The Tlamino Project comprises a block of two contiguous licences granted in November 2016, Donje Tlamino and Surlica-Dukat, totaling 192 square km. The project is located in the southeast of the country, bordering Macedonia and Bulgaria. The DonjeTlamino licence hosts two main targets, Barje and Liska. The Surlica-Dukat licence includes the Karamanica target.
The licences are located in the Serbo-Macedonian Massif (“SMM”), a belt of greenschist to amphibolite metamorphic facies, Silurian-aged mid-crustal rocks that runs through Serbia along a north-south axis, extending southwards through Macedonia and Bulgaria and into Greece. In Serbia, the SMM lies west and sub-parallel to the upper Cretaceous Timok Belt, which hosts a number of copper-gold porphyry-epithermal deposits. The SMM is under-explored when compared to the Timok Belt, having seen lead and zinc exploration work by the Yugoslav government and Yugoslav state companies from the 1950s to the 1970s, but far less exploration post-2000. In Greece, the SMM hosts several well-known gold deposits including the Skouries high-grade Au-Cu porphyry and the Olympias Au-rich, polymetallic carbonate replacement deposit, both owned by Eldorado Gold.
Medgold’s licences are located along the Macedonian and Bulgarian borders, approximately 40 km southeast of the city of Vranje, in southeast Serbia. They cover areas of Paleozoic metasediments, including calcareous schists and marbles, which have been intruded by a series of Oligo-Miocence aged porphyritic felsic hypabyssal intrusives, volcano-clastics and dykes, and locally covered with recent alluvial sediments (conglomerates). Contact zones between the intrusive rocks and favourable country rock are responsible for the known base and precious metal showings within the licence areas. Fairly extensive exploration was completed by the Yugoslav government and Yugoslav state companies in the 1950s to 1970s for lead and zinc. Precious metals are often referenced in the historical and archival exploration documentation, but were not the focus of any exploration efforts, nor systematically documented. Today, it is recognized that these mineralized systems are structurally controlled, intermediate sulphidation epithermal in nature, and their lack of historical precious metal exploration presents significant exploration upside for Medgold.
The Tlamino Gold Project includes two historical showings: Liska and Barje. Both showings are associated with a regional east-west striking detachment fault, which in the vicinity of these showings has been overlain by conglomerates. Mineralization is located at the contact of the basement metamorphic rocks and the base of the conglomerate cover. Liska, located approximately 1.5 km to the southwest of Barje, was drilled in the 1970s by Yugoslav state companies, and a lensoid-shaped mineralized volume of rock with 1-2 wt.% combined Pb-Zn was found to strike NE towards Barje. The mineralization at Liska is located at the base of the Miocene conglomerate and parallel to the slope of the detachment fault. Liska was found to contain little precious metals. At Barje, base metal contents are lower, but precious metals are found in much higher concentrations. The area between the two showings is overlain by a thin conglomerate cover likely in the range of 50 – 100 metres in thickness, and Medgold considers the exploration potential under the conglomerate, between the two showings, to be excellent.
It was recognised that the Liska-Barje prospect, is hosted by tectonic breccia developed along a regionally extensive, low-angle detachment fault.
The lead-zinc mineralization, especially the gold- and silver-rich zone at Barje is hosted by gneissic rocks immediately beneath Eocene conglomerate and intercalated sandstone. Inspection of the drill core recovered by Dundee Precious Metals group at Barje suggests that the fragmental host rock is a tectonic breccia formed along the Crnook detachment fault during the final brittle stages of core complex exhumation (Sillitoe, 2016). The observed breccia contains clasts of muscovite-rich, Doganica-type gneissic granite, metamorphic quartz, amphibolite and perhaps other rocks, and is underlain by non-brecciated amphibolite, representing the top of the Crnook dome. The fragmental host rock to the lead-zinc mineralization at the nearby Liska prospect is likely to be a similar tectonic breccia.
Mineralization at Liska and Barje occurs as irregular veinlets and patches hosted in tectonic breccia which is partly silicified and sericitised. The sulphides are mostly dominated by pyrite, arsenopyrite, galena and sphalerite.
Recent Medgold Exploration Work
At the end of 2016, Medgold completed a series of saw-cut surface channel samples over the outcrop at Barje, where approximately 70 m x 25 m of mineralized tectonic breccia is exposed on surface at the edge of the conglomerate cover. A total of 132 linear samples of 1 m in length by approximately 8 cm in width and 4 cm in depth, were collected from seven channels, designed to test as large an areal extent of the outcrop as possible. Three channels were cut across the outcrop in an east-west direction, while four channels were cut across the outcrop in a general north-south direction. Gold assays ranged from 0.78 g/t Au to 132.5 g/t Au, with an average grade of 8.11 g/t Au and a median grade of 4.74 g/t Au. Silver concentrations ranged from 10.3 g/t Ag to 2110 g/t Ag, with an average grade of 210.6 g/t Ag and a median grade of 111.5 g/t Ag.
Applying a top-cut of 31.104 g/t Au (affects 4 / 132 samples) and 700 g/t Ag (affects 6 / 132 samples), the channel length-weighted assay averages are summarized as follows:
|Channel||Orientation||Length (m)||Au (g/t)||Ag (g/t)||AuEq (g/t)*||Pb (%)||Zn (%)|
*Gold equivalent (AuEq) calculated for gold and silver using a gold:silver price ratio of 70:1.
The channel samples described here represent the sampling of an outcrop face. Medgold’s current exploration model for Barje is premised on the interpretation that the outcrop face represents a faulted oblique cross-section through ‘strata-bound’ mineralization striking NE-SW, and located at the base of the conglomerate sequence, directly analogous to the mineralization at Liska. However, Medgold does not yet have direct observational evidence to suggest its interpretation is correct. The reader is cautioned therefore that the true thickness of the mineralization described here is unknown, and further work will be required before the true thickness of mineralization can be determined.
Following the previous channel sampling undertaken at the Barje outcrop, a second phase of diamond saw-cut channels was completed and assayed, to further extend the channel sample coverage to the limits of the outcrop. A total of 73 samples were collected, each of 1 metre in length, for a total of 73 metres of channeling, using the same sampling procedures. The objective of the work was to extend the channel lines further to the east and north of the exposure, where previous samples ended in high-grade assays.
A summary of the length-weighted results is shown in the table below.
|Channel||Length||Au (g/t)||Ag (g/t)||As (g/t)||AuEq (g/t)*||Pb (ppm)||Zn (ppm)|
*AuEq is calculated from Au & Ag using a price ratio of 70:1
The channel samples described here represent the sampling of an outcrop face. The Company’s current exploration model for Barje is premised on the interpretation that the outcrop face represents a faulted oblique cross-section through ‘strata-bound’ mineralization. However, the Company does not yet have direct observational evidence to suggest its interpretation is correct. The reader is cautioned therefore that the true thickness of the mineralization described here is unknown, and further work will be required before the true thickness of mineralization can be determined.
Adding results from Channel 02, from the first phase of sampling, to Channel 11, from the second phase, creates a contiguous channel interval of 84 metres at 5.6 g/t Au and 105.2 g/t Ag (or 84 metres at 7.1 g/t AuEq, using a 70:1 Ag:Au price ratio). This channel, in combination with the other parallel and conjugate channels, clearly demonstrates a consistently high-grade mineralized zone extensive over a broad area. From a total of 205 samples, combining both phases of sampling, and applying a top-cut of 31 g/t Au (affects 4 samples) and 700 g/t Ag (affects 6 samples), the average grade is 5.6 g/t Au and 130 g/t Ag, and 198 samples (97%) returned assays greater than 1 g/t Au. The overall area sampled is approximately 100 metres by 30 metres. Mineralization appears open to the west, north, and east.
A full table of selected geochemical results can be downloaded here: Selected geochemical results from Barje adit.
Quality Assurance and Quality Control
Channel sampling at Barje followed a standardized protocol to ensure representative and unbiased quantities of material from across each sample. Samples were delivered by Medgold personnel directly to the assay lab prep facilities in Bor, Serbia. Samples were analysed by ALS Chemex using analytical method codes Au-ICP21 and ME-MS61, with overlimits for gold and silver analysed by GRA21, and for Ag, Pb, and Zn by OG62. Medgold routinely inserted appropriate multi-element geochemical standards and blanks into its sample stream at Barje, and additionally collected regular field duplicate samples.
Following a detailed structural interpretation of the geology between the Barje and Liska prospects, the Company has completed an Induced Polarization / Resistivity (IP-Res) geophysical study which has identified a high chargeability anomaly which extends to the west of the Barje outcrop under cover for over 1 kilometre.
The objective of the 39 line-kilometre IP-Resistivity program was to analyse an area covering 4 square kilometres, focusing on the Barje-Liska prospects, for near-surface sulphide-rich mineralization. The program commenced at the Liska prospect, which has been historically drill-tested for Pb-Zn mineralization by the former Yugoslav state companies in the 1950s and 1970s, and results from both the drilling and IP-Resistivity survey support the geological model of relatively flat-lying mineralization at the contact of the basement rocks and the overlying schists.
At Barje, located 1.5 kilometres to the northeast of Liska, a large high-chargeability anomaly was identified just west of the Barje outcrop. The anomaly measures approximately 1 kilometre east to west and approximately 400 metres north to south. The southern limit of the anomaly appears to track a large-scale regional detachment fault, which has been assumed to be a principal control on mineralization at both Barje and Liska, and its surface expression trends east-west. The anomaly continues northwards, which is considered to be the northerly extension of the same detachment fault, but beneath cover and steepening topography. Interestingly, the high-grade saw-cut channel sampling completed at the main Barje outcrop is located on the eastern flank of the chargeability anomaly. At this stage, it is unknown whether the chargeability anomaly is directly related to gold mineralization; however it is clear that the surface rocks exposed in the area of the chargeability anomaly consist of schists which display similar alteration and mineralization as seen in the schist stratigraphically overlying the mineralization at Barje. The Barje outcrop itself is observed in the chargeability data as a weaker NNE trending corridor; this also constitutes an exploration target to be followed up.
The Company has designed a 2,000 metre diamond drilling program to commence following the receipt of land-holder permissions and the establishment of a semi-permanent camp at Tlamino.
The Karamanica prospect is located in the Surlica-Dukat Licence, and is located approximately 8 km to the west of Barje, The Karamanica target is located on the southwestern margin of the Crnook dome, hosted by upper crustal schists of the Vlasina unit. Karamanica is dominated by a series of large-scale northwest-trending faults, which cut packages of schists, highly deformed calc-schists, and quartz-feldspar porphyry dykes.
Medgold has completed a program of detailed mapping and rock sampling, plus grid-soil sampling,at Karamanica, with samples collected on a 200m by 50m grid. Initial reconnaissance work has identified strongly altered and brecciated felsic volcanics, locally significant calcareous schists, graphitic schists, limestones, and zones of galena-sphalerite and pyrite-silica mineralization. Despite poor outcrop exposure in the area, a total of 129 rock chip samples have been collected to date on the prospect, with 14 returning assays greater than 1 g/t Au. The rock chip samples returned highs of 11.1 g/t Au, 7.1 g/t Au and 5.5 g/t Au, typically associated with the pyrite-silica mineralization.
Assays from a recent soil sampling campaign define two large anomalies with consistent soil geochemistry with > 50 ppb Au-in-soil, within which are significant linear zones of >100 ppb Au. The highly anomalous soil geochemistry and favourable lithological units and fault structures demonstrate the high prospectivity of the Karamanica Prospect.
The first soil anomaly extends over an area of approximately 1 km by 1 km, and is associated with a regional northwest-trending fault, which offsets felsic volcanic rocks from basement schists and calcareous schists. The second, located approximately 1 km north of the first anomaly, extends over approximately 800 m by 600 m. Mineralization appears to be associated with of the presence of disseminated to massive sulphides within the host calcareous schists. The same fault structure hosts blind massive carbonate-replacement Pb-Zn-Ag mineralization.
In the spring we expect to complete a ground geophysical survey over the main prospective zones of anomalous soil and rock chip geochemistry, with the aim of drill testing Karamanica later in 2018.
The Tlamino Project area was explored in the latter half of the 20th century by the Yugoslav national geological survey and by Yugoslav state exploration companies for their lead and zinc potential. Liska returned higher base metal values and was explored more comprehensively, but it appears neither showing was systematically evaluated for gold and silver. The lead-zinc mineralization at Liska was drilled by Yugoslav state companies in the 1960s and 1970s. The mineralization at Liska was found to consist of an elongate lensoid body approximately 30 m in thickness, located at the base of the conglomerate and trending to the NNE towards the Barje showing.
A total of 4,657m from 37 holes were drilled between 1974 and 1977. A resource estimation undertaken in 1983 calculated 4.862 Mt at 0.54% Pb and 1.00% Zn. A further resource estimation of 6.8 Mt at 0.44% Pb, 1.12% Zn and 8 g/t Ag was referenced in Serbian literature in 1996, 2001 and 2002. Reconstructions of the drilling by Medgold show that the mineralization was still open to the NE when drilling ceased, and indeed the last reports on the area indicate that drilling between Barje and Liska was planned future work (that was never undertaken).
These resource estimates are historical in nature and are described in the documents referenced below. A qualified person has not done sufficient work to classify the historical estimates as current mineral resources, and Medgold is not treating the historical estimates as current mineral resources.
These estimates were made using the Russian resource categorization system, developed in the USSR in the 1960s. This system divides resource categories into three major groups: prognostic resources (P1, P2, P3), evaluated reserves or resources (C2), and fully explored reserves or resources (A, B, C1). The Liska mineralization was drilled on sections, almost exclusively with vertical holes, and polygonal bounding volumes from parallel sections with weighted average grades were used to estimate the deposit’s tonnage and grade. The documents reviewed by Medgold indicate that the Yugoslav state companies categorized the Liska deposit into B and C1 categories. The reader is cautioned that there is no general equivalence between resource categories as defined by the Russian system and the resource categories as defined by the Canadian Institute of Mining. Particularly, the Russian system does not explicitly separate technical and economic factors. It should not be construed that Medgold interpret the historical records as being indicative of any resources, historical or current, that can be attributed directly into CIM resource categories.
The work described in the various historical reports appears to have been done to a high standard, and Medgold believes it is reliable. However, as complete records for the drilling have not been found, and as no core from these drilling campaigns appears to still exist, it is not possible for Medgold to verify this historical resource. It is likely that a full re-drilling of the mineralization would be necessary in order to verify the historical resource as current.
The historical resource estimation at Liska, which shows a significant volume of mineralized rock to exist at the contact of the overlying conglomerates and detachment faulted basement is considered by Medgold to be highly significant for the exploration upside of Barje. The approximately 30 m thick, strata-bound mineralization at Liska is considered by Medgold to potentially be analogous to that of the mineralization at Barje, whereby a low-angle detachment fault underlies and represents the principal control upon the distribution of mineralization. Geochemically, Liska assays 1-2 wt% combined Pb & Zn but is only anomalous in precious metals. Barje, conversely, shows lower base metals but much higher contents of gold and silver. During a site visit by consulting geologist, Dr. Richard Sillitoe, he stated that the “markedly higher gold and silver values at Barje compared to those at Liska could be a product of temperature-controlled mineralization zoning.”
In the mid2000s, Avala Resources (now Dundee Precious Metals; DPM) explored the area and completed multiple geochemical surveys and rock chip sampling and trenching near Barje.
A total of 4 diamond drill holes, for 831.2 m, were completed by Avala Resources in 2007 in the vicinity of the Barje showing. Medgold recently acquired a dataset from DPM, containing regional exploration data covering our recently granted licences as well as the drilling data from Barje.
One drill hole targeted the Barje outcrop, but Medgold considers that it was collared in a down-faulted block below Barje and consequently missed the Barje mineralization. A further three drill holes were completed by DPM, located to the east of the Barje outcrop. These intersected sequences of tectonic breccias considered by Medgold to represent the Crnook detachment fault, as at Barje, but off the Liska-Barje axis. This axis may play an important role in focusing mineralization. Mineralization within the tectonic breccias in these holes was locally anomalous.
Maric, A. (1983) Tehnicko-ekonomska ekspertiza mogucnosti eksploatacije rudne strukture Podvirovi-Bozilovo leziste i tehnicko-ekonomska ekspertiza mogucnosti eksploatacije rudnih lezista u podrucju Karamanice. SOUR Geozavod, Beograd.
Simic, M. (1996) Metalogenija zone Mackatica-Blagodat-Karamanica. Doktorska disertacija Rudarsko-geoloskog Fakulteta, Beograd, pp 256. (Metalogeny of Mackatica-Blagodat-Karamanica. PhD thesis; Faculty of Geology and Mining, Belgrade)
Simic, M. (2001) Metalogenija zone Mackatica-Blagodat-Karamanica. Posebna izdanja Geoinstituta, Beograd, v.28.
Silitoe, R. (2016) Gold and Exploration of Medgolds Precious and Base Metal Prospects in Serbia – Internal Report.
Simic, M. (2002) Lezista i pojave zlata u Srbiji. Radovi Geoinstituta, Beograd, v37, 5-66.