En la presente tesis se estudia la aplicación de la técnica de voladura de pre-corte en las galerías de desarrollo de la mina subterránea MARSA para reducir la sobrerotura en el macizo rocoso, para tal efecto se considerarán los aportes que brindan las disciplinas de geomecánica, geología, perforación y voladura. La investigación se llevó a cabo en la cordillera oriental de los Andes, al norte de Perú en la provincia de Pataz, donde se encuentra el Batolito de Pataz, yacimiento de tipo orogénico asociado a procesos de metamorfismo y caracterizado por vetas auríferas; específicamente en el área de influencia de las actividades de la Unidad Minera San Andrés. Con la voladura de pre-corte se obtendrá una mejor estabilidad en las labores de desarrollo dando como consecuencia la reducción de la sobrerotura en el macizo rocoso. Se realizaron estudios geomecánicos para designar el tipo de roca de la zona y de esta manera poder realizar una malla de perforación adecuada, así como la selección de los explosivos adecuados para asegurar no afectar el macizo rocoso. Del mismo modo, se realizó la comparación de los costos involucrados en el diseño de la voladura convencional en contraste con la voladura de pre-corte. De manera teórica y cuantitativa, se demuestra que mediante la aplicación de la voladura de pre-corte es posible reducir la sobrerotura en el macizo rocoso y mejorar la estabilidad física de las labores de desarrollo. / The present thesis studies the application of the pre-cut blasting technique in the development galleries of the MARSA subway mine to reduce the overburden in the rock mass, for this purpose the contributions provided by the disciplines of geomechanics, geology, drilling and blasting will be considered. The research was carried out in the eastern cordillera of the Andes, north of Peru in the province of Pataz, where the Batolito de Pataz is located, an orogenic type deposit associated with metamorphism processes and characterized by gold veins, specifically in the area of influence of the activities of the San Andres Mining Unit. With the pre-cutting blasting, a better stability in the development works will be obtained, giving as a consequence the reduction of the overburden in the rocky mass. Geomechanical studies were carried out to designate the type of rock in the area in order to be able to carry out an adequate drilling mesh, as well as the selection of the appropriate explosives to ensure that the rock mass is not affected. Likewise, the costs involved in the design of conventional blasting in contrast to pre-cutting blasting were compared. In a theoretical and quantitative way, it is demonstrated that through the application of pre-cutting blasting it is possible to reduce the overburden in the rock mass and to improve the physical stability of the development works. / Tesis

Idag finns det ett behov för mer förståelse kring odetonerade sprängämnen i anläggningsindustrin. Dessa sprängämnen som lämnas kvar kan ha förödande konsekvenser och leda till dödsfall. Varför sprängämnen inte detonerar under sprängning kan bero på många faktorer såsom klimat, handhavandefel och fabrikationsfel. Generellt sätt är det farligare i arbeten på ett område där det har sprängts tidigare eftersom det är svårare att förutse farorna.Det saknas en klar rutin kring hanteringen av dessa sprängämnen och befintliga dokument kring kan förbättras.För att få förståelse kring ämnet behövs det studier i åldringsprocess, referensobjekt, hantering och orsaksfaktorer till de odetonerade sprängämnena. Även grundläggande information om hur bergschaktning och sprängning går till är nödvändigt.Trafikverket har därför ett påtalat behov av att skapa en rutin och kartläggning kring problemet.Målet är att underlätta hanteringen, förebygga skador och rädda liv. Odetonerade sprängämnen som detonerat under arbete har orsakat ett antal dödsfall i Sverige. Nollvisionen i byggbranschen kräver att ämnet ska lösas. I denna rapport är målet att skapa en rutin som kan underlätta hanteringen och komplettera nuvarande dokument men även analysera uppkomsten av odetonerade sprängämnen. Med hänsyn till erfarenheter och litteraturstudier ligger denna rapport som grund för fortsatta studier och forskning. / There is a need for higher understanding regarding unexploded ordnance in the infrastructure industry. These explosives that are left behind can have grave consequences and result in the loss of life. Why explosives don`t detonate during blasting may be due to several factors like climate, handling-error or factory errors. Generally, it is more dangerous to work in an area where previous blasting has occurred because it is harder to predict the dangers. There is a lack of routines for handling unexploded ordnance and current documents can be improved.To gain understanding on the matter you need to study aging process, specific cases, handling and possible reasons of unexploded ordnances. Also, basic knowledge about rock removal and rock blasting is required.The Swedish department of transportation (Trafikverket) has a strong need to create a routine and mapping of the issue. The goal is to facilitate handling, prevent damages and save lives.Unexploded ordnance that have detonated during labor have caused several deaths in Sweden.The no deaths vision of the construction industry demands that the problem be solved. In this report the goal is to create a routine and facilitate handling and to supplement current documents but also to analyze the emergence of unexploded ordnance. With regard for past experiences and literature studies this report stands as a foundation for continued studies and research.

A method to estimate blast-induced damage in rock considering both stress waves and gas expansion phases is presented. The method was developed by assuming a strong correlation between blast-induced damage and stress wave amplitudes, and also by adapting a 2D numerical method to estimate damage in a 3D real case. The numerical method is used to determine stress wave damage and provides an indication of zones prone to suffer greater damage by gas expansion. The specific steps carried out in this study are: i) extensive blast monitoring in hard rock at surface and underground test sites; ii) analysis of seismic waveforms in terms of amplitude and frequency and their azimuthal distribution with respect to borehole axis, iii) measurement of blast-induced damage from single-hole blasts; iv) assessment and implementation of method to utilize 2D numerical model to predict blast damage in 3D situation; v) use of experimental and numerical results to estimate relative contribution of stress waves and gas penetration to damage, and vi) monitoring and modeling of full-scale production blasts to apply developed method to estimate blast-induced damage from stress waves. The main findings in this study are: i) both P and S-waves are generated and show comparable amplitudes by blasting in boreholes; ii) amplitude and frequency of seismic waves are strongly dependent on initiation mode and direction of propagation of explosive reaction in borehole; iii) in-situ measurements indicate strongly non-symmetrical damage dependent on confinement conditions and initiation mode, and existing rock structure, and iv) gas penetration seems to be mainly responsible for damage (significant damage extension 2-4 borehole diameters from stress waves; > 22 from gas expansion). The method has the potential for application in regular production blasts for control of over-breaks and dilution in operating mines. The main areas proposed for future work are: i) verification of seismic velocity changes in rock by blast-induced damage from controlled experiments; ii) incorporation of gas expansion phase into numerical models; iii) use of 3D numerical model and verification of crack distribution prediction; iv) further studies on strain rate dependency of material strength parameters, and v) accurate measurements of in-hole pressure function considering various confinement conditions.

A method to estimate blast-induced damage in rock considering both stress waves and gas expansion phases is presented. The method was developed by assuming a strong correlation between blast-induced damage and stress wave amplitudes, and also by adapting a 2D numerical method to estimate damage in a 3D real case. The numerical method is used to determine stress wave damage and provides an indication of zones prone to suffer greater damage by gas expansion. The specific steps carried out in this study are: i) extensive blast monitoring in hard rock at surface and underground test sites; ii) analysis of seismic waveforms in terms of amplitude and frequency and their azimuthal distribution with respect to borehole axis, iii) measurement of blast-induced damage from single-hole blasts; iv) assessment and implementation of method to utilize 2D numerical model to predict blast damage in 3D situation; v) use of experimental and numerical results to estimate relative contribution of stress waves and gas penetration to damage, and vi) monitoring and modeling of full-scale production blasts to apply developed method to estimate blast-induced damage from stress waves. The main findings in this study are: i) both P and S-waves are generated and show comparable amplitudes by blasting in boreholes; ii) amplitude and frequency of seismic waves are strongly dependent on initiation mode and direction of propagation of explosive reaction in borehole; iii) in-situ measurements indicate strongly non-symmetrical damage dependent on confinement conditions and initiation mode, and existing rock structure, and iv) gas penetration seems to be mainly responsible for damage (significant damage extension 2-4 borehole diameters from stress waves; > 22 from gas expansion). The method has the potential for application in regular production blasts for control of over-breaks and dilution in operating mines. The main areas proposed for future work are: i) verification of seismic velocity changes in rock by blast-induced damage from controlled experiments; ii) incorporation of gas expansion phase into numerical models; iii) use of 3D numerical model and verification of crack distribution prediction; iv) further studies on strain rate dependency of material strength parameters, and v) accurate measurements of in-hole pressure function considering various confinement conditions.

La presente investigación se desarrolló en Compañía Minera Cerro de Pasco (CMCP) donde se busca aplicar el uso del Plasma como agente de fragmentación de macizo rocoso en sectores productivos de la mina cercanas a zonas de expansión urbanas. La finalidad del estudio consiste en comparar los valores de Velocidad Pico Partícula (VPP) entre el uso de Plasma Frag Be vs el ANFO a una distancia promedio igual en ambos casos. En tal sentido, se construye el modelo matemático Imperialist Competitive Algorithm (ICA) – linear, el cual permite estimar valores de VPP y a su vez modificar las variables de entrada como el burden, el espaciamiento, la longitud de taco, el factor de carga, la cantidad máxima de Plasma por disparo y la distancia entre el punto de fragmentación y la ubicación del sismógrafo. El modelo ICA-linear queda validado mediante la aplicación de 4 indicadores de rendimiento estadísticos los cuales son: el coeficiente de determinación, el error cuadrático medio, el error absoluto medio y el error porcentual absoluto medio cuyos resultados son 0.817, 5.001, 1.979 y 14% respectivamente. Los resultados de comparar los valores de VPP a una distancia promedio de 172 metros como se determinó según el estudio, en el caso del Plasma Frag Be los valores estimados son nulos, es decir no se registrarán valores a dicha distancia, mientras que en el caso del ANFO los registros muestran un valor promedio de 8.802 mm/s para la misma distancia mencionada, lo cual demuestra que los valores de VPP en el caso del uso del Plasma como fragmentador de macizo rocoso son considerablemente menores que cuando se utiliza ANFO. / The present research was developed at Compañía Minera Cerro de Pasco (CMCP) where the aim is to apply the use of Plasma as a rock fragmentation agent in productive sectors of the mine close to urban expansion areas. The purpose of the study is to compare the values of Peak Particle Velocity (PPV) between the use of Plasma Frag Be vs ANFO at an equal average distance in both cases. In this sense, the Imperialist Competitive Algorithm (ICA) - linear mathematical model is built, which allows estimating PPV values and in turn modifying the input variables such as the burden, spacing, stemming, power factor, maximum charge of Plasma per delay and the distance from the blast-point to the seismograph. The ICA-linear model is validated by applying 4 statistical performance indicators which are: the determination coefficient, the mean square error, the mean absolute error and the mean absolute percentage error whose results are 0.817, 5.001, 1.979 and 14% respectively. The results of comparing the PPV values at an average distance of 172 meters as determined by the study, in the case of Frag Be Plasma the estimated values are zero, that is, no values will be recorded at that distance, while in the case of ANFO the records show an average value of 8,802 mm/s for the same distance mentioned, which shows that the PPV values in the case of the use of Plasma as a rock mass fragmentation device are considerably lower than when ANFO is used. / Tesis

La presente investigación plantea la implementación de un Modelo Integral de Voladura para optimizar los procesos de voladura en unidades mineras subterráneas. Este modelo consta de seis pasos. En primer lugar, proceso de recopilación de información, el cual registra datos del macizo rocoso, reportes de voladura y fragmentación. Segundo, criterios termodinámicos, para la selección de explosivos. Tercero, algoritmos de Roger Holmberg y Peter Calder, para el diseño de malla de perforación y voladura controlada, respectivamente. Cuarto, utilización del programa de simulación de voladura JkSimblast, en el cual se simulará la malla de perforación obtenida. Quinto, pruebas de campo, en las cuales, se utilizará la simulación obtenida en el paso anterior y será implementada en terreno. Por último, la evaluación estadística del modelo mediante el coeficiente Alfa de Cronbach, el cual, medirá la fiabilidad de los cinco procesos, mediante la correlación de los pasos descritos. Este modelo se verificó en Compañía Minera Santa Luisa, Unidad Huanzalá, con los siguientes resultados: se redujo de 14 a 7 % los niveles de sobrerotura; con respecto a la fragmentación, se disminuyó el P80 a 7.71 pulgadas. El indicador de daño por voladura (BDI) disminuyó de 1.03 a 0.87. Asimismo, el factor de carga y el factor de potencia disminuyeron en 24% y 43.18 %, respectivamente. Por último, los costos de excavación se redujeron de $ 399.49 a $ 374.15 por metro de avance. / This research proposes the application of a Comprehensive Blasting Model to optimize blasting processes in underground mining units. This model consists of six steps. Firstly, the information gathering process, which records rock mass data, reports of blasting, fragmentation, etc.; second, thermodynamic criteria, for the selection of explosives. Third, algorithms of Roger Holmberg and Peter Calder, for the design of controlled drilling and blasting mesh, respectively; fourth, use of the JkSimblast blasting simulation program, in which the obtained perforation mesh will be simulated. Fifth, field tests, in which the simulation obtained in the previous step will be used and will be implemented in the field. Finally, the statistical evaluation of our model using Cronbach's Alpha coefficient, which will measure the reliability of the five processes, through the correlation of the steps described. This model was verified in the Santa Luisa Mining Company, Huanzalá Unit, with the following results: the levels of overbreaking were reduced from 14 to 7%; regarding fragmentation, the P80 was decreased to 7.71 inches. The blast damage indicator (BDI) decreased in value from 1.03 to 0.87. Also, the load factor and power factor decreased by 24% and 43.18%, respectively. Lastly, excavation costs were reduced from $399.49 to $374.15 per meter of advance. / Tesis

Archaeological artefacts excavated today are in a worse preserved state compare to those artefacts found before 1945. Previous research highlighted soil acidification as the main cause. However, not much research has been done to analyse other causalities, such as the spread of road salt during the wintertime and the potential deterioration that salt (sodium chloride) might cause on the physical cultural heritage. Nonetheless, it is proven that salt causes corrosion on infrastructure and on porous stone, masonry, and other composite materials in buildings. The aim of this work is to investigate how road salt move from the road surface (municipal– and state roads) and beyond, what factors might contribute to increased geographical spread and how we can limit the potential risk of damage associated with the spread of road salts to ancient historical sites. The research methods presented in this paper is a mix of field sampling study together with GIS– and literature analysis. The results show that the road salts spread according to an exponential decaying rate, where most of the road salts being spread 5–10 meters beyond the roadside. This means that cultural heritage sites within this buffer–area could be susceptible to salt induced damage to physical structures and deposited artefacts made from metals, rock, brick, and other material. Thereby it is pivotal to highlight the possible actions that can prevent the spread of road salts in a geographical landscape, and its effect on the physical cultural heritage.

In many cases, the functional performance of additively manufactured components can only be ensured by finishing the functional surfaces. Various methods are available for this purpose. This paper presents a procedure for selecting suitable processes for finishing laser beam melting additive–manufactured parts which is ultimately based on technological knowledge. It was experimentally proven that the use of several consecutive finishing processes is beneficial to achieve better surface quality. One finishing process chain was particularly effective (namely particle blasting/vibratory grinding/plasma electrolytic polishing) and the technological limits of this method were investigated in this study. The optimal parameters for this process combination ensured a surface roughness Sa < 1 µm.

No description available.