Determination of work index of Filin Kokuwa Gold Deposit in Toro Local Government, Bauchi State Nigeria

This report shows the work index of Filin Kokuwa Gold ore sample in Bauchi State, Nigeria. The “reference sample (granites)” were sourced from outcrops of granites around Toro town. The samples were crushed, ground, and pulverized using appropriate laboratory milling machine. 80% passing size for the gold ore and granites samples were obtained at 100μm sieve size for the ball mill feeds and products respectively. The work indexes of reference samples i.e. granites were used to calculate the work index of the Filin Kokuwa gold ore sample. The values of 13.277kWh/ton and 15.192kWh/ton were obtained respectively for the two different reference granites samples used and 14.21kWh/ton as their average which is the value of the work index of the Filin Kokuwa gold ore deposit. The energy required for grinding the ore was found to be 3.581kW.

Coexisting Tetrahedrite–(Zn) and Sphalerite at the Teremki Gold-Ore Deposit (East Transbaikalia): Chemical Composition and Formation Conditions

Paragenetic associations of tetrahedrite-(Zn) and sphalerite are distinguished in the Teremki gold-ore deposit. The chemical composition of coexisting minerals of this association is determined. The Sb/(Sb + As) and Fe/(Fe + Zn) ratios in tetrahedrite-(Zn) vary from 0.66 to 0.97 and from 0.28 to 0.40, respectively. A negative correlation was established between Sb/(Sb + As) and Fe/(Fe + Zn) ratios. Contents of Fe in sphalerite change from 0.88 to 1.43 wt % (1.5–2.5 mol % FeS). Temperature and sulfur fugacity when precipitation of tetrahedrite-(Zn)–paragenesis were estimated: they range from 130 to 280°C and from 10–13.2 to 10–8.1 bars, respectively.

DEPENDENCE OF QUALITATIVE AND QUANTITATIVE INDICATORS OF ORE RESERVES ON THE MAXIMUM PERMISSIBLE INTERVAL OF UNCONDITIONAL ORES OF THE SOTK GOLD ORE DEPOSIT

At the Sotk gold ore deposit, the following morphological types of ore bodies can be distinguished: vein zones; veins and vein-like bodies; mineralized dykes and a vein zone in gabbro - massifs. The deposit is characterized by rather difficult mining and technical conditions. The enclosing rocks of the near-ore bodies have undergone intense hydrothermal changes at a distance of 5,0...10,0 m to 50,0 m, as a result of which, within the boundaries of these zones, the enclosing rocks have lost their strength and stability. The stability of the host rocks is also greatly influenced by postore tectonic faults, which are widespread in the field. The ore is also volatile. The strength factor of ore and host rocks varies from 3 to 20, with a predominance of 8...13. Hydrothermally altered metasomatites, which make up the mineralized zones, are prone to caking. The ore loosening factor is 1,25...1,40. The average bulk density of ore is 2,6 t / m3, and the bulk density of the host rocks is 2,3... 3,2 t / m3. At the deposit, conditioned and substandard intervals alternate with each other and there is no clearly expressed regularity of their spatial location, which predetermines the use of the ore-bearing factor when calculating ore reserves. The ore content ratio is determined by the ratio of the amount of conditioned ores to the total amount of ore mass, and the amount of conditioned ores is determined using the condition parameter “maximum - allowable range of substandard ores or waste rocks” included in the reserve calculation. For the Sotk gold ore deposit, the regularities of changes in ore reserves in the subsoil, the gold content in the ore massif and the ore content factor from the “maximum allowable to an increase in ore reserves in the subsoil and the ore content ratio with a decrease in the gold content in the ore massif and vice versa are revealed.

ON THE AGE AND GEODYNAMIC FACTORS OF THE FORMATION OF GOLD MINERALIZATION AT THE MALINOVKA DEPOSIT

An interpretation of the first obtained Re-Os dating of pyrite and arsenopyrite of the Malinovsky gold ore deposit is given. A comparison of the obtained data and the known dates of the ore-bearing granitoids of the ore field made it possible to determine the age of mineralization at 100-90 Ma. This age corresponds to the time of completion of the Alb-Cenomanian transform margin of Asia continent geodynamic setting with significant left-shear kinematics, as indicated in the article by the structural features of the localization of ore bodies and magmatic bodies. The distribution of gold ore deposits in this time within the Sikhote-Alin orogenic belt and in the shear structures of the south of the Korean Peninsula are noticeably shown.

DISCOVERY, DEVELOPMENT AND STUDY OF THE KIROVSKYI GOLD ORE DEPOSIT OF AMUR PROVINCE (AMUR REGION, RUSSIA)

The history of the discovery, development and study of the Kirovskyi gold ore deposit in the Priamur gold-bearing province is considered. The deposit is attributed to the gold-bismuth type of vein deposits of the gold-sulfide-quartz formation. Gold mineralization is genetically related to the formation of the Dzhalinda intrusion of Early Cretaceous granitoids or a series of later dikes of «variegated» composition. The isotopic age of gold mineralization, determined by the Rb-Sr method, is in the fork 131-126 Ma. Further prospects of the deposit are associated with the search for large-volume deposits with stockwork type ore bodies.

HISTORY OF DISCOVERY AND STUDY OF «ZOLOTAYA GORA» DEPOSIT OF PRIAMUR GOLD-BEARING PROVINCE (AMUR REGION, RUSSIA)

Information about the history of discovery, development and study of the gold ore deposit «Zolotaya Gora» in Priamur gold-bearing province is present. The deposit is represented by six gold-sulfide-quartz veins located in the zone of crumpling and diaphthoresis along the gneisses and crystalline schists of the Archean. Ore bodies intersect with diorite porphirites of the Mesosoic age. The deposit had the richest gold-sulfide-quartz ores in the Amur region with an average gold grade of about 120-140 g/t. The isotopic age of mineralization, determined by Rb-Sr method, is 155±7 million years.

Gold-tourmaline mineralization in carbonaceous shales of the Kumak deposit (South Ural)

The article discusses the geological structure of the Kumak gold ore deposit, confined to the Early Carboniferous Anikhov graben of the East Ural uplift. It is composed of sericite-quartz-carbon and quartz-carbon-tourmaline schists of the Bredy Formation (C1bd). Black shale deposits are carbonaceous type and belong to terrigenous-carbonaceous and silicon-carbonaceous formations. Among the main minerals in shales are noted: quartz, sericite, carbonates, sulfides, tourmaline and carbonaceous matter. The field is characterized by a wide variety of gold ore mineralization. Rich ore zones are noted at the intersection of the East Anikhov faults oriented in the north–south direction and the branching tensile fractures in the north-north-east and north-west directions. In the ore mineral association prevailing here, finely dispersed gold is associated with small crystals of pyrite, arsenopyrite and concentrates nearby abundant tourmaline areas. The fine intergrowth of tourmaline and gold indicates the synchronism of their formation and allows us to distinguish a quartz-tourmaline gold ore formation within the Kumak deposit, comparable with a number of objects in East Transbaikal and Tuva. The most probable source of tourmaline mineralization in sericite-quartz-carbon schists could be metamorphically transformed boron-containing marine sediments saturated with clay particles and Corg. The microprobe study of gold grains taken from carbonaceous shales and weathering crusts made it possible to attribute them to the high-grade (919–1000) type, which is the leading one in the gold ore mineralization of the considered deposit. It is established that in the zone of hypergenesis, gold grains are not homogeneous. Here, secondary redeposition of gold takes place in the form of small spongy high-grade aggregates, as well as the formation of a rim on some grains with clear signs of refinement and purification from impurity elements. The geological works were carried out under State Contract No. 0246-2019-0078. The analyses were supported by the regional Grant for Science and R&D, Agreement No. 23 dated August 18, 2019. The studies into gold composition were executed in the framework of state-financed scientific topic No. AAAA-A19-119072390050-9. The authors express thanks to S. A. Yagudin for the analysis implementation and to E. O. Kalistratov for the help in description of polished sections. Further thanks are extended to R. S. Kisil and V. S. Panteleev for the help in the field works.