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The process mineralogy of a skarn-type refractory Cu-Mo ore in Peru was studied systematically by means of optical microscope, chemical mule-element analysis and phase analysis in order to establish reasonable flowsheet and beneficiation med of Cu-Mo ore. The results show that the mam useful elements of the ore are Cu and MO, and the grades are 0. 58% and 0. 019%, respectively. The mineral composition of the ore is complex, the man useful minerals are chalcopyrite, chalcocite, molybdenite, etc. The gangue mnerals are quartz, feldspar, mica, serpentine, template, chlorite, and tee. The copper and molybdenum minerals is fine, and often occurs along the edges, holes and cracks of pyrite or magnetite or gangue mineralize. A small amount of micro-fine chalcopyrite is distributed sparsely in gangue minerals, and the distillation relationship is complex, which affects the dressing recovery of copper and molybdenum [ABSTRACT FROM AUTHOR]

Trace metals continue to generate environmental pollution problems because of their persistence in the environment, representing a hazard for living organisms. Although recent studies have reported trace metal environmental pollution in soils of some parts of Lima, there is still much about trace metal pollution that needs to be explored. Using feral pigeons (Columba livia) as biomonitor could facilitate rapid assessments of trace metal contamination in cities like Lima. In this study, we determined the concentrations of lead (Pb), cadmium (Cd), zinc (Zn), copper (Cu), molybdenum (Mo), selenium (Se), iron (Fe) and strontium (Sr) in the liver of 21 pigeons from three sites with industrial, urban and rural land-use characteristics. Our results showed that when compared to the rural site, the concentrations of Pb, Zn, Cu, Se, Fe and Sr were significantly higher in both the industrial and urban sites. These findings suggest the existence of a trace metal concentration gradient with higher concentrations in both the industrial and urban sites. Such gradient is consistent with the land-use characteristics of each one of the three sites, corroborating the environmental pollution problems associated with them. Overall, our study provides powerful evidence of the use of feral pigeons as biomonitor of trace metal pollution in Lima and other cities from Peru and the world. To our knowledge, this is the first trace metals assessment done in pigeons in Peru. [ABSTRACT FROM AUTHOR]

The stable isotope composition of molybdenum (Mo) and zinc (Zn) in mine wastes at the Antamina Copper–Zn–Mo mine, Peru, was characterized to investigate whether isotopic variation of these elements indicated metal attenuation processes in mine drainage. Waste rock and ore minerals were analyzed to identify the isotopic composition of Mo and Zn sources, namely molybdenites (MoS 2 ) and sphalerites (ZnS). Molybdenum and Zn stable isotope ratios are reported relative to the NIST-SRM-3134 and PCIGR-1 Zn standards, respectively. δ 98 Mo among molybdenites ranged from − 0.6 to + 0.6‰ (n = 9) while sphalerites showed no δ 66 Zn variations (0.11 ± 0.01‰, 2 SD, n = 5). Mine drainage samples from field waste rock weathering experiments were also analyzed to examine the extent of isotopic variability in the dissolved phase. Variations spanned 2.2‰ in δ 98 Mo (− 0.1 to + 2.1‰) and 0.7‰ in δ 66 Zn (− 0.4 to + 0.3‰) in mine drainage over a wide pH range (pH 2.2–8.6). Lighter δ 66 Zn signatures were observed in alkaline pH conditions, which was consistent with Zn adsorption and/or hydrozincite (Zn 5 (OH) 6 (CO 3 ) 2 ) formation. However, in acidic mine drainage Zn isotopic compositions reflected the value of sphalerites. In addition, molybdenum isotope compositions in mine drainage were shifted towards heavier values (0.89 ± 1.25‰, 2 SD, n = 16), with some overlap, in comparison to molybdenites and waste rock (0.13 ± 0.82‰, 2 SD, n = 9). The cause of heavy Mo isotopic signatures in mine drainage was more difficult to resolve due to isotopic heterogeneity among ore minerals and a variety of possible overlapping processes including dissolution, adsorption and secondary mineral precipitation. This study shows that variation in metal isotope ratios are promising indicators of metal attenuation. Future characterization of isotopic fractionation associated to key environmental reactions will improve the power of Mo and Zn isotope ratios to track the fate of these elements in mine drainage. [ABSTRACT FROM AUTHOR]

Reactive transport models have proven abilities to simulate the quantity and quality of drainage from mine waste rock. Tracer experiments indicate the presence of fast and slow flow regimes in many heterogeneous waste-rock piles. Although multidomain models have been developed specifically for systems with such distinctive hydrodynamics, there have been limited applications of multidomain reactive transport models to simulate composite drainage chemistries from waste-rock piles to date. This work evaluated the ability of dual-domain multicomponent reactive transport models (DDMRTMs) to reproduce breakthrough curves of conservative (chloride) and reactive (molybdenum) solutes observed at a well-characterized experimental waste-rock pile at the Antamina Mine, Peru. We found that the DDMRTM simulations quantitatively matched eight-year-long records of conservative transport through the waste-rock pile when parameterized mainly with field-measured properties obtained from the site and limited calibration. The DDMRTM model also provided a reasonable match to field observations of the reactive solute. The limited calibrated parameters are physically realistic, corroborating the ability of these multidomain models to reproduce the complex reactive-transport processes governing polluted rock drainage from large-scale waste-rock piles. • Dual-domain multicomponent reactive transport model to simulate waste rock drainage. • History matching against breakthrough curves from experimental Antamina waste rocks. • Nice matching against BTCs of chloride conservative and reactive solutes. • Only one fitting parameter; others were estimated a priori and physically realistic. [ABSTRACT FROM AUTHOR]

The Paleocene to Eocene southern Peru porphyry belt contains three significant porphyry Cu-Mo deposits at Cuajone, Quellaveco, and Toquepala. Ten new zircon U-Pb Sensitive High Resolution Ion Microprobe-Reverse Geometry (SHRIMP-RG) ages for Cuajone and Toquepala, together with published ages for Quellaveco, establish a magmatic history characterized by episodic events. Punctuated magmatism at Cuajone is distributed over approximately 13 m.y., at Toquepala over 8 m.y., and at Quellaveco over 6 m.y. The ages of the porphyry intrusions hosting or associated with the introduction of Cu and Mo at the three deposits show remarkable similarity, with emplacement beginning and ending at approximately 56.5 to 53.0 Ma at Cuajone, 57.0 to 54.0 Ma at Toquepala, and at 58.4 to 54.3 Ma at Quellaveco. Field relations coupled with the U-Pb ages for synmineral intrusions suggest very similar timing of the cupriferous hydrothermal systems, with the youngest pyritiferous and Cu-poor hydrothermal systems being associated with porphyry intrusions as much as 2 m.y. younger than significant Cu introduction. Overall, the porphyry Cu-Mo intrusive complexes represent the youngest magmatic complexes formed during the Late Cretaceous and early Tertiary arc, having formed prior to eastward migration of the magmatic locus. [ABSTRACT FROM AUTHOR]

Abstract: We study fish scales as a proxy of fish abundance and preservation biases together with phosphorus from fish remains (Pfish) in a sediment core retrieved off Callao, Peru (12°1′S, 77°42′W; water depth=179m; core length=52cm). We interpret our results as a function of changing redox conditions based on ratios of redox-sensitive trace elements (Cu/Al, Mo/Al, Ni/Al, Zn/Al, V/Al), terrigenous indicators (Fe in clays, Ti, Al), and biogenic proxies (CaCO3, biogenic opal, total nitrogen, organic carbon, barite Ba). The core covers roughly 700 years of deposition, based on 210Pb activities extrapolated downcore and 14C dating at selected intervals. Our fish-scale record is dominated by anchovy (Engraulis ringens) scales followed by hake (Merluccius gayii) scales. The core presented an abrupt lithological change at 17cm (corresponding to the early 19th century). Above that depth, it was laminated and was more organic-rich (10–15% organic carbon) than below, where the core was partly laminated and less organic-rich (<10%). The lithological shift coincides with abrupt changes in dry bulk density and in the contents of terrigenous and redox-sensitive trace elements, biogenic proxies, and fish scales. The remarkable increase in redox-sensitive trace elements in the upper 17cm of the core suggests more reducing conditions when compared with deeper and older horizons, and is interpreted as an intensification of the oxygen minimum zone off Peru beginning in the early 19th century. Higher fish-scale contents and higher Pfish/Ptotal ratios were also observed within the upper 17cm of the core. The behavior of biogenic proxies and redox-sensitive trace elements was similar; more reduced conditions corresponded to higher contents of CaCO3, Corg, total nitrogen and fish scales, suggesting that these proxies might convey an important preservation signal. [Copyright &y& Elsevier]