SASA, North Macedonia

Low cost zinc and lead production

CAML took 100% ownership of the Sasa underground zinc-lead mine in 2017. The mine is located in northeastern North Macedonia, approximately 150km east of the capital city, Skopje, and 10km north of the local town, Makedonska Kamenica.

The Sasa deposit was discovered during a exploration period between 1954 and 1965. Trial mining commenced in 1965 and, in 1966, the mine commenced commercial production under state ownership. The mine was closed in 2002 and entered bankruptcy due to lack of funding. The Solway Investments Group subsequently purchased the mine, invested in new equipment and recommenced operations in 2006. In 2015, Fusion Capital and Orion Mine Finance Group acquired the asset, before its eventual sale to CAML in 2017.

Sasa lies within the Serbo-Macedonian Massif, a region that hosts numerous lead and zinc deposits, stretching across Serbia, North Macedonia, Bulgaria, eastern Greece and into Turkey. The Svinja Reka and Golema Reka deposits at Sasa are located on the eastern flank of a copper molybdenum porphyry deposit at Osogovo.

Mineralisation occurs as stratiform deposits hosted predominantly by schists and marbles at Svinja Reka and by gneisses at Golema Reka. Hydrothermal fluids and bedding parallel faulting are responsible for the metasomatism of the host sediments that produce the skarn and base metal mineralisation. The deposits consist of well-defined lenses of lead-zinc-silver mineralisation, dipping at approximately 35 degrees and ranging in thickness from 2 to 30 metres.

9 YEARS

Sasa mine life

SASA OVERVIEW

Watch to understand how we produce zinc and lead concentrates at Sasa.

Central Asia Metals North Macedonian Project

Lead and Zinc Mine owned by Central Asia Metals in North Macedonia

RECENT PRODUCTION

The following table shows recent Sasa mine and concentrate production for the past eight years.

Year	Units	2017	2018	2019	2020	2021	2022	2023	2024	2025
PLANT FEED
Feed	t	793,332	804,749	820,491	820,215	830,709	806,653	805,621	760,514	799,080
Pb grade	%	3.98	3.90	3.77	3.85	3.52	3.63	3.70	3.71	3.35
Zn grade	%	3.18	3.31	3.29	3.37	3.14	3.15	2.97	2.87	2.61
LEAD CONCENTRATE
Production	t (dry)	40,757	40,317	40,366	41,289	37,893	38,439	39,136	37,595	35,643
Recovery	%	94.6	93.6	94.5	94.3	93.1	93.4	93.1	94.4	94.1
Grade	%	72.9	73.6	72.3	72.0	71.8	71.2	71.0	70.8	70.6
Pb in concentrate	t	29,881	29,388	29,201	29,742	27,202	27,354	27,794	26,617	25,156
ZINC CONCENTRATE
Production	t (dry)	43,676	46,128	47,104	47,583	44,383	42,824	40,226	36,967	35,614
Recovery	%	85.5	84.6	86.5	86.1	84.9	84.6	85.0	85.2	85.7
Grade	%	49.4	48.9	49.6	50.0	49.9	50.1	50.6	50.2	50.2
Zn in concentrate	t	21,585	22,532	23,369	23,815	22,167	21,473	20,338	18,572	17,881

Sasa Mineral Resources and Ore Reserves (PDF)

How we produce Zinc and Lead Concentrates

Sasa is an underground zinc and lead mine which produces approximately 800,000 tonnes of ore each year. The mine consists of three orebodies – Svinja Reka, Kozja Reka and Golema Reka. Svinja Reka is accessed via two declines from the surface, with an internal shaft for services and material and is currently the only orebody being mined at Sasa.

Ore is drilled using single boom jumbos, blasted and then excavated with underground loaders. The main haulage levels are at 80 metre intervals, with sub-levels every 7 to 10 metres depending on the mining methods.

From 2023, the Sasa team has been transitioning from the historical top-down sub-level caving (SLC) mining method to the new bottom-up methods of cut and fill stoping (C&F) and long-hole stoping (LHS) with paste backfill. Both historical voids and new excavations will be backfilled with paste material containing cemented tailings to provide support, rather than allowing the roof to cave, as is the case with the SLC method.

Once blasted, 60% to 70% of the ore is then sent via ore passes to the 830 metre level where it is transported by rail wagons to the Golema Reka shaft for hoisting, and the remaining 30 to 40 % is hauled to surface using trucks via the decline infrastructure. This ratio will change as the new Central Decline is extended to the bottom of the mine, providing a more efficient transport system.

Once at surface, ore is crushed in three stages. The milling circuit involves two parallel sets of rod mills, spiral classifiers and ball mills to ensure the extracted material is the appropriate size for liberation by flotation at approximately 74 microns.

The processing plant operates both lead and zinc flotation processes, producing separate concentrates which are filter pressed to generate products containing 5-9% moisture. The lead concentrate contains, on average, 71% lead and the zinc concentrate contains, on average, 50% zinc. The concentrates are stored in two separate bays before being loaded into haulage trucks for sale to smelters.

How we produce Zinc and Lead Concentrates

CAPITAL ProjectS

Over the past three years, CAML has been working on three significant transition Capital Projects at its Sasa operation:

Construction of a paste backfill plant and associated underground reticulation system
Construction of a dry stack tailings plant and associated landform
Development of a new, larger cross section and direct-access decline, known as the Central Decline

The purpose of these investments is to:

Facilitate the transition of Svinja Reka’s mining method from SLC to a combination of SLC, C&F and LHS
Maximise the extraction of the underground resources at Sasa by utilising paste backfill to improve the geotechnical characteristics of the mine and by using more selective mining methods
Create a safer and more sustainable underground mining operation whilst also extending the life of mine (LOM)
Reduce the environmental footprint by ensuring that Sasa does not have to build and operate another downstream tailings facility following TSF4 during its remaining life to 2039. Instead, tailings will be stored on the new dry stack tailings facility or utilised as paste backfill underground
Allow CAML to set a target of 70% of Sasa’s LoM mineral waste being stored in a more environmentally responsible manner by the end of 2026 and a long-term target of 75% reduction in surface water abstraction by the end of 2026.

Both C&F and LHS are more selective mining methods than SLC. This transition will allow the mine to adapt to the changing orebody, achieve higher recovery of mineral resources and reduce the dilution from mining unmineralised material. These bottom-up mining methods involve drilling, blasting and mucking out the ore, followed by filling the voids with a backfill paste material containing cemented tailings for support.

To implement this method, a paste backfill plant has been built, along with associated reticulation pipework and boreholes to transport the material underground. Tailings from the processing facilities are sent to the paste backfill plant to be thickened and pressed to reduce the water content, and then mixed with cement to form a slurry to produce paste of the optimal consistency. This paste is then distributed underground to fill the stopes.

A key component of CAML’s Capital Projects at Sasa is the construction of a dry stack tailings plant and associated landform, which was completed in Q1 2025. To generate dry stack tailings, mineral waste is filter pressed to remove almost all of the moisture and then stacked on a purpose-built landform. This solution to storing mineral waste is seen as a more environmentally attractive approach than a traditional wet tailings facility.

Sasa has developed a new Central Decline into the Svinja Reka orebody. The Central Decline is larger in cross-section than the existing access in order to improve ventilation and potentially facilitate the use of electric vehicles in the future. The decline provides a more direct route to the orebody at depth, ensures that the operation is more efficient, mitigates risk associated with hoisting and provides an additional means of emergency egress. Development totalled 3,735 metres, and was completed in December 2024.

The Central Decline is now operational and is fully serviced with power, stage pumping, and cuddies mined at 200-metre intervals.

Streaming agreement with OR Royalties INC

Due to a long-standing streaming agreement with OR Royalties, CAML receives approximately $6/oz for its silver production for the life of the Sasa mine.