Mineralogical - geochemical characteristics of gold mineralization and its potential in the Tuong Duong area, Nghe An province

Tuong Duong area, Nghe An province is considered as a high potential area of gold deposits such as the Yen Na - Yen Tinh, Ban Bon, Xieng Lip, and Na Khom gold occurrences. Based on synthesizing, geological processing data, analysis and complement of the 15 thin sections, 10 thick sections, 02 scanning electron microscope and 05 ICP - MS samples, results show that the gold mineralization has fomed from hydrothermal activities at low - moderate temperature, belonging to quartz - sulfur - gold mineral deposit type. The gold contents in orebodies vary from medium to high values, with average contents ranging from 0.8÷6.55 (g/ton). Results also provide an overview of the prospect of gold resources, serving as a basis for determining the Au prospective areas in Tuong Duong, Nghe An province. The direct calculation method for metallization parameters and Huvo methods are applied in this paper to estimate gold resources in the study area, resulting in 2.21 tons of Au - metal.

Mineralogy and genesis of the Oleninskoe gold deposit (Kola Peninsula).

Data on geology of the Oleninskoe deposit, and results of mineralogical and geochemical investigations of ores and altered rocks are presented. Mineralization is connected with granite porphyry sills, an end member of gabbrodiorite-diorite-granodiorite complex of minor intrusions. The main alteration processes are diopsidization and biotitization, formation of quartz-muscovite-albite, quartz-aresenopyrite-tourmaline, and quartz metasomatic rocks. More than 50 ore minerals (sulfides, sulfosalts, tellurides, and native metals) were identified in the ore, including 20 minerals of silver and gold. Mineral associations in the ore and sequence of mineral formation are defined. Five generations of gold-silver alloys are identified, its composition covers spectrum from native silver to high-grade gold. Mineralized fluids in the deposit are of high salinity (sodium and calcium chlorides), and rich in As, Sb, Pb, Cu, Zn, and Ag. The Oleninskoe deposit is classified as an epithermal metamorphosed gold deposit.The book is of interest for specialists in economic geology, mineralogy and geochemistry of ore deposits.

Mineralogy of precious metals in ores of the Yubileinoe porphyry gold deposit (Kazakhstan)

Gold and silver mineralogy is studied in ores of the Yubileinoe porphyry gold deposit (Kazakhstan). Native gold is the major gold mineral. Its fneness varies from 970‰ in magnetite-hematite assemblage to 733–860‰ in pyrite-chalcopyrite assemblage. Silver occurs as admixture in native gold and, occasionally, as silver telluride. Native gold is associated with bi and Pb minerals: rucklidgeite, galenaclaustalite, and tetradymite-kawazulite. According to chlorite geothermometry, the Au, Ag and bi minerals precipitated at temperatures of 250-230 °С. These features are typical of the porphyry gold deposits worldwide. Figures 5. Tables 3. References 17.

Mining development will face obstacles in Argentina

Subject Outlook for the mining sector. Significance President Alberto Fernandez has singled out mining among the sectors that could attract much-needed foreign investment. However, recent emergency measures seeking to boost public revenues and avoid a currency run could further deter investors. Accumulated exploration investments reached nearly 1 billion dollars over the past four years, but actual development of projects has been moving slowly. Impacts Environmental issues will continue to prompt popular pushback against mining projects. Anti-mining sentiment among citizens will clash with provincial governments’ need to boost growth and revenues. Any gold output increases are likely to come from associated gold mineral in large copper projects.

Evaluation of the inhibition process effect “Preg-robbing” for gold recovery (AU)

Currently, the National Society of Mining, Petroleum and Energy (SNMPE) states that in recent years the production of gold in Peru has reduced, since in 2016 there was a production of 153 MT, compared to 2005 with a production of 208 MT. Until 2018, a production decrease of 5.4% was established and in 2017 a decrease of 11.3%. Currently there is a need to develop research on gold extraction processes in low recovery minerals with traditionally used processes, due to the complex structure of gold that prevents their extraction. It is necessary to evaluate new processes that are environmentally friendly and that are sustainable in the environmental and economic aspects. In the present work, the applicability of leaching with NaCl and KNO3 in acid medium in a sulphurous gold mineral was evaluated, through the process of leaching with oxidizing salts, which allows to process hydrometallurgy the various forms of gold minerals present in nature. The sample is composed in percentages by Quartz 24%, Carbonates Dolomite 22%, Calcite 6%, Arsenopyrite 19%, Pyrite 5%, Galena 4% and clays associated with traces of Native Au-Electrum, which were interfering with the process of leaching of the sample. A pretreatment by gravimetric concentration was carried out using the Falcón equipment, with the aim of releasing the encapsulated gold and eliminating the interfering agents, facilitating the leaching action of the oxidizing salts. When testing the concentrations of the oxidizing salts, it was found that for the concentrations of 86.86 g/l of NaCl, 21.96 g/l of KNO3 and 125.93 g/l of H2SO4, a maximum recovery of 26.62% gold was obtained. Based on the results from the factorial design, an increase in gold extraction performance was observed; obtaining a maximum recovery of 29.31% of the gold; in the process it was determined that dissolved gold is affected by the presence of clays, producing the "Preg-robbing" effect of the valuable metal and consequently decreasing the recovery of gold after 8 leaching hours. According to the results, it is concluded that the leaching process with oxidizing salts in acidic medium for the type of mineral used, is mainly affected by the presence of coarse gold and electrum associated with clays, establishingconditions of degree of release according to the granulometry in the gold leaching process.