Project of the Week: Arras Minerals

21st February 2022

 

 

Mountain belts, or orogens, form during the collision, subduction, and uplift of crustal plates, which is the general basis of plate tectonic theory. While some younger mountain belts such as the Rockies or Andes, formed due to the subduction of oceanic plates, it takes 10’s to 100’s of millions of years for ocean basins to close and continental crust to collide. Continental collision creates massive orogens, exhuming billions of years of geologic history, creating a great exploration opportunity to search for older mineral deposits. The largest collisional orogen? How about the Central Asian Orogenic Belt (CAOB), which stretches from China to southwest Russia and started forming more than 1 billion years ago. All those rocks, all that time — you can bet there are some deposits there!

Silver Bull Resources (OTCQB: SVBL, TSX: SVB) and the subsidiary company Arras Minerals Corp are looing at one of the newest discoveries in the CAOB, the Beskauga Copper-Gold project in northeast Kazakhstan (Fig. 1). About 70 km to the southwest of Pavlodar, the Beskauga project was initially discovered during Soviet-era exploration in the 1980’s. Despite this, district-scale efforts only began in 2007, with the release of ground magnetic survey and drill core assays over the last decade. Building on these results, Silver Bull optioned the project from its former owner, Copperbelt AG in August 2020. Over the three license areas, Silver Bull has rights to explore and operate over 917 km2.

Figure 1. A. Regional satellite photo of Kazakhstan. B. Location of claims. Note: Stepnoe and Ekidos are held by a Silver Bull subsidiary called Ekidos LLP, registered in Kazakhstan. The small block missing is a salt mine, which is not owned by Silver Bull.

The Beskauga deposit is a copper-gold porphyry system associated with the intrusion of diorite-granodiorite into Ordovician sedimentary rocks sometime in the early Paleozoic. The porphyry mineralization occurs within the igneous rocks, associated with dikes of variable calc-alkalic compositions which have been named the Shangirau Complex. The project is divided largely into two zones, which occur in different intrusions, Beskauga Main and Beskauga South (Fig. 2). In both target areas, sedimentary cover can be up to 40 m thick (less in the south), meaning the surface expression is partly blind. Despite this, drilling has revealed huge intercepts of low-grade porphyry mineralization at Beskauga Main and epithermal overprint at Beskauga South.

Figure 2. Geological map of the Beskauga concession, highlighting igneous rocks which host porphyry mineralization and drill collar locations at Beskauga Main and Beskauga South.

Ground-based geophysics carried out in 2012 indicates a ~9 km2 magnetic anomaly with increased chargability at depth - a signal often attributed to the pyritic zone of porphyry systems. This interpretation is reinforced by drilling which started in 2007 and has increased since the Silver Bull take over in 2020. Shallow drilling yielded near-surface anomalies in copper and gold, while diamond core drills have revealed additional molybdenum and silver mineralization. In 2021, 101 drill cores were compiled for the Beskauga Main target for a resource estimate with 207 Mt of indicated ore at 0.23 % Cu, 0.35 g/t Au, and 1.09 G/t Ag, with an additional ~150 Mt of ore inferred. While the total size and grade make it small as a copper porphyry, and intermediate as a gold porphyry, the combined yield and byproduct metals mean the Beskauga Main target is viable and ready for more exploration!

Figure 3. Schematic diagram outlining porphyry alteration zones and the abundance of sulfides in each zone. The high-pyrite zone is linked to magnetic anomalies that drive the discovery of many under-cover porphyries, (from Berger et al. (2008).

Those results were the basis for the more recent exploration program and drilling by Arras Minerals, and boy has it been a good season for them! Recent deep drilling (up to 1 km!) has returned assay results of 973.2 meters of mineralization (0.56 g/t Au, 0.33% Cu, and 1.89 g/t Ag) which is open at depth - including more than 500 meters of 1.14 % CuEq (0.78 g/t Au, 0.47 % Cu, and 2.59 g/t Ag) (Fig. 4; January 2022 News Release). While this is the first core of a 30,000 m drill program, it is clearly exciting for the company. “The results from this first hole highlight the considerable potential we see at the Beskauga Project. The first holes of our planned program are designed to test previously indicated mineralization…we are very much looking forward to an exciting 2022,” said Tim Barry, CEO of Arras Minerals.

Figure 4. Selected core samples highlight stockwork veining and mineralization from the Beskauga project from the most recent drill core. (January 2022 News Release).

Other porphyry systems have been discovered in the region, and the CAOB is no stranger to Cu-Au mineralization systems (see the supergiant Oyu Tolgoi, Mongolia). Easter Kazakhstan hosts a cluster of such porphyry deposits, including operating deposits such as Kounrad (near Balkhash, about 600 km south) and Bozshakol about 180 km to the west. Kazakhstan, though politically restrictive, recently updated its mining code from a contract-based system to a licensing system based on the Australian model with government licenses granted for up to 6 years. This has prompted a recent splash in terms of mining operations in Kazakhstan, which represent 14% of the GDP of the national economy.

The Beskauga project is accessed through the field operations office in Ekibastuz by gravel roads through the arid steppe of the Kazakh countryside. The site is accessible by 2-wheel drive vehicles but can be difficult during the winter. Power is readily available in the region, though water is scarce. Passing 18 km from the project site, a canal through Ekibastuz will be the primary source and has been deemed adequate for a large-scale mining operation.

All in all, Arras Minerals and Silver Bull have positioned themselves in a good way moving forward with the project. Porphyry mineralization in the CAOB makes for a markedly open exploration space, and the license area allows for exploration in the vicinity of the Beskauga project. With good news to kick off the year, let’s hope for the best out of this expanding porphyry system in eastern Kazakhstan!

References:

Arras Minerals, News Report, January 31, 2022 - https://www.globenewswire.com/news-release/2022/01/31/2376020/0/en/Arras-Minerals-Intercepts-973-2m-0-82-CuEq-Including-531m-1-14-CuEq-Starting-From-44m-Below-Surface-on-the-Beskauga-Project-in-Northeastern-Kazakhstan.html

Berger, B.R., Ayuso, R.A., Wynn, J.C. and Seal, R.R., 2008. Preliminary model of porphyry copper deposits. US geological survey open-file report1321, p.55.

Urbisinov, S., Freiman, G., Sharp, A., 2021. NI 43-101 Technical Report for Silver Bull Resources. https://silverbullresources.com/site/assets/files/5975/csa-beskauga-ni-43-101-final.pdf

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.