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Watkins Glen, CO, United States

Yang R.,Orica United States Inc.
International Journal of Energetic Materials and Chemical Propulsion | Year: 2011

This paper studied the density effect of the gassed emulsion product on the resistance to static and dynamic precompression. The study revealed that the resistance to precompression of a gassed emulsion is controlled by the void ratio (density) of the product. When the void ratio of the product is below 14%, the resistance to dynamic precompression is only 2000 psi (13.8 MPa), under which the product was dead pressed (failed to initiate). When the void ratio of the product is above 21%, the resistance to dynamic precompression is found to be superior to strong glass microballoon product. However, the current perception that gassed emulsion has an ability to recover from precompression to detonate within a few milliseconds aftershock is not supported by experiments. The resistance to static pressure of gassed products was also measured and found to decrease with the decrease of the void ratio ranging from 24 to 10%. Tests in the study were mainly conducted in a laboratory. A field trial was conducted with specially designed blast pattern and firing sequence. © 2011 by Begell House, Inc. Source


Yang R.,Orica United States Inc. | Kay D.B.,Orica
Tunnelling in Rock by Drilling and Blasting: Workshop Hosted by FRAGBLAST 10 - The 10th International Symposium on Rock Fragmentation by Blasting | Year: 2013

Blast vibration control is of vital importance for tunnel blasting in urban environments. Due to the expensive nature of urban tunnelling projects, it is always necessary to maximize excavation productivity while controlling the blast vibration under prescribed limits. Using field tests to explore various design scenarios is time consuming and costly. It is worthwhile to use a reliable computer model of blast vibration to assist in selection of blast design options to maximize each blasting opportunity. A project was conducted to test a blast vibration prediction model for tunnel blast vibration. A series of tunnel blast rounds were fired and tri-axial vibration waveforms from the blasts were recorded with several seismographs at distances ranging from 10 to 100 metres from the blasts. Seed waveforms were obtained from the cut holes in each round. Over 60 seed waveforms were collected and the charge weight scaling law for the signature hole PPV was established. A vibration model with Multiple Seed Waveforms (MSW) as input for a point of interest was developed in recent years by the present authors. The MSW blast vibration model has been applied successfully in open cut and quarry blasting situations. From the literature, it appears that there may not be any seed wave based vibration modeling work for tunnel blasting. In this paper the MSW model is applied to tunnel blasting and some specific issues associated with tunnel blast modelling are addressed. The capability of the model in terms of the PPV and frequency prediction is demonstrated in the paper. The paper demonstrates the MSW blast vibration model is a useful tool for managing tunnel blast vibration with the potential to optimize round by round design. A few of the design scenarios were modelled and the results are discussed in terms of managing the vibration below the limit while maximizing tunnel advance rate. Source


Yang R.,Orica United States Inc. | Scovira D.S.,Orica United States Inc. | Patterson N.J.,Orica Canada Inc.
Rock Fragmentation by Blasting - Proceedings of the 9th International Symposium on Rock Fragmentation by Blasting, FRAGBLAST 9 | Year: 2010

In an urban production quarry, blasting close to a city boundary requires management of the vibration peak particle velocity of vector sum (PVS). Blasting is required to come within 30 meters of the boundary. An optimal technical solution was obtained through an integrated approach of signature hole vibration monitoring and modeling. A series of signature holes were fired and full vibration waveforms from these holes were recorded with several seismographs at distances ranging from 20 to 100 meters from the signature holes. Following the signature hole vibration monitoring, several production blasts were monitored with an array of seismographs. A vibration model using multiple seed waveforms for a point of interest was applied to the case assisting in the selection of blast design parameters. The selected blast designs were implemented and are proving to be effective in managing the vibration below the limit while maintaining high productivity. The capability of the model in terms of the PVS of particle velocity and frequency predictions is demonstrated in the paper. With the signature hole data as the input to the model, the model prediction agrees well with field measurements of PVS of particle velocity and amplitude spectrum from production blasts. © 2010 Taylor & Francis Group. Source


Preece D.S.,Orica United States Inc. | Yang R.,Orica United States Inc. | Pilz J.,Rio Tinto Technology and Innovation | Zavodni Z.M.,Rio Tinto Technology and Innovation
Rock Fragmentation by Blasting - Proceedings of the 9th International Symposium on Rock Fragmentation by Blasting, FRAGBLAST 9 | Year: 2010

An overland conveyor was constructed at a surface coalmine to reduce the truck haul distance and make the operation more efficient. An important element in this system is a truck dump facility to transfer coal from truck to conveyor. The coal is dumped from above and processed through a crusher before loading onto the conveyor that carries it to the coal processing facility. The configuration of the mechanically stabilized earth (MSE) retaining wall is typical of many mining operations and utilizes a series of MSE walls surrounding a crusher to create a "pocket". The Owner requested that the potential for blast vibration damage to the wall be assessed and criteria developed to reduce the potential for blast induced damage. This paper presents the methodology used to assess such blast effects, a comparison to measured values and demonstrates the conservatism inherent in simplistic earthquake based analysis. © 2010 Taylor & Francis Group. Source


Lownds C.M.,Orica United States Inc. | Steiner U.,Orica Germany GmbH
SME Annual Meeting and Exhibit 2010 | Year: 2010

Electronic detonators have been in commercial use for a decade, with an excellent safety record. This paper lists known incidents involving electronic detonators. Typical standards required by regulatory bodies for static electricity and electromagnetic fields are reviewed. The performance of some detonators is compared to these standards; in general the minimum standards are easily exceeded. The general resistance of electronic detonators to extraneous electrical energy that can be derived from the body of test results is compared to danger levels for exposure of humans to these energies; it is shown that electronic detonators can safely tolerate higher electrical energies than people can. This comparison includes comparable data for electric detonators, which are shown to be more vulnerable to extraneous electrical energy than people are. Electronic detonators also bring significant safety benefits in blasting due to their testability, two-way communications, reliability, programmability and precision. The links between these attributes and enhanced safety are discussed with examples from actual blasting. Although electronic detonators are usually more vulnerable to extraneous electricity than non-electric initiation systems, the paper shows that the net safety benefit in handling and blasting is in favor of electronic detonators, which are the safest initiation system that has ever been offered to the mining industry. Source

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