Project of the Week: Prospech

22nd November 2021

 

 

With some of the oldest historic mines in the world, Europe is no stranger to mining. With a some exceptions, mining in Central Europe has dwindled in the last century, with few active exploration projects and even fewer extraction operations. With the energy transition looming in the shadow of the recent COP26 climate agreements in Glasgow, the implementation of green energy power grids and consumer products necessitates new extraction of metals from local sources. The European economic bloc of 27 countries makes up the 3rd largest economy in the world, and it is about time that we start seeing new exploration across the continent. For critical, base, and precious metals, this will depend on market factors and governmental support for mining. With metal prices strong and surging in recent years, it is no surprise that the gold market is driving some of these new projects in Europe and globally.

As is often the case, the burden (read: joy) of exploration falls to the juniors, and Prospech Mining (ASX: PRS) is one of the new players in the gold exploration game. With 6 exploration projects in Slovakia, Prospech and its subsidiaries have been operating since 2014 and have several gold-silver exploration projects in the Western Tethyan Orogenic Belt. These 6 exploration licenses cover 204 km2 in Slovakia with a focus on epithermal gold and silver mineralization near the tiny village of Hodruša - Hámre, about 200 km east of Vienna, Austria. Let’s take a quick look at some of these epithermal projects as well as other base metal and tungsten resources in Prospech’s Slovakian portfolio.

Figure 1. Štiavnica Church, located on a hill in the central part of the caldera center. The Štiavnica district has seen mining operations for over 500 years for its gold and silver deposits — the richest in the Western Carpathian mountains.

Štiavnica Stratovolcano

Four of Prospech’s 6 exploration concessions are located on the flanks of the Štiavnica stratovolcano, a remnant of the Carpathian Arc which began forming around 24 million years ago. This magmatic arc formed due to subduction of the European plate beneath remnant crustal blocks, forming several magmatic centers. The Štiavnica volcanic complex erupted several stages of magmatism, which are observed in the modern geologic record, including the emplacement of multiple porphyritic intrusions 15.0 - 11.4 Ma (Fig. 2; Rottier et al., 2020). Each stage of magmatism was associated with different styles of mineralization, from Cu-Au porphyry formation and associated skarn deposits on the flanks of the volcano to localized epithermal deposits and polymetallic veins cutting through the volcanic center. To date, an estimated 80 t Au, 4000 t Ag, 70,000 t Zn, 55,000 t of Pb, and 8000 t Cu have been extracted from the district, and Prospech hopes to add to those numbers in the future (Rottier et al., 2020).

Fig. 2 License map of the Štiavnica region claims for Prospech Mining Ltd. Red lines indicate mapped mineralized vein systems.

<>The largest concession at the Hodruša - Hámre claim focuses on the historical Banská Štiavnica mining district, composed of northeast trending epithermal veins with high-grade silver and gold mineralization. Nearby orebodies such as the active Rozália Mine (operated by Slovenská banská) and the Ignac target (owned by Prospech) are controlled by the intersection of these faults with a low-angle detachment structure which runs directly through Prospech’s claim. Diamond core drilling at the Ignac target has returned mineralization in several styles (stockwork veins, visible Au, high grade Ag) with grades reaching 15.6 g/t Au and 117 g/t Ag. Drilling and grab samples at other targets in the contract area have returned grades of 28.3 g/t Au and 582 g/t Ag (grab samples at Anton project) and 58 g/t Au and 7,400 g/t Ag in a mineralized quartz zone at the Schopfer target (https://prospech.com.au/hodrusa). While the mineralization is often localized, the high grades and extent of historical mining near the Hodruša - Hámre project are cause for excitement!

The other licenses in the Štiavnica Volcanic Complex are Nova Bana, Rudno, and Pukanec projects, located about 15 km west of Hodruša - Hámre. These deposits are characterized by north trending mineralized veins which have been mapped in recent field seasons. These exploration projects have revealed what is hoped to be a shallowly eroded epithermal system with banded quartz veins hosting visible gold and the silver-bearing mineral, acanthite, at the Krakauer vein, which has been traced up to 600 m along strike (Fig. 3). Drilling data from the Krakauer vein in the Nova Bana license, released on October 13, 2021, indicate intercepts of 2.5 m of 2.12 g/t Au and 35.2 g/t Ag, with evidence of even higher-grade splays from rock chip sampling of 283 g/t Au and 1,700 g/t Ag with increasing grade-thickness east of the main vein. The Rudno and Pukanec projects are both vein hosted projects as well, with indications of low-sulfidation gold and silver veins similar to Nova Bana. As a whole, this style of epithermal mineralization is well known in another Tethyan deposit: the Ada Tepe gold deposit in Bulgaria, which exhibits similar structural features and mineralization with high-grade silver and gold intercepts, which are highly profitable. Additionally, historical mining in the district allows for easy access to old underground workings, such as the Pukanec project, which has more of these workings than any other active project in Slovakia.

Figure 3. Low-sulfidation epithermal veins from the Krakauer target highlighting acanthite and gold. Quartz banding is called ‘ginguro’ texture, and is common in world-class gold-silver deposits, such as Ada Tepe in Bulgaria.

Jasenie Exploration License

The Jasenie exploration license, located about 90 km north of the Hodruša - Hámre license, is being developed with different deposit styles and resources in mind. The Kysla target, an east-west trending scheelite deposit with significant gold mineralization, is the primary focus of the Company at Jasenie. Gold is hosted in quartz veins, with surface samples assayed at an average of 8.58 g/t in a high-grade zone. Tungsten occurs as scheelite in stockwork veining and has yielded grades of up to 2.5 % WO3 in some of the gold-poor zones. Inferred resource estimates at Kysla suggest the target contains 71,000 ounces gold and 6,612 tonnes WO3. Other targets to the south of the Kysla Au-W belt are potential targets for gold, antimony, lead, and silver.

Cejkov-Zemplin License

The Cejkov-Zemplin License is located in eastern Slovakia, across the country from the other other 5 licenses, and targets base metal epithermal mineralization. Hosted in dacitic and diorite-porphyry rocks, this epithermal system represents the low-temperature mineralization associated with classic magmatic-hydrothermal deposits (i.e., porphyries). Preliminary exploration drill cores from the Slovakian Geological Survey have intersected two epithermal veins of interest: VS-19 with 2.5 m of 514 g/t Ag, 13.4% Pb, 8.3% Zn and VS-20 with 3.7 m of 127 g/t Ag, 10.2% Pb, 11.6% Zn (Fig. 4). Prospech hopes to release drill core data from the 2021 drill season and to continue exploration in 2022.

Figure 4. Base metal (Pb + Zn + Ag) mineralization from the VS-20 core with massive galena (gray/silver) and sphalerite (brown). Note multiple stages of mineralization separated by quartz (white bands between sulfides).

The Tethyan metallogenic belt hosts deposits from France to China along the massive crustal suture zone, from Cretaceous porphyry Cu to Neogene epithermal gold. Slovakia is leading the way, with governmental regulations making space for mineral exploration, drilling, and underground extraction from new and historical deposits. Prospech Mining Ltd is one of the new players in this centuries-old game, and they are hoping to be a part of the pro-mining shift that Europe needs for its economic and environmental future.


References:

Rottier, B., Audétat, A., Koděra, P. and Lexa, J., 2020. Magmatic evolution of the mineralized Štiavnica volcano (Central Slovakia): evidence from thermobarometry, melt inclusions, and sulfide inclusions. Journal of Volcanology and Geothermal Research401, p.106967.

Corporate Presentation, 14th October 2021, Miocene Caldera hosted mineralisation in the Western Tethyan in Slovakia - Implications for the Pacific Rim. https://static1.squarespace.com/static/58214edcf7e0ab8dd17aa65e/t/616783fb61f61b0e0c000a38/1634173975690/Prospech+-+Society+Resource+Geology+-+Final.pdf

News Release, Prospech Mining Ltd., 13th October 2021, FURTHER GOLD SILVER DRILL RESULTS FOR KRAKAUER PROSPECT https://static1.squarespace.com/static/58214edcf7e0ab8dd17aa65e/t/616649d6d9909b000bc85a1d/1634093533989/pjn10984.pdf

https://prospech.com.au/

Aaron Hantsche

View posts by Aaron Hantsche
Aaron Hantsche recently obtained his PhD in Geology from the University of Geneva in Switzerland, where he studied distal Pb-Zn skarn deposits in southern Bulgaria. Magmatic-hydrothermal deposits are his primary focus, with a bent towards geochemical vectoring tools and field geology. In addition to his work as a geologist, Aaron is a director for the science communication platform, Ore Deposits Hub. His passion for mineral deposits and geo-communication led him to join the Spotlight Mining writing team in October 2021.