Gold Fields Research Articles

Age of granodiorite porphyry and beresite from the Darasun gold field, eastern Transbaikal region, Russia

The Darasun ore field situated in the southern West Stanovoi Terrane near the Mongolia-Okhotsk Suture comprises the Darasun (>100 t Au), Talatui (∼38.2 t Au), and Teremki (3 t Au) lode gold deposits. In the opinion of many researchers, the Darasun deposit is spatially and paragenetically linked to granodiorite porphyry of the Amudzhikan Complex and related metasomatic rocks (beresites). Whole-rock samples of granodiorite porphyry, monomineralic fractions of plagioclase, K-feldspar, and biotite, as well as sericite from beresite (26 samples in total), were analyzed by the Rb-Sr method. Eight biotite and sericite samples were analyzed by the K-Ar method. The Rb-Sr mineral isochrons obtained for individual granodiorite porphyry samples yielded initial 87Sr/86Sr ratios varying from 0.70560 to 0.70591. The consistent results of both methods allowed us to accept the ages of granodiorite porphyry and beresite as 160.5 ± 0.4 and 159.6 ± 1.5 Ma, respectively. The age of granodiorite porphyry of the Amudzhikan Complex of 160.5 ± 0.4 Ma corresponds to the boundary between the Early and Middle Jurassic and marks the completion of collision between the East Siberian and Mongolia-China continents and related orogeny. Since that time, the eastern Transbaikal region has been involved in the postorogenic (within-plate) stage of evolution, characterized by the formation of large gold, uranium, and other ore deposits.

Gold complexes as antimicrobial agents: an overview of different biological activities in relation to the oxidation state of the gold ion and the ligand structure

Interest in antimicrobial gold complexes originated from the work of Robert Koch at the end of 19th century, who demonstrated that potassium dicyanidoaurate(I), K[Au(CN)2], showed activity against Mycobacterium tuberculosis, a causative agent of tuberculosis. Subsequently, a large number of gold(I) and gold(III) complexes have been evaluated as possible antimicrobial agents against a broad spectrum of bacteria, fungi and parasites. The first part of the present review article summarizes the results achieved in the field of antibacterial and antifungal activity of gold(I) and gold(III) complexes. The represented gold(I) complexes have been divided into three distinct classes based on the type of coordinated ligand: (i) complexes with phosphine-type ligands, (ii) complexes with N-heterocyclic carbene ligands and (iii) various other gold(I) complexes, while the results related to the antibacterial and antifungal gold(III) complexes have been mainly focused on the organometallic-type of complexes. The second section of this article represents findings obtained from the evaluation of antimalarial activity of gold complexes against chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum parasite. Antimalarial gold(I) and gold(III) complexes have been divided into the following classes, based on the nature of the coordinated ligand: (i) complexes with chloroquine and its derivatives, (ii) complexes with N-heterocyclic carbene ligands, (iii) complexes containing functionalised alkynes and (iv) thiosemicarbazonato ligands, as well as (v) other gold(I) and gold(III) complexes. In the last section of the review, gold(I) and gold(III) complexes have been reported to be potential agents against parasites that cause amoebiasis, leishmaniasis and trypanosomiasis. A systematic summary of these results could contribute to the future design of new gold(I) and gold(III) complexes as potential antimicrobial agents.

Сдвиговые дуплексы Ганеевского месторождения золота (Южный Урал)

Сдвиговые дуплексы Ганеевского месторождения золота (Южный Урал)

Impact of ISO 14001 Environmental Management System on Key Environmental Performance Indicators of Selected Gold Mining Companies in Ghana

The impact of ISO 14001 Environmental Management System (EMS) on waste management, noise level, air quality, energy consumption, and number of reported environmental incidents as key environmental performance indicators was assessed. The assessment was based on annual and monthly environmental data and report from the selected gold mining companies (Gold Field Ghana Limited (GFGL) and AngloGold Ashanti (AGA)) before and after the implementation of the management system. Interviews with environmental managers and staff as well as field observations were also conducted. The results show that the implementation of ISO 14001 EMS by the two gold mining companies led to significant environmental improvements, particularly in waste management, reported environmental incidents, and energy consumption. Segregation of waste was adopted in both companies to ensure appropriate disposal mechanisms to mitigate pollution. Energy consumption significantly decreased in AGA following certification because of the energy conservation policy adopted by the company. In addition, the implementation of the standard brought significant increase in the total number of reported environmental incidents due to the incident reporting protocol inherent in the environmental management system. In all, it was clear that the management system is related to the environmental objectives and targets of the individual organisations and commitment towards fulfilment of the set objectives.

Keeping an eye on gold

Unlike the metal itself, the gold markets are always changingand you haveto haveyoureyeswideopento keepup. Thisisespecially true in the field of gold nanotechnology, wherescientists around the world are advancing our understandingof this special form of gold year in, year out.This special issue of Gold Bulletin offers a series of 16research articles describing cutting edge advances in the fieldof gold nanotechnology. The common thread of this work isthe GDR Or-nano, a research network set up in France in2006 with the support of CNRS (Centre National de laRecherche Scientifique, the French fundamental researchorganization). Or-nano (which stands for gold-nano) hasorganized and run a wide variety of meetings and eventsover the last 8 years, involving approximately 450 re-searchers along the way.The successes of Or-nano community are numerous andincludeavarietyofnewresearchcollaborations,thelaunchofnew projects, many invited lectures, and the training of thenext generation of PhD students and postdocs.In early 2013, a call to the community was issued forsubmissions to Gold Bulletin. After the usual review process,16 articles have been accepted, bringing together 86 authorsand 17 different research institutions into this special issue.This isa fairly accurate snapshot of the work achievedbyOr-

Multivariate analysis of regolith sediment geochemical data from the Jinwozi gold field, north-western China

The study of deep-penetrating geochemistry of arid desert terrains in the Jinwozi gold field, north-western China has generated a data set of multi-element geochemistry, characterised by high complexity and variability leading to difficulties in integration and interpretation. Three multivariate statistical methods, i.e., factor analysis (FA), hierarchical cluster analysis (HCA) and discriminant analysis (DA) were applied to a subgroup of the data set in order to define the element associations, to identify the anomalies and to classify the regolith samples. The geochemical patterns of arid desert terrains were thus interpreted with the aid of statistical techniques. The subgroup consists of Au, Ag, As, Hg, Cu, Mo, Sb and Zn concentrations of regolith samples collected from two traverse lines and five overburden boreholes. Two factors with eigenvalues greater than 1 extracted by FA account for approximately 81% of the total variance. Specifically, factor 1 explains 52% of the total variance and is highly loaded by a combination of Au–As–Hg–Ag. This combination could represent the major mineralisation and three anomalous sites have been determined. Two of which are located over the known deposit. Factor 2 explains 29% of the total variance and has positive loadings on Cu and Zn denoting the minor mineralisation and diagenesis. High positive scores of both factors could be considered as an indication of the mineralisation. Silver, As, Cu and Zn are the most effective indirect indicator elements in the Jinwozi. The HCA was then applied to the classification of samples taken from the five boreholes at the three anomalous sites. Three geochemically distinct clusters, named A1, A2 and A3, resulted from the HCA. Samples from cluster A1 with high concentrations of Au, Ag, As, Hg, Cu and Zn are highly-mineralised. In addition, samples from cluster A2 and A3 can be generally treated as non-mineralised. The DA confirmed the results obtained from the HCA. The spatial distribution of the clusters shows vertical symmetric distribution of highly-mineralised samples over the deposit. This confirms the effectiveness of the FA in delineation of the anomalies in the Jinwozi. The integration of the FA, HCA and DA proved to be an effective tool in the field of deep-penetrating geochemistry.

From the roof top into the mine

Abstract This article focuses on two of my films: Through the Dark Mine (Abraham, Film Tales, Bangalore, 2013) about the Kolar Gold Field Mines (1864–2001), and I Saw a God Dance (Abraham, Film Tales, Bangalore, 2012) – a short documentary film about the charismatic dancer Ram Gopal (1912–2003). The title of the article, ‘From the roof top into the mine’, reflects my attempt to juxtapose these two ostensibly different films, crafted out of found-footage, in order to see how they work side by side, metaphorically and historically. Both films illustrate mid twentieth-century modes of living and inform on the century’s modern and industrial practices such as film, dance and industrial gold mining. Working with and writing about the found footage used in making these two films represents in my opinion a form of archaeology of marginal practices in film. My composite films share a particular geographical area, and I have edited them as to create a visual path to experiencing the interiors of a gold mine and the intricate intimacy of the dancing form proposed by an exceptionally talented and beautiful gay performer. In writing this article, which is structured as a free-style essay, I developed new perspectives on my initial interpretations of the original visual material, and also on the formal concerns surrounding the structure and aesthetics of experiential and experimental film.

Constraints on the timing of the Tennant Event and associated Au–Cu–Bi mineralisation in the Tennant Region, Northern Territory

Detrital zircon dating of the Warramunga Formation that hosts iron-oxide Au–Cu–Bi mineralisation in the Tennant Region indicates that this unit was deposited after ca. 1860Ma. Intrusive felsic porphyries within the Warramunga Formation have U–Pb zircon ages of 1847.5±2.4, 1847.4±2.8, 1846.3±2.9 and 1848.9±2.2Ma, consistent with a single magmatic event at about 1848Ma. Peperitic margins of some of these intrusions indicate that deposition of the Warramunga Formation continued to about the time of porphyry emplacement. The Tennant Creek and Hill of Leaders granites have ages of 1851.1±3.5Ma and 1845.5±2.4Ma respectively, indistinguishable from those of the felsic porphyries, and consistent with previous interpretations that the porphyries are the high-level equivalents of the granitoids of the Tennant Supersuite. Felsic porphyry at the White Devil mine with an age of 1847.4±2.8Ma cross-cuts ironstone that hosts mineralisation, and the S1 foliation, indicating that ironstone formation and deformation occurred soon after deposition of the host succession. Alteration associated with Au–Cu–Bi mineralisation overprints the White Devil porphyry, providing a maximum age for mineralisation. Minimum ages of 1851–1847Ma for mineralisation are provided by previous 40Ar–39Ar age determinations, indicating that mineralisation, deformation and magmatism took place during the ca. 1850–1845Ma Tennant Event, contemporaneous with, or shortly after, the last stages of deposition of the Warramunga Formation. Although there is a close temporal association between mineralisation and felsic intrusive rocks of the Tennant Supersuite, the intrusive rocks are only weakly fractionated, suggesting they were not a significant source of Au and Cu. A felsic volcaniclastic rock from the Rover gold field 90km southwest of Tennant Creek yielded a unimodal zircon age group of 1842.3±4.5Ma, allowing correlation with the younger parts of the Warramunga Formation or the unconformably overlying ca. 1840Ma Ooradidgee Group. Although a detailed correlation remains uncertain, the simplest interpretation is that the Au–Cu–Bi mineralisation at the Rover Field occurred at a broadly similar time to that at Tennant Creek.

Three-dimensional geoelectric model of the Kirovograd ore area of the central part of the Ukrainian Shield

The authors give their 3D geoelectric model of the Kirovohrad ore district and consider aspects related to the association of uranium manifestations of albitite formation, gold fields and manifestations of graphite with anomalies of increased electrical conductance at the depths in the range of 0—100 m, 0,1—2,5 km, 2,5—20 km, 25—30 km and 50—120 km.

How you start matters: A comparison of Gold Fields' Tarkwa and Damang Mines and their divergent relationships with local small-scale miners in Ghana

This paper argues that actions of large-scale mining companies at the early stages of a mining project establish a legacy which sets the tone for that mine's long-term relationship with the local artisanal and small-scale mining (ASM) stakeholders. This paper compares the experiences of Gold Fields' Tarkwa and Damang mines and the divergent histories of each of these mines' relationship with local small-scale mining stakeholders. Circumstances at Damang during the discovery and early development of the project drove a rift between the mine and the ASM community. As the mine developed, a chain of ASM engagement strategies were enacted in an attempted to repair the relationship but which has never able to regain sufficient trust between the mine and ASM stakeholders. At the nearby Tarkwa mine, ASM confrontations have been much easier to manage. Despite early disagreements at Tarkwa, a relationship characterized by greater trust between the mine and ASM communities was established early and therefore ASM engagement strategies have been simpler and more effective. This paper will conclude that establishing and maintaining a positive mine legacy as early as the exploration phase of a mining project is critical to maintaining a positive, trust-based relationship between LSM companies and their local ASM stakeholders over the life of a mine.

Luxury and locality in a late medieval book of hours from south-west England

This paper describes and analyses a previously unrecorded Sarum book of hours of considerable artistic and textual interest. Seven of its pages have bar-frame borders illuminated in a distinctive and remarkable style. Four of these pages also have initials with figure-subjects, some of which are contextually unusual or unique. There is also an initial with a coat of arms displaying a black engrailed cross on a gold field (the arms of Mohun of Dunster in west Somerset). While the manuscript cannot be linked to a member of the Mohun family, the occurrence of a Somerset toponym in an obit dated 1429 in the calendar and the early addition to the litany of St Urith of Chittlehampton show that it was owned by someone who lived in Somerset or Devon in the early fifteenth century. Indeed, the book may also have been made in this region. Several features of its border illumination are paralleled in the Sherborne Missal (London, British Library, Additional ms 74236), produced in north Dorset or Somerset in the decade c 1398–c 1408. The parallels suggest a relationship (not necessarily direct) between the two manuscripts. Certainly, the book of hours discussed here is closer in style to the missal than it is to manuscripts made in or around London in the same period.

Exploration of gold mineralization in a tropical region using Earth Observing-1 (EO1) and JERS-1 SAR data: a case study from Bau gold field, Sarawak, Malaysia

Bau gold mining district, located near Kuching, Sarawak, Malaysia, is a Carlin style gold deposits. Geological analyses coupled with remote sensing data were used to detect hydrothermal alteration rocks and structure elements associated with this type of gold mineralization. Image processing techniques, including principal components analysis, linear spectral unmixing, and Laplacian algorithms, were employed to carry out spectrolithological–structural mapping of mineralized zones, using Advanced Land Imager, Hyperion, and JERS-1 synthetic aperture radar scenes covering the study area and surrounding terrain. Hydrothermally alteration mineral zones were detected along the SSW to NNE structural trend of the Tai Parit fault that corresponds to the areas of occurrence of the gold mineralization in the Bau limestone. The results show that potentially interesting areas are observable by the methods used, despite limited bedrock exposure in this region and the constraints imposed by the tropical environment.

Fields of gold

Fields of gold

Estimating South Africa’s black adult female social classes, demographic differentials and determinants

How to incorporate women into class analysis has been a topic of heated controversy. There is a growing demand in the private sector inSouth Africato provide demographic information by social class following the demise of apartheid, especially among the Black population. This study imputes social classes among Black females inSouth Africafrom survey data using the Living Standards Measure, and examines demographic differentials among the imputed classes as well as determinants of social class. The results indicate that, although Black females constituted the largest percentage (76%) of South Africa’s female population aged 15 years and above in 2007, Blacks had the smallest percentage of accomplished middle class females (22%) and highest percentage of lower class females (39%) compared to the White or Mixed populations. Some of the demographic differentials were as expected. However, the lower mortality among children born to Black lower class females compared with the mortality among children born to emerging Black middle class females was unexpected. Being a female head or acting head of household was found to be significantly and negatively associated with being in the accomplished middle class among Black females. Eric O. UDJO, research director, University of South Africa, Bureau of Market Research, Theo van Wijk Building, Gold Fields Entrance, Unisa Muckleneuk Campus, Pretoria 0002, South Africa. E-mail: udjoe@unisa.ac.za.

Multiple methods for regional- to mine-scale targeting, Pataz gold field, northern Peru

Gold production in the Pataz district, northern Peru, is derived from mesothermal veins hosted by the Pataz batholith and basement-hosted epithermal and carbonate–base metal veins. At the regional scale, processing of Advanced Spaceborne Thermal Emission and Reflection Radiometer data can be used to delineate district-scale argillic alteration. One such area extends for tens of kilometres NNW of Vijus in the Maranon Valley. At the southern end of this area, basement-hosted quartz–carbonate–sulfide veins in faults support artisanal gold-mining operations. SEM analyses show that the alteration envelopes around these faults are dominated by illitic clays. These artisanal gold workings highlight the economic potential of the largely unexplored parts of the district-scale argillic alteration zone, further north. At the district scale, paleostress modelling maps areas of low minimum stress during Carboniferous ENE–WSW shortening, based on a new 1:25 000 geological map of the Pataz district. The resulting distribution of low minimum stress is used to predict sites of rock fracture under high fluid pressure, and consequent vein formation. These areas of low minimum stress occupy 11% of the modelled area but contain 50% of the known veins in the Pataz district. Some areas of low minimum stress contain no known veins, and where these are poorly explored or poorly exposed, they are proposed as potential targets for gold exploration. In combination with SEM microanalysis, ASD hyperspectral reflectance analysis of drill core samples shows that visible proximal sericitic alteration around batholith-hosted auriferous veins is predominantly phengitic illite. Automated software interpretation of ASD reflectance spectra using The Spectral Assistant shows that sericite in cryptic alteration distal from auriferous veins varies from mainly illite adjacent to the phengitic illite zone, to more distal muscovite. Reactivation of faults and mineralised vein contacts during the largely Cenozoic Andean orogeny produced chlorite alteration that locally overprints proximal phengitic illite alteration. ASD spectrometry identifies relict phengitic illite in some chloritic alteration zones and thus indicates proximity to mineralised veins at the deposit scale. Elevated pathfinder element concentrations within proximal phengitic illite alteration zones around batholith-hosted veins do not extend more than a few metres beyond the visible alteration envelope. The alkali alteration index [(Rb + Cs)/Th]N is elevated above background levels for up to 15 m beyond the visible sericite alteration zone in one of two holes investigated. In the other hole, both [(Rb + Cs)/Th]N and 3K/Al can be used as a lode-scale vector to gold-bearing veins within broad intersections of visible sericite alteration.

The Coat of Arms in Fra Filippo Lippi’s Portrait of a Woman with a Man at a Casement

The Coat of Arms in Fra Filippo Lippi’s <i>Portrait of a Woman with a Man at a Casement</i>

Dark field imaging of rattle-type silica nanorattles coated gold nanoparticles &amp;lt;italic&amp;gt;in vitro&amp;lt;/italic&amp;gt; and&amp;lt;italic&amp;gt; in vivo&amp;lt;/italic&amp;gt;

Gold nanoparticle is a promising nanomaterial used in the field of biological imaging, cancer diagnosis and treatment. However, the research of gold nanoparticles in the dark field imaging using the light scattering characteristics is still rare and the biocompatibility has become an important problem that plagued its application. In this paper, we synthesized a novel nanostructure in which 13 nm gold nanoparticles exist in the cavity of the core-shell silica structure. This nanostructure remained gold particle dark field imaging characteristics, and improved the monodispersity and biocompatibility of gold nanoparticles. Cytotoxicity experiments show good biocompatibility of SN@GN in vitro . Acute toxicity in mice showed that the maximum-tolerated dose of SN@GN greater than 200 mg/kg, significantly improve the biocompatibility of gold nanoparticles. This study provides an important experimental basis of SN@GN in the medical imaging application.

ChemInform Abstract: π‐Acid Mediated Insertion of Alkynes into Carbon—Heteroatom σ‐Bonds

AbstractReview: about 100 refs.

ChemInform Abstract: Gold in Total Synthesis: Alkynes as Carbonyl Surrogates

AbstractReview: 30 refs.

山东鲁东地区中生代构造–岩浆事件与金矿成矿作用

山东鲁东地区处于特提斯、古亚洲洋和太平洋三大构造域的结合部位，它们的相互作用过程决定并影响着鲁东的成矿环境，在中生代区内有印支和燕山二次造山事件。燕山造山事件在鲁东地区表现为三个造山幕，每一幕表现为挤压与伸展的旋回性，这种旋回性是鲁东金矿和多金属矿成矿的地质背景。中生代构造演化对山东的构造–岩浆事件、沉积环境和成矿作用起着制约与控制作用，岩浆–沉积–构造–成矿事件与区域构造事件具有相互耦合性，金矿、多金属矿的形成与定位同燕山期三个构造幕紧密相联，3期成矿事件160~140 Ma、130~110 Ma和105~80 Ma则与玲珑、郭家岭和伟德山岩体的构造–岩浆热事件相耦合。文章在统计区内已报道的金矿成矿年龄样品318件的基础上，划分了81~105 Ma、110~130 Ma和141~160 Ma三个年龄集中区间，按照成矿作用、矿床类型和成矿时序，认为区内成矿作用与三个构造幕同步，为第一幕Mo-W-Au、第二幕Au-Ag和第三幕Cu-Pb-Zn-Mo-Au成矿作用。Mo-W-Au成矿系列典型矿床是邢家山钼钨矿、铜矿和留村金矿；Au-Ag成矿系列是鲁东地区主成矿期的表现形式，可进一步分为与早白垩世壳幔岩浆作用有关的Au、Ag矿床成矿亚系列、与早白垩世壳幔岩浆作用有关的Au、Ag、Cu、多金属矿床成矿亚系列和与早白垩世壳幔岩浆期后热液活动有关的Cu、Au、Fe、Ag、硫铁矿矿床亚系列，其典型矿床为焦家金矿、三山岛金矿和玲珑金矿等。Cu-Pb- Zn-Mo-Au成矿系列与伟德山造山晚期闪长岩–花岗闪长岩–花岗岩组合、浅成–超浅成石英闪长玢岩–花岗闪长斑岩–石英二长玢岩组合和青山群石前庄组中酸性火山喷发建造关系密切，是区内金矿的叠加成矿期及多金属矿的主成矿期，成矿年龄81~105 Ma。 Eastern Shandong Province is situated at the intersection of three tectonic domains as Tetisi, Paleo-Asian Ocean and Pacific Ocean. Interaction process of these three global tectonic domains control and affect the metallogenic environment of eastern ShandongProvince. This area has experienced lndosinian orogenic event and Yanshanian oro- genic event during Mesozoic period. Yanshanian orogenic event represents three tectonic episodes. Each episode repre- sents cyclicity of extrusion and extension. This cyclicity is the geological background of mineralization in Ludong gold deposit and other polymetallic deposits. Mineralization geological environment of three world-class gold fields with the reserve over one thousand tons, such as Sanshaodao gold field, Jiaojia gold field and Linglong gold field have the char- acteristics of uniqueness and induplication. Mesozoic tectonic evolution controls tectonic-magmatic event, sedimentary environment and gold mineralization. There is a strong coupling relationship between magma-sedimentary-tectonism -mineralization event and regional tectonic evolution. The formation and location of gold deposits and polymetallic deposits also have close connections with three tectonic episodes of Yanshanian orogenic event. Three mineralization events (160 - 140 Ma, 130 - 110 Ma and 105 - 80 Ma) have coupling relationship with three regional tectonic-magmatic hydrothermal events of Linglong rock mass, Guojialing rock mass and Weideshan rock mass respectively. On the basis of gold mineralization ages gained from 318 samples which have been reported in this area, three age concentration periods have been divided as 81 - 105 Ma, 110 - 130 Ma and 141 - 160 Ma. According to mineralization, deposit types and ore-forming sequences, it is regarded that mineralization in this area is synchronous with three tectonic episodes. That is the first Mo-W-Au tectonic episode, the second Au-Ag tectonic episode and the third Cu-Pb-Zn-Mo-Au tectonic episode mineralization. Typical deposits of Mo-W-Au metallogenic series are Xiangjiashan molybdenum and tungsten deposit, copper deposit and Liucun gold deposit. Au-Ag metallogenic series are major representative type of main min- eralization stages in eastern Shandong Province. It can be further divided into Au-Ag metallogenic sub-series which has close relation with mantle-crust magma interaction in early Cretaceous period; Au-Ag-Cu metallogenic sub-series which has close relation with mantle-crust magma in early Cretaceous period; and Cu-Au-Fe-Ag metallogenic sub-se- ries which has close relation with post-magmatic hydrothermal in early Cretaceous period. Typical deposits are Jiaojia gold deposit, Sanshandao gold deposit and Linglong gold deposit. Cu-Pb-Zn-Mo-Au metallogenic series is the main stage of superimposition mineralization and polymetallic mineralization with a mineralization age at 81 - 105 Ma. This series is closely related to the diorite-granodiorite-granite and quartz diorite porphyry-granodiorite porphyry-monzonite porphyry of the late Weideshan orogenic stage, and acid-intermediate volcanic-sedimentary formation of Shiqianzhuang formation in Qingshan Group.