Some approaches to improve knowledge about subsidence processes in underground mining

Pòster amb el resum gràfic de la tesi doctoral en curs, que forma part de l'exposició "Doctorat en Recursos Naturals i Medi Ambient de la UPC Manresa. 30 anys formant en recerca a la Catalunya Central 1992-2022".The authors would like to thank the support of ICL-Iberia for the data provided, also UPC and Santander bank for providing FPIUPC scholarship.Postprint (published version

Metalogénesis del yacimiento San José, Oruro, Bolivia

Premi Emili Viader 2018El distrito minero de Oruro se encuentra ubicando en la Faja Estannífera de la Cordillera Central Andina, que aloja diversos depósitos de Sn-Zn-Pb-Ag. El depósito de San José es uno de los más representativos de este distrito desde el punto de vista económico. Más allá de los productos metálicos tradicionales, la Faja Estannífera podría convertirse en un blanco de exploración para elementos como el indio, por el potencial de la paragénesis de minerales con altas concentraciones de este elemento crítico para el desarrollo de tecnología. La mineralogía a detalle del depósito de San José había sido someramente estudiada anteriormente, sin embargo una actualización de la mineralogía de un yacimiento tan emblemático como este era imperioso. La mineralización del depósito de San José se presenta en dos estilos principales: (a) mineralización rica en Sn, representada por vetas de cuarzo con casiterita, y (b) mineralización de Zn-Pb-Ag, en diseminaciones, representadas por esfalerita, galena y estannita. Se ha puesto especial énfasis en las fases de sulfosales encontradas en este depósito debido a la gran variedad en el mismo, así mismo muchas de ellas solo han sido reportadas en este yacimiento. Dentro de ellas el grupo de la estannita sobresale debido a los contenidos de indio presentes en la mina. Se hallaron valores excepcionales de In en fases de sakuraiita, petrukita y roquesita. El depósito de San José muestra evidencia de concentraciones anómalas de indio, las cuales probablemente puedan repetirse en depósitos similares en otras zonas de la Faja estannífera en la Cordillera Central Andina.Award-winnin

Subsidence management and prediction system: a case study in potash mining

Peer ReviewedObjectius de Desenvolupament Sostenible::12 - Producció i Consum ResponsablesObjectius de Desenvolupament Sostenible::9 - Indústria, Innovació i InfraestructuraPostprint (published version

Service-learning in engineering: analysis of students experiences in development cooperation

Peer ReviewedObjectius de Desenvolupament Sostenible::4 - Educació de QualitatObjectius de Desenvolupament Sostenible::6 - Aigua Neta i SanejamentObjectius de Desenvolupament Sostenible::3 - Salut i BenestarObjectius de Desenvolupament Sostenible::13 - Acció per al ClimaObjectius de Desenvolupament Sostenible::17 - Aliança per a Aconseguir els ObjetiusPostprint (published version

Mineralogy and mineral chemistry of the Au-Ag-Te-(Bi-Se) San Luis Alta Deposit, Mid-South Peru.

A mineralogical and mineral chemistry study was carried out in the San Luis Alta telluriderich gold deposit, mid-south Peru, to contribute towards determining its formation and improving the ore processing. The San Luis mineralization is considered an intrusion-related gold deposit located in the Arequipa segment of the Coastal Batholith. The mineralization occurs in quartz veins hosted in diorites and granodiorites from the Tiabaya Super-Unit. These veins are sulfide-rich in the deep areas and contain abundant iron oxides. Sulfides are mainly pyrite with minor chalcopyrite and galena. Native gold and telluride minerals are abundant. Mineral chemistry was determined using an electron microprobe. The mineralogy of veins was classified into four stages. Gold occurs in the three last stages either in large grains, visible to the naked eye, or, more frequently, in grains of less than 10 m. Gold appears as grains encapsulated in pyrite, Fe oxides, quartz and filling fractures. The first stage is characterized by the deposition of quartz and massive pyrite, which does not contain gold. During the second stage, hessite, calaverite, petzite and altaite are formed. Additionally, Bi-tellurides, mainly volynskite, rucklidgeite, kochkarite and tellurobusmuthine, are formed. Some of these minerals occur as blebs encapsulated in pyrite, suggesting that a Bi-Te-rich melt was formed from the ore-forming hydrothermal fluid and transported the Au and Ag elements. This stage was followed by a fracturing event and tellurobismuthite, tetradymite and montbrayite precipitated. In the last stage, a supergene replacement formed covellite, bornite and goethite. Te-Bi minerals do not appear in this stage, but selenium minerals occur in minor amounts. Chlorargyrite and iodargyrite occur and are associated with gold

Experiences of mining engineering students in cooperation for development

Future engineers, in addition to technical knowledge, should incorporate in their academic curricula aspects that contribute to make mining a sustainable activity. This will contribute to changing the concept that society has about mining and to be a socially accepted activity. In the mining engineering studies at the Universitat Politècnica de Catalunya (UPC), students have the opportunity to develop cooperation projects together with professors and other staff members. They all collaborate with artisanal miners from different underdeveloped countries, mainly from Latin America, and contribute to making mining more environmentally friendly. Moreover, they have the opportunity to acquire a social sensitivity that can be of great importance during the development of their professional career. This study presents some experiences of undergraduate, master, and doctoral students in cooperation activities in mining. The projects were developed as a collaboration between UPC and universities or NOGs in Latin America. The activities have been carried out in underdeveloped areas where mining is practiced with a high environmental impact and poor use of resources. A survey among the participants in the projects shows the students' favourable perception of this activity.This work has been carried out with the support of the Centre de Cooperació per al Desenvolupament (CCD-UPC), which financed the Cooperation projects. We thank the NGO Mineria per al Desenvolupament for its contribution to the development of the projects

Process mineralogy of the tailings from Llallagua: towards a sustainable activity

Peer ReviewedObjectius de Desenvolupament Sostenible::17 - Aliança per a Aconseguir els ObjetiusObjectius de Desenvolupament Sostenible::12 - Producció i Consum ResponsablesObjectius de Desenvolupament Sostenible::4 - Educació de QualitatPostprint (published version

Experiences of Mining Engineering students in cooperation for development

Peer ReviewedObjectius de Desenvolupament Sostenible::3 - Salut i BenestarObjectius de Desenvolupament Sostenible::8 - Treball Decent i Creixement EconòmicObjectius de Desenvolupament Sostenible::13 - Acció per al ClimaObjectius de Desenvolupament Sostenible::17 - Aliança per a Aconseguir els ObjetiusPostprint (published version

Assessment and characterization of subsidence in the Catalan potash basin

Tesi amb continguts retallats per motius de confidencialitat(English) The importance of potash is inevitable to life on the planet earth as it is required by living mechanisms including plants, animals and human beings. In Europe, this vital ore is produced mainly by Germany and Spain, which consists of up to 10% of the global supply. As a matter of fact, higher demand for potash may be required due to population growth. This may lead to increasing potash mining activities, which might create instability with regard to the geomechanical features of the mining areas and potential environmental and social impacts. The main objective of this research is to approach innovative models that can describe the geomechanical behavior of the Catalan Potash Basin deposit. Including concern about surface subsidence, high deformations and collapses of underground potash mining, with the ultimate goal of improving the present working conditions and mitigating the environmental impacts. Four Specific objectives have been defined; (1) The creation of a model to predict subsidence based on the geomechanical parameters of the ore deposit. (2) The Geochemical characterization of the pelitic and insoluble phase detected between the saline beds and within them. (3) The characterization of the surface subsidence basin, including boundary angle and distance of influence. (4) The assessment of the deformations in the underground mining facilities. To achieve these objectives, a combination of FEM, InSAR, GPS, Laser Scanner and Geochemical techniques has been used to predict the subsidence and achieve a better geomechanical behavior characterization of it, which have resulted in two main outcomes. First, it has been established that numerical 2D modeling is a useful tool for planning land management and mining operations, providing the flexibility and predictability needed to manage huge surfaces and reduce environmental consequences. The approach is also adaptable to other subsurface infrastructure types. Second, the subsidence basin has been successfully characterized. Third, pelitic layers with insoluble mineralogy within saline lithologies have successfully undergone geochemical examination. However, to expand the study area to include the entire active ore deposit mineralogy, additional examination will be required. Fourth, the laser scanner technique has been satisfactorily assessed, it has given important insights into the displacements that occur during the early opening of an underground mining drift affirming that it is a suitable technique to be implemented for routinely tracking deformations in the geomechanical management of the ore deposit. However, it is necessary to perform a precise topographic control of the targets used, in order to correctly georeference the point clouds produced by the laser scanner. Furthermore, characterization of the subsidence has been successfully assessed in the eastern portion of the Catalan Potash Basin. With the help of the methods mentioned, it was possible to evaluate a large dataset and identify four unique zones, one of which was experiencing residual subsidence. Mining firms may choose to use this flexible and effective method and apply it to other studies involving subsidence. In the end, based on the results and objectives achieved in the study, suggestions for further research have been proposed, which can further advance the knowledge in this line of research. The structure of the thesis is as follows: Chapter 1 introduces the case study and states the objectives and hypothesis developed in the research. In chapter two, an extensive and precise bibliographic review is made. Chapter 3 describes the methodologies followed in the different investigations developed. Chapter 4 presents the results and discusses them. Finally, Chapter 5 presents the conclusions and proposes future research to improve and complement the knowledge obtained.(Català) La potassa és essencial per a la vida en el planeta Terra, ja que és necessària per a tots els éssers vius que hi habiten, com les plantes, els animals o els éssers humans. A Europa, aquest mineral es produeix principalment a Alemanya i a Espanya, la seva producció consisteix fins al 10% de l'oferta mundial. A causa de l'increment de la població mundial, és possible que sigui necessària una major demanda de potassa, fet que podria conduir a què les activitats mineres haguessin d'arribar a profunditats majors per tal d'extreure aquest recurs essencial, incrementant la inestabilitat d'aquestes infraestructures així com la pos s ibilitat de generar impactes ambientals i socials, com és el cas de la s ubs idència superficial. L'objectiu principal d'aquesta recerca és aproximar models innovadors que puguin descriure el comportament geomecànic del dipòsit de la Conca Potàssica Catalana, així com, de la subsidència superficial, les altes deformacions que actuen en la zona, amb l'objectiu final de millorar les condicions de treball actual i mitigar els impactes ambientals. S'han definit quatre objectius específics; (1) La creació d'un model per predir la subsidència basada en els paràmetres geomecànics del dipòsit de mineral. (2) La caracterització geoquímica de la fase pelítica i insoluble detectada entre els llits salins i dins d'ells. (3) La caracterització de la conca de subsidència superficial, incloent-hi l'angle crític de subsidència i la distància d'influència. (4) L'avaluació de les deformacions en les instal·lacions mineres subterrànies. Per aconseguir aquests objectius, predir la subsidència i aconseguir una millor caracterització del comportament geomecànic, s'han utilitzat una combinació de tècniques analítiques, anàlisis FEM, InSAR, GPS, làser escàner i algunes tècniques geoquímiques que han donat lloc a quatre resultats principals. En primer lloc, s'ha establert un modelatge numèric 2D, aquesta és una eina útil per a la planificació de la gestió del terreny i les operacions mineres, que proporciona la previsió i flexibilitat necessàries per gestionar grans superfícies i reduir les conseqüències mediambientals. Aquest enfocament és adaptable a altres tipus d'infraestructura subterrània. En segon lloc, les capes pelítiques amb mineralogia insoluble dins de les litologies salines s'han examinat geoquímicament amb èxit. No obstant això, per ampliar l'àrea d'estudi, així incloure tota la mineralogia de dipòsit, serà necessari un examen addicional. En tercer lloc, s'ha caracteritzat amb èxit la part oriental del dipòsit de la Conca Potàssica Catalana, s'ha avaluat un conjunt extens de dades i identificat quatre zones úniques, incloent-hi una àrea amb subsidència residual. En quart lloc, la tècnica de l'escàner làser ha estat aplicada satisfactòriament, ha donat informació important sobre els desplaçaments que es produeixen durant l'obertura inicial d'una galeria minera subterrània, confirmant que és una tècnica adequada per ser implementada per avaluar les deformacions que succeeixen en la producció diària d'una mina subterrània. No obstant això, és necessari mantenir un control topogràfic precís de les ubicacions on es localitzen les dianes necessàries per a georeferenciar correctament els núvols de punts produïts per aquesta tècnica. Gràcies a la visió pràctica i precisió dels mètodes i resultats aconseguits, les empreses mineres poden optar en utilitzar aquests mètodes flexibles i eficaços i aplicar-los a altres estudis de subsidència. Addicionalment, basantse en els resultats i objectius assolits en l'estudi, s'han proposat suggeriments per continuar avançant en el coneixement d'aquesta línia de recerca.DOCTORAT EN RECURSOS NATURALS I MEDI AMBIENT (Pla 2012

Estudi del comportament geomecànic de les diferents tipologies salines de la conca potàssica catalana

Cabanasses is an ore deposit located in the Catalan potash basin, whichis part of the Cardona evaporite formation in the Ebro Valley, 75 km northwest of Barcelona. The depositis configured by8 salt lithologies, formedby layers of clay-sized particles.Saline materials, under high stress,behave as a visco-plastic formcalled creep. This characteristic has a crucial influence to safety,production rate and costs. Therefore, it is necessary to study the properties of the salt lithologies as well as the characteristics of the clay-size particles, considering thesurfaces correspond to the weakness planesin order to find the best working conditions. Two different approacheshave been applied in this study:the laser scan and several geomechanical tests.The laser scan is a very useful tool to define the convergence of the drifts, obtaining a 3D model.Data from twodrifts was taken every week,called GC-01 and GC-02respectively. Three measurementsfor the GC-01 and four measurement for theGC-02, comparing the sections among them from week to week everymetre, using five control pointsin each section:1 on the roof, 2 on the roof corners and2 on the walls. The movements in all five control points were analysedin order to define the maindeformationmechanism. According to obtained results, it waspossible to observe the main deformation movement, seeing a considerable convergence displacement that reduces the cross-sections over time.In the caseof GC-01, the deformation increases progressively and homogeneouslywithout exceeding 2 cm per week in the 5 control points. WhileGC-02displays an irregular behaviour,either in the overall convergence or each individual point.Being more pronounced in the upper area, producing a flattened drift,wherethe deformations can exceed 10 cm per week.On the other hand, geomechanical testswere performed. Samples were collectedfrom each representative lithology of the mine, consideringthe potential weakness planes.Initially, roughness measurements were done in all the sample. Subsequently, the main geomechanical characteristics were analysed, such as natural and dry density, humidity and quantification of the insoluble particles of each lithology.These insoluble particles were analysed by several analytical techniques, using:theScanning electron microscopy (SEM) with analysis by energy-dispersive X-ray spectroscopy (EDS) and theX-ray powder diffraction (XRD). Obtaining information about the mineralogy of theircomposition, since the study of the mineral particles that form the joints is essential to understand the mechanisms ofthe stratarupture.The characteristics of the saline lithologies have been defined, providing a base to continue studying the saline behaviour in Cabanasses’ ore deposit. The study of the weakness planes has also provided useful information to increase the knowledge about the geomechanical behaviour of the ore deposit, as well as to understand that roughness could be a very important parameter to consider