container configuration and may be easily drained or flushed from these containers when necessary to do so. This characteristic can be effectively utilized to reduce the hazard period during assembly or disassembly operations.

Jan 1, 1975

By Shad M. Sargand, Manseok Chang, Glenn A. Hazen

Customarily, peak particle velocity of surface wave vibrations has been the recommended criterion for the prediction of blast damage to structures. Currently blast spectrum and natural frequencies of a structure have been also recognized as important for predicting damage potential. While others have considered the importance of structural frequencies, they have not analyzed the structural response spectrum when establishing damage criteria.

Jan 1, 1992

By Ettore Contestabile, Cameron Thomas

Implosive-type electrical/mechanical connectors such as XECONEX have been used extensively for joining electrical transmission lines. This implosive action of explosives has also been applied to other forms of high energy metal working with excellent results. However, as with many other products, the inherent blast energy of these units has caused some environmental concerns especially when used in proximity to inhabited areas.

Jan 1, 1995

By Laurence Neufville

Proper risk assessment and blast design are very desirable to the execution of a blast. Not only will this ensure that it achieves its desired outcome, but the probability of complaints and litigation will be reduced. Blasting engineers rely heavily on site-specific data for analysis and input to the blast design equations, and therefore data collection is critical to this process. The traditional approach to data collection is to carry out site-specific reconnaissance by visiting the site, but the time spent doing so can be reduced if a remote sensing approached is adopted.

Jan 1, 2009

By Chen Aiping, Wei Banyun, Chen Canchang

"The gaseous explosives consisting of combustible gas and combustion-supporting gas wereused in the opening end of a steel pipe and the ignition was in the closed end of the pipeusing continuous air feed within the permissible length limit of industrial equipment, theexperimental results show the mechanisms of forced transition from combustion todetonation and what is the effective equipment for the transition."

Jan 1, 1993

By Greg Rappard, Francois Holowenczak, James Rickard

The King George V (KGV) Shaft forms part of MTR Corporation Limited (MTRCL) Works Contract 703 extension of the underground West Island Line on Hong Kong Island. The Shaft and the associated adit was the sole access to excavate the running tunnels. Originally during the Detailed Design stage, it was concluded that blasting was not feasible at the KGV Shaft due to the close proximity of sensitive receivers in the form of residential buildings, electrical cables and hospitals. As a result, the Contractor planned to excavate the Shaft using mechanical means with a programme time of seven months. The Contractor appointed a Sub-contractor to analyse the feasibility of excavating the Shaft by blasting. The Sub-contractor reviewed the proposal and recommended the use of an innovative blasting technique that had never been previously employed in Hong Kong. The Sub-contractor recommended the Shaft be blasted using DetNet electronic delay detonator technology, manufactured by AEL Mining Services in South Africa, with an initial 1.5m depth of water ballast covering the blast face. The electronic delay detonators provided initiation accuracy to ensure there would be no overlap between sequentially detonating blastholes. The water ballast makes use of the effect of energy lost through the shock front causing the water to break up into droplets creating a spray dome resulting in the attenuation of the energy imparted into the surrounding rock mass. Various tests have demonstrated that both the maximum overpressure and impulse density are significantly reduced when water of a minimum depth is in direct contact with detonating explosives. This innovative blasting technique reduced the excavation programme by three months, saved HK$5 million in direct costs and totally mitigated the impacts on the public and other stakeholders nearby the KGV Shaft. Peak Particle Velocities (vibrations) rarely exceeded 2-3mm/sec (0.08-0.12in/sec) at a distance of 30-40m (98-131ft) from the blast location and air overpressure levels were reduced below the Hong Kong target level of 120dBL. In total, 24 blasts were fired with an average advance of 1.6m (5.25ft) with an average powder factor of 2.03kg/m3 (0.127lb/ft3) to 1.84 kg/m3 (0.114lb/ft3). The initiation pattern had 5ms between sequentially detonating blastholes and 20ms between adjoining rings.

Jan 1, 2013

By Dave Harrison, Phyllis Hasser, Ken Eltschlager

The beginning There was the video:– “Understanding Vibrations from Blasting” – 2002 to 2004 in development – Dale Ramsey ad hoc Public Education committee chair – Available At the ISEE bookstore Public Education and Public Relations Committee • Standing ISEE committee 2004 • Co-Chairs – Ken Eltschlager, Dave Harrison • Purpose: "Develop and conduct programs on public education and public relations. Public education programs will focus on public awareness, understanding, and appreciation of the explosives industry. Public relations programs will concentrate on providing blasting professionals with the tools to assist in the public's understanding of the explosive industry and in the appropriate ways to respond to local community issues."

Jan 1, 2007