Antimony-Gold mineralization in Rates (Northern Portugal)

2021 ◽  
Author(s):  
Alexandre Lima ◽  
Rui Frutuoso ◽  
Sara Leal ◽  
André Vieira ◽  
Maria Ribeiro
Keyword(s):  
Gold Mineralization ◽  
Sulfide Mineral ◽  
Mining District ◽  
Portable Xrf ◽  
Field Reconnaissance ◽  
Petrographic Analyses ◽  
Mineralogical Study ◽  
Rock Chip ◽  
Mining Works ◽  
North Western

<p>In the Dúrico-Beirão mining district several paragenetic associations have been described in gold mineralizations, including Sb-Au. The objective of this research was the study of the Sb-Au mineralization in the Rates area, from field reconnaissance of the mineralized structures by soil sampling to the petrographic and mineralogical study of the parageneses associated with this gold mineralization, mined by the Romans.</p><p>The portable XRF was used to measure Sb and As in farms and forest soils. The observed Au-Sb-As anomalies in the Rates area must be linked to Lagoa Negra mine by the same north-western trend fault. Historical mining works have been identified both in Lagoa Negra and in Rates, where rock-chip sampling returned results up to 30 g/t Au from the Rates prospect.</p><p>Some rock samples from Rates were studied by geochemical and petrographic analyses and were analysed in detail by scanning electron microscopy. The results indicate that the paragenetic association in Rates is Sb-Au, with stibnite as primary Sb sulfide mineral, valentinite as alteration mineral, and gold in native and granular form.</p><p><strong>Acknowledgment</strong></p><p>The work was financial supported within the compass of the ERA-MIN/0005/2018—AUREOLE project, FEDER through operation POCI-01-0145-FEDER-007690 funded by the Programa Operacional Competitividade Internacionalização—COMPETE2020 and by National Funds through FCT within the ICT (reference UIDB/04683/2020).</p>

scholarly journals Mineralogical Study and Genetic Model of Efflorescent Salts and Crusts from Two Abandoned Tailings in the Taxco Mining District, Guerrero (Mexico)

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 871
Author(s):  
Teresa Pi-Puig ◽  
Jesús Solé ◽  
Adriana Gómez Cruz
Keyword(s):  
Genetic Model ◽  
Rietveld Method ◽  
Short Wave ◽  
Mining District ◽  
X Ray Diffraction ◽  
Wet Season ◽  
X Ray ◽  
Icp Ms ◽  
Mineralogical Study ◽  
Plasma Mass Spectrometry

The mineralogy of surface crusts and efflorescent salts of two old abandoned tailings (Xochula and Remedios) of the mining district of Taxco, Guerrero, was studied by short-wave infrared spectroscopy (SWIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The chemistry of the selected samples was studied with induced coupled plasma mass spectrometry (ICP–MS). Principal mineralogy is composed of hydrated sulfates of iron (di-trivalent), other less-soluble sulfates such as gypsum and jarosite, and oxides–hydroxides of iron, all of which are the result of the weathering of sulfides (mainly pyrite) accumulated in mining waste. Using quantitative X-ray diffraction (Rietveld method) and the spatial distribution of secondary minerals, two main zones (lateral and central) have been established in both tailings. The genetic model for their formation shows that the secondary iron minerals (sulfates, oxides, and hydroxides) in these deposits have been formed at least in three different stages, mainly by oxidation, dissolution, and precipitation processes in combination with dehydration and primary sulfides neutralization reactions. The chemical analyses of some salts confirm the presence of potentially toxic elements (PTE) in their structure and therefore indicate that the dissolution of the efflorescences in these deposits is a potential source of contamination during the wet season.

The Geology and Mineralogy of the Loulo Mining District, Mali, West Africa: Evidence for Two Distinct Styles of Orogenic Gold Mineralization

2013 ◽  
Vol 108 (2) ◽  
pp. 199-227 ◽  
Author(s):  
D. M. Lawrence ◽  
P. J. Treloar ◽  
A. H. Rankin ◽  
P. Harbidge ◽  
J. Holliday
Keyword(s):  
West Africa ◽  
Gold Mineralization ◽  
Orogenic Gold ◽  
Mining District ◽  
Orogenic Gold Mineralization

Gold distribution in the Val-d'Or Formation and a model for the formation of the Lamaque–Sigma mines, Val-d'Or, Quebec

1991 ◽  
Vol 28 (5) ◽  
pp. 706-720 ◽  
Author(s):  
Mehmet F. Taner ◽  
Pierre Trudel
Keyword(s):  
Gold Mineralization ◽  
Regional Metamorphism ◽  
Analytical Techniques ◽  
Shear Zones ◽  
Gold Deposits ◽  
Mining District ◽  
Volcanic Complex ◽  
Geothermal Systems ◽  
Gold Mines ◽  
Geothermal Activity

Recent lithogeochemical studies by accurate analytical techniques (e.g., instrumental and radiochemical neutron-activation analyses) have been used to explore the possibility of using gold distribution in the research for new gold deposits; these show that anomalous gold distribution occurs in some parts of the Val-d'Or Formation in the Val-d'Or mining district of Quebec. Gold lithogeochemistry in the Val-d'Or Formation has shown that it is possible to distinguish: (i) background values (1.4–3.5 ppb Au); (ii) zones of primarily anomalous gold values around the Lamaque–Sigma mines (median: 15 ppb Au); (iii) enrichment halos around gold orebodies (median: 70 ppb Au); and (iv) secondary gold enrichment in shear zones. We conclude that the Val-d'Or Formation is auriferous, i.e., anomalously rich in gold at least in some of its parts and contains the Lamaque – Sigma gold mines, representing 68% of the total gold production in the district. The Val-d'Or Formation is part of a central volcanic complex within an island-arc system. The centre of this complex is located in the main Lamaque plug, and this environment may be compared to high-temperature active geothermal systems that are commonly responsible for the formation of epithermal gold deposits. Gold mineralization at Sigma and Lamaque is considered to be related to a late hydrothermal phase or a retrograde phase of regional metamorphism. For the formation of the gold deposits, two distinct and successive events are postulated: (i) a gold-rich synvolcanic geothermal activity and (ii) a late remobilisation from the host rocks followed by deposition of gold ore within favourable structures.

An Analysis Of The Interaction During Simultaneous Use Of Copper Ore And Salt Deposits In The LGOM Mines With Regard To Displacement And Deformation Of Rock Mass

2015 ◽  
Vol 60 (2) ◽  
pp. 535-548
Author(s):  
Edward Popiołek ◽  
Zdzisław Kłeczek ◽  
Zygmunt Niedojadło ◽  
Ryszard Hejmanowski ◽  
Wojciech Skobliński ◽  
...  
Keyword(s):  
Rock Mass ◽  
Land Surface ◽  
Mineral Resources ◽  
Theoretical Models ◽  
Mining District ◽  
Copper Ore ◽  
Rock Mass Deformation ◽  
Mining Works ◽  
Mining Tremors ◽  
The Impact

Abstract Excavation of the two bedded deposits of mineral resources in a small vertical distance may cause additional increased mining risks (rock mass deformation, rock bursts and mining tremors, threat to land surface). This paper considers the impact of excavation of the copper ore deposit on the bed of rock salt located above it and the opposite, in terms of displacements and deformations. We used the theoretical models of processes verified by previous in situ observations in the mines of the Legnica-Głogów Copper Mining District. We analysed the potential for reducing the risks, among others, through coordination of mining works.

Age and sources of gold mineralization in the Marmato mining district, NW Colombia: A Miocene–Pliocene epizonal gold deposit

2008 ◽  
Vol 33 (3-4) ◽  
pp. 505-518 ◽  
Author(s):  
Colombo Celso Gaeta Tassinari ◽  
Fabio Diaz Pinzon ◽  
Juaquin Buena Ventura
Keyword(s):  
Gold Deposit ◽  
Gold Mineralization ◽  
Mining District

scholarly journals PROSPECTS OF NEWLY DISCOVERED UGUR AREA IN THE NORTHWEST OF THE GEDABEY ORE DISTRICT (LESSER CAUCASUS, AZERBAIJAN)

2021 ◽  
pp. 53-63
Author(s):  
N. Imamverdiyev ◽  
V. Baba-zadeh ◽  
S. Mursalov ◽  
A. Valiyev ◽  
M. Mansurov ◽  
...  
Keyword(s):  
Gold Mineralization ◽  
Gold Silver ◽  
Rock Chip ◽  
Hydrous Ferric Oxides ◽  
Lesser Caucasus ◽  
Exploration Area ◽  
Drill Holes ◽  
Positive Results ◽  
East West ◽  
Ore District

The article describes Ugur exploration area located in Gedabey Ore District of the Lesser Caucasus in NW of Azerbaijan. Results of trenches and channels sampling on the surface, RC bore holes and summary of significant drill intercepts (>0.29 ppm Au) of Ugur Exploration area are presented. It has been established that The deposit is enlarged by highly gold-silver result of surface outcrop rock chip samples over an area of 2.5 kms North-South by 2 kms East-West, with the Reza gold deposit located in the central part. Out of metallic minerals crystalline hematite was observed. On surface intensive barite and barite-hematite vein and veinlets, also gossan zones were observed. The main mineralization zones have been sampled in three trenches at a distance up to 270 m by trenches #1, #2 and #3 and received positive results for gold and silver. Also there have taken approximately 550 samples from outcrop #1 and #2. On the main orebody at surface centre there occured secondary quartzites with vein-veinlets barite-hematite mineralization over which there remain accumulations of hydrous ferric oxides cementing breccias of quartz and quartzites. And in erosion parts "reddish mass" being oxidation product of stock and stockverk hematite ores were observed. Representing typical gossans, these accumulations by the data of trenches for thickness about 5-10 m contain gold 0.3-2.0 ppm and silver 1.0-15.0 ppm. Ten diamond drill holes, named UGDD 01-10 were drilled in the center part of the deposit. The drill holes were sampled mainly in 1 meter lengths from the top of the hole to the bottom. The core samples were marked and placed into standard boxes. Significant intervals of weighted averages greater than 0.29 ppm over down hole intervals of 1 metres or greater (>0.29 ppm Au and >0.9 m) are summarized in table 3 below. In conclusion, the outcropping alteration at the deposit is typical of the upper steam-heated levels of high-sulfidation epithermal (HSE) deposits, which in most mineralized systems of this type, may cap higher-grade gold mineralization which is hosted by underlying vuggy and oxide zones.

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