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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Insights into the History of Pyrite Mineralization at the Round Mountain Gold Mine, Nevada: A Detailed Microanalytical Study of the Type 2 Ore

Daniel, Blakemore 03 August 2020 (has links)
No description available.
32

Genetic relationships and origin of the Ädelfors gold deposits in Southeastern Sweden

Wiberg Steen, Tobias January 2018 (has links)
Ädelfors is situated ca 17 km east of Vetlanda, Jönköping County, in the N-S striking Trans-scandinavian igneous belt and is a part of the NE-SW striking 1.83-1.82 Ga Oskarshamn-Jönköping belt emplaced during a continental subduction towards the Svecofennian continental margin. The continental arc hosts the 1.83 Ga metasedimentary Vetlanda supergroup composed of foliated metagreywacke, metasandstone and metaconglomerate. The sequence is intercalated by mafic and felsic volcanites and hosts the Cu-Au-Fe-mines at Ädelfors. Ädelfors mining field consists of ca 330 mineralized quartz veins hosting both copper, gold and iron. The iron mines Nilsson’s iron mine (NFE) and Fe-mine (FE), the copper mine Kamelen (KM) and the gold mines Brånad’s mine (BR), Adolf Fredrik’s mine (AF), Old Kron mine (GKR), Old Kolhag’s mine (GKO), Thörn mine (TH), New Galon mine (NG), Stenborg’s mine (ST), Tysk mine (TG), Hällaskallen (HS) and Fridhem (FR) have been investigated to deduce a possible genetic relation between the veins and their origin. Sulfur isotope ratios have also been conducted on pyrite from KM, AF and FE. The veins can stucturally be divided into several groups. AF, GKR, ST, NG, TH and possibly NFE are striking 10-70° with a dip of 55-70°. BR, GKO and KM are striking 110-140° with a dip of 80-90° whereas TG and HS strike 90-110° dipping 85°. Fridhem, being distal to the other mines, strikes 70° and dips 80°. A chlorite-quartz-biotite-sericite-rich metapelite hosts the veins in all localities except; FR where a layered, beresitizised felsic volcanite rich in plagioclase, sericite, biotite and quartz hosts disseminated pyrite; and NFE, HS and NG which are hosted by a mafic tuffite. Quartz veins are mainly milky and equigranular, exceptions are FE with black pyrite-bearing quartz veins, cutting through the banded magnetite-metapelite and KM with its dynamically recrystallized quartz. Chlorite-, zeolite-, carbonate-, hematite-, amphibole-, kalifeldspar-, sericite-, biotite- and epidote alteration has been observed among the localities. The ore minerals are dominated by: fractured sub- to euhedral pyrite in cataclastic aggregates or selvage bands, interstitial chalcopyrite in pyrite, marcasite, pyrrhotite, gold and sporadic chalcopyrite diseased sphalerite and arsenopyrite. Previously not reported tetradymite, staurolite, galena and Ce-monazite have also been observed. Bismuthinite and tetradymite as inclusions in pyrite were observed in AF, GKR, FR and TG. Gold was observed in AF, BR, GKR and TG as inclusions in pyrite or quartz with a Au/Ag median of 78.41. HS distinguishes itself with Au/Ag ratios of 4.66-5.25. The trace element ratios in pyrite reveal two major types of pyrite. 1) found in FE and KM (pyrite type 1) with Co/Ni ratio of 10.94, Bi/Au of 1.79, Bi/S of 0.037, Au/Ag of 11.13, S/Se of 235.96 and As/S of 0.006. 2) found in NG, GKO, ST, TH, AF, NFE, HS, GKR, BR, FR, TG and as stringers in KM4 py1 pyrite type 2) with an average Co/Ni ratio of 5.26, Bi/Au of 1.95, Bi/S of 0.031, Au/Ag of 4.19, S/Se of 0 and As/S of 0. δ34S values strengthens this grouping as KM and FE has 1,3-2,6 ‰ and AF 3,6-3,8 ‰. The following geological interpretation has been concluded: The banded iron formation in FE is the earliest mineralization and was later fractured, emplacing quartz veins with pyrite of type 1. During this event, the Cu-vein in KM was also formed. A second generation of fractures, emplaced after the Småland granitoids formed, were filled with quartz and pyrite of type 2 at mesozonal depth. This is the main stage of gold mineralization and includes NG, GKO, ST, TH, AF, NFE, GKR, BR, FR and TG. During this event, pyrite of type 2 was added to KM, causing recrystallizing of the quartz. HS is possibly emplaced last or altered as it is more enriched in silver. Morphology, mineralogy, alterations, mineral chemistry and sulfur isotope signatures indicates an orogenic origin of the gold-rich quartz veins at Ädelfors as well as the copper-rich vein in KM. / Ädelfors ligger ca 17 km öster om Vetlanda, Jönköpings län, i det N-S strykande Transskandinaviska granit och porfyrbältet och är en del av det NÖ-SV strykande 1,83-1,82 Ga Oskarshamn-Jönköpingsbältet (OJB) bildad i en kontinental subduktionszon i kanten av den Svecofenniska kontinentalplattan. I denna kontinentalbåge ligger Vetlanda supergruppen som är en metasedimentär del av OJB bestående av starkt folierad 1,83 Ga metagråvacka, metasandsten och metakonglomerat med inlagringar av mafiska och felsiska vulkaniter. Ädelfors gruvfält består utav ca. 330 kvartsgångar förande mestadels guld men också koppar. Järnmineraliseringar i form av bandad järnmalm finns också i området. Geologin, mineralogin och pyritens kemiska sammansättning från järngruvorna Nilssons järngruva (NFE) och Fe-gruvan (FE), koppargruvan Kamelen (KM) och guldgruvorna Brånadsgruvan (BR), Adolf Fredriks gruva (AF), Gamla Krongruvan (GKR), Gamla Kolhagsgruvan (GKO), Thörngruvan (TH), Nya Galongruvan (NG), Stenborgs gruva (ST), Tyskgruvan (TG), Hällaskallen (HS) och Fridhem (FR) har undersökts för att finna eventuella genetiska likheter. Svavelisotopförhållande har fastställts för pyrit från AF, FE och KM. Strukturellt kan gångarna delas in i ett antal grupper. AF, GKR, ST, NG, TH och möjligtvis NFE stryker 10-70° och stupar 55-70°. BR, GKO och KM stryker 110-140° och stupar 80-90° medan TG och HS stryker 90-110° och stupar 85°. Fridhem stryker 70° och stupar 80°. En klorit-kvarts-sericit-biotitrik metapelit utgör värdbergarten i alla gruvor förutom; FR där den utgörs av en beresitiserad felsisk vulkanit rik på plagioklas, sericit, biotit och kvarts med disseminerad pyrit; och NFE, HS, NG vilka har en mafisk tuffitisk moderbergart. Kvartsgångarna är mjölkvita med undantag för FE:s svarta, pyritförande kvarts vilket uppträder som sprickfyllnad i den bandade järnmalmen och är senare bildad. Kvartsen i KM är starkt dynamiskt omkristalliserad. Svag till måttlig foliation är vanlig i sidoberget med undantag av stark foliation i TG och NFE, vilka är lokaliserade i förkastningssprickor med stark kloritförskiffring av värdbergarten. Klorit-, zeolit-, karbonat-, hematit-, amfibol-, kalifältspat-, sericit-, biotit- och epidotomvandling förekommer i majoriteten av lokalerna. Malmmineralen är dominerande sprött deformerad subhedral till euhedral pyrit som kataklastiska aggregat eller band, interstitiell kopparkis i pyrit, markasit, magnetkis, guld och sporadiskt kopparkissjuk zinkblände och arsenikkis. I det här arbetet har även tetradymit, staurolit, blyglans och Ce-monazit observerats. Bismutinit och tetradymit i form av inneslutningar i pyrit observerades i AF, GKR, FR och TG. Guld observerades i AF, BR, GKR och TG som inneslutningar i pyrit eller fritt i kvarts med Au/Ag medianvärde på 78,41, avvikande är HS med värden mellan 4,66-5,25.    Förhållanden mellan spårelement i pyrit indikerar två typer av pyrit. Typ 1 funnen i FE och KM har följande värden: Co/Ni = 10,94, Bi/Au = 1,79, Bi/S = 0,037, Au/Ag = 11,13, S/Se = 235,96 och As/S = 0,006. Typ 2 funnen i NG, GKO, ST, TH, AF, NFE, HS, GKR, BR, FR, TG och som sliror i KM4 py1 har följande värden Co/Ni = 5,26, Bi/Au = 1,95, Bi/S = 0,031, Au/Ag = 4,19, S/Se = 0 and As/S = 0. δ34S värden styrker denna uppdelning där KM och FE har värdena 1,3-2,6 ‰ och AF 3,6-3,8 ‰. Den geologiska utvecklingen av fältet har tolkats som följande: FE-gruvans bandade järnmalm är den tidigaste mineraliseringen vilket följs utav uppsprickning och läkning av kvarts med pyrit typ 1 som också bildar kopparmineraliseringen KM. Senare sprickzoner efter Smålandsgraniternas intrusion läks av kvarts med pyrit typ 2 på mesozonalt djup vilket bildar NG, GKO, ST, TH, AF, NFE, GKR, BR, FR, TG och omkristalliserar och introducerar nya pyritsliror i kvartsen i KM. HS bildas möjligtvis sist eller har blivit omvandlad eftersom den är anrikad på silver. Morfologi, omvandlingar och svavelisotop-signaturer tyder på ett orogent ursprung för Ädelfors guldrika kvartsådror samt den kopparrika kvartsådern i KM.
33

Desenvolvimento de um método simplificado para obtenção de adesão à zircônia / Development of a simplified method for obtaining membership of the zirconia

Ogliari, Aline de Oliveira 10 December 2012 (has links)
Made available in DSpace on 2014-08-20T14:30:09Z (GMT). No. of bitstreams: 1 Dissertacao_aline_oliveira_ogliari.pdf: 2899521 bytes, checksum: 3a5e7870376f999dd52a171e479c76e9 (MD5) Previous issue date: 2012-12-10 / The aim of this study was to develop a simplified method for bonding to yttriastabilized zirconia ceramic. The method was based on deposition of a reactive silica layer on the ceramic surface followed by heat treatment. The study comprised six steps: (i) preparation of solutions using four concentrations of tetraethyl orthosilicate (TEOS) and zirconium tert-butoxide (ZTB) diluted in hexane; (ii) cutting and polishing of the zirconia substrate; (iii) organic silica-based treatment before (infiltration, INF) or after (coating, COA) zirconia sintering; (iv) analysis by scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS); (v) G-Raman confocal spectroscopy analysis; (vi) shear bond strength to zirconia tested after 24-h and failure analysis. An untreated (control) and a commercial reference (Rocatec Plus, 3M ESPE) groups were tested. Quantitative data were analyzed using ANOVA and Tukey s post hoc test (P < 0.05). SEM micrographs showed that zirconia surface was covered by silica nanoparticle clusters. EDS and G-Raman analyses confirmed composition of this layer. The bond strength results showed that most groups that received coating (COA) and infiltration (INF) presented higher bonding potential than the untreated (control) group. Almost all experimental groups were similar to commercial reference. Mixed failures were predominant. In conclusion, the present study introduces a novel, simple, and cost-effective method to provide adhesion to yttria-stabilized zirconia ceramic. Both the method of silica deposition (if before or after zirconia sintering) and concentration of organic silica precursors have a significant impact on the adhesion of methacrylates to the treated zirconia / O objetivo deste estudo foi desenvolver um método simplificado para obtenção de adesão a uma cerâmica de zircônia estabilizada por ítria. O método foi baseado na deposição de uma camada reativa de sílica na superfície cerâmica seguida por tratamento térmico. O estudo compreendeu seis etapas: (i) preparo de 4 soluções contendo tetraetilortosilicato (TEOS) e tert-butóxido de zircônio (ZTB) diluídos em hexano; (ii) corte e polimento do substrato de zircônia; (iii) tratamento com os precursores orgânicos antes (infiltração, INF) ou depois (cobertura, COA) da sinterização da zircônia; (iv) análise por microscopia eletrônica de varredura e espectroscopia de energia dispersiva (MEV-EDS); (v) análise por espectroscopia confocal G-Raman; (vi) avaliação de resistência de união ao cisalhamento 24h após preparo e análise de falha. Grupos sem tratamento (controle) e uma referência comercial (Rocatec Plus, 3M ESPE) foram testados. Dados quantitativos foram analisados usando ANOVA e teste post hoc de Tukey (P < 0,05). Os resultados de MEV mostraram que a superfície da zircônia foi coberta por aglomerados de nanopartículas de sílica, sendo esta composição confirmada por EDS e análise de G-Raman. Os resultados do teste mecânico mostraram que a maioria dos grupos que receberam cobertura (COA) e infiltração (INF) apresentaram maior resistência de união que o grupo sem tratamento (controle). A maioria dos grupos experimentais foram similares à referência comercial. Falhas do tipo mistas foram predominantes. Em conclusão, o presente estudo introduz um método novo, simples e de baixo custo para promover adesão a cerâmicas de zircônia estabilizada por ítria. Tanto o método de deposição de sílica (se antes ou após sinterização da zircônia) e a concentração de precursores orgânicos de sílica têm impacto significativo na adesão de metacrilatos à cerâmica tratada
34

Redukce korozních vrstev mosazi pomocí nízkotlakého nízkoteplotního plazmatu / Brass Corrosion Layers Reduction by Low-Pressure Low-Temperature Plasma

Řádková, Lucie January 2015 (has links)
This thesis presents results of the corrosion layers removal which could be found on the archaeological artefact surfaces. The low pressure low temperature plasma reduction was used for this purpose. Brass samples were chosen for this study. Two different ways have been used to form model corrosion layers. Several sets of corrosion layers were prepared in laboratory in two different corrosion atmospheres, namely ammonia atmosphere and atmosphere of hydrochloric acid. These samples were placed into desiccator. Small quantities of sand were added to some sets of samples so samples with sandy incrustation were prepared. The corrosion layers had been usually formed during four weeks. The second way, which was used to prepare model corrosion layer, was the natural corrosion in soil or compost. In this case, the corrosion layers had been formed approximately 2 years. The samples were treated in the low pressure (150 Pa) cylindrical Quartz reactor (90 cm long and 9.5 cm in diameter) with a pair of external copper electrodes connected via the matching network to a radiofrequency generator (13.56 MHz). The flows of working gases were set by independent mass flow controllers. Whole system was continuously pumped by the rotary oil pump which was separated from the discharge reactor by liquid nitrogen trap with aluminium chips eliminating dust and reactive species from the gas flow. Each sample was placed on a glass holder at the reactor center. Plasma was generated in pure hydrogen or in mixture of hydrogen and argon. Total flow of working gas was 50 sccm. Different ratios of gas mixture were tested, the ratio 30 sccm hydrogen and 20 sccm argon flows was the best. RF discharge was used in a continuous and pulsed regime. Pulsed mode was carried out with various duty cycle at the frequency of 1000 Hz. There were two ways of temperature monitoring. The sample temperature during the treatment was monitored by a K-type thermocouple installed inside the sample in the first case. Thermometer optical probe was connected to the sample surface by a small stainless plate and allowed continuous sample temperature monitoring in the second way. Safe object temperature for copper and copper alloys is 100–120 °C. To avoid exceeding this temperature, power control or the duty cycle in pulse mode were automatically controlled if thermometer optical probe was used. Plasma chemical treatment is based on generation of reactive atomic hydrogen in plasma discharge. The main reactions during reduction were reactions between oxygen and chloride contained in the corrosion layer and the hydrogen ions and neutral atoms generated in the plasma. These reactions create an unstable OH radical, which emits light in the region of 306–312 nm. This radiation was detected by the optical emission spectroscopy using Ocean Optics HR4000 spectrometer with 2400 gr/mm grating. Data obtained from this method were used to calculate rotational temperatures and integral intensity of OH radicals that were used for the process monitoring. Corrosion layer was not completely removed during the reduction, but due to the reactions which occur in the plasma corrosion layer became brittle and after plasma chemical treatment can be removed easily. The SEM-EDS material analyses were carried out before and after treatment of some samples. Some samples were analysed by XRD analysis. EDS analysis showed that amount of oxygen and chloride was decreased, mainly at 400 W pulse mode.
35

Initiation and Propagation of Localized Corrosion of Mild Steel in Marginally Sour Environments

Zhang, Wei January 2020 (has links)
No description available.
36

To Make Iron of Iron : A Comprehensive Analytical Study of Spade Shaped Iron Bars

Pappas Adlerburg, Nickolas T. January 2017 (has links)
This thesis aims to provide adequate analytical information on the spade shaped iron bars of Norrland and central Sweden. While their significance has been thoroughly debated for decades, analytical research on them has been confined to cases of single artefacts or theoretical interpretations of their value, meaning and origin. In this study a comprehensive approach is taken into consideration. Based on X-Ray fluorescence (XRF), scanning electron microscopy (SEM) and metallographical analysis this thesis seeks to facilitate new interpretations on quality, production centres and usage based on analytical results. Aiming to settle some of the long lasting questions regarding the artefacts while producing results which can further the discussion by raising new questions, previously unasked.
37

Premières productions de céramiques turques en Anatolie occidentale : Contextualisation et études techniques / The First Production of Turkish Ceramics in Western Anatolia : Contextualisation and Technical Studies

Burlot, Jacques 11 September 2017 (has links)
Depuis les années 1990, des études archéométriques ont permis d’attester la production de nouveaux types céramiques en Anatolie occidentale, liée à l’installation de populations turques dans la région à partir de la fin du XIIIe siècle. Parmi ces nouveaux types figurent des céramiques dont les formes et les décors, très répandus dans le monde islamique, témoignaient de l’introduction de nouvelles techniques de fabrication.Sur la base d’un échantillonnage de 87 tessons découverts sur cinq sites turcs et trois sites de Crimée, l’étude, associant approche archéologique et analyses physico-chimiques, a permis de proposer des cadres chronologiques pour ces premières productions turques et de déterminer les techniques de fabrication de leurs revêtements – engobes et glaçures – servant au décor. La définition de ces techniques repose essentiellement sur des analyses élémentaires et structurales par MEB-EDS et par spectrométrie Raman, dont les résultats permettent de confirmer l’utilisation de nouvelles recettes et de nouveaux matériaux.Alors que les décors des céramiques byzantines étaient essentiellement constitués d’une glaçure plombifère transparente, colorée par une gamme réduite d’oxydes métalliques et reposant sur un engobe argileux, les décors des premières céramiques turques, d’époque beylik, produites dans la région, étaient bien plus variés. Leurs glaçures, témoignent d’une plus grande diversité, aussi bien dans la nature des fondants et des opacifiants, que dans celle des colorants utilisés.Considérée comme l’un des premiers types de céramiques ottomanes, la Miletus Ware présente le décor le plus élaboré. L’engobe n’est plus argileux, mais synthétique, préfigurant ainsi les productions plus tardives à pâte synthétique d’Iznik qui feront la renommée de la céramique ottomane au XVIe siècle. Notre étude a ainsi permis de caractériser et de contextualiser les évolutions techniques qui marquent la transition entre céramiques byzantines et ottomanes en Anatolie occidentale. / Since the 1990s, archaeometric studies have attested to the production of new types of ceramic in Western Anatolia, linked to the arrival of Turkish populations in the region from the end of the 13th century. Among these new types are ceramics whose shapes and decoration are very commonly found in the Islamic world, and which show the introduction of new techniques of fabrication.Taking a sample of 87 sherds discovered at five Turkish sites and three sites in the Crimea, this study, combining an archaeological approach with physicochemical analyses, enabled us to propose a chronological framework for these initial Turkish productions and to determine the techniques of fabrication of their coatings – slips and glazes – used for the decoration. The definition of these techniques relies in the main on elementary and structural analyses by SEM-EDS and by Raman spectroscopy, the results of which permit us to confirm the use of new recipes and new materials.While the decoration of Byzantine ceramics was essentially constituted of a high-lead transparent glaze, coloured by a reduced range of metallic oxides resting on a clay slip, the decoration of the initial Turkish ceramics, from the Beylik period, produced in the region, were much more varied. Their glazes attest to a greater diversity in the nature of the fluxes and opacifiers, as well as in the colorants used. Considered to be one of the first types of Ottoman ceramics, the Miletus Ware shows the most elaborate decoration. The slip is no longer clay-based but synthetic, prefiguring in this way the later production using synthetic paste of the Iznik Fritwares upon which the fame of 16th century Ottoman ceramics was based. Our study thus enabled us to characterise and contextualise the technical evolution which marked the transition from Byzantine to Ottoman ceramics in Western Anatolia.
38

The application of the modified crude settleable dust approach as a viable asbestos mineral test method

Kwata, Maphuti Georgina 11 1900 (has links)
Text in English with abstracts and keywords in English, Afrikaans, Sepedi and Sesotho / Soil and other geological materials found on the crust of the Earth are known to be rich in naturally occurring silicate minerals. Asbestos is one of the fibrous silicate minerals that was mined predominantly in some regions of Limpopo, Mpumalanga and Northern Cape provinces in South Africa. Despite the cessation of asbestos mining due to associated human health effects in 2002, there is still a concern about possible environmental exposure to asbestos fibres. A single asbestos fibre is made of millions of microscopic needle-like fibrils which break easily to produce inhalable size fractions that are reported to cause lung diseases. The main source of asbestos fibres in former mining areas is asbestos mine dumps and asbestos contaminated surface soil. Asbestos mine dumps in Limpopo Province are partially rehabilitated, while in Mpumalanga Province they are not rehabilitated and all these dumps are now under the care of government because the original owners have abandoned them. The settleable dust is the first indicator of airborne dust pollution and the rate of settleable dust rates was used to select the sites to be monitored. A pilot study was conducted to test the performance of the ASTMD1739:1998 and ASTM D 1739:1970 methods. The method was further modified and optimized to measure asbestos load in settleable dust samples. A total ten sites located around vulnerable human settlements that are in close proximity to the abandoned asbestos mine dumps were chosen in Mpumalanga and Limpopo Provinces respectively. Airborne, surface and trapped dust samples were collected once a month around human settlements that are in close proximity to the abandoned asbestos mine dumps from April 2016 to June 2017. Airborne dust samples were collected using the official settleable dust monitoring method, the general particulate matter E-sampler and the official asbestos Air-Con 2 sampler. Surface dust was collected outdoors around the settleable dust collection units using a brush and dust pan and was stored in labeled zipper bags made of plastic material. Trapped dust samples were collected using sticky tape both indoors and outdoors around the window panes, on surfaces of furniture and on windscreens of old cars and were stored in labeled closed containers. Surface soil samples were also screened with the hand held asbestos analyser before collection. The samples were extensively and carefully prepared and handled to avoid or minimize cross contamination using standard laboratory methods and were analysed using calibrated analytical instruments. An adapted method (ASTMD 1739:1970) was used to determine the presence of asbestos hazard in a form of mineral count. This method was also used for the identification of asbestos and other minerals in different dust samples using the XRD technique. Physical features of all minerals such as the shape, size and type were also determined as part of the characterization process using the SEM-EDS technique. The ASTMD1739:1998 method gave rise to higher retention of settleable dust, hence it was found to be more efficient. Unfortunately, this best performing method is not legislated or regulated by the government. This researcher concludes that the reasons could be due to the different shapes of the windshield designs (which means the different designs of windshields) at may make it difficult to standardize and control. However, this information gap provides an opportunity of a longer focused study of this method with the intention of finding a standardized windshield design that could be recommended for use in the country. Secondly, the units that had both water and algaecide gave rise to higher settleable Mpumalanga. Three exceedances of 600 mg/m2/day of residential limit regulated through National Dust Control Regulation no.28 of 2013 presented in decreasing order in Limpopo were 2724 mg/m2/day at Site E, 1638 mg/m2/day at Site D and 834 mg/m2/day at Site B in the same month of March 2017 . The XRF data of metal oxides, including these top three [Si(IV)O2, Fe2(III)O3 and Al2(III)O3], confirm the dominance of silicate minerals in surface dust samples from both provinces. The XRD mineralogy data from filtered settleable dust show the dominance of the amphibole asbestos particulates ranging from 18 to 56 % in Limpopo province and 2.0 to 3.0 % in Mpumalanga province. Low presence of serpentine minerals with the highest being 2.0 % and 7.0 % in Limpopo and Mpumalanga provinces respectively. About 8.0 to 43 % of amphibole asbestos minerals were measured on trapped dust in Limpopo together with zero detection of serpentine. No asbestos minerals were detected on trapped dust from Mpumalanga, despite the close proximity of the unrehabilitated asbestos mine dumps All airborne asbestos fibres that were captured on the filter substrates were a bove the limit value of 100 f/mL of air. The highest airborne asbestos fibre and concentration counts m easured were 40 fibres and 0, 00434 f /mL concentration in October 2017 at Site A. The second highest fibre count concentration was measured in June with 0,00287 f/mL at Site A in September 2017 and 0,01085 f/mL at the Site D in June 2017 monitoring sites. Again, the highest in June 2017 with 0,00125 f/mL for Site A for Limpopo Province. In Mpumalang a the lowest asbestos fibre concentration which are be low the OHSA no. 39 of 1993 and MDHS 39/ 4, 1995 0.1 f/mL and 100 f/mL However, from the safety perspective all asbestos fibres or minerals inhaled are a hazard to human health. The study established that the adapted asbestos mineral count method succeeded in identifying and quantifying the asbestos minerals that existed in the settleable dust samples from the study areas. These outcome s were successfully validated with the test undertaken using both the officially (Air Con 2 sampler) and unofficial (E sampler) recognized method of asbestos fibre count. The adapted mineral count method provides the research community with an alternative, cost effective and user friendly method of analysis. Also, the validation method s gave additional new information. Of a total of 120 of ex- posed filter papers used in the official asbestos fibre Air Con 2 sampler, 28 filters had positive presence of asbestos fibres, making it 23 collection efficiency And of the 100 exposed filt er papers used in for E samplers, only 8% collection efficiency was recorded. The results means that the official asbestos fibre Air Con 2 sampler has 23 more collection efficiency than the general particulate matter E sampler for air- borne asbestos monitoring. The impact of these results could also be that a general particulate matter high volume sampler c ould still be used for asbestos fibre monitoring in the absence of a specific and selective Air Con 2 sampler, as long as the user appreciates abo ut 23 collection deficiency. These findings go a long way in helping to make air quality research domain accessible. Since the ASTM D1739:1998 method has been found to perform better than the officially recognized method, this study recommends that the regulators of air quality in the country consider it. But, the method will first require some improvement and standardization particularly the different wind shield designs before it could be officially accepted as the method of collection and analyses for settleable dust. It is hoped that the air quality research community will take up the challenge. / Grond en ander geologiese materiale wat op die aardkors aangetref word, is bekend dat hulle ryk is in silikaatminerale wat natuurlik voorkom. Asbes is een van die veselagtige silikaatminerale wat hoofsaaklik in sommige streke van die Limpopo, Mpumalanga en Noord-Kaap Provinsies in Suid-Afrika ontgin is. Ondanks die staking van asbesmynbou in 2002 as gevolg van gepaardgaande gesondheidseffekte op mense, is daar steeds kommer oor moontlike blootstelling aan asbesvesels in die omgewing. 'n Enkele asbesvesel bestaan uit miljoene mikroskopiese naaldagtige vesels wat maklik breek om partikels van inasembare grootte te produseer wat volgens berigte longsiektes veroorsaak. Die belangrikste bron van asbesvesels in voormalige myngebiede is asbesmynhope en besmette asbesoppervlakgrond. Asbesmynhope in Limpopo Provinsie word gedeeltelik gerehabiliteer, terwyl hulle in Mpumalanga Provinsie nie gerehabiliteer word nie, en al hierdie mynhope is nou onder die regering se toesig omdat die oorspronklike eienaars die mynhope verlaat het. Die neerslagbare stof is die eerste aanduiding van stofbesoedeling in die lug en is gebruik om die terreine wat gemoniteermoet word, te kies. 'n Loodsstudie is uitgevoer om die prestasie van die ASTMD1739:1998 en ASTMD1739:1970 metodes te toets. In die loop van die studie is 'n amptelike ASTMD1739:1970 metode gebruik en toegepas vir die versameling van neerslagbare stofmonsters. In Mpumalanga en Limpopo Provinsies respektiewelik is daar altesaam tien (10) terreine gekies rondom kwesbare menslike nedersettings wat naby die verlate asbesmynhope geleë is. Stofmonsters in die lug, oppervlak en wat vasgevang is, is een keer per maand versamel vanaf April 2016 tot Junie 2017 rondom menslike nedersettings in die nabyheid van die verlate asbesmynhope. Stofmonsters in die lug is versamel volgens die amptelike neerslagbare stofmoniteringsmetode, die E monsternemer en die Air-Con 2 monsternemer. Oppervlakstof is buite met behulp van 'n kwas en stofpan rondom die neerslagbare stofopvangeenhede opgevang en is in gemerkte ritsakke van plastiekmateriaal geberg. Stofmonsters wat vasgevang is, is met behulp van kleeflint, binne en buite, om vensterruite, op meubeloppervlaktes en op voorruitte van ou motors versamel, en is in gemerkte geslote houers geberg. Oppervlakgrondmonsters is ook voor versameling met die draagbare asbesanaliseerder gefilter. Die monsters is breedvoerig en sorgvuldig voorberei en hanteer om kruisbesmetting tot ‘n minimum te beperk deur gebruik te maak van standard laboratoriummetodes en is ontleed met behulp van gekalibreerde analitiese instrumente. 'n Aangepaste metode is gebruik om die teenwoordigheid van asbesgevaar in 'n vorm van mineraaltelling te bepaal. Hierdie metode is ook gebruik vir die identifisering van asbes en ander minerale in verskillende stofmonsters met behulp van die XRD tegniek. Die fisiese kenmerke van alle minerale soos die vorm, grootte en tipe is ook bepaal as deel van die karakteriseringsproses met behulp van die SEM-EDS tegniek. Die ASTMD1739:1998 metode het gelei tot 'n hoër retensie van neerslagbare stof, en daarom is gevind dat dit doeltreffender is. Ongelukkig word hierdie metode wat die beste presteer nie deur die regering gewettig of gereguleer nie. Hierdie navorser kom tot die gevolgtrekking dat die redes kan wees as gevolg van die verskillende vorms van die voorruitontwerpe wat dit moeilik kan maak om dit te standaardiseer en te beheer. Hierdie inligtingsgaping bied egter 'n geleentheid tot 'n langer gefokusde studie van hierdie metode met die doel om 'n gestandaardiseerde voorruitontwerp te vind wat aanbeveel kan word vir gebruik in die land. Tweedens het die eenhede wat beide water en alge-suurwater gehad het, gelei tot 'n hoër neerslagbare stof in Mpumalanga Provinsie. Drie oorskrydings wat in dalende volgorde in Limpopo aangebied is, was 2724 mg/m2/dag op perseel E, 1638 mg/m2/dag op perseel D en 834 mg/m2/dag op perseel B in dieselfde maand van Maart 2017. Die XRF data van metaaloksiede, met inbegrip van hierdie top drie [Si(IV)O2, Fe2(III)O3 en Al2(III)O3], bevestig die oorheersing van silikaatminerale in oppervlakstofmonsters van beide provinsies. Die XRD mineralogiedata van gefiltreerde, neerslagbare stof toon die oorheersing van die amfibool asbesdeeltjies wat wissel tussen 18 en 56 % in Limpopo Provinsie en 2.0 en 3.0 % in Mpumalanga Provinsie. Daar is ‘n lae teenwoordigheid van serpentynminerale met die hoogste onderskeidelik 2.0 % en 7.0 % in die Limpopo en Mpumalanga Provinsies onderskeidelik. Ongeveer 8.0 tot 43 % van die amfibool asbesminerale is op vasgevangde stof in Limpopo gemeet, tesame met geen opsporing van serpentyn. Geen asbesminerale is opgespoor in die vasgevangde stof van Mpumalanga nie, ondanks die nabyheid van die ongerehabiliteerde asbesmynhope. Alle asbesvesels in die lug wat op die filtersubstrate vasgelê is, was bo die grenswaarde van 100 f/mL lug. Die hoogste asbesvesel en konsentrasietellings in die lug gemeet, was 40 vesels en 'n konsentrasie van 2.083 f/mL in Oktober op Terrein A. Die volgende hoogste veseltellingkonsentrasie is in Junie gemeet met 6.590 f/mL op die Terrein A en 5.272 f/mL op die Terrein D moniteringsterreine. In Mpumalanga was die hoogste asbesveselkonsentrasie 2.190 f/mL in Junie en 2.083 f/mL in November op Terrein D. Uit ‘n veiligheidsperspektief is alle asbesvesels of minerale wat ingeasem word egter 'n gevaar vir die mens se gesondheid. Die studie het vasgestel dat die aangepaste asbesmineraaltellingmetode daarin geslaag het om die asbesminerale wat in die neerslagbare stofmonsters uit die studiegebiede bestaan te identifiseer en te kwantifiseer. Hierdie uitkoms is suksesvol bekragtig met die toets wat onderneem is met behulp van die amptelik erkende metode vir die telling van asbesvesel. Die aangepaste mineraaltellingmetode bied aan die navorsingsgemeenskap 'n alternatiewe, koste-effektiewe en gebruikersvriendelike ontledingsmetode. Aangesien daar gevind is dat die ASTMD1739:1998 metode beter presteer as die amptelik erkende metode, beveel hierdie studie aan dat die reguleerders van luggehalte in die land dit oorweeg. Maar die metode sal eers verbetering en standaardisering verg, veral die verskillende windskermontwerpe voordat dit amptelik aanvaar kan word as die metode om neerslagbare stof te versamel en te ontleed. Daar word gehoop dat die gemeenskap wat luggehalte navors die uitdaging sal aanpak. / Mabu le dišomišwa tše dingwe tša bothutaswika tše di hwetšagalago bokagodimo ba Lefase di tsebja di e na le diminerale tše dintši tša tlhago tše di diragalago ka tlhago. Marela ke e ngwe ya diminerale tše di nago le dimela tše di ntši kudu tše di bego di epšwa kudu mafelong a mangwe a diphrofentshe "diphrofentsheng tša Limpopo, Mpumalanga le North Cape Afrika Borwa. Le ge go feditšwe go epšwa marela ka lebaka la ditlamorago tše amanago le maphelo a batho ka 2002, go na le pelaelo malebana le go utullwa ga malwetši a marela. Fibre ke ye ngwe ya marela ye e dirilwego ka maekrosekopiki tše dimilione tše di ka senyegago bonolo go tšweletša khemobonolo yeo e hlamago malwetši a mafahla. Sehlodikgolo sa malwetši a marela mafelong a mathomo ao go bego go le meepo ke sekoti sa marela le mabu a ka godimo ga marela. Dikoti tša meepo ya Marela Phrofentsheng ya Limpopo di mpšhafaditšwe ka tsela ye itšego, eupša Phrofentsheng ya Mpumalanga ga se tša mpšhafatšwa gomme mafelo a ka moka a laolwa ke mmušo gobane beng ba tšona ba di tlogetše. Lerole le ka rarollwago ke sešupopele sa tšhilafalo ya moya e dirwago ka moya gomme se be se šomišwa go kgetha mafelo ao a loketšwego go hlokomelwa. Go ile gwa dirwa tekolo ya go leka tšhomo ya mekgwa ya ASTMD1739: 1998 le ASTM D 1739: 1970. Ge re ntše re tšwela pele ka thuto, go šomišitšwe mokgwa wa semmušo wa ASTM D1739: 1970 gomme wa šomišwa lebakeng la go kgoboketša sampole ya lerole e ka rarollwago. Mafelo a lesome (10) a hweditšwe kgauswi le bodulo ba batho bjo bo lego kotsing ka dikoti tša meepo ya marela di ile tša kgethwa diphrofentsheng tša Mpumalanga le Limpopo ka go latelana. Disampole tša moya tša ka godimo ga lefase, godimo le tše di khutilego di ile tša kgoboketšwa ga tee kgweding kgauswi le bodulo ba batho tše di bego kgauswi kudu le dikoti tša meepo ya marela go tloga ka la 2016 Mopitlo go fihla ka Phupu 2017. Mehuta ya lerole ye sepetšwago ke moya e ile ya kgoboketšwa go šomišwa mokgwa wa semolao wa go tšweletša lerole, E-sampler le sampole ya Air-Con 2. Lerole la ka godimo le be le kgoboketšwa ka ntle go rarela dikarolo tša go kgoboketša lerole go šomišwa poratšhe le pane ya kota gomme le bolokelwa ka mekotleng e nago le zipper ye dirilwego ka polasetiki. Sampole ya lerole le le bego le gaeletšwe le ile la kgoboketšwa ka theipi ya go momela bokagareng le bokantle bja morumofasetere,mabotong a phahlo , le godimo ga galasebokapele dikoloing tša kgale gomme tša bolokwa ka gare ga didirišwa tšeo di makilwego. Disampolo tša mabu a ka godimo di be di hlahlobjwa gape ka mokgwa wa go kgwa ka letsogo ke mohlahlobi wa marela pele go kgoboketšwa. Disampole di be di lokišitšwe kudu ebile di dirilwe ka tlhoko go efoga tšhilafalo ka mekgwa ye tlwaelegilwego ya laporatori gomme ba e hlahloba ba šomiša didirišwa tša go hlahloba. Mokgwa o ikgethilego o šomišwa go hwetša bogona ba kotsi ya marela ka mokgwa wa palo ya diminerale. Mokgwa wo o be o šomišitšwe gape le go bošupong ba marela le diminerale tše dingwe ka gare ga disampole tše di fapanego tša lerole go šomišwa mokgwa wa XRD. Dibepegopono tša diminerale ka moka go swana le sebopego, bogolo le mohuta le tšona di be di tšewa e le karolo ya tshepetšo ya pharodipataka go bogolo le mohuta le tšona di be di tšewa e le karolo ya tshepetšo ya pharodipataka go šomišwa mokgwa wa SEM-EDS. Mokgwa wa ASTMD1739: 1998 o ile wa dira gore go bolokwe lerole le phagameng ka go fetolegago, ka gona go hweditšwe gore le šoma gabotse kudu. Ka bomadimabe, mokgwa wo o tšweletši kudu ge o ngwadišwa ke molao go mmušo. Monyakišiši wo o phetha ka gore mabaka e ka ba ka lebaka la dibopego tše di fapaneng tša meralo ya setsi sa moya se se ka dirago gore go be boima go tseba le go laola. Le ge go le bjalo, sekgoba se sa tshedimošo se fa monyetla wa go ithuta nepišo e telele ya maikemišetšo a go hwetša moralo o tiišitšwego wa moya o ka šišinywago gore o šomišwe ka nageng. Ya bobedi, diyuniti tše di bego di e na le meetsi le algaecide di ile tša tšweletša maemo a phagamego Mpumalanga Phrofentsheng. Ditekanyetšo tše tharo tše di tšweleditše ka tatelano ya taolo e fokotšegago e be e le 2724 mg/ m2/ letšatši go Site E, 1638 mg / m2/ letšatši go Site D le 834 mg/ m2/ letšatši go Site B kgweding ye tee ya Hlakola 2017 Dintlha tša XRF tša di-oxide tša tšhipi, go akaretša tše tše tharo tša godimo [Si (IV) O2, Fe2 (III) O3 le Al2 (III) O3], di tiiša boleng bo phagameng ba diminerale tša silrate mehuteng ya lerole ye e tšwago diphrofentsheng ka bobedi. Dintlha tša XRD tša mineralogy tše di tšwago leroleng le tšhilafatšong di ka tšewa di bontšha phelo ya marela ya amphibole go tloga go 18 go iša go 56% phrofentsheng ya Limpopo le 2.0 go iša go 3.0% phrofentsheng ya Mpumalanga. Bogonatlase ba diminerale tša serpentine tše phagameng ka go fetišiša e le 2.0% le 7.0% diphrofentsheng tša Limpopo le Mpumalanga ka go latelana. Go lekana 8.0 go iša go 43% ya diminerale tša marela tše lekantšwego di ile tša lekanywa leroleng le ageeletšwego ka Limpopo gammogo le go utullwa ga serpentine. Ga go na diminerale tša marela tše di hweditšwego leroleng le ageeletšwego le tšwago Mpumalanga, le ge e le kgauswi kgauswi le dikoti tša mope wa maraba wa marela se a mpšhafatšwago. Mehuta ka moka ya moya ya marela ye e bego e swerwe ka gare ga moya o bego o Mehuta ka moka ya moya ya marela ye e bego e swerwe ka gare ga moya o bego o le ka godimo wa boleng ba moya wa 100 f /mL. Mohuta o phagamego go fetišiša wa moya wa marela le dipalo tša mahlorišo a lekantšwego e be e le tše 40 le bogolo ba 2.083 f /mL ka Diphalane go Site A. Tekanyomahloriš e latelago ya fiber e lekantšwe Phupu ka 6.590 f /mL go Site A le 5.272 f /mL Site D mafelong a tlhahlobo. Nageng ya Mpumalanga, di-fibre tša marela tše phagamego ka go fetišiša e be e le 2.190 f / mL ka Phupu le 2.083 f /mL ka Dibatsela go Site D. Le ge go le bjalo, go latela ponego ya tšhireletšo, fibre ka moka tša marela goba diminerale tše di hengwago di kotsi maphelong a botho. Boithuto bo bo utullotše gore mokgwa wo lekantšwego wa marela o bontšhitšwegošupo o atlegile go kgetholla le go hlakola diminerale tša marela tše di bego di le gona ka gare ga disampolo tša lerole le tšwago mafelong a boithuto. Sephetho se se netefaditšwe katlego le tlhahlobo ye e dirilwego e šomišwago mokgwa wo amogetšwego ke molao wa marela fiber. Mokgwa o lekantšwego wa diminerale o thuša setšhaba sa dinyakišišo ka mokgwa o mongwe wa tlhahlobo ye e šongwago, gabotse e bile ye botho. Go tloga go mokgwa wa ASTM D1739: 1998 o hweditšwe o šoma gabotse go feta mokgwa wo amogetšwego ke molao, thuto ye e šupetša gore balaodi ba boleng ba moya nageng ba e nagane. Empa, mokgwa wo o tla hloka mpšhafatšo le maemo pele kudu meralo ye fapaneng ya thebe ya moya pele e ka amogelwa ke molao e le mokgwa wa go kgoboketša le go sekaseka lerole le le ka rarolwago. Re tshepa gore setšhaba sa dinyakišišo tša boleng ba moya se tla tšea bothata bo. / Mobu le lisebelisoa tse ling tsa jioloji tse fumanehang bokaholimo ba Lefatše li tsejoa li na le liminerale tse ngata tsa tlhaho tse etsahalang ka tlhaho. Asbestos ke e 'ngoe ea liminerale tse nang le silika e ngata e neng e chekoa haholo libakeng tse ling tsa liprofinse tsa "liprofinse tsa Limpopo, Mpumalanga le North Cape Afrika Boroa. Leha ho felisoa morafo oa asbestos ka lebaka la litlamorao tse amanang le bophelo bo botle ba batho ka 2002, ho ntse ho na le ts'oenyeho mabapi le ho pepesetsoa ha tikoloho likhoele tsa asbestos. Fiber e le 'ngoe ea asbestos e entsoe ka likhoele tse limilione tse kang nale tse tsoang habonolo ho hlahisa likaroloana tse sa bonoeng tse tlalehang libaka-mafuamatšo. Mohloli o ka sehloohong oa likhoele tsa asbestos libakeng tseo pele e neng e le tsa meepo ke lithako tsa asbestos le mobu o silafetseng oa asbestos. Likotlo tsa merafo ea Asbestos Profinseng ea Limpopo li nchafalitsoe ka tsela e itseng, athe Profinseng ea Mpumalanga ha e nchafatsoe 'me libaka tsena kaofela li laoloa ke mmuso hobane beng ba tsona ba ba lahlile. Lerōle le ka rarolloang ke letšoao la pele la tšilafalo ea moea e tsoang ka moea mme le ne le sebelisetsoa ho khetha libaka tseo li lokelang ho-shebelloa. Ho ile ha etsoa boithuto ba ho leka ts'ebetso ea mekhoa ea ASTMD1739: 1998 le ASTM D 1739: 1970. Ha re ntse re tsoela pele ka thuto, ho sebelisitsoe mokhoa oa semmuso oa ASTM D1739: 1970 'me oa sebelisoa bakeng sa ho bokella sampole ea lerōle e ka rarolloang. Sebaka sa libaka tse leshome (10) tse fumanehang haufi le bolulo ba batho ba tlokotsing tse haufi le libaka tse lahliloeng tsa meepo ea asbestos li ile tsa khethoa liprofinseng tsa Mpumalanga le Limpopo ka ho latellana. Lisampole tsa moea tse ka holim'a lefatše, holimo le tse patiloeng li ile tsa bokelloa hang ka khoeli ho potoloha libaka tsa bolulo tsa batho tse haufi haholo le libaka tse lahliloeng tsa moepo oa asbestos ho tloha ka Mmesa 2016 ho fihlela ka Phuptjane 2017. Mefuta ea lerōle e tsamaisoang ke moea e ile ea bokelloa ho sebelisoa mokhoa oa semolao oa ho hlahisa lerōle, E-sampler le sampole ea Air-Con 2. Lerōle le kaholimo le ne le bokelloa ka ntle ho potoloha likarolo tsa ho bokella lerōle le sebelisa brashi le pane ea patsi mme le bolokiloe ka mekotleng e nang le zipper e entsoeng ka thepa ea polasetiki. Mehlala ea lerōle e neng e tšoasehile e ile ea bokelloa ho sebelisoa theipi e khangoang ka tlung le kantle kahare ho lifensetere, ka holim'a thepa ea ka tlung le lifensetereng tsa likoloi tsa khale 'me li bolokiloe ka har'a lisebelisoa tse koetsoeng. Meetso ea mobu e kaholimo le eona e ile ea hlahlojoa ka letsoho le ts'oaroang ka asbestos pele ho pokello. Mehlala e ne e hlophisitsoe haholo ebile e entsoe ka hloko ho qoba ho silafatsa kapa ho fokotsa tšilafalo ea tšebeliso ea mekhoa e tloaelehileng ea laboratori mme e ile ea hlahlojoa ho sebelisoa lisebelisoa tsa tekanyetso. Mokhoa o ikhethileng o sebelisitsoe ho fumana ho ba teng ha kotsi ea asbestos ka mokhoa oa palo ea liminerale. Mokhoa ona o ne o boetse o sebelisoa bakeng sa ho khetholla asbestos le liminerale tse ling ka har'a disampole tse fapaneng tsa lerōle ho sebelisoa mokhoa oa XRD. Litšobotsi tsa 'mele tsa liminerale tsohle tse kang sebopeho, boholo le mofuta le tsona li ne li nkuoa e le karolo ea ts'ebetso ea sebopeho ho sebelisa mokhoa oa SEM-EDS. Mokhoa oa ASTMD1739: 1998 o ile oa etsa hore ho bolokoe lerōle le phahameng ka ho fetelletseng, ka hona ho fumanoe hore le sebetsa hantle haholo. Ka bomalimabe, mokhoa ona o atlehileng ka ho fetisisa ha o ngolisoe ke molao kapa 'muso. Mofuputsi enoa o phethela ka hore mabaka a ka ba teng ka lebaka la sebopeho se fapaneng sa meralo ea setsi sa moea se ka etsang hore ho be thata ho tseba le ho laola. Leha ho le joalo, lekhalo lena la tlhaiso-leseling le fana ka monyetla oa ho ithuta ho tsepameng molemong oa mokhoa ona ka sepheo sa ho fumana moralo o tiisitsoeng oa moea o ka khothalletsoang hore o sebelisoe ka har'a naha. Ya bobedi, diyuniti tse neng di na le metsi le algaecide li ile tsa hlahisa maemo a phahameng a ho tsetsahala Mpumalanga. Litekanyetso tse tharo tse fanoeng ka tatellano ea taolo e fokotsehang e ne e le 2724 mg/ m2/ letsatsi ho Site E, 1638 mg /m2/ letsatsi ho Site D le 834 mg / m2/letsatsi ho Site B ka khoeli e tšoanang ea Hlakubele 2017. Lintlha tsa XRF tsa li-oxide tsa tšepe, ho kenyelletsa tsena tse tharo tse holimo [Si (IV) O2, Fe2 (III) O3 le Al2 (III) O3], li tiisa boleng bo phahameng ba liminerale tsa silrate mefuteng ea lerōle e tsoang liprofinseng ka bobeli. Lintlha tsa XRD tsa mineralogy tse tsoang lerōleng le ts'ilafatsoang li ka nkuoa li bonts'a phello ea asbestos ea amphibole ho tloha ho 18 ho isa ho 56% profinseng ea Limpopo le 2.0 ho isa ho 3.0% profinseng ea Mpumalanga. Boteng bo tlase ba liminerale tsa linoha tse phahameng ka ho fetisisa e le 2.0% le 7.0% liprofinseng tsa Limpopo le Mpumalanga ka ho latellana. Hoo e ka lerōleng le ts'oaroang ho la Limpopo hammoho le ho sibolloa ha noha. Ha ho na liminerale tsa asbestos tse fumanoeng lerōleng le tsubelletsoeng le tsoang Mpumalanga, leha ho le haufi le marang-rang a litopo tsa asbestos tse sa ntlafatsoang. Mefuta eohle ea moea e kang asbestos e neng e hapiloe kahare ho moea o ne o le kaholimo ho boleng ba moea oa 100 f /mL. Mofuta o phahameng ka ho fetisisa oa moea oa asbestos le lipalo tsa mahloriso tse lekantsoeng e ne e le likhoele tse 40 le boholo ba 2.083 f /mL ka Mphalane ho Site A. Khakanyo e latelang ea fiber fiber e latelang e lekantsoe ka Pherekhong ka 6.590 f /mL ho Site A le 5.272 f /mL setsing D libaka tsa tlhahlobo. Naheng ea Mpumalanga, li-fiber tsa asbestos tse phahameng ka ho fetisisa e ne e le 2.190 f /mL ka Phuptjane le 2.083 f /mL ka Pulungoana ho Site D. Leha ho le joalo, ho latela pono ea ts'ireletso, likhoele tsohle tsa asbestos kapa liminerale tse kentsoeng li kotsi bophelong ba motho. Boithuto bo fumane hore mokhoa o lekantsoeng oa "asbestos" o ntlafalitsoeng o atlehile ho tseba le ho hlakisa liminerale tsa asbestos tse neng li le teng ka har'a mehlala ea lerōle e tsoang libakeng tsa boithuto. Sephetho sena se netefalitsoe ka katleho le tlhahlobo e entsoeng e sebelisang mokhoa o amohetsoeng ka molao oa asbestos fiber count. Mokhoa o lekantsoeng oa liminerale o thusa sechaba sa lipatlisiso ka mokhoa o mong oa tlhahlobo o sebetsang, o sebetsang hantle ebile o sebelisang botsoalle. Ho tloha ha mokhoa oa ASTM D1739: 1998 o fumanoe o sebetsa hantle ho feta mokhoa o amohetsoeng ka molao, thuto ena e khothaletsa hore batsamaisi ba boleng ba moea naheng ba e nahane. Empa, mokhoa ona o tla hloka ntlafatso le maemo pele haholo mealo e fapaneng ea thebe ea moea pele e ka amoheloa ka molao e le mokhoa oa ho bokella le ho sekaseka lerōle le ka rarolloang. Re tšepa hore sechaba sa lipatlisiso tsa boleng ba moea se tla nka bothata bona. / Environmental Science / Ph. D. (Environmental Sciences)
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Geological characterization of rock samples by LIBS and ME-XRT analytical techniques

Elvis Nkioh, Nsioh January 2022 (has links)
One of the major challenges in earth sciences and mineral exploration has been to determine with high accuracy and at a fast rate the elemental composition as well as the general chemistry of a rock sample. Many analytical techniques e.g., scanning electron microscopy (SEM) have been employed in the past with a certain degree of success, but their analyses usually require a lengthy sample preparation and time-consuming measurements which produce results at a much slower rate than techniques whichrequire less or do not require any sample preparation at all. SEM images the surface of a sample by scanning it with a high-energy beam of electrons in a raster scan pattern, where the primary electron beam produced under very low air pressure vacuum scans across the sample by striking it, and a variation of signals produce an image of the surface, or its elemental composition together with energy dispersive X-rays. Alternatively, laser induced breakdown spectrometry (LIBS) and multi energy X-ray transmission (ME-XRT) are non-contact measurement scanning techniques, capable of producing faster results than SEM-EDS which makes them suitable for real time measurements and analyses as they do not slow down the pace of a project being carried out. LIBS is a spectroscopic technique used to characterize and detect materials where a highly energetic laser pulse is focused onto the surfaces of solids, liquids or gases resulting in atomic and molecular species to emit light at specific wavelengths which is collected with a spectrometer and analysed using a computer. Comparably, ME-XRT is a sensor-based sorting technique involving the planar projection of X-ray attenuation of a particle stream, distributed on a fast conveyor belt, where they are scanned and evaluated while passing and an image is recorded by a line scan detector.      Eleven rock samples were analysed in this study. They include four rock type samples: granite, basalt, sandstone, and gneiss, all obtained from Luleå University of Technology (LTU) sample storage and seven ore type samples which include a porphyry Cu sulphide ore, a porphyry Cu oxide ore, a porphyry Cu-Au-Ag ore, an apatite iron ore (AIO), an iron-oxide copper gold ore (IOCG), an orogenic gold ore and a volcanogenic massive sulphide ore (VMS).       The SEM results give a semi-quantitative elemental composition of the rocks, which may be usedto discriminate mineralisation. Energy dispersive X-ray spectroscopy (EDS) maps may be used to identifygeological features and secondary electron (SE) images may be used to understand the topography of the rock samples. The SEM has a low penetration depth rate but produces moderate to high accuracy resultsdepending on the settings and calibrations. It requires a lengthy sample preparation, and its analytical time is often too long for routine industrial application. LIBS results also provide rock elemental compositions similar to the SEM, which may be quantitative if the same spectrometer is used for all elements and calibrated against a standard. It also produces element maps similar to the SEM-EDS maps. LIBS analyses yield high accuracy results but at a low penetration depth. There are no standard calibrations for the LIBS measurements, which limits quantification. LIBS measurements do not require any form of sample preparation. ME-XRT analyses result in rock chemical data portraying a light material fraction (aluminium-like) and a heavy material fraction (iron-like) which may be used to distinguish different rock samples based on the closeness of their effective atomic number Zeff to that of aluminium and iron respectively. It’s analysis also produces low-resolution images of the analysed rock samples. The image resolution is too low to allow interpretation of the data in the context of the structures and textures in the rock samples. It has a higher penetration depth than LIBS and SEM-EDS producing more volumetric data but with a lower accuracy in terms of the amount of information obtained. Only two elements are used for ME-XRT calibration measurements, if many elements of varying atomic numbers could be used, it would have the ability to provide a more reliable data. Samples must have a maximum and minimum thickness; thus, sample preparation is required to regulate the rock thickness.      SEM and LIBS provide element compositions of minerals and element distribution maps required by geologist in their daily activities during exploration and mining. This information can be considered the most useful obtained from all three techniques. However, LIBS analyses are faster, and its maps are of higher quality even at the same resolution as the SEM-EDS. This makes the LIBS preferable for real time measurements and analyses. Geological activities like drill core logging, mine mapping and sampling for grade control all require fast results for project continuity and LIBS is suitable for this purpose as it can keep up with the pace of these activities. SEM analytical technique provides semi-quantitative data which is more accurate than the LIBS data and thus, preferable for usage in research institutions and universities.ME-XRT can reveal information on the internal structures or different rock sample compositions. This makes it a suitable technique in distinguishing ore from waste material especially in iron ore mining and processing where the iron needs to be separated from the siliceous waste and sorting is also required prior to beneficiation to avoid equipment destruction by abrasive quartz. LIBS and ME-XRT analytical techniques complement each other in terms of analytical capabilities as LIBS has a low penetration depthrate but high accuracy results while the ME-XRT has a high penetration depth rate but low accuracy results. They are both fast scanning techniques that can be used for real time measurements and analyses and if their analytical prowess can be improved, the combination of these two fast analytical techniques may enable us to obtain high quality data and may as well be what is needed by geologists in the future.

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