Kopylovskoye was Kopy Goldfields’ first project – and also lent the company its name. The Kopylovskoye gold bedrock prospect was acquired by the company at the end of 2006 – early 2007. Historically, approximately 1.75 Moz of alluvial gold has been mined immediately west of Kopylovskoye.
After the acquisition, Kopy Goldfield’s team of geologist prepared a comprehensive exploration program for Kopylovskoye prospect. The program was focused on exploring the mineralization at depth and outside the contour of proven reserves with the target to prove a deposit of above 1 Moz of gold. The bedrock gold mineralization is up gradient of the alluvial mining and in the same drainage.
FACTS ABOUT KOPYLOVSKOYE-CLUSTER
Mineral resources according to GKZ : C1+C2: 332 koz, P1+P2+P3: 803 koz
Mineral resources according to Jorc : Indicated: 37 firstname.lastname@example.org g/t. Inferred: 80 email@example.com g/t. Signed by SRK Consulting 2010
Valid until: 2020-2035
Ownership Kopy Goldfields AB: 0 %
License area: 80 sq km
A license for the area that provides rights for bedrock gold prospecting and production was issued in 2004. Today, the Kopyloskye cluster includes the licences for Kopylovskoye, Pravovesenny, Takhtykan and Vostochnaya, covering a total area of 80 km2. The resource potential is estimated at 1 Moz of gold and the licenses are valid through to 2020-2035 with possibilities for further extensions.
During 2016, Kopy Goldfields will renew the exploration and mining permits for the Kopylovskoye project and potentially run a bulk sample test to confirm grades and the volume of the mineralization.
The gold mineralization at Kopylovskoye is preferentially hosted in sericite-altered carbonaceous shale/slate spatially and genetically associated with saddle reefs and quartz vein stockworks +/- pyrite that have exploited cleavage and bedding planes in the hinge zone, limbs and parasitic folds of a highly compressed overturned anticline. From bulk sampling and pilot-scale mining and processing conducted in 2004 and 2005, gold grades ranging from 1.4-7.0 g/t, and averaging 3.1 g/t can be expected from strataform intervals typically 2-10 m thick.
The Kopylovskoye anticline has been mapped and modelled from drilling over a strike length of 2.0 km. The axial plane of the anticline is oriented with a strike of 282° dipping 70° to the northeast. It is a highly compressed asymmetric fold with a north-dipping (45-50°) north limb and a slightly overturned, near vertical south limb. The crest is narrow, open and is well delineated by surface excavations. The fold axis is double plunging. It plunges shallowly (7-10°) to the southwest at an azimuth of 282°, and plunges at an angle of 2-3° in an easterly direction (azimuth 100-110°). However, due to rising surface topography to the east, the fold hinge is buried increasingly deeper eastward beneath cover.
Fracture cleavage developed during intense folding of the sequence has resulted in five favorable structural settings for quartz-pyrite veins and gold mineralization including:
- Fold-hinge stockwork-vein zones (largest exploration potential)
- North-limb bedding-parallel saddle reefs
- Axial plane thrust faulting
- Parasitic folds and boundings
- Radial fractures
The fold-hinge stockwork-vein zone is by far the most important and potentially most economic structural setting for gold mineralization at Kopylovskoye. Veins at the crest of the anticline become stacked and are typically flat lying in accordance with bedding. The hinge zone is the focus of energy during folding, so it experiences the highest degree of deformation, including bedding parallel slip and tensional expansion. This leads to fractures both parallel and perpendicular to bedding, producing open space for a network of crosscutting.
Where the hinge of the fold is shallow and has been preserved, i.e. not eroded, it has the highest potential for economic mineralization on the property. The hinge zone would be mined as a shallow open pit with minimal dilution. The hinge zone #1 has been preserved on the west end of the property in the area that contains the existing C1 and C2 Russian TKZ reserves.
A grain size analysis of gold conducted in 2005 indicated that gold from the fold-hinge stockwork-vein zone is coarse, with approximately 50% > 1 mm. In regards to processing, the coarse gold may be free milling.
The hinge zones #2 and 3 were identified during 2009. There is also a potential of discovering new hinge zones in the eastern part of the license area.
Rocks at Kopylovskoye are transitional between sedimentary and metamorphic and have been subjected to a combination of diagentic and metamorphic processes as well as weak hydrothermal alteration. Protolith shale has been preferentially metamorphosed to slate, while sandstone has typically been more resistant. However, locally, sandstone has been converted to metasandstone and schist as evidenced by recrystallized silica cement and localized flattening and reorientation of fragments and micaceous components.
In general, the alteration is weak, consisting of discontinuous zones of pervasive silicification and carbonatization, and selective iron-carbonate replacement of medium-grained disseminated pyrite. In core, both fine and coarse crystalline brassy pyrite was observed, sometimes with pressure shadows reflecting structural deformation. Previous studies of pyrite species suggest both primary authigenic pyrite, with low-grade gold associated (0.5-1.5 g/t Au), and secondary hydrothermal pyrite with higher grade gold associated (5.5-16.1 g/t Au) are present.
Chlorite is the product of clay recrystallization and occurs near veins suggesting hydrothermal origins. Recent core logging indicates chlorite is much more prevalent on the south limb of the anticline than on the north limb.
The lithology at Kopylovskoye is comprised of Proterozoic terrigenous sediments of the third subsuite of the Dogaldynski Suite (Pt3dg3), which is divided into two horizons:
- Upper horizon (dg33) – mostly sandstone (80%); and
- Lower horizon (dg23) – interbedded slate and sandstone (70% of sandstone and 30% of slate).
All of the known mineralization at Kopylovskoye is hosted in the lower horizon (dg23). Varieties of this horizon include minor black shale, siltstone, phyllite and schist. The thickness of beds in dg23 varies from 20cm to 15 m, with an average thickness of 4 m to 5 m.
Sandstone in the lower horizon is fine- to medium-grained, and poorly sorted. Grain sizes range from 0.005-0.5 mm, rarely 1.0-1.5 mm. Sandstones are most commonly monomictic, with quartz as the prevailing mineral. Feldspar rock fragments are also present. Sandstones are cemented by silica and clay. Accessory minerals include zircon, tourmaline, sphene, apatite, and epidote
Slate is divided into micaceous phyllite and carbonaceous phyllite. It is comprised of 35-60% sericite, 50% sulfide, 20-35% brown feldspar and 10-25% quartz. Accessory elements are tourmaline and florencite.
RESULTS OF 2011 EXPLORATION ACTIVITIES
A mineral resource estimate within JORC Code was signed by SRK Consulting.
- 5 788 meters of RC-drilling down to maximum 180 meter
RESULTS OF 2010 EXPLORATION ACTIVITIES
The 3 D model was confirmed and upgraded. Please find model here.
- 1774 m RC – drilling
- 950 m diamond drilling
- 444 m trenching
RESULTS OF 2009 EXPLORATION ACTIVITIES
In 2009 exploration efforts on Kopylovskoye were focused to digest and interpret exploration results of 2007-2008. During the year we processed and analyzed all the remaining core, RAB and trench samples, including
- Trench – 982 samples
- RAB – 538 samples
- Core cuttings -1000 samples
The new assay tests identified a mineralized gold interval in the trench #340 of 69 meters with grade 5.3 gr/ton (including interval of 19 meters with grade 19.2 gr/ton). Trench #340 crossed the outcrop of saddle reef structure #2 at surface thus confirming its high resource potential. Trench #348 crossed 49 meters of mineralized zone with average grade 0.6 gr/ton including 22 meters interval with grade 1.4 gr/ton. This trench has crossed outcrop of saddle reef structure #3.
Based on the new and historic data a 3D geological model for the deposit was developed.
RESULTS OF 2007-2008 EXPLORATION ACTIVITIES
At the end of 2006 – early 2007, the Kopylovskoye gold bedrock prospect was acquired by the Kopylovskoye Group.
A Kopy AB team of geologists prepared a comprehensive exploration program for the Kopylovskoye prospect. The program was focused on exploring the mineralization at depth and outside the contour of the proven reserves.
During 2007-2008, the following exploration work was carried out:
- 4081 meters of core wells of 76mm diameter were drilled at 45 degrees. Core sample recovery was 96%, core diameter – 61 mm.
- 117 000 m3 of trenches with total length of 6160 meters were excavated. By the end of 2008, 1443 meters of trench surface were documented, 1405 channel samples taken.
- 112 RAB wells were drilled with total length 2941 meters to the depth of 40m. Drilling was done with 110 mm diameter drilling bit at angle of 60 degrees.
In June 2011, Kopy Goldfields reported the first mineral resource within the JORC Code signed by SRK Consulting, Reno-Office in US on the Kopylovskoye project. It showed 117koz of Indicated and Inferred resources (in total 717 koz Russian GKZ C1+C2+P1 gold resources).
The estimation is based on trench samples, core-drilling and RC- drilling along a strike of around 1 km and down to maximum 180 meter; totally 6.8 km of drilling.
During 2016, the Company targets to renew exploration and mining permits for Kopylovskoye project in order to update and extend the license terms and run a bulk sample test to confirm historic grades and volume of mineralization. All necessary documents have been filed and the relevant permits and extended license terms are expected during the autumn 2016. The Company’s goal for the Kopylovskoye cluster is to find a partner or form joint ventures to continue mapping out the promising cluster. This would mean that the development process could be speeded up.