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Spectacular Wealth
Bridging print culture and performance, Spectacular Wealth draws on eighteenth-century festival accounts to explore how colonial residents of the silver-mining town of Potosí, in the viceroyalty of Peru, and the gold-mining region of Minas Gerais, in Brazil, created rich festive cultures that refuted European allegations of barbarism and greed. In her examination of the festive participation of the towns’ diverse inhabitants, including those whose forced or slave labor produced the colonies’ mineral wealth, Lisa Voigt shows how Amerindians, Afro-descendants, Europeans, and creoles displayed their social capital and cultural practices in spectacular performances.Tracing the multiple meanings and messages of civic festivals and religious feast days alike, Spectacular Wealth highlights the conflicting agendas at work in the organization, performance, and publication of festivals. Celebrants and writers in mining boomtowns presented themselves as far more than tributaries yielding mineral wealth to the Spanish and Portuguese empires, using festivals to redefine their reputations and to celebrate their cultural, spiritual, and intellectual wealth.
eBook
Trace element composition and U-Pb ages of cassiterite from the Bolivian tin belt
The Bolivian tin belt is a metallogenic province in the Eastern Cordillera of the Andes known for its Sn, W, Ag, and base metal deposits. Cassiterite, which is a major constituent in many magmatic-hydrothermal ore deposits from the Bolivian tin belt, can incorporate dozens of elements within its crystal lattice, making it a useful geological tracer mineral and also a potential host of critical elements. New U-Pb dating of cassiterite yields Late Triassic (Kellhuani deposit) and Late Oligocene to earliest Miocene (Viloco, Huanuni, and Llallagua deposits) ages. These ages confirm that Sn mineralization in the Bolivian tin belt occurred at least in two separate events during two major magmatic episodes apparently triggered by mantle upwelling, decompression melting, and basalt production promoting high heat flow into the overlying crust. The composition of studied hydrothermal cassiterite yields some geochemical trends that are attributed to its distance to the causative intrusion and/or level of emplacement. For example, cassiterite is generally enriched in Nb and Ta and yields higher Ti/Zr and Ti/Sc ratios in samples from xenothermal ore deposits located adjacent to intrusive complexes relative to shallow xenothermal and epithermal ore deposits. Therefore, these geochemical trends in cassiterite are useful tracers pointing to magmatic-hydrothermal centers. REE distribution in cassiterite was likely influenced by boiling processes, which resulted in tetrad-type irregularities. Cassiterite from the Bolivian tin belt is unattractive as a source for Nb (interquartile range [IQR] 4.84–0.037 ppm), Ta (IQR 0.0924–0.0126 ppm), and Ge (IQR 3.92–0.776 ppm). Some deposits, however, contain cassiterite relatively enriched in In (IQR 96.9–9.78 ppm, up to 1414 ppm) and Ga (IQR 92.1–3.03, up to 7437 ppm), that could constitute an attractive supplementary source for these elements in addition to sulfide minerals in the same deposits.
Journal Article
Geotourism and Local Development Based on Geological and Mining Sites Utilization, Zaruma-Portovelo, Ecuador
This study offers a detailed assessment of the geosites and mining sites present in the Zaruma-Portovelo mining district (Ecuador) through their qualitative and quantitative assessment. It shows up the potentiality of this area taking advantage of its geological-mining heritage. The methodological process includes: (i) compilation and inventory of all the sites within the study area with particular geological or mining interest; (ii) preparation of reports and thematic cartography, (iii) assessment and classification of the elements of geological-mining interest; (iv) SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis and TOWS (Threats, Opportunities, Weaknesses, Strengths) matrix preparation seeking strategies to guarantee the viability of geotourism. A total of 16 sites of geological interest and 11 of mining interest were identified. The 77% of these sites was proved to be of high and very high interest in scientific terms. Likewise, their susceptibility to degradation assessed from their vulnerability and fragility was found to be high or very high in the 30% of the cases. As for the protection priority, all the studied sites obtained a medium-high result. Finally, the study based on the SWOT-TOWS revealed the possibility of applying action strategies in order to facilitate the compatibility of geotourism with the current productive activities, despite the difficult situation in the study area created by mining activities.
Journal Article
A Mineralogical Museum as a Geotourism Attraction: A Case Study
The Zaruma-Portovelo mining district in Ecuador, and in particular, Portovelo City, is home to the oldest mining museum in the country. This museum, named Museo Mineralógico Magner Turner (MMMT in Spanish), is a centre that reflects, through its collections, the history and culture of this territory. This work aimed to evaluate the MMMT as a possible geosite by analysing its contributions to the geomining heritage of the Zaruma-Portovelo district, and thus, to enhance it and promote its collections as a geotouristic attraction. The work involved three phases: (i) describing the museum and its surroundings; (ii) a semiquantitative evaluation of the museum using the Brilha method and a geosites assessment model (GAM); and (iii) a qualitative evaluation using the Delphi and SWOT methodologies to define strategies and proposals for museum development. The results obtained by the semiquantitative evaluation of the geosite with the Brilha method reflect high scientific (330/400), educational (380/400) and touristic (365/400) appeal. The applied GAM shows the museum as a geosite with high principal and additional value, placing it in the Z33 field of the global valuation matrix. In addition, the semiquantitative and qualitative evaluation made it possible to describe the importance of the museum and its collections in the development of the area. The study carried out qualified the museum as a mining site with an appropriate valuation, an example of ex-situ geological heritage conservation and a basis for geotourism development.
Journal Article
Assessing Soil Quality and Heavy Metal Contamination on Scheelite Mining Sites in a Tropical Semi-arid Setting
The study area lies in a semi-arid setting of Brazil that comprises some of the largest scheelite mines in the country, but information regarding the mining impacts on the soil quality are relatively scarce. Here, we studied the changes in the soil physical and chemical characteristics caused by the scheelite mining activities in northeast Brazil, including the impacts on heavy metal concentrations in soils. Soil quality was evaluated in three sites: non-mining (reference), mining, and post-mining. The soil samples were physically and chemically characterized and had their content of the heavy metals Cd, Cr, Cu, Ni, Pb, and Zn determined. The results showed that mining activities significantly impacted soil quality. The main environmental degradation caused by scheelite mining was soil compaction, alkalization, and decreasing of soil organic matter, nitrogen, and phosphorus contents. Besides, the soil concentrations of Cd, Cr, Cu, Ni, Pb, and Zn were higher than the soil guideline values (SGVs) for metals proposed by the Environmental Protection Agency of Brazil. The soil characteristics varied widely in the three conditions of the study (non-mining, mining, and post-mining); therefore, our data provide a base for soil quality assessments of areas impacted by scheelite mining. Due to the improvement in soil physical and chemical characteristics promoted by the spontaneous vegetation cover of old tailings piles, the post-mining sites were statistically grouped with the non-mining areas. Such a result highlights the crucial role that vegetation plays in the recovery of mined sites.
Journal Article
Tennantite-(Cd), Cu6(Cu4Cd2)As4S13, from the Berenguela mining district, Bolivia; the first Cd-member of the tetrahedrite group
Tennantite-(Cd), Cu10Cd2As4S13, was approved as a new mineral species from the Berenguela mining district, Pacajes Province, La Paz, Bolivia. It occurs as black metallic anhedral grains, up to 1 mm across, associated with baryte, montmorillonite and secondary Cd-sulfates (aldridgeite, niedermayrite and voudourisite). In reflected light, tennantite-(Cd) is isotropic and grey with brownish tints. Reflectance data for the four COM wavelengths in air are [λ (nm): R (%)]: 470: 30.0; 546: 30.1; 589: 28.2; and 650: 25.8. Electron microprobe analysis gave (in wt.% - average of 11 spot analyses): Cu 40.56(32), Ag 0.05(5), Fe 0.04(1), Zn 1.91(63), Cd 11.32(1.09), Hg 0.04(7), As 19.04(43), S 26.78(30), total 99.74(53). On the basis of ΣMe = 16 atoms per formula unit (apfu), the empirical formula of tennantite-(Cd) is Cu9.98Ag0.01Cd1.57Zn0.46Fe0.01As3.97S13.05. Tennantite-(Cd) is cubic, I43m, with unit-cell parameters a = 10.3088(2) Å, V = 1095.53(6) Å3 and Z = 2. Its crystal structure was refined by single-crystal X-ray diffraction data to a final R1 = 0.0152 on the basis of 359 unique reflections with Fo > 4σ(Fo) and 22 refined parameters. Tennantite-(Cd) is isotypic with other tetrahedrite-group minerals. Its crystal-chemistry is discussed and previous findings of Cd-rich tetrahedrite-group minerals are briefly reviewed.
Journal Article
First U-Pb LA-ICP-MS in situ dating of supergene copper mineralization: case study in the Chuquicamata mining district, Atacama Desert, Chile
Since the second half of the twentieth century, exotic copper mineralization represents a prime target for many mining exploration companies operating in the hyperarid Atacama Desert, in northern Chile. Although there is evidence that the emplacement of such deposits took place during specific Tertiary climatic periods and relief formation, many uncertainties remain regarding the exact timing for their deposition and/or the genetic link between the exotic deposits and the primary porphyry copper deposits. We present a first attempt of U-Pb dating of copper-rich minerals from the Mina Sur exotic deposit from the Chuquicamata mining district. A suite of Mn-rich black chrysocolla clasts surrounded by pseudomalachite bands has been characterized and dated in petrographic context using both nanosecond and femtosecond in situ laser ablation ICP-MS analyses. U-Pb dating on pseudomalachite bands yields a crystallization age of 18.4 ± 1.0 Ma. For the Mn-rich chrysocolla clasts, the 206Pb/238U apparent ages range from 19.7 ± 5.0 Ma to 6.1 ± 0.3 Ma, a spread interpreted as the result of U and/or Pb mobility linked to fluid circulation following crystallization. This study demonstrates that supergene copper mineralization can be directly dated by the U-Th-Pb method on pseudomalachite. Furthermore, the age obtained on pseudomalachite indicates that Mina Sur copper deposition took place at ca. 19 Ma, about 11 m.y. after the unroofing and hydrothermal alteration of the Chuquicamata deposit, a result that is consistent with the supergene ages already known in the Atacama Desert.
Journal Article
The Montecristo mining district, northern Chile: the relationship between vein-like magnetite-(apatite) and iron oxide-copper–gold deposits
The Montecristo district, northern Chile, is one of the few places worldwide where there is a direct relationship between magnetite-(apatite) (MtAp) mineralization and iron oxide-copper–gold (IOCG) mineralization. The MtAp mineralization includes Ti-poor magnetite, fluorapatite, and actinolite and is crosscut and partially replaced by a younger IOCG mineralization that includes a second generation of actinolite and magnetite with quartz, chalcopyrite, pyrite, and molybdenite. The MtAp stage at Montecristo is interpreted as the crystallized iron-rich melts that used the pre-existing structures of the Atacama Fault System as conduits. These rocks later acted as a trap for hydrothermal IOCG mineralization. Geochronology data at Montecristo indicate that the host diorite (U–Pb zircon 153.3 ± 1.8 Ma, 2-sigma), MtAp mineralization (40Ar-39Ar in actinolite, 154 ± 2 Ma and 153 ± 4 Ma, 2-sigma), and the IOCG event (Re-Os on molybdenite, 151.8 ± 0.6 Ma, 2-sigma) are coeval within error and took place in a time span of less than 3.4 Ma. The εHfi and εNdi values of the host diorite are + 8.0 to + 9.8 and + 4.3 to + 5.4, respectively. The whole-rock 87Sr/86Sri values of the IOCG mineralization (0.70425 to 0.70442) are in the lower end of those of the MtAp mineralization (0.70426–0.70629). In contrast, εNdi values for the IOCG mineralization (+ 5.4 and + 5.7) fall between those of the MtAp rocks (+ 6.6 to + 7.2) and the host diorite, which suggests that the IOCG event was related to fluids having a more crustal Nd (εNdi < + 5.7) composition than the MtAp mineralization. This likely reflects the mixing of Nd from the MtAp protolith and a deep magmatic-hydrothermal source, very likely an unexposed intrusion equivalent to the host diorite. Sulfur isotope compositions (δ34S, + 0.3 to + 3.4‰) are consistent with a magmatic source.
Journal Article
Selection of reactive mixture for biochemical passive treatment of acid mine drainage
Acid mine drainage, characterized by low pH and high concentrations of sulfate and metals, is a worldwide problem. Passive bioreactors under sulfate reduction conditions are a sustainable technology for the treatment of waters impacted with acid mine drainage. Effectiveness and sustainability of the treatment depends on the selection of a balanced reactive mixture composed of an organic carbon and nitrogen source for sulfate-reducing bacteria. Different mixtures of organic and inorganic materials were tested searching which could be used for the treatment of acid drainage produced in the Zipaquirá Mining District of Colombia. Six organic materials that are readily available in this zone were studied for their ability to serve as substrate for sulfate-reducing bacteria. Five reactive mixtures were then tested for 45 days in eighteen batch bioreactors under anaerobic conditions for their efficiency to increase pH and alkalinity, as well as enhancing sulfate reduction and metal removal. The hydraulic conductivity and porosity of the mixtures were also measured. The results showed that all mixtures were efficient for increasing pH and alkalinity, reducing sulfate (>70 %), and removing Fe
2+
and Zn
2+
(>99 %), but only two mixtures removed Mn
2+
(>69 %). One reactive mixture, containing 15 % cow manure, 10 % mushroom compost, 25 % sajo sawdust, 20 % gravel, 15 % limestone, and 15 % sediment, with permeability of 4.5 × 10
−2
cm s
−1
and porosity of 0.49–0.53, was the most promising option for use in passive bioreactors for treating acid mine drainage in the Zipaquirá Mining District.
Journal Article