Mining District Research Articles

Sulphide petrology and ore genesis of the stratabound Sheep Creek sediment-hosted Zn–Pb–Ag–Sn prospect, and U–Pb zircon constraints on the timing of magmatism in the northern Alaska Range

The Sheep Creek prospect is a stratabound Zn–Pb–Ag–Sn massive sulfide occurrence in the Bonnifield mining district, northern Alaska Range. The prospect is within a quartz–sericite–graphite–chlorite schist unit associated with Devonian carbonaceous and siliceous metasedimentary rocks. Volcanogenic massive sulfide (VMS) deposits in the district are hosted in felsic metavolcanic rocks (362 ± 2 Ma) associated with siliciclastic and carbonaceous sedimentary rocks that overlie the stratigraphic sequence hosting the Sheep Creek prospect. Felsic metaigneous rocks in underlying units are 372 ± 4 to 366 ± 4 Ma. Sheep Creek is atypical of the other sulfide deposits in the district in (1) having Sn grades up to 1.2%; (2) being contained in fine-grained, quartz-rich rocks and quartz–pebble conglomerate that likely originated as chert and chert-clast sediment, respectively; and (3) showing minimal evidence of volcanic components in the host rocks. Comparison of immobile trace-element proportions for graphitic and siliceous rocks from the Sheep Creek area with those for argillite associated with the Bonnifield VMS deposits indicates a continental volcanic-arc provenance for the former and a within-plate and passive margin provenance for the latter. In contrast to previously published interpretations, our data analysis supports a clastic-dominated (CD) rather than a VMS affinity for the Sheep Creek prospect. In our model, Zn–Pb–Ag–Sn mineralization formed by syngenetic or early diagenetic processes on or beneath the seafloor, possibly in the shallow-water environment of an outer continental shelf setting. Potential analogues are the Paleozoic CD deposits in the Canadian Selwyn Basin outboard of the Laurentian continental margin.

State-Owned Factories Rented from the Treasury: Zlatoust Mining District During the Period of “Commercial Law” 1811–1829

State-Owned Factories Rented from the Treasury: Zlatoust Mining District During the Period of “Commercial Law” 1811–1829

Deep Structure of Nanling-Xuancheng Ore District, Eastern China: Insights from Integrated Geophysical Exploration

As the depth of mineral exploration increases, integrated geophysical methods are increasingly playing a crucial role in prospecting deep structures at the district scale. The Nanling-Xuancheng ore district is the eighth ore district in the middle-lower Yangtze metallogenic belt in China. To reveal the deep structure of the mining district, this study mainly focuses on regional high-precision gravity and magnetic data and integrates the interpretation of magnetotelluric and reflection seismic data from a key area. By using a 2.5D joint inversion method with prior information constraints, new insights into the deep structures, tectonic deformation, and magmatic activity are obtained. Structurally, the Nanling-Xuancheng ore district presents a structural pattern of “two uplifts and two depressions” composed of multi-level thrust-overturned and folds formed by Mesozoic depressions, which has a three-layer structure in the vertical direction (shallower than 10 km). Tectonically, the main faults in the study area trend NW, which intersect with NE-trending and EW-trending faults to form a branching structure from deep to shallow. The fault intersections provide pathways for magma intrusion. The distribution of deep-seated concealed magmatic rocks shows the characteristic pattern of “a primary magma source spawning multiple subsidiary intrusion”.

Silver, cobalt and nickel mineralogy and geochemistry of shale ore in the sediment-hosted stratiform Nowa Sól copper–silver deposit, SW Poland

The Nowa Sól deposit is a part of the newly discovered Northern Copper Belt and is situated some 30 km NW of the Lubin–Sieroszowice mining district (the so-called New Copper District) in SW Poland. The ore horizon spans across the upper part of the Lower Permian (Rotliegend) terrestrial redbeds and the lower part of the Upper Permian (Zechstein) marine rocks. It comprises three lithotypes: sandstone, shale and carbonate. The high-grade shale ore has polymetallic characteristics and is a crucial host for by-product metals such as Ag, Co and Ni (studied in this paper), but also Mo, V and Re. The results of bulk-rock and electron microprobe as well as mineralogical (optical and scanning electron microscope) data of the mineralized, organic-rich shale ore from the Nowa Sól deposit are presented. This thin stratigraphic horizon, ranging from 0.06 to 0.59 m, shows notable concentrations of critical metals, including on average 15.9 wt% Cu, 715 grams per tonne (g t -1 ) Ag, 318 g t -1 Co and 345 g t -1 Ni. It constitutes less than 10% of the total ore mass, but accounts for 36% of the Ag, 40% of the Ni and 42% of the Co found within the deposit. The ore sulfides in the mineralized shale in the Nowa Sól deposit include chalcocite, djurleite and bornite, accompanied by digenite, covellite, tennantite, galena, sphalerite and pyrite. The Ag content within the Cu sulfides exhibits a linear decrease: chalcocite > djurleite > bornite. Three primary Ag minerals are identified within the shale ore, namely native Ag, Ag amalgam and stromeyerite. Two types of Ag amalgam are observed: Hg-rich and Hg-poor. Cobaltite and gersdorffite represent the primary Co and Ni minerals, occurring as micrometre-sized inclusions within chalcocite and djurleite. Textural observations suggest that the Ag, Co and Ni mineralization postdates the major phase of Cu sulfide precipitation. It is shown that in the Nowa Sól deposit, the Kupferschiefer horizon has acted as a geochemical barrier for the above-mentioned metals during protracted time, from early syndepositional to late epigenetic stage of basin evolution. Supplementary material: The supplementary material contains the results of the electron microprobe analyses and the specific experimental conditions employed for these analyses – available at https://doi.org/10.6084/m9.figshare.c.6873631

The Book by J. P. Eberhard on Applied Mathematics from the Book Collection of Kolyvan-Voskresensk Mining Plants

The purpose of the article is to consider the book by J. P. Eberhard (Johann Peter Eberhard, 1727– 1779) “Beiträge zur Mathesi Applicata...” (1757) in the context of the reconstruction of the composition of the foreign part of the book collection of Kolyvan Voznesensk mining plants. The edition is a collection of articles on applied mathematics, devoted to the issues of mechanics, optics and gnomonics and intended, according to Eberhard,“for students attending his lectures, for other teachers to prepare and conduct classes, and for those who want to help themselves in the study of applied mathematics”. The article defines the affiliation of the book to the library collections of the Kolyvan Voznesensk mining plants on the basis of service marks, reflecting the earliest stages of the use of the copy as a part of the Altai state libraries collections, attention is paid to thepersonality of the German author, whose works undoubtedly were a part of the scientific and technical thought of Europe in the second half of the XVIII century, the content of the articles composing the book and their compliance with the tasks of the Altai mining industry are revealed. The work “Beiträge zur Mathesi Applicata...” is considered in the context of other works, the continuation of which, according to the author's definition, it is and which, according to our assessment, are also presented in the book collection of the Kolyvan-Voskresensk mining plants. The results of the study expand the idea of the scale of J. P. Eberhard's personality and the relevance of his work for professional mining education and ensuring the production process in the Altai Mining District in the XVIII century, also add to the history of creation of the first in Siberia scientific technical library collection.

Patterns of accumulation and baseline values for metals in agricultural soils from a copper mining region in southern Peru

As global copper demand surges, it's vital to conduct a thorough analysis of metal concentrations in the agricultural soils of mining districts. This is especially pertinent for the Andean region, where, in the face of clear soil degradation, there's a notable lack of in-depth research. This study is the first attempt to characterize variations in the concentration of 17 metals in the agricultural soils of Moquegua – a region with a long history of mining activity that contributes significantly to Peru's position as the world's second-largest producer of copper. The surface horizons of 336 agricultural soils under vegetable crops were sampled between 9 and 3,934 m above sea level (m.a.s.l.) to determine the total content of metal nutrients (MNs) (Ca, Mg, K, Na, Fe, Cu, Mn, Zn) and heavy metals (HMs) (Cd, Cr, Ni, Pb, As, Co, Ba, V, Al) by inductively coupled plasma-optical emission spectrometry (ICP-OES). The accumulation of metals was found to increase with altitude. The study identified hotspots with a high concentration of metals and spatial patterns in their geographic distribution. The observed median values for As (70.9 mg/kg), Cd (7.1 mg/kg), and Pb (89.7 mg/kg) represent the highest metal concentrations among the identified clusters. Notably, these values surpass the Environmental Quality Standards (ECA) set for agricultural soils in Peru. As there are no local standards for all the metals studied, our results can serve as reference values for guiding land management practices, particularly in the context of copper mining.

Share ownership and the introduction of no liability legislation in nineteenth-century Australia

The no liability company – where investors are not liable for uncalled parts of their shares – is unique to Australasia. Deploying a large dataset, we provide the first empirical examination of the effects of this new corporate type on company formation and shareholding. Victorian gold mining was the earliest and most pervasive user of no liability. No liability companies largely replaced limited liability within a decade of the legislation in 1871, which was more rapid than the transition from unlimited to limited liability companies in several other nations. No liability firms attracted a broader range of investors, geographically beyond the mining districts, and amongst occupations most conscious of their benefits, especially gentlemen and financiers who believed they were less risky because of the removal of call liabilities and the mitigation of previous regulatory failures. No liability was a response to the high risks of gold mining in an itinerant early settler society.

Bio-Monitoring of Metal(loid)s Pollution in Dry Riverbeds Affected by Mining Activity.

The aim of this study was to evaluate the most abundant native plants that could be used as a bio-monitor of metal(loid) concentration in dry riverbeds affected by mining activities. Three plants species and their respective rhizospheric soils were sampled from the El Beal (Piptatherum miliaceum, 15 samples), La Carrasquilla (Foeniculum vulgare, 10 samples), and Ponce (Dittrichia viscosa, 12 samples) dry riverbeds from the mining district of Cartegena-La Unión (SE Spain). There is scanty bibliography of the capacity of these species to be used as bio-monitors in the dry riverbeds. Plants categorized as a bio-monitor were established according to the bioaccumulation factor (BF), mobility ratio (MR), and linear correlations between metal(loid) concentrations in plants tissues (root or stem)-rhizospheric soils. The rhizospheric soils were highly contaminated for As, Cd, Pb, and Zn (Cf ≥ 6), and moderately contaminated for Mn (1 ≤ Cf < 3). Piptatherum miliaceum presented on Cd similar mean concentrations on rhizospheric soil and root, BF = 1.07, with a strong correlation soil-root (r = 0.61, p = 0.02). Therefore, of the three species with the capacity to grow in the area, Piptatherum miliaceum showed characteristics to be considered as a bio-monitor for Cd, with a BF > 1, and a positive-significant correlation between the rhizospheric soil and roots.

Alicyclobacillus sp. SO9, a novel halophilic acidophilic iron-oxidizing bacterium isolated from a tailings-contaminated beach, and its effect on copper extraction from chalcopyrite in the presence of high chloride concentration

Many acidophilic iron-oxidizing bacteria used in the mining industry for the bioleaching of sulfidic minerals are intolerant to high chloride concentrations, resulting in problems where chloride occurs in the deposit at high concentrations or only seawater is available. In search for strains tolerating such conditions a tetrathionate- and iron-oxidizing bacterium was isolated from a tailings-contaminated beach sample at Portman Bay, Cartagena-La Union mining district, Spain, in the presence of 20 g l−1 (0.34 M) sodium chloride. The isolate was able to form spores, did not grow in the absence of NaCl, and oxidized ferrous iron in the presence of up to 1.5 M (∼87 g l−1) NaCl. Genome sequencing based on a combination of Illumina and PacBio reads revealed two contigs, a circular bacterial chromosome of 5.2 Mbp and a plasmid of 90 kbp, respectively. The chromosome comprised seven different 16S rRNA genes. Submission of the chromosome to the Type (Strain) Genome Server (TYGS) without preselection of similar sequences revealed exclusively type strains of the genus Alicyclobacillus. In the TYGS analyses the respective most similar species were dependent on whether the final tree was derived from just 16S rRNA, from the genomes, or from the proteomes. Thus, TYGS analysis clearly showed that isolate SO9 represents a novel species of the genus Alicyclobacillus. In the presence of artificial seawater with almost 0.6 M chloride, the addition of Alicyclobacillus sp. SO9 improved copper dissolution from chalcopyrite (CuFeS2) compared to abiotic leaching without bacteria. The new isolate SO9, therefore, has potential for bioleaching at elevated chloride concentrations.

Metallogenic model of the Eocene Santa María and Antares Zn-Pb(-Ag) skarn deposits, Velardeña Mining District, Durango, Mexico

The Santa María and Antares Zn-Pb(-Ag) skarn deposits in the Velardeña Mining District are located in central–NW Mexico. They lie 470 m apart along the contact between Oligocene felsic intrusions and Cretaceous limestones, and were developed during prograde, retrograde, post-ore (Santa María), and late stages. Firstly, the prograde stage was formed by fluids at ~ 600 °C and 15 wt% NaCl equiv., and consists of garnet + wollastonite ± clinopyroxene and biotite ± K-feldspar assemblages. Secondly, the retrograde/ore stage was formed by fluids at 300–500 °C with salinities of 20–30 wt% CaCl2 (Santa María) and > 40 wt% NaCl equiv. (Antares). It comprises assemblages of chlorite, amphibole, epidote, calcite, scapolite, quartz, sericite, adularia, fluorite, and muscovite associated with sphalerite, pyrite, galena, pyrrhotite, arsenopyrite, chalcopyrite, and Pb-Bi-Sb sulfosalts. Thirdly, the post-ore stage was formed by fluids at ~ 400 °C and 20–30 wt.% CaCl2 and comprises poorly mineralized calcite veins. Fourthly, the late stage was formed by fluids at < 300 °C and 20–30 wt.% CaCl2 (Santa María) and ~ 15 wt% NaCl equiv. (Antares), and crystallized tetrahedrite-group minerals and pyrite + marcasite. δ18Ofluid between ~ 14‰ and 23‰ at Santa María and between ~ 12‰ and 17‰ at Antares show a less-modified magmatic affinity for mineralizing fluids at Antares; δ13Cfluid between 0‰ and –6‰ register recycling of sedimentary C. Moreover, sulfides with δ34SVCDT between –3‰ and 2‰ reveal a magmatic source for S. Altogether, these data suggest that, at Santa María, magmatic-derived fluids actively interacted with the wall rocks, whereas at Antares the fluid-rock interaction was milder. In both deposits, metal deposition was triggered by the cooling and neutralization of ore-bearing fluids with carbonate rocks. Our 40Ar/39Ar dates for adularia of ca. 37.5 Ma place the deposits within the Eocene–early Miocene metallogenetic epoch of central–NW Mexico, during which other world-class skarn-epithermal systems were emplaced (e.g., Concepción del Oro and Mazapil-Peñasquito).

Application of the Water Quality Index to Assess Groundwater Quality in the Bou Dhar Mining District in Beni Tajjit (High Atlas, Morocco)

Application of the Water Quality Index to Assess Groundwater Quality in the Bou Dhar Mining District in Beni Tajjit (High Atlas, Morocco)

Investigation of Gold Recovery and Mercury Losses in Whole Ore Amalgamation: Artisanal Gold Mining in Nambija, Ecuador

Mercury is a highly toxic pollutant that can negatively affect human health and the environment; informal mining is one of the main sources of anthropogenic mercury release due to the separation or concentration by amalgamation that is still used to recover gold directly from ore. In the Nambija mining district, there is still informal mining based on practically no technical knowledge, which uses amalgamation as a processing technique for gold recovery. The production tasks that directly affect the handling of mercury during the in situ grinding–amalgamation process are monitored here. Experimental grinding tests were initially carried out in a “chancha” bar mill for a range of ore sizes and as a function of time; then, experimental tests were performed at the macro-level on grinding cycles in Chilean mills. Considering the characteristics of the ore mineral and the operation of the Chilean mills, it was determined that it is possible to reduce the Hg input to mill by up to 20% (at source). Experimental grinding–amalgamation tests were carried out at different times along with a grain size analysis of the ore; the recovery establishes the grinding time and the fraction in which the gold is extracted in a greater proportion, which affects the control of the amalgamation times. The mercury dosage used by the miners in the amalgamation process should be reduced, considering trials where there is better gold recovery and with the purpose of also reducing mercury losses; eventually, it is possible to jointly achieve an increase in gold recovery.

The Transportation Revolution and the English Coal Industry, 1695–1842: A Geographical Approach

Cross sections of coal prices in England for 1695, 1795, and 1842 are used to infer transportation rates by sea, river, canal, and road. The effectiveness of monopolies, the degree of market integration, and the patterns of regional supply of each mining district are then established. The growth rates of productivity in sea, river, and road transport from 1695–1842 are computed and combined with a social savings assessment of canals to measure the overall growth in the productivity of shipping coal. Productivity growth was substantial but had a surprisingly limited impact on the geography of production and consumption.

Активність фотосинтетичного комплексу бріофітів на трансформованих територіях видобутку вугілля

It was investigated the seasonal dynamic of photosynthetic pigments content in shoots of the Ceratodon purpureus from different positions and local growing on dumps of the Chervonograd mining district. It was established that the quantitative composition of the a &amp; b chlorophyll (chl a and chl b), ratio of the a/b and chlorophylls/carotenoids (Chl/K) in the moss cells changed depending on the position of their local growing on dumps and microclimatic conditions: temperature regime, solar radiation and humidity of the substrate. It was found that in April on open areas where Ceratodon purpureus grew, the content of chlorophyll a in its shoots increased, in July the amount of green pigment (chl a) significantly decreased, and the a/b ratio was lower than in spring. In the summer, content of the carotenoids in the moss cells on the illuminated areas increased, compared to the spring indicators, which prevented possibility of the photooxidation and formation of the free radi­cals under conditions of high insolation and temperature. In autumn, the content of both green pigments and auxiliary pigments in the Ceratodon purpureus shoots, selected from different positions of dumps, mostly decreased, compared to the summer indicators. Chan­ges in quantity and ratio of pigments in different periods of the year on the dumps testified about adaptive character of the mosses photosynthetic system, which contributed to more efficient using of the different intensities solar radiation. Depending on the position on the rock dumps and the degree of their reclamation, the indicators of the chlorophyll index for mosses synusiae were determined. It was found that the indicators of the chlorophyll index depended on the ecological conditions of moss growing in the technogenic environment, the composition of the bryoflora, the amount of green pigments in the photosynthetic organs, and the area of the assimilating surface. For the studied briosynusiae the largest stock of phytomass and the indicators of the chlorophyll index was determined on the dump of the “Nadiya” mine, and the smallest on the dump of the Central Enrichment Factory in the monospecies group Ceratodon purpureus – syn. Were established higher productivity indicators in synusiae, which includes Campylopus introflexus with biomorphic structure of the dense turf, which forms the largest over ground phytomass in growing conditions, compared to other species. The chlorophyll index can serve as an important criterion for assessing the participation of mosses in the production process of plant cover on transformed territories.

Tree-rings analysis to reconstruct atmospheric mercury contamination at a historical mining site.

Mercury (Hg) is a global environmental concern due to its toxicity (especially high in methylated form) and the long-range distribution of its gaseous elemental form (GEM). Hg-contaminated areas, such as abandoned mining sites, pose intrinsic difficulties for their management and heavy monitoring costs. In these environments, plant-based solutions may play a key role in the ecosystem quality assessment and support remediation strategies, combining reliability and cost-effectiveness. In this study, we adopted a biomonitoring approach by using tree rings of four different species collected in the proximity of the mining-metallurgical area of Abbadia San Salvatore, central Italy, a major former Hg mining district whose reclamation is currently in progress. Our dendrochemical analysis was aimed at identifying the historical changes of local atmospheric Hg contamination and at singling out, for the first time in the study area, other potentially toxic elements (PTEs) associated with the past mining activity. Collected cores dated back to early as 1940 and provided the temporal patterns of atmospheric Hg emission vs the produced liquid quantities, so reconstructing the historical impact of the mining site on nearby terrestrial ecosystems and resident human population. Current GEM contamination was found about twenty times lower than that of the fully operational mine periods. From a first survey on other PTEs, thallium (Tl) and lead (Pb) appeared to be potentially associated with the mining activity, thus suggesting new working assumptions for further dendrochemical analyses and for the inclusion of Pb in human biomonitoring surveys of the Mt. Amiata area, actually not present in the control list. The results prompt a more thorough assessment by tracking for a longer time span a critical site that is an ideal open-field lab to study the ecophysiology of different tree species in relation to environmental behavior of PTEs for better-assessing wildlife and human exposures.

The Altai Mining District Officers’ Activities for Acquisition of the Barnaul Public Library in 1830–1850

The Altai Mining District Officers’ Activities for Acquisition of the Barnaul Public Library in 1830–1850

Traditional ecological knowledge, perceptions and practices on insect pollinator conservation: A case of the smallholder farmers in Murundu ward of Mufulira mining district of Zambia

Traditional ecological knowledge, perceptions and practices on insect pollinator conservation: A case of the smallholder farmers in Murundu ward of Mufulira mining district of Zambia

Elucidating the Role of Hydrocarbons in Cinnabar (HgS) Ore Formation: A Model for Hg Mineralization in the Terlingua Mining District, Big Bend National Park, SW Texas

Abstract The genetic relationship between organic-rich source rocks and Hg deposits remains the subject of debate. This paper evaluates the role of organic-rich source rocks in cinnabar ore formation in the Terlingua mining district, Texas, which was deposited at relatively shallow depths in Cretaceous sedimentary rocks spatially related to intrusive alkali igneous rocks. The mineralization formed at ~45 bar and ~200°C. The aqueous ore-forming fluid had a pH of ~5 to 7 and was H2S saturated. Cinnabar was deposited as a result of H2S oxidation through mixing and cooling with local meteoric water. Both Hg0(org) and Hg0(aq) species were likely important in cinnabar ore formation. However, recent studies on the solubility of Hg0 in hydrocarbons show that at cinnabar saturation, Hg0 is more than an order of magnitude more soluble in hydrocarbons (Hg0(org) = 163 mg/kg) than Hg0 in water (Hg0(aq) = 10.8 mg/kg). Despite their proximity in some deposits, conditions of ore formation of the rare Hg oxychloride and sulfate minerals are not compatible with conditions under which most cinnabar ores formed, requiring fO2 conditions orders of magnitude more oxidizing, a relatively high chloride ion activity (&amp;gt;10–1), and alkaline conditions, with pH &amp;gt; 10. Mass dependent fractionation versus mass independent fractionation of Hg isotope data from Hg-bearing minerals in Terlingua support a genetic link to the source of Hg being the organic-rich marls and tuffaceous black shales of the Lower Eagle Ford Formation. This source rock is chronostratigraphically equivalent to the Lower Cretaceous oceanic anoxic event (OAE-2), which defines the Cenomanian-Turonian boundary. OAE-2 represents the culmination of a global anoxic ocean event at ~94.1 Ma, believed to be a consequence of volcanic activity associated with a large igneous province. Mercury was sequestered by the organic-rich source rocks of the Lower Eagle Ford Formation and associated coeval ash and tuffs. Tabular igneous bodies that intruded and uplifted the local stratigraphy formed the Terlingua monocline and provided a source of heat for hydrothermal activity and maturation of organic matter. The subsequent generation and migration of liquid hydrocarbons and formation brines from the Lower Eagle Ford Formation transported Hg0(org) updip toward the hinge line of the Terlingua monocline where mixing with oxygenated meteoric water and subsequent oxidation of H2S produced the cinnabar-rich ores.

Seroprevalence survey of SARS-CoV-2, community behaviors, and practices in Kansanshi and Kalumbila mining towns.

Coronavirus disease 2019 (SARS-CoV-2) was declared a global pandemic by WHO after it spreads quickly around the world from its source city in Wuhan. Africa has some of the lowest documented SARS-CoV-2 incidences globally, with over 9 million confirmed cases as of December 2022. This may be due to efficient mitigation, outbreak response, or demographic traits. Surveillance capability may have suffered as nations changed funding, regulations, and testing plans. Therefore, this study was to document the prevalence of SARS-CoV-2, its characteristics, and the socio-economic characteristics in the two mining districts of Solwezi and Kalumbila of Zambia. Between 28 March and 26 April 2021, a cross-sectional cluster-sample survey of households in two mining districts of Zambia was conducted. Twenty standard enumeration areas (SEAs) were randomly selected in Kansanshi (17 SEA) and Kalumbila (3 SEA) from a total of 67 SEA that encompass the two mines. Members of households aged <5 years were not eligible to participate in the survey. All participants that consented to participate in the interview were also asked to consent to test for SARS-CoV-2 infection using a rapid diagnostic test (RDT), which tested for recent infection and past exposure to the virus (IgM and IgG, respectively). Out of the total sample of 3,047 that were present for the interview, 622 of them agreed to test for COVID-19. Of the total that tested for SARS-CoV-2, 2.6% were IgM positive while 9.0% were IgG positive. Despite the above results, 1,586 participants that agreed to the interview indicated a low self-risk assessment of getting COVID-19 (46.5%) or someone (45.5%). On the public health measures, participants who did handwashing more than usual (65.0%), not hand sanitizing more than usual (69.0%), not disinfecting surfaces in their households than usual (87.5%), not avoiding drinking from bars or nightclubs (90.6%), and not wearing a mask when out in public places (71.1%). In the logistic multivariable model, participants with age 24 years and above (AOR = 2.94; 95% CI = 1.10, 7.81) and having experienced symptoms of SARS-CoV-2 (AOR = 2.60; 95% CI: 1.33, 5.05) had a significant effect on testing positive for SARS-CoV-2. Although the results showed that active COVID-19 prevalence in Solwezi and Kalumbila communities surrounding the two mines was low, exposure to infection was five times high. Government and mining firms should continue to sensitize the community members on the preventive measures of COVID-19 and continue with community testing so that all those positive but without symptoms can self-isolate and those with symptoms and sick can be admitted to the hospital.

The features of the placement of gold deposits in Algeria

Relevance and purpose of the work. In the world market of precious metals, the value of gold is constantly growing, which determines the increase in production volumes and the need to increase resources through the search and exploration of new deposits. Te famous gold deposits in the Algerian People’s Democratic Republic are concentrated in its southern part, known as the In-Uzzali gold mining district. Te search for new deposits can be carried out afer understanding the geological features of the structure of the territory and establishing patterns of the occurrence of gold mineralization to certain geological elements. Research methods. Te research is based on the analysis of the published works of the predecessors. Te paper provides an analysis of the geological structure of the Akhaggar shield region, within which the In-Uzzali gold ore district is located. Results of the work. Te structural and tectonic structure of the district is considered. Te main features of gold-ore objects of the southern part of the Algerian Sahara (Hoggar Shield) were revealed, which allow to attribute the known deposits to three trips by association with groups of rocks: mylonites and ultramylonites (Tirek, Amesmessa); granites and syntectonic granites (Tekoyat); meta-sedimentary rocks (Tiririn, Abeggi). Tey were found to be confned to greenstone belts of Proterozoic age and belonging to the gold-quartz-sulfde formation. Recommendations for further study are given. Conclusions. Gold mineralization was detected in the objects of the In-Uzzali region in the area of the Hoggar shield. Based on the geological structure of the area, its study and conditions of localization of gold mineralization, the investigated area can be considered promising enough for the discovery of gold ore objects and replenishment of the mineral resource base of Algeria.