お知らせ • Jan 25
East Star Resources plc Announces Substantial Copper-Lead-Zinc Deposit Identified on Rudny Altai, Kazakhstan
East Star Resources Plc announced that, as a result of a detailed literature review following its successful 2022 helicopter electromagnetic ("HEM") survey, it has identified a substantial copper-lead-zinc-deposit ("Cu-Pb-Zn") located within its 100% owned 'RA3' licence, centrally located in the world-class Rudny Altai VMS belt. The newly identified polymetallicvolcanic and sediment hosted exhalative sulphide ("VSHMS") deposit (the "Verkhuba Deposit") is within the greater Verkhuba Ore District which includes the (previously announced) four Priority 1 HEM anomalies, and has the potential to become a deposit of regional significance. The Verkhuba Ore District is situated in an anticlinal structure (Luninskaya Anticline) composed of Devonian volcanogenic and sedimentary formations. The Verkhuba Ore District hosts more than 24 occurrences of Cu-Pb-Zn mineralisations, including four VMS/VSHMS deposits where mineral resources have been estimated in the Kazakhstan GKZ system in the C2 and P1 resource categories. The Company also delineated several untested EM targets during the 2022 HEM survey programme. The Verkhuba Ore District covers an area of 10 km x 3 km elongated principally in an E-W direction. East Star's licence, 1795-EL, covers the eastern and the western part of the Verkhuba ore field and includes the old Pokrovskoye-2 VMS mine and the Verkhuba Deposit. Surface outcrops of sulphide ore within the Verkhuba Ore District have been known since the bronze age with the first geological description and small-scale mining in the 17th century. The systematic geological study of the area started in the 1920s. The Verkhuba Deposit was delineated between 1970 and 1990 (completing just prior to the dissolution of the Soviet Union) as part of a greater Verkhuba Ore District exploration programme which included 9,104.5 m of shallow non-core holes and 142 diamond holes totaling 67,581.5 m of drilling. Diamond drilling was conducted across the area on a 200 m x 400 m grid, with infill drilling on 100 m x 200 m grids and 75 m x 100 m grids on the Deposit. Core recoveries were between 40-80% with average core recovery in mineralisation of 72%. Mineralisation occurs as stratabound sheet- and ribbon-like bodies principally striking E-W. Ore bodies pinch and swell, probably related to paleogeographic controls by the basin architecture and remobilisation by post-depositional tectonics. Up to seven parallel high-grade Cu-Pb-Zn sulphide horizons occur in two lithological units and are mapped on surface over 10 km strike length. Mineralisation in the lower level is hosted by carbonaceous siltstone and limestone, while the upper level is tied to the contact of clayey siltstones and sandstones with felsic volcanic rocks. High-grade and thick mineralised zones occur within the ore deposit which are related to Middle Devonian volcanic centres. Cu-Zn zonation appears to have a spatial control inferred to be related to proximity to the hydrothermal source of sulphide brines. Au mineralisation may be related to later stage fluids infiltrating along post-depositional faults. East Star is continuing to digitise all available historic drilling data over the Verkhuba Deposit to build a 3D model. This model will allow better interpretation of controls on ore distribution, including structure and paleogeography of the volcano-sedimentary basin, location of the main lithological boundaries and faults controlling mineralisation. Results of the 3D model will also be used to generate a Mineral Resource Estimate and Exploration Target for the Verkhuba Deposit and guide future drilling. According to a historical resource drilling report, 10 bulk sulphide ore samples from the Verkhuba Deposit were tested in several metallurgical laboratories of Kazakhstan between 1988-1989, including by the Institute of Non-Ferrous Metals in Ust-Kamenogorsk and the processing metallurgical plant of the Berezovskoe VMS deposit. The studied ores had different mineral composition and varied in weight from 9.7 kg to 1,500 kg. Four mineralogical ore types (Cu-Zn, Zn-pyrite, Cu-Pb-Zn, and Pb-Zn) were defined based on grades of copper, zinc and lead and content of pyrite. The sulphide mineralisation is simple with a mineral composition of pyrite, chalcopyrite, galena and sphalerite. East Star conducted a HEM survey between May and July 2022. In total, 50 anomalies were identified across the Rudny Altai licence areas, with priority targets defined by size, continuity, and association with known geochemical anomalies, magnetic or IP anomalies, and association with favorable structural or lithological indicators such as the presence of rhyolite, which is a common footwall indicator for the region. A region of untested priority targets were identified in the NE of the Rudny Altai area. Based on additional geological information, these untested HEM targets are now interpreted to be spatially related to the Verkhuba Ore District. These include: HeliTEM _A_11 target is a strong, narrow, double peak, strike extensive and very shallow anomaly (from about 25 m) coinciding with a very strong magnetic anomaly. HeliTEM_A_12 target is a strong single peak late time response, coinciding with a strong magnetic anomaly, at about 100 m deep and associated with phyllic alteration zone in granite porphyries, rhyolitic lava and siltstones mapped at surface. Two anomalies are adjacent to the historic Pokrovskoye Mine. The massive sulphide ore body was reported as 150 m long by 200 m wide and up to 22 m thick with average ore grades of 11.5% Cu, 3.3% Pb and 12% Zn. The ore body was mined in open pit to 70 m depth until 1979. HeliTEM_AA_9 target is a large, shallow, highly conductive, strike-extensive, strong north-east striking and moderately dipping conductor, coinciding with a moderate magnetic anomaly and big enough to represent a large ore zone, with no known prior exploration history. HeliTEM_A_9 target is a large, shallow, strike-extensive, double peak anomaly dipping towards the east, also with no known prior exploration history. The presence of multiple anomalies within a 10 km x 3 km area including; a historic high-grade VMS open pit deposit (Pokrovskoye), the drilled Verkhuba Deposit, and several untested EM, IP and magnetic anomalies, implies a long-lived system producing multiple high-grade ore bodies from several hydrothermal vents related to the same metal source.
