Copper Basin Research Articles

The tectonic development of the Central African Plateau: evidence from shear-wave splitting

SUMMARY The Central African Plateau comprises a mosaic of numerous Archean terranes—the Congo, Bangweulu and Kalahari Cratons—sutured in a series of Proterozoic to early Cambrian orogenic events. Major upper-crustal deformation and complex craton margin fault zones reflect the region’s diverse tectonic history: rifting during the Neoproterozoic, collision during the Pan-African orogeny, and more recently, Permo-Triassic Karoo rifting and the Pliocene development of the Southwestern branch of the East African Rift. The tectonic evolution and extent to which the lithospheric mantle has been re-worked by each tectonic event is poorly understood. New seismograph networks across the Plateau provide fresh opportunity to place constraints on the plate-scale Precambrian-to-Phanerozoic processes that have acted across the region. Utilizing data from seismograph deployments across the Central African Plateau, including the new Copper Basin Exploration Science network—a NW–SE-trending, 750-km-long profile of 35 broad-band stations—we explore lithospheric deformation fabrics associated with past and present tectonic events via a shear-wave splitting study of mantle seismic anisotropy. Results reveal short length-scale variations in splitting parameters (fast direction: $\phi$, delay time: $\delta$t), suggestive of a fossil lithospheric fabric cause for the observed anisotropy. A lack of fault-parallel $\phi$ across the Mwembeshi shear zone, suggests it may be too narrow at mantle depths, a thin-skinned, crustal-scale feature, and/or did not experience sufficient fault parallel shear-strain during its last active phase to form a lithospheric deformation fabric discernible via teleseismic shear-wave splitting. In the heart of the Lufilian Arc, we observe abrupt changes in splitting parameters with NE–SW, N–S and NW–SE $\phi$ and 0.5 s $< $$\delta$t$< $ 1.2 s evident at short length-scales: no single, uniform, anisotropic lattice preferred orientation (LPO) fabric defines the entire region. This is consistent with the view that multiple episodes of deformation shaped the Lufilian Arc, or perhaps that pre-existing fabrics, relating to Neoproterozoic Katangan Basin development, have failed to be completely overprinted by the Pan-African orogeny. Near the Domes, where most intense crustal re-working is thought to have taken place during the Pan-African orogeny, there is a cluster of null and low $\delta$t splits which likely reflects the lack of organized LPO fabrics, perhaps due to the presence of depth-dependent anisotropy. The neighbouring Congo Craton margin is marked by consistently weak anisotropy ($\delta$t$\lt $ 0.7 s) indicating a weak horizontal alignment of olivine at mantle lithospheric depths, typical of several Archean terranes worldwide.

Sustainable and clean water distillation by parabolic dish collector and different heat absorber and thermal storage materials: An experimental study

In this study, an integrated solar distillation unit with a parabolic dish collector and a spherical solar water distillation unit is designed. The use of parabolic dish collector increases the evaporation rate of the saltwater in the lower chamber (basin) of the spherical distillation unit considerably. The performance of solar water distillation system is investigated for different types of basin material, including copper, zinc, and iron. In the second part, the gravel is used in the copper basin of solar distillation system as the thermal energy storage material. The thermal efficiency, water productivity, exergy efficiency, and freshwater production cost of the integrated solar distillation system with different types of basin materials are studied. The thermal efficiency of the integrated solar distillation system with the copper, zinc, and iron basins was 13.97 %, 10.72 %, and 9.88 %%, respectively. The water productivity of the integrated solar distillation system with copper, zinc, and iron basins was 2.592 kg, 2.27 kg, and 1.825 kg, respectively during 9 h of experiment. The exergy efficiency of the integrated solar distillation system with the copper basin was better than the zinc and iron basins. The gravel can increase the productivity of solar distillation system up to three times in the sunset and night hours.

Numerical and Analytical Determination of Rockburst Characteristics: Case Study from Polish Deep Copper Mine

A simplified analytical method useful for ductile ground support design in underground mine workings is presented. This approach allows for maintaining the stability of sidewalls in rectangular openings extracted in competent and homogeneous rocks, especially in high-pressure conditions, favoring rockburst event occurrence. The proposed design procedure involves the typical assumptions governing the limit equilibrium method (LEM) with respect to a triangular rock block expelled from a sidewall of a long mine excavation subjected to normal stresses of the values determined based on the Maugis’s analytical solution concerned with stress distribution around the elliptical opening extracted within the homogeneous infinite elastic space. This stage of the local assessment of rock susceptibility to ejection from the walls of the excavation allowed for determining the geometry of the block whose ejection is most likely in a given geological and mining situation. Having extensive information about the geometry of the excavations and the properties of the surrounding rocks, it was possible to make an exemplary map of the risk from rockburst hazard, developed as the 2D contours of safety indexes’ values, for special-purpose excavations such as heavy machinery chambers, main excavations, etc. in conditions of selected mining panel of the deep copper mine at Legnica-Głogów Copper Basin, Poland. Another important element of the obtained results is the calculated values of the horizontal forces potentially pushing out the predetermined rock blocks. These forces are the surplus over the potential of frictional resistance and cohesion on the surfaces of previously identified discontinuities or on new cracks appearing as a result of overloading of the sidewalls. Finally, the presented algorithm allows us to perform quantitative tracking of rockburst phenomena as a function of time by determination of acceleration, velocity, and displacement of expelled rocks. Such information may be useful at the stage of designing the support for underground workings.

Combined approach for assessing metal(loid)s leaching, mobility and accumulation in a specific near-neutral (pH) environment of a former Cu-smelting area in the Old Copper Basin, Poland

Topsoils, soil profiles, water, and stream sediments as well as slags and rocks were analyzed to assess the extent and severity of environmental pollution resulting from historical Cu mining and smelting in the vicinity of Leszczyna, Old Copper Basin, SW Poland. Numerous tailings, smelting wastes, and Cu-rich rocks were disposed in the study area, causing long-term leaching and accumulation of various metal(loid)s. Surrounding the anthropogenically impacted area, two types of geochemical background are distinguished, one of which is associated with rocks and soils that are naturally enriched in metal(loid)s and the second one is free of them. The presence of significant anthropogenic changes combined with natural enrichment creates a highly complex environmental situation with regard to different sources of metal(loid)s. Additionally, the ore-hosting carbonate rocks are responsible for specific near-neutral (pH) conditions. With a focus on numerous elements (Cu, Zn, Pb, Ni, As, Cd, Co, Ba, and Cr) we studied spatial and vertical metal(loid)s distributions in soils to determine elements fate under near-neutral conditions. We applied the Synthetic Precipitation Leaching Procedure (SPLP) to evaluate the leaching potential of geogenic and anthropogenic materials and the Acid Neutralization Potential (ANP) test to measure the impact of slags on the pH of local soils. The EDTA extraction indicated high (bio)availability of Cu, Cd, Pb, and Zn, and suggested that metals from Cu-rich rocks are substantially more mobile than these of metallurgical origin. Our data indicate significant metal(loid)s mobility from surface-deposited wastes, especially into soils and stream sediments. The study proves that in the near-neutral conditions wastes are mainly subjected to short-time, rainfall-associated leaching, which is responsible for mobilization of labile metal(loid)s fractions (especially Cu, Pb, Zn, and Cd).

Hydrogen sulphide (H2S) migration in groundwater of the Zechstein strata in the Legnica-Głogów Copper Basin and its vicinity, SW Poland

Hydrogen sulphide (H2S) occurs in groundwater in various lithostratigraphic units of the Zechstein Basin in the Legnica-Głogów Copper Basin (SW Poland). This region is located in the Fore-Sudetic Monocline within which, several tens of kilometres NE of the study area, at greater depths, natural gas fields with hydrogen sulphide (H2S) occur. The Main Dolomite (Ca2), in which H2S-containing natural gas has accumulated, is younger than the Zechstein Limestone (Ca1), which is actively mined. The Ca2 and Ca1 formations are separated by a thick anhydrite succession including a wedge-shaped salt body. Hydrochemical analyses of 18 groundwater samples taken from different horizons within the Zechstein strata showed spatial variability ofH2S and chloride concentrations. A conceptual model of groundwater flow with dissolved H2S in the Zechstein formations was developed. H2S migration is associated with groundwater flow between the Ca2 and Ca1 aquifers through fissures in the anhydrite strata that separate them. Hydraulic contact through fissures in the anhydrite layers is the result of long-term exploitation of the underground copper deposit. Groundwater flow between the layers is influenced by a large change in the piezometric pressure of the groundwater in the depression cone caused by mining drainage.

Blood Lead Level and Handgrip Strength in Preadolescent Polish Schoolchildren.

Environmental pollutions, particularly toxic elements such as lead, are among the most significant factors affecting the growth and functional development of children. The aim of this study was to evaluate the effect of blood lead levels on handgrip strength (HGS) in urban children resident in the Copper Basin of Lower Silesia, Poland, controlling for the effects of chronological age, body size and socioeconomic status. The study included 165 boys (9−11 years of age) and 79 girls (9−10 years of age) from Polkowice town. Anthropometric measurements involved height, body mass and grip strength of the left and right hands. Maternal education was a proxy for socioeconomic status. Based on the median value of blood lead level (3.10 µg/dL), the two groups-below and above/equal median value-were defined. Analysis of covariance revealed that age (all p < 0.001), sex (at least p < 0.01), BMI (all p < 0.001), and blood lead level (at least p < 0.05) had a significant effect on the three indicators of HGS (right hand, left hand, average), while the level of maternal education did not significantly affect HGS (p > 0.05). The results of this study indicate a potentially negative effect of elevated blood lead level on grip strength in preadolescent children, irrespective of sex.

Augmentation and prediction of wick solar still productivity using artificial neural network integrated with tree–seed algorithm

This study introduces a modified artificial neural network (ANN) model based on the tree–seed algorithm (ANN-TSA) to predict the freshwater yield of conventional and developed wick solar stills. The proposed method depends on improving the performance of the ANN through finding the optimal weights of the neurons (elementary units in an ANN) using the TSA. The use of developed wick solar still (DWSS) with copper basin results in increasing the freshwater productivity by about 50% compared with that of conventional wick solar still (CWSS) with steel basin. Then, the proposed ANN-TSA method is utilized to predict the hourly productivity (HP) of CWSS with steel basin and DWSS with copper basin. The real recorded data of the system were used to train the developed models. The predicted HP results of the CWSS and DWSS using ANN-TSA as well as ANN were compared with the experimental results obtained. The present study proves that ANN-TSA can be used as an effective tool to predict the HP of the CWSS and DWSS better than the ANN based on different statistical criteria (R2, RMSE, MRE, and MAE).

Secular Changes in the Age of Menarche of Rural and Urban Girls from an Industrial Region of Poland in Relation to Family Structure.

Purpose: The consequence of better living conditions for every subsequent generation is the phenomenon of change in the rate of maturation and body dimensions. The aim of this study was to evaluate the intergenerational changes in the age of menarche of girls living in rural and urban communities in the industrial region of Poland using samples from two different centuries and to determine the relationship between family structure (two-parent and single-parent) and sexual maturation of the girls in both environments. Methods: The study included 3643 rural and urban girls aged 7–16 from southwestern Poland (Copper Basin). The research was cross-sectional in each environment around 2000 and 2010, and it was carried out twice. Two types of family structure were taken into account: two-parent and single-parent families. The median age of menarche and odds ratio (OR) of menarche depending on the place of residence and family structure were calculated. The status quo method was used when assessing the age of menarche. Results: In both groups, the age of menarche significantly decreased during the decade. The median age of menarche in the urban girls was lower compared with their rural peers, but a significant difference was found only during the second examination (a decade after the first examination). There were no significant changes in menarche during the decade regarding family structure (neither in girls from two-parent families nor those from single-parent families), except in rural girls from two-parent families. Comparing the median age of menarche of girls from two-parent families with girls from single-parent families (urban and rural) showed lower median values in the girls from two-parent families, but no differences were significant. Conclusions: The acceleration of the maturation rate over the last decade has been observed among both rural and urban girls. Environmental differences in maturation rates between rural and urban girls increased over the course of the decade, and the difference between the rural and urban girls’ age of menarche was statistically significant in the second examination (around 2010).The living conditions related to family structure did not significantly affect the timing of menarche.

Age at Menarche in Urban Girls Exposed to Lead in the Copper Basin, Poland.

Simple SummaryLead is an environmental pollutant that negatively affects human growth, development and health. However, research into its effect on age at menarche (first menstruation), a proxy for maturation, is, to some extent, inconclusive. In this study, we identified that lower than currently acceptable blood lead level was related to later menarche. However, body weight and fatness had a moderating effect on this relationship, decreasing its significance.Lead negatively affects human growth and development. In this research, we aimed to assess the effect of elevated blood lead level on age at menarche (AM), controlling for body mass index (BMI) and estimated fatness. The sample included 490 girls aged 7–16 examined in Polkowice town (Copper Basin, Poland) in 2008. Measurements included height, weight, skinfold thicknesses and estimated percentage of body fat. AM was assessed using the status quo method. Blood samples were taken for lead level assessment. Two groups were defined based on the median blood lead level for the total sample of children (3.7 µg/dL). Logistic regression models were used to assess the association between AM and independent variables. The results indicated that menarche in the higher blood lead level group was significantly later compared to the lower blood lead level group (p < 0.01). This relationship remained only marginally significant when BMI (p < 0.10), sum of skinfolds (p < 0.09) or percentage of fat (p < 0.08) were controlled. The results revealed that a lower blood lead level (3.7 µg/dL) than the currently acceptable threshold (5 µg/dL) is related to a later AM; however, this relationship is moderated by body fatness, which may decrease its significance.

An Early Egyptian Copper Basin: Characterization and Case of Warty Corrosion

The work aims to study the manufacturing technique, microstructure features, and morphology and mechanism corrosion of a hammered copper basin belonging to one of the early metallurgy ages in ancient Egypt ( the old kingdom). The examination and analysis were carried out by USB microscope, polarized light microscope, scanning electron microscope equipped energy dispersive X-ray and X-ray diffraction. The results revealed that the basin was made of pure copper metal and manufactured as one piece by a hammering method. Metallographic examination showed a recrystallized microstructure, composed by the mechanical process for manufacturing the basin throughout hammering and annealing. The cylindrical body (rim) was in well- preserved state although it was covered with a thin layer of usual green corrosion products. The pustules of warty corrosion were formed on the inner surface of the rim. The curly shape of malachite corrosion were also observed. The morphology and mechanism of warty corrosion were presented and the difference between this type and the pitting corrosion was discussed. The characterization of the basin contributed to understanding and evaluating the preservation condition, which contributes to choosing the appropriate conservation process.

Reconstruction of Copper Smelting Technology Based on 18–20th-Century Slag Remains from the Old Copper Basin, Poland

This research was conducted on historical copper slags from Leszczyna and Kondratów in Lower Silesia, Poland. The area, formerly known as the Old Copper Basin, was a mining and smelting centre between the 18th and 20th centuries, with a dominant period in the 19th century. Cu-carbonates and residual chalcocite dominate local strata-bound copper deposits. Ore bodies are restricted to carbonate strata. A geochemical and mineralogical study of slag samples from four research sites allowed us to establish that a low amount of sulphur in slags results from S-poor ores, and pyrite with gypsum was implemented as reducing agents. Arkose sandstones served as a flux. During smelting, oxygen availability was limited, and temperature exceeded 1200 °C (18th- and 19th-century smelting) and 1400 °C (20th-century smelting). Calculated viscosity indexes mark the low efficiency of metal separation between the silicate and metallic phases. The skeletal and dendritic form of the crystals proved that slag melt was relatively rapidly cooled after formation, usually in air conditions. We estimated that approx. 2000 m3 of slag was created during the leading smelter (Stilles Glück) activity. The research provided various details of the historical copper smelting technological process in Leszczyna and Kondratów.

Validation of Rayleigh Wave Theoretical Formulation with Single-Station Rotational Records of Mine Tremors in Lower Silesian Copper Basin

The classical Rayleigh surface rotational wave in terms of its theoretical notation and, resulting from this, properties associated with the induced seismic phenomena in mines are presented. This kind of seismic wave was analysed in-depth from the point of view of the parameters governing the form of its mathematical notation based on the similarity to the records obtained during the induced seismicity in near-field 6-DoF monitoring. Furthermore, conducted field measurements made it possible to relate the amount of the emitted seismic energy to the expected highest amplitude of rotational vibrations in the entire field of their impact on the rock mass. As a result, this made it possible to impose the completely defined R wave to the numerical models of given objects; the safety level, when subjected to the dynamic load induced by the rotational wave, would be an objective of the performed analyses. The conducted preliminary analyses were prepared for a plane strain state, for which the values of seismic rotations were evaluated concerning the energy and the distance of the seismic event’s source. As a result of the performed simulations, it was found that the results of the calculations matched with a satisfying degree with the field seismic measurements of the rotational ground motion induced by propagating the seismic wave. Such a verified analytical description of the theoretical formulas can be the basis for the implementation of R-wave characteristics into seismic codes and numerical analyses of object stability in the Lower Silesian Copper Basin region.

Comparative study on passive solar still with copper and mild steel absorber basin trays

To address the demand for water, an economically viable and technically feasible solution is desalinating water in to pure water by using solar stills. There are many factors which affect the performance of the solar still. The productivity and performance of a passive solar still is influenced significantly by climatic parameters like intensity of solar radiation, ambient temperature, wind velocity and design parameters like collector area, aperture ratio, glass thickness, water depth and insulation. Further, the process operating parameters like difference in temperature between surface water and glass cover plate shall be improved for maximizing the yield. In this research article the performance of the solar still with Copper basin is compared to that of Mild steel. Experiments have been carried out in the month of June by using the two different absorber basin trays while maintaining a water depth of 10 mm in the basin. Based on the study outcome Copper basin exhibited a better performance.

Near-Field Measurement of Six Degrees of Freedom Mining-Induced Tremors in Lower Silesian Copper Basin.

The impact of seismicity on structures is one of the key problems of civil engineering. According to recent knowledge, the reliable analysis should be based on both rotational and translational components of the seismic wave. To determine the six degrees of freedom (6-DoF) characteristic of mining-induced seismicity, two sets of seismic posts were installed in the Lower Silesian Copper Basin, Poland. Long-term continuous 6-DoF measurements were conducted with the use of the R-1 rotational seismometer and EP-300 translational seismometer. In result data collection, the waveforms generated by 39 high-energy seismic events were recorded. The characteristic of the rotational component of the seismic waves were described in terms of their amplitude and frequency characteristics and were compared with translational measurements. The analysis indicated that the characteristic of the rotational component of the seismic wave differs significantly in comparison to translational ones, both in terms of their amplitude and frequency distribution. Also, attenuation of rotational and translational components was qualitatively compared. Finally, the empirical formulas for seismic rotation prediction in the Lower Silesian Copper Basin were developed and validated.

Mapping the Recovery Process of Vegetation Growth in the Copper Basin, Tennessee Using Remote Sensing Technology

The Copper Basin (CB) of southeastern Tennessee, known as the Ducktown Mining District, is a classic example of forest and soil destruction due to extensive mining and smelting operations from the mid-1800s until 1987. The smelting operation released a sulfur dioxide by-product that formed sulfuric acid precipitation which, in combination with heavy logging, led to the complete denudation of all vegetation covering 130 km2 in CB. The area has since been successfully revegetated. This study used remote sensing technology to map the different episodes of this vegetation recovery process. A time series of Landsat imagery acquired from 1977 through 2017 at 10-year intervals was used to map and analyze the changes in vegetation cover in CB. These maps were used to generate a single thematic map indicating in which 10-year period each parcel of land was revegetated. Analysis shows that the extent of non-vegetated areas continuously decreased from about 38.5 to 2.5 km2 between 1977 and 2017. The greatest increase in vegetation regrowth occurred between 1987 and 1997, which was the period when all mining and smelting activities ceased. This research could be very useful to better understand the recovery process of areas affected by mining and smelting processes.

THE ANALYSIS OF SEISMIC LOAD CHARACTRESITIC OBSERVED IN THE LOWER SILESIAN COPPER BASIN

One of the major problems associated with the excavation of the copper deposits in underground mines in Poland is the relatively high level of seismic activity. Numerous high-energy tremors can negatively affect the stability of underground workings and can have a destructive impact on the infrastructure located at the surface as well. As predicted, the seismic activity increases along with the depth of mining operations. Therefore, to face these threats, a number of organizational and technical prevention methods have been applied in the mines. One of them is the assessment of the effect of additional dynamic loads on the structures behaviour with the use of numerical modelling. Recently there have been some possibilities of conducting dynamic analyses, i.e. using the finite element method that allows gathering information on the changes in stress conditions or deformation levels within the analysed object. Unfortunately, these kinds of calculations are usually performed after the occurrence of an unwanted event, so it is rather a post factum method. This is mainly due to the lack of information about the worst scenario of seismic wave distribution. At the same time, during the preliminary risk assessment, in most cases, only the maximum predicted value of seismic wave amplitudes is taken into consideration. Other dynamic parameters such as dominant frequency and duration of seismic wave are usually omitted.&#x0D; In this paper, the time-frequency characteristics of induced seismic waves observed within the Lower Silesian Copper Basin were analysed. Based on the high-energy seismic events database, dominant frequencies, amplitudes and tremor durations were determined. Then the correlation between each parameter, i.e. the energy of each tremor and their hypocentic distance from the seismic source and monitoring station were determined.

Enhancing thermal performance and modeling prediction of developed pyramid solar still utilizing a modified random vector functional link

This study introduces a modified random vector functional link (RVFL) as an alternative prediction method for the thermal performance of a developed pyramid solar still (DPSS), which consists of a copper basin integrated with graphite nanofluids. Experimental work is performed to investigate the performance enhancement of the DPSS. The real experimental data are recorded and utilized to build the proposed prediction models based on artificial neural network (ANN). Four ANN prediction models are presented, evaluated and compared to strength the prediction of the thermal performance of the DPSS. Different six statistical criteria are used to determine the optimal prediction model to be implemented in the prediction of the hourly freshwater (HF) and instantaneous energy efficiency (IEE) of the DPSS. From the experimental investigation, the use of proposed DPSS has total freshwater productivity of 5.26 L/m2. The performed comparative study shows that the proposed RVFL approach tunned by firefly algorithm (FA), called FA-RVFL, is of optimal performance to be the best model among the investigated prediction models. The proposed FA-RVFL model is characterized by a determination coefficient of 0.981 and 0.999 and regression values of 0.996 and 0.999, respectively for the total data sets of HF and IEE. The present study shows the efficiency of proposed DPSS to enhance the freshwater capacity. Besides, it proves that FA-RVFL can be used as an effective tool to predict the thermal performance of the solar stills compared to the other models with no need for further experiments, thus saving financial expenses, effort, and time.

Influence of basin metals and novel wick-metal chips pad on the thermal performance of solar desalination process

In this study, efforts were made to enhance the performance of inclined wick solar still (IWSS) by integrating different basin metals and a novel wick-metal chips pad. Three different metal materials (aluminum, copper, and steel) were used as basin and their metal chips were sandwiched in a novel wick-metal pad. Experiments were carried out to figure out the influence of different basin metal materials and their metal chips filled in a wick pad on the thermal performance of IWSS. The enhanced solar still was compared with conventional inclined wick solar still (CIWSS). Results revealed that using aluminum and copper basins led to increase the productivity by 34.23% and 54.26%, respectively, compared with CIWSS. The use of metal chips sandwiched between two layers of wicks (wick-metal chips pad) caused an increase in the daily production by about 27.76%, 41.54, and 65.3% for steel, aluminum, and copper, respectively. This implies that the basin materials and the novel wick pads with metal chips, which acted as evaporation surface and heat storage medium, played a vital role in enhancing productivity. Also, the maximum thermal efficiency was 60.98% for the modified IWSS with copper basin and a novel wick-copper chips pad. While, the maximum thermal efficiency for the CIWSS with steel basin was 37%. To understand the temperature distribution through different layers of desalination surfaces, a numerical simulation was carried out under real weather conditions using the finite element software; COMSOL Multiphysics. Results showed that, there was a good agreement between experimental work and numerical investigation.

Influence of reagent dose on the flotation selectivity of copper ore from LGOM area (SW Poland)

The influence of amount of flotation reagents on the efficiency of copper ore flotation in standard laboratory experiments was investigated. The aim of the study was to evaluate the effect of collector and frother amount on the selectivity of copper upgrading during flotation process of dolomite-shale ore from Fore-Sudetic Monocline area (Legnica-Glogow Copper Basin). The amount of collectors added in industrial conditions was the starting point for the process assessment. Since the dose of flotation reagents influences on the quality and quantity parameters of obtained concentrates, a decrease or increase of reagent dosage can have a major impact on the overall metal production costs at the mining-metallurgical complex.

Coarse muscovite veins and alteration in porphyry systems

Coarse muscovite veins and alteration occur in porphyry copper and porphyry molybdenum-copper systems within the Laramide arc in Arizona, as well as at the Yerington district in Nevada. This work describes coarse muscovite in veins and altered wall rock in porphyry systems in this region and documents mineral assemblages, mineral compositions, spatial and temporal relationships, and hydrogen isotopic compositions. Coarse hydrothermal muscovite is documented in the roots of porphyry Cu ± Mo systems, as well as in and above the ore bodies in porphyry Mo-Cu systems, and it is compared to coarse hydrothermal muscovite (greisen) in lode Sn-W-Mo systems.Basin and Range extension has exposed coarse hydrothermal muscovite in several Laramide and Jurassic porphyry Cu (±Mo) systems, at paleodepths of ~3 to 12 km: Miami-Inspiration, Sierrita-Esperanza, Copper Basin (Crown King), Granite Mountain (roots of the Ray porphyry system), Gunnison (Texas Canyon stock), Grayback (Kelvin-Riverside district), Sycamore Canyon, the New Cornelia mine (Ajo district), and two systems in the Yerington district. Muscovite is the dominant mica in these coarse muscovite veins and associated alteration, with common K-feldspar and albite (An00-06), common accessory hematite, rutile, pyrite, and apatite, and rare accessory chalcopyrite, fluorite, molybdenite, wolframite, and scheelite. Coarse hydrothermal muscovite yields δD compositions that suggest formation from fluids that are dominantly magmatic-hydrothermal in origin. Whole-rock compositions of coarse hydrothermal muscovite show common gains in K and loss of Ca ± Na. Coarse muscovite veins and alteration in porphyry copper systems postdate mineralized potassic veins and form too deeply to overlap with shallower acidic forms of alteration (sericitic, advanced argillic).Variation in mineral assemblage, mineral compositions, and mineralization of coarse hydrothermal muscovite correlate with the composition of Laramide stocks. Porphyry Mo-Cu systems contain coarse muscovite alteration assemblages with the highest mineral diversity and trace-element enrichment. Coarse muscovite veins and alteration in porphyry Mo-Cu systems related to stocks ranging from quartz monzonite to granite in composition form at shallower paleodepths and occur within and above the associated orebodies. In contrast, coarse muscovite veins and alteration associated with subalkaline porphyry copper systems occur at deeper levels, in some cases overlapping with the bottom of potassic alteration and the ore body but extending well into the roots of the system in the underlying granitoid cupola. In these latter systems, zones of coarse muscovite alteration typically are poorly mineralized and mineral assemblages are less varied. These characteristics suggest that coarse muscovite-forming fluids are predominately of magmatic-hydrothermal origin and exsolved from late-stage, fractionated magmas of the larger pluton that sourced porphyry stocks and dikes responsible for porphyry copper mineralization. In some instances, however, the exposed coarse muscovite alteration is associated with a petrologically unrelated, commonly more felsic, later intrusion, rather than being related to late exsolution of fluid from the same crystallizing stock or batholith.