The importance of mineralogical knowledge in the sustainability of artisanal gold mining: a mid-south Peru case

Mineralogy and gold processing techniques from several mining areas of the Nazca-Ocoña gold belt, Mid-South Peru, were investigated to assess the efficiency of gold extraction methods in relation to their mineralogy. The deposits from this belt are intrusion gold related to mineralization in quartz veins. Native gold occurs as micrometric grains encapsulated in pyrite and in minor amounts in other sulfides and quartz. Electrum is found mainly in fractures of pyrite and attains up to 35 wt. % Ag. In addition to these occurrences, gold tellurides also occur and they are abundant in San Luis. Gold processing is carried out by amalgamation with mercury and/or cyanidation. The comparison of the gold grade in the mineralizations and in the residual tailings indicates that a significant amount of gold is not recovered using the mercury amalgamation process and also, in the case of the gold recovery by cyanidation, except when cement was added to the cyanide solution. This was due to an increase in the pH that favours the dissolution of the gold matrix. In the cyanidation process carried out in tailings previously treated with mercury, part of the mercury retained in them is released to the atmosphere or to the cyanidation fluids.Peer ReviewedPostprint (published version

Patrimonio geológico y urbanístico de Manresa (Cataluña)

La observación de las rocas nos da mucha información de la historia de la formación del lugar del que proceden. Estas además de in situ, en el campo, se pueden observar en el laboratorio o, simplemente en las calles y edificaciones de las ciudades. Manresa, ubicada al centro de Cataluña, es una ciudad en la que se pueden observar construcciones con una amplia gama de rocas. El objetivo del trabajo es promover la geología entre las personas y transmitir una relación entre esta y la sociedad, ya que en la mayoría hay una relación directa de la geología con la vida cotidiana. Para ello se realizaron cuatro itinerarios. Dos de ellos son exteriores por las calles y plazas de la ciudad, donde se pueden observar rocas ubicadas en los pavimentos y fachadas y de edificios. Otros dos itinerarios son interiores, uno dentro de la Seu Vella de Manresa y el otro en la Cova de Sant Ignasi. Para ello se han diseñado trípticos donde se muestran los itinerarios y los puntos de máximo interés y una página web donde poder descargarlos y seguir los itinerarios mediante teléfonos móviles con conexión a internet. The observation of the rocks gives us much information on the formation history of the place of origin. These as well as in situ in the field can be observed in the laboratory or just in the streets and buildings of cities. Manresa, located in the heart of Catalonia, is a city in which buildings can be seen with a wide range of rocks . The aim of this work is to promote geology between people and convey a relationship between it and society, and in most there is a direct relationship of geology to everyday life. For this there were four routes. Two of them are outside in the streets and squares of the city, where you can see rocks located in the floors and walls and buildings. Two other routes are internal, one inside the Old Cathedral of Manresa and the other in the Cova de Sant Ignasi. This has been designed leaflets showing routes and points of maximum interest and a website where you can download and follow the itineraries through mobile phones with internet connection.Peer Reviewe

Patrimonio geológico y urbanístico de Manresa (Cataluña)

La observación de las rocas nos da mucha información de la historia de la formación del lugar del que proceden. Estas además de in situ, en el campo, se pueden observar en el laboratorio o, simplemente en las calles y edificaciones de las ciudades. Manresa, ubicada al centro de Cataluña, es una ciudad en la que se pueden observar construcciones con una amplia gama de rocas. El objetivo del trabajo es promover la geología entre las personas y transmitir una relación entre esta y la sociedad, ya que en la mayoría hay una relación directa de la geología con la vida cotidiana. Para ello se realizaron cuatro itinerarios. Dos de ellos son exteriores por las calles y plazas de la ciudad, donde se pueden observar rocas ubicadas en los pavimentos y fachadas y de edificios. Otros dos itinerarios son interiores, uno dentro de la Seu Vella de Manresa y el otro en la Cova de Sant Ignasi. Para ello se han diseñado trípticos donde se muestran los itinerarios y los puntos de máximo interés y una página web donde poder descargarlos y seguir los itinerarios mediante teléfonos móviles con conexión a internet. The observation of the rocks gives us much information on the formation history of the place of origin. These as well as in situ in the field can be observed in the laboratory or just in the streets and buildings of cities. Manresa, located in the heart of Catalonia, is a city in which buildings can be seen with a wide range of rocks . The aim of this work is to promote geology between people and convey a relationship between it and society, and in most there is a direct relationship of geology to everyday life. For this there were four routes. Two of them are outside in the streets and squares of the city, where you can see rocks located in the floors and walls and buildings. Two other routes are internal, one inside the Old Cathedral of Manresa and the other in the Cova de Sant Ignasi. This has been designed leaflets showing routes and points of maximum interest and a website where you can download and follow the itineraries through mobile phones with internet connection.Peer ReviewedPostprint (published version

Patrimonio geológico y urbanístico de Manresa (Cataluña)

La observación de las rocas nos da mucha información de la historia de la formación del lugar del que proceden. Estas además de in situ, en el campo, se pueden observar en el laboratorio o, simplemente en las calles y edificaciones de las ciudades. Manresa, ubicada al centro de Cataluña, es una ciudad en la que se pueden observar construcciones con una amplia gama de rocas. El objetivo del trabajo es promover la geología entre las personas y transmitir una relación entre esta y la sociedad, ya que en la mayoría hay una relación directa de la geología con la vida cotidiana. Para ello se realizaron cuatro itinerarios. Dos de ellos son exteriores por las calles y plazas de la ciudad, donde se pueden observar rocas ubicadas en los pavimentos y fachadas y de edificios. Otros dos itinerarios son interiores, uno dentro de la Seu Vella de Manresa y el otro en la Cova de Sant Ignasi. Para ello se han diseñado trípticos donde se muestran los itinerarios y los puntos de máximo interés y una página web donde poder descargarlos y seguir los itinerarios mediante teléfonos móviles con conexión a internet. The observation of the rocks gives us much information on the formation history of the place of origin. These as well as in situ in the field can be observed in the laboratory or just in the streets and buildings of cities. Manresa, located in the heart of Catalonia, is a city in which buildings can be seen with a wide range of rocks . The aim of this work is to promote geology between people and convey a relationship between it and society, and in most there is a direct relationship of geology to everyday life. For this there were four routes. Two of them are outside in the streets and squares of the city, where you can see rocks located in the floors and walls and buildings. Two other routes are internal, one inside the Old Cathedral of Manresa and the other in the Cova de Sant Ignasi. This has been designed leaflets showing routes and points of maximum interest and a website where you can download and follow the itineraries through mobile phones with internet connection.Peer Reviewe

The importance of mineralogical knowledge in the sustainability of artisanal gold mining: a mid-south Peru case

Mineralogy and gold processing techniques from several mining areas of the Nazca-Ocoña gold belt, Mid-South Peru, were investigated to assess the efficiency of gold extraction methods in relation to their mineralogy. The deposits from this belt are intrusion gold related to mineralization in quartz veins. Native gold occurs as micrometric grains encapsulated in pyrite and in minor amounts in other sulfides and quartz. Electrum is found mainly in fractures of pyrite and attains up to 35 wt. % Ag. In addition to these occurrences, gold tellurides also occur and they are abundant in San Luis. Gold processing is carried out by amalgamation with mercury and/or cyanidation. The comparison of the gold grade in the mineralizations and in the residual tailings indicates that a significant amount of gold is not recovered using the mercury amalgamation process and also, in the case of the gold recovery by cyanidation, except when cement was added to the cyanide solution. This was due to an increase in the pH that favours the dissolution of the gold matrix. In the cyanidation process carried out in tailings previously treated with mercury, part of the mercury retained in them is released to the atmosphere or to the cyanidation fluids.Peer Reviewe