Zgounder is an underground silver mine located in Morocco. The mine is said to be the second most important silver mine in the country after the Imiter Mine.
The project is owned by a joint venture between Aya Gold and Silver’s subsidiary Zgounder Millennium Silver Mining (85%) and The Office National des Hydrocarbures et des Mines (ONHYM) of the Kingdom of Morocco (15%).
The mine began commercial production in January 2019. It has a throughput of 700 tonnes per day (tpd).
In September 2022, Aya signed an agreement to acquire ONHYM’s 15% interest in the Zgounder project and five adjacent permits to the silver mine. The transaction, once complete, will consolidate Aya’s ownership interest in Zgounder to 100%.
Location and site details
The Zgounder Project is located in the province of Taroudant, approximately 260km east of the City of Agadir in the central region of the Anti-Atlas Mountains, Morocco.
The project covers an area of 16km2 with an exploitation licence valid until 17 October 2027.
Overall, the Zgounder Mine area has seven exploration permits, which are not contiguous with the Zgounder mining permit. They collectively cover 96 km2.
The site is accessible from Agadir by N10 road traversing 216km east to Taliouine from where a hillside paved road runs northwards 50km to the Askaoun Village.
From Askaoun, the mine can be accessed by a 5km gravel road. A 260km paved road from Marrakesh to Askaoun via Agouim is under construction.
The Zgounder silver deposit has a history of exploration since ancient times.
In 2014, Maya Gold & Silver (now Aya) selected GoldMinds Geoservices for the first NI 43-101 compliant Mineral Resource estimation and a Preliminary Economic Assessment (PEA) of the mine.
A Pre-Feasibility Study (PFS) was also announced in May 2014 followed by the commencement of processing operations in July 2014.
The first silver pour was achieved in August 2014.
Surface diamond drilling programmes were conducted in 2015 and 2017 to increase the mineral resource of Zgounder and intersect silver-rich mineralisation in the East Zone.
In 2018, Aya announced the updated Mineral Resources Estimate and the Preliminary Economic Assessment (PEA) of the property. A year later, the flotation plant began commercial production.
A feasibility study for expansion to 2,700 tpd was completed in February 2022.
The study results show that the production is expected to quadruple from the present level to 6.8 million oz of silver at low LOW AISC of $9.58/oz. The expansion of the project is expected to be completed by 2024.
Geology and mineralisation
The geology at Zgounder consists of volcano-sedimentary formations attributed to the Precambrian II. The formation is intruded to the west by the Askaoun Granodioritic Massif (later Precambrian II-III).
The structures are overlaid in the east by the volcano-sedimentary rocks of the Quarzazate series (P II) and Neogene phonolites.
The volcano-sedimentary formations consist of a mixed sequence of metavolcanic rocks, metasedimentary rocks, dolerite, and granodiorite intrusions.
Described as a Neoproterozoic epithermal hypogene system, the deposit shares common characteristics with the giant Imiter silver deposit.
The geology is divided into three formations, two with major clastic component intercalated with volcanics (the Blue and Brown Formations) overlaid by an acid ignimbrite volcanic complex (the Black Formation).
The mineralisation occurs at the top of the Brown Formation with economic silver concentrations found as vertical bodies, complex clusters, veinlets, shear zones, and at the intersection of the east-west and north-south fractures. They are preferentially present at the contact zones between dolerite and schist.
As of 13 December 2021, the Zgounder silver mine was estimated to contain 9,765,000 tonnes of proven and probable mineral reserves at 306 g/t Ag for 96,057,000 oz. Inferred mineral resources are 542,000t at 367 g/t Ag for 6,395,000 oz.
The 2022 mineral reserves are 8.59 million tonnes at 257g/t of silver for 70,876,000 oz.
Mining and Ore Processing
Zgounder mine uses a combination of open pit mining, reclamation of historical tailings, and underground mining.
The material from the open pit mining will be loaded into 8x6 trucks and transported to the destination. At the end of the open pit mine life, the surrounding historical tailings will be reclaimed using a loader and trucks and no drilling, blasting, and crushing will be needed.
The underground mine will be mined with a combination of drift and fill and long hole stoping which will continue for over 11 years.
The processing includes three facilities: Existing Plant one (Cyanidation Plant), Existing Plant two (Floatation Plant), and New Plant three.
The Cyanide Plant will continue to treat 180t/d of mineralised feed and silver sludge from it will be transferred to the New Plant three for refining.
The Floatation Plant will continue to treat 500t/d of mineralised material delivering concentrate slurry along with floatation tails will be pumped to the New Plant three for refining and leaching.
The floatation tails will then combine with the New Plant’s floatation tailings in the Leaching-CIP circuit.
The new processing facility has a nominal throughput of 2,000t/d and a head grade of 210g/t Ag.
The existing infrastructure at Zgounder included laboratory, fuel storage, offices, warehouses, storage tanks, 700t/d processing capacity (floatation and cyanide plants included), camp, underground mine and related facilities, waste stockpiles, and tailings storage facility (TSF) capacity for five years production.
The new process plant features crushing, grinding, floatation, intensive leach reactor, counter current decantation, cyanidation, ADR process and Merrill-Crowe.
Other infrastructure include electrical line, substation, new emergency power facilities, additional fuel storage tanks, new open pit including waste storage stockpiles, new automation and telecommunication system among others.
Contractors involved and agreements
On 15 March 2022, Zgounder Millenium Silver Mining signed an interconnection agreement with the Office National L’Electricite et del l’Eau Potable (ONEE) for the construction of 60kv powerline and substation upgrades.
CMAC-Thyssen was selected for carrying out the vertical underground mine development including Alimak raises in 5 April, 2022. TRAV SOUSS MASSA secured the contract to conduct the lateral underground mine development.
In July 2022, Aya completed the Front-End Engineering Design (FEED) for Zgounder’s expansion with Lycopodium.
In 2015, the European Bank for Reconstruction and Development (EBRD) granted $6m loan for the Zgounder Expansion project.
On 15 September 2021, Aya closed a C$70m Bought Deal Public Offering. At the time of announcement, Ana said that the proceeds are expected to be used for the expansion of its Zgounder Mine.
On 25 October 2022, Zgounder Millenium Silver Mining secured a $100mn debt financing package for the expansion project. This includes a Senior Debt Facility of $92m from EBRD, while the Climate Investment Funds via its Clean Technology Fund (CTF) with provide $8m.