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Copyright of ESPOCH Congresses: The Ecuadorian Journal of S.T.E.A.M. is the property of Knowledge E DMCC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study shows the results obtained by PetroBlast S.A.S. Company during the damage control vibrations generated by underground blasting in tunnels and adjacent galleries as part of case studies. The research studies in more details the knowledge of principle of vibrations caused by explosions and its effect on the contour of underground structures, using numerical simulations through software applied to the registered seismic signals. We conclude that vibration velocities and dynamic stresses have an effect on different positions of the tunnel lining, considering that the maximum particle velocity (VPM) directly influences the inland of covering and maximum stresses decrease with rising from the surrounding rock. The VPM recommended safety threshold is 100 mm/s for intact coating. However, in coatings with some type of cracking, the recommended safety thresholds will be around 25 mm/s and 50 mm/s of VMP. These results provide important experiences for future research where seismic control is necessary in underground excavations considering that Colombia is a country located in the northern part of the South American Andes, it is essential to make road tunnels to access to most of the country. [ABSTRACT FROM AUTHOR]

The purpose of the study was to determine the effective values for tensions extinction coefficient when charges are detonated in the tension state model at massif of gneissic rocks from Catoca mine, in order to obtain the blasting passport for HEF-100 and RIOGEL KUPULA-S explosive substances. The methodology proposed by Pedro Alexandre for the El Cacao quarry (Cuba) was used based on Borovikov and Vaniagin's tensions extinction coefficient model. The analytical values obtained from spall and cracking radium and less resistance line from values between 1.35 and 1.5 of the extinction coefficient, are acceptable in a probable range for the experimental calculation of blasting passport in the rock massif for mining-technical conditions in which blasting works are carried out at Catoca mine. [ABSTRACT FROM AUTHOR]

The purpose of this work was to analyze the structural performance of houses located around mining exploitation sites where blasting take place. Triaxial receivers were used in monitoring and controlling the blasting to determine in a timely manner if vibration values generated inside the houses cause damage to the buildings in accordance with local and international standards. The results were obtained from data processing by means of the Fourier Transform and the Transfer Function, calculating the fundamental or resonance frequency on the house and the relative velocity spectrum, PSRV. For speed and distance parameters used, it was obtained that particle velocities for transverse, vertical and longitudinal signals generated by blasting are below the safe verge (3.0 mm / s) recommended by the regulations, so the structure of houses under study are not affected by explosions at the mining sites. [ABSTRACT FROM AUTHOR]

Copyright of Bistua: Revista de la Facultad de Ciencias Básicas is the property of Facultad de Ciencias Basicas de la Universidad de Pamplona and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bistua: Revista de la Facultad de Ciencias Básicas is the property of Facultad de Ciencias Basicas de la Universidad de Pamplona and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bistua: Revista de la Facultad de Ciencias Básicas is the property of Facultad de Ciencias Basicas de la Universidad de Pamplona and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Due to its importance and influence in the design of the blasting works taking into consideration the action of the explosion in the environment, in this work the main physical-mechanical properties of the embedding rocks are determined and the structure of the massif, constituted by gneisses, is analyzed at the Catoca mine. The density, volumetric mass, limit of resistance to simple static compression, limits of resistance to static traction and velocity of the longitudinal elastic waves were the properties determined in the massif; In the case of the structural study, with the use of the geological method, the systems and families of cracks were surveyed. As a result, the values of the aforementioned properties and the characterization of the different sectors of the mine according to their properties and cracking are offered, aspects of capital importance for the design of the blasting of the box rocks. [ABSTRACT FROM AUTHOR]

Having proper rock masses characterization is of great importance in underground mining works to make the right decisions in terms of sustenance and other tasks like is the case of drilling and blasting. Here it is proposed the built of a geomechanical table based in the GSI through which to decide the drilling grid configuration applies for each rock type. This improves production cycles and explosives consumption in blasting. This table is created from experimental trials in blasting of panels with different drilling grid geometries, the ranging from 60X60cm up 80X80 cm; and the main parameter to ensure is a maximum particle size of 30 cm after the blasting with 24.6% costs reduction. [ABSTRACT FROM AUTHOR]

The contour blasting design for section II of the Levisa-Mayarí tunnel in the East-West transfer route was developed by implementing a novel methodology, which is based on the properties of explosive substances and their effects on a rocky massif. The calculation was completed considering decoupling the detonating cord loads in the contour drill holes and the Senatel MagnafracTM compact loads for the group of cut and stringline holes. The results were: a reduction of excess excavations in the tunnel and obtaining a cross section close to the mining area required for the project with associated significant savings of time and resources. [ABSTRACT FROM AUTHOR]

In Cuba, mining of building material quarries is managed empirically. Rock extraction methods to be implemented are selected based on specialist expertise. In order to theoretically determine an adequate extraction method for conducting mining operations in the Pilon mine, a procedure was implemented. This procedure includes rocky massif structural analysis, identification of rock physical-mechanical properties and their geomechanical domains. Based on this information, it was possible to select the extraction method using the Karpuz graph. Two domains were identified in Pilon, according to which the most appropriate rock extraction methods were chosen: blasting for the first one and very hard ripping for the second one. [ABSTRACT FROM AUTHOR]

The morphology and electrochemical behavior of niobium coating obtained by thermal plasma spray process on a substrate of steel API 5L X65 was evaluated. The coating was obtained, using electrical current of 500 A, 15 g/min of powder and 2.0 L/min of argon gas. The preparation of the substrate surface was performed with preheating and abrasive blasting with alumina. After thermal spraying, the morphology of the coating was analyzed by scanning electron microscopy (SEM), while the surface roughness was evaluated by profilometry, hardness by Vickers microhardness test and adhesion by bending at 180°. The corrosion resistance of the coating was evaluated from the polarization test in 3.5% NaCl solution. The results show that the coating presented cracking and lack of padding between the plates sprayed, relative high hardness and deficient adhesion to the substrate. However, the values of current density carried by the system compared to uncoated steel were reduced. [ABSTRACT FROM AUTHOR]

At present, criteria based on empirical and semi-empiricals formulas are used to put across the cylindrical triturable cut with the compensation hole for rocks breakage in subterranean excavations of a little and middling section. They are only valid in the concrete conditions for which they were created. The triturability criterion, which is obtained starting from modelling of the strain and stress field, is proposed. Experimental blasting was carried out to validate this criterion, and the results were compared with blasting done by Langefors' criterion. It was proved that the use of the proposed criterion does not rescind the fulfillment of Langefors' one. In the designed blastings with triturability criterion, an equal or superior advance of 0,35 -0,4 meters was obtained, as well as an increase of the shot hole use in 3-5%. [ABSTRACT FROM AUTHOR]

In the laboured of the quarry of arid The Cacao is faced a problem in the primary explosions, obtaining of a high percentage of pieces with superior dimensions to those admitted by the subsequent links of the technological chain, it causes the necessity of the secondary fragmentation, which brings about numerous inconveniences and the rise in the price of all the works and the increase of the production cost. For a rational design of the explosions is required to know the physical properties of rocks as well as the action of the explosion in the medium. In this work are specified the results of the study of the action of the explosion in the medium caused by the detonation of a compact load of explosive substance. [ABSTRACT FROM AUTHOR]

Introduction. Aceros Industriales S.A. is a company founded in 1977 and works on transforming in cold ferrous and non-ferrous materials (tefilation). They used, from the beginning of the company, the chemical stripping process, due to the fact that in that time it was the only technology available. Methodology. In 2005 Aceros Industriales S.A. makes the decision of getting a world level concerning its technology, by changing its productive system and acquiring equipments for shot blasting and decalamination of brushes, thus eliminating the chemical stripping. Results. By the mechanical stripping process, a decrease of environmental damage was achieved (diminishing in DQO and mud generation, among others), a better performance of the industrial process, the incorporation of industrial incomes diminished, maintenance and operation of the shot blasting and decalamination units got easier and a saving rate of 86 million of Colombian Pesos was achieved. Conclusion. This situation showed us that cleaner production opportunities are very important for the metal processing industries. [ABSTRACT FROM AUTHOR]