SIGNIFICANCE OF THE METALLURGICAL INDUSTRY OF AZERBAIJAN IN THE NON-OIL SECTOR, THE ROLE OF AZERGOLD CJSC IN THE ECONOMY OF THE REPUBLIC

Geological surveys carried out by the Closed Joint Stock Company (CJSC) AzerGold for the exploration of new deposits and expansion of production areas are giving positive results. For an effective assessment of reserves at the fields, AzerGold CJSC conducts intensive exploration work and drills deep wells in these fields. Since 2017, AzerGold CJSC has been mining Chovdar, Agyokhush, Tulallar, Marakh, Filizchay etc others and Jayirchay gold, as well as it carries out various works on fine metal deposits. The latest financial indicators of AzerGold CJSC give reason to say that it is a stable company. It is expected that AzerGold CJSC will react faster to the growth rates in the world markets due to the work carried out at new gold deposits and efficient use of resources. The net profit of a Closed Joint Stock Company has been growing at a higher rate over the years. AzerGold CJSC produces ingots and coins from Azerbaijani gold and silver in various historical designs. Bars and coins are currently sold in stores owned by Italdizain Group, Levata Group and SI Luxury World, which have a long history of selling premium goods. AzerGold CJSC will soon become better known in the local and international markets as a gold producer of the country. AzerGold CJSC issues bonds, increases the company's technological capabilities for gold production and strengthens production in order to bring more gold to the world market. Recent financial indicators of AzerGold CJSC give grounds to say that it is a stable company. The company's revenue, net profit and total capital of the company in 2019 increased several times compared to 2018. Keywords: AzerGold CJSC, geological exploration works, drilling works, production works, efficiency.

An Integrated Approach to Assess the Environmental Impacts of Large-Scale Gold Mining: The Nzema-Gold Mines in the Ellembelle District of Ghana as a Case Study

The mining industry is a significant asset to the development of countries. Ghana, Africa’s second-largest gold producer, has benefited from gold mining as the sector generates about 90% of the country’s total exports. Just like all industries, mining is associated with benefits and risks to indigenes and the host environment. Small-scale miners are mostly accused in Ghana of being environmentally disruptive, due to their modes of operations. As a result, this paper seeks to assess the environmental impacts of large-scale gold mining with the Nzema Mines in Ellembelle as a case study. The study employs a double-phase mixed-method approach—a case study approach, consisting of site visitation, key informant interviews, questionnaires, and literature reviews, and the Normalized Difference Vegetation Index (NDVI) analysis method. The NDVI analysis shows that agricultural land reduced by −0.98%, while the bare area increases by 5.21% between the 2008 and 2015 periods. Our results show that forest reserves and bare area were reduced by −4.99% and −29%, respectively, while residential areas increased by 28.17% between 2015 and 2020. Vegetation, land, air, and water quality are highly threatened by large-scale mining in the area. Weak enforcement of mining policies, ineffective stakeholder institution collaborations, and limited community participation in decision-making processes were also noticed during the study. The authors conclude by giving recommendations to help enhance sustainable mining and ensure environmental sustainability in the district and beyond.

Beneficiation of recycled process water at DRDGOLD's ERGO plant, and its effect on gold recovery

SYNOPSIS To conserve fresh water resources and comply with environmental regulations, DRDGOLD, a South African gold producer re-treating surface tailings, has transitioned to a fully closed water circulation system. Consequently, the accumulation of contaminants, as well as addition of reagents, has led to changes in water composition that have compromised leach performance and overall gold recovery. A two-sample t-test confirmed a significant difference in gold recoveries between the use of Rand Water, which was used as a benchmark, and untreated process water. Atomic absorption analysis of ERGO's process water, confirmed the presence of iron, nickel, zinc, and manganese. A study of the effect of the identified contaminants on gold recovery showed that iron, nickel, and zinc have the largest negative effect on gold recovery, with iron and nickel being more detrimental than zinc. Sulphates were shown to have a possible passivation effect, which also influenced gold recoveries, although to a lesser extent than the heavy metals. Calcium, when present in excess, had a positive influence on gold recovery indicating the possible formation of a calcium aurocyanide complex. Lime softening successfully reduced the heavy metal and sulphate concentrations, and the gold recoveries obtained with the treated process water were similar to those as achieved with Rand Water. Keywords: gold tailings, re-processing, water quality, gold recovery.

PRECISE AGES FOR LODE GOLD MINERALIZATION IN THE XIAOQINLING GOLD FIELD, SOUTHERN MARGIN OF THE NORTH CHINA CRATON: NEW CONSTRAINTS FROM IN SITU U-Pb DATING OF HYDROTHERMAL MONAZITE AND RUTILE

The Xiaoqinling gold field, located along the southern margin of the North China craton, is the second largest gold producer in China, which comprises more than 1,200 auriferous quartz veins with a proven gold reserve of at least 800 tons. Previously, the absolute age of the gold metallogenesis in this area has not been well defined due to the lack of suitable dating minerals. This study presents new in situ laser ablation-inductively coupled plasma-mass spectrometry U-Pb ages of coexisting hydrothermal monazite and rutile for the Fancha gold deposit in this area, which yielded 206Pb/238U ages of 127.5 ± 0.7 Ma (n = 65, mean square of weighted deviates [MSWD] = 1.8) and 129.7 ± 4.3 Ma (n = 37, MSWD = 1.4), respectively. Both ages overlap within analytical uncertainty at the 2σ level of significance, suggesting that both gold-bearing veins were emplaced at ca. 128 Ma. Mineralogical observations indicate that the monazite and rutile precipitated simultaneously with gold from the hydrothermal fluid. Our new data, combined with recently published monazite age, define a more precise gold episode, demonstrating that the gold endowment of the Xiaoqinling area was formed during a relatively brief period at ca. 130 to 127 Ma. We suggest that auriferous fluids were generated as a result of interactions between the enriched mantle and the lower crust, which was driven by westward flat slab subduction of the Paleo-Pacific plate during the late Mesozoic. The peak of lithospheric thinning during the postsubduction may have led to the rapid release of gold from the fertilized mantle. Consequently, the large number of gold-bearing veins in the Xiaoqinling area may ultimately be related to the tectonic evolution and mantle fluid processes that occurred during Early Cretaceous lithospheric extension.

Ore geology, fluid inclusion, and stable isotope constraints on the origin of the Damoqujia gold deposit, Jiaodong Peninsula, China

The Damoqujia gold deposit within the Zhaoping Fault Zone on Jiaodong Peninsula in eastern China is hosted primarily by Mesozoic granitoids and contains >60 t of gold, making it an important gold producer. Three mineralization stages are distinguished (early, middle, and late): (K-feldspar)–sericite–quartz–pyrite, quartz – gold – polymetallic sulfides, and quartz–carbonate. Gold deposition occurred mainly in the middle stage. The primary fluid inclusions of three stages are mainly homogenized at temperatures of 236–389, 191–346, and 104–251 °C, with salinities of 2.96–11.33, 1.39–17.28, and 0.53–11.48 wt.% NaCl equivalent, respectively. Fluid inclusion studies indicate that the metallogenic system evolved from CO2-rich mesothermal homogeneous fluids to CO2-poor aqueous fluids due to inputs of meteoric waters. The gold was carried as a bisulfide complex in the ore-forming fluids. Precipitation of gold was caused by a combination of fluid immiscibility and water–rock interaction. Studies of the fluid inclusion characteristics (medium temperature, CO2-rich, and low salinity H2O–CO2–NaCl homogeneous system), hydrogen and oxygen isotopes ([Formula: see text] = –1.0‰ to 7.6‰, δD = –109‰ to –77‰), sulfur values ([Formula: see text] = 4.5‰ to 8.5‰), and regional geological events show that the ore-forming fluids reservoir was likely metamorphic in origin. Based on the immiscibility of fluid inclusion assemblages, the estimated depth and pressure of trapping are 8.3–10.2 km and 83–276 MPa, respectively, corresponding to the depth and pressure of mineralization.

Study of Radarfacies in Auriferous Placers at Baixada Cuiabana, Mato Grosso (Brazil)

The state of Mato Grosso (MT) is the fifth largest gold producer in Brazil, with much of it coming from the Baixada Cuiabana region. In this region, gold occurs in primary deposit associated with quartz veins and their host metasedimentary rocks of the Cuiabá Group and secondary sedimentary deposits (such as colluviums, alluviums and eluviums), the latter being quite profitable and easy to exploit. The gold exploitation in these areas often results in deforestation of the Pantanal biome, as mining uses random subsoil scarification to locate the deposits. In this study, the Ground Penetrating Radar (GPR) geophysical method was applied to differentiate and locate alluvial, colluvial and eluvial deposits. This may help to mitigate the local deforestation process. Thus, the acquisition of GPR data took place in a gold mine located in the municipality of Nossa Senhora do Livramento. The GPR recordings were done with a 200 MHz shielded antenna, along with ditches and gravel exposures. The results show variability of the electromagnetic wave velocity between 0.085 to 0.146 m/ns, with normalized amplitudes of -1 to 1 ranging between maximum values of -0.8 and 0.8. The lowest velocity values were found for gravels of alluvial origin. The intermediate velocity of 0.090 m/ns is associated with eluviums and the highest velocity (0.146 m/ns) is associated with gravel of colluvial origin. GPR was efficient to distinguish secondary sedimentary deposits in the Baixada Cuibana, becoming a prospective alternative for the region.

IN SITU DATING OF HYDROTHERMAL MONAZITE AND IMPLICATIONS FOR THE GEODYNAMIC CONTROLS ON ORE FORMATION IN THE JIAODONG GOLD PROVINCE, EASTERN CHINA

The Jiaodong gold province, the largest gold producer in China, formed in a setting dominated by a 30-m.y. episode of Izanagi plate rollback and widespread extension, concomitant with late Mesozoic craton destruction. This study presents new high precision in situ sensitive high-resolution ion microprobe (SHRIMP) U-Th-Pb and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb ages for hydrothermal monazite from the largest of the Jiaodong gold deposits, which were previously dated as indicating ore formation over a few tens of millions of years when applying sericite Ar-Ar, zircon U-Pb, and less robust analytical techniques. Our U-Pb dating on monazite from the Jiaojia and Linglong deposits in western Jiaodong yielded consistent ages at ca. 120 Ma. The new geochronologic results, coupled with recently reported in situ monazite dates from smaller deposits in western Jiaodong, reveal that the deposits that host most of the ≥4,000-t Au resource formed during a relatively brief period at ca. 120 Ma. In eastern Jiaodong, the much smaller resource may have formed about 5 m.y. later, recorded by 114.2 ± 1.5 Ma gold mineralization at the Rushan deposit. The postsubduction opening of a slab gap at ca. 120 Ma is the most likely cause of the extensive gold mineralization in Jiaodong. The gap induced a local and rapid devolatilization of the hydrated mantle wedge at submelt temperatures. The transient event included release of a major volume of gold-transporting aqueous-carbonic fluid that was stored in the wedge into major NNE-trending structures in the overlying lithosphere.

The creation of objects of the Kazakh culture with the use of additive technologies

The article presents material about the main prospects for the introduction and operation of new additive technology in the Republic of Kazakhstan. Additive technology (3D printing) is a global phenomenon that contributes to the development of new industries that use digital technologies. 3D printing is necessary for the production of quality products. Kazakhstan, the world’s fifteenth largest gold producer, does not actively promote the jewellery industry. Jewellery is an obligatory attribute of a family celebration and an element of the national culture of Kazakhstan. Jewellery products purchased in Kazakhstan are only 10% local; all the rest are from Russia, Turkey and Europe. New production of jewellery products using three-dimensional modelling and additive technologies should become an image industry in Kazakhstan, due to exclusivity and affordable cost

Dependence Structure Analysis and VaR Estimation Based on China’s and International Gold Price: A Copula Approach

Since 2013, China has become the world’s largest gold producer and consumer. To gain the corresponding global pricing power in gold, many actions have been taken by China in recent years, including the International Board at Shanghai Gold Exchange, Shanghai-Hong Kong Gold Connect and Shanghai Gold Fix. Our work studies the dependence structure between China’s and international gold price and examines whether these moves are changing the dependence structure. We use GARCH-copula models to detect the dynamic dependence and tail dependence. The research period is set to contain the Financial Crisis in 2008, the dramatical plunge of gold price in 2013 and a series of black swan events in 2016. The empirical study shows that some event driven dependence structure breaks are statistically insignificant. And the time-varying Symmetrized Joe-Clayton copula is the best copula to model the dependence structure based on AIC value. Finally, an example of applications of this dependence structure is given by estimating the VaR of an equally weighted portfolio with a simulation-based method.