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sasa - central asia metals

sasa - central asia metals

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

The Sasa deposit was discovered during a period of exploration between 1954 and 1965. Trial mining commenced in 1965 and, in 1966, the mine commenced commercial production as a state-owned entity. The mine closed in 2002 and was placed into bankruptcy due to lack of funding. The Solway Investments Group subsequently purchased the mine, invested in new equipment and operations resumed in 2006. Solway Group later sold the mine to Fusion Capital and Orion Mine Finance Group in 2015.

Sasa lies within the Serbo-Macedonian Massif, which hosts a large number of lead and zinc deposits and extends through Serbia, North Macedonia, Bulgaria, eastern Greece and into Turkey. The mines Svinja Reka and Golema Reka deposits 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 are well defined lenses of lead zinc silver mineralisation, which dip at about 35 degrees and range in thickness from 2 metres to 30 metres.

Sasa is an underground zinc and lead mine that produces approximately 820,000 tonnes of ore each year. Accessed by adit, the Svinja Reka deposit is currently mined using a sub-level caving method, which utilises the geotechnical characteristics of the weak hanging wall to allow the rock to cave naturally into the void remaining after ore has been blasted.

Main haulage levels are at 80 metre intervals, with sub-levels every 7 metres. Ore drives are typically 3.5 metres by 3.5 metres. Ore is mined using a top down approach without backfill. Ore is drilled using single boom jumbos, blasted and then excavated with underground loaders.

From the second half of 2022 the Sasa team will transition to a new mining method, cut and fill stoping, with approximately 90% of ore being extracted using this method by 2024. The voids will then be backfilled with paste material containing tailings to provide support, rather than allowing the roof to cave as is the case with the current sub-level caving method.

Once blasted, 70% of the ore is then sent via ore passes to the 830m level where it is transported by rail wagons to the Golema Reka shaft for hoisting, and the remaining 30% is hauled to surface via the adit.

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

The processing plant then operates both lead and zinc flotation processes, producing separate concentrates that are filter pressed to produce products containing 5-9% moisture. Silver is also produced and this reports to the lead concentrate. The lead concentrate contains c.73% lead and the zinc concentrate contains c.49% zinc. The concentrates are stored in two separate bays before being loaded into haulage trucks for sale to smelters.

A Life of Mine study was commissioned in order to investigate the efficiency of operations at Sasa, including a review of the current sub-level caving mining method, and to determine recommendations that would optimise productivity.

The study recommended the transition from sub-level caving to cut and fill stoping, a more selective mining method, that will not only result in maximum recovery of mineral resources, but will also enable safer operating practices as well as longer-term improvements to tailings disposal. The Cut and Fill Project has been approved by the Board and the transition to the new mining method will take effect in the second half of 2022, with approximately 90% of ore being extracted using this method by 2024. In order to move to cut and fill stoping and therefore ensure effective long-term operations for the life of the mine at Svinja Reka, several practical changes will be implemented at site.

Cut and fill stoping is a more selective mining method than sub-level caving, which is expected to achieve greater recovery of ore as well as reducing the dilution of ore with un-mineralised material. It is a bottom-up mining method involving drilling, blasting and mucking out of ore before filling voids.

The cut and fill mining method involves filling mined voids with a backfill paste material containing tailings to provide support, rather than allowing the roof to cave as is the case with the current sub-level caving method. In order to achieve this, a backfill plant will be constructed, along with associated reticulation pipework to transport this material underground. Tailings from the processing facilities will be sent to the backfill plant to be thickened and pressed to contain 80% solids, and then mixed with a slurry containing cement, fly ash and water to produce a paste of the appropriate consistency. This is then distributed underground to fill stopes.

Given that a major component of the backfill material will be tailings generated from the Sasa processing plant, it is estimated that over 40% of Svinja Rekas life of mine tailings will be stored underground. Approximately 30% of tailings will be stored in the current TSF4, and CAML is advancing studies with a view to dry stacking the remainder and therefore eliminating the need to construct further tailings dams in the future. The Company is firmly committed to the environmental and socially responsible disposal of tailings for the long term.

central asian countries - worldatlas

central asian countries - worldatlas

Central Asia is an extremely large area of mountains, vast deserts, and grassy steppes. It is bordered by the Caspian Sea in the west and China in the east, and by Afghanistan to Russia in the south and north. The region has historically been linked with the nomadic people acting as a crossroad for the movement of people and goods within Eurasia. The crossroads position has often intensified conflicts within the region. Central Asia is made up of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. The five nations have a total population of 69 million people with Uzbekistan having the highest population.

central asia | britannica

central asia | britannica

Central Asia, central region of Asia, extending from the Caspian Sea in the west to the border of western China in the east. It is bounded on the north by Russia and on the south by Iran, Afghanistan, and China. The region consists of the former Soviet republics of Kazakhstan, Uzbekistan, Tajikistan, Kyrgyzstan, and Turkmenistan.

Central Asias landscape can be divided into the vast grassy steppes of Kazakhstan in the north and the Aral Sea drainage basin in the south. About 60 percent of the region consists of desert land, the principal deserts being the Karakum, occupying most of Turkmenistan, and the Kyzylkum, covering much of western Uzbekistan. Most of the desert areas are unsuitable for agricultural use except along the margins of the Amu Darya and Syr Darya river systems, which wind their way northwestward through Kyrgyzstan, Tajikistan, and eastern Uzbekistan and Turkmenistan after rising in mountain ranges to the south and east. Those two major rivers drain into the Aral Sea and provide most of the regions water resources, though northern Kazakhstan is drained by rivers flowing north into Russia. On the east and south Central Asia is bounded by the western Altai and other high mountain ranges extending into Iran, Afghanistan, and western China.

Central Asia experiences very dry climatic conditions, and inadequate precipitation has led to heavy dependence on the Syr Darya and Amu Darya for irrigation. The region as a whole experiences hot summers and cool winters, with much sunshine and very little precipitation. The scarcity of water has led to a very uneven population distribution, with most people living along the fertile banks of the rivers or in fertile mountain foothills in the southeast; comparatively few live in the vast arid expanses of central and western Kazakhstan and western Uzbekistan and Turkmenistan.

The five largest ethnic groups in Central Asia are, in descending order of size, the Uzbek, Kazakh, Tajik, Turkmen, and Kyrgyz. All those groups speak languages related to Turkish except for the Tajik, who speak a language related to Persian. Islam is the dominant religion, with most adherents belonging to the Sunni branch. As a result of the regions historical incorporation into Russia and then the Soviet Union, large numbers of Russians and Ukrainians give it a distinctive multiethnic character. Population growth in Central Asia was quite rapid in the 20th century as a result of high birth rates and Soviet health measures that brought down mortality rates. The region experienced environmental problems in the late 20th century that were due to the effects of rapid agricultural development, overdependence on irrigation, and the effects of Soviet nuclear-weapons testing in some areas.

Central Asias economic activity is centred on irrigated agriculture in the south and on heavy and light industry and mining in Kazakhstan. Under Soviet rule the area supplied most of the U.S.S.R.s cotton and was a major supplier of coal and other minerals for industrial use. Irrigated cotton growing is dominant in the east and southeast, while there is some dry farming of wheat in the far northern provinces of Kazakhstan, where the Soviets Virgin and Idle Lands program of the 1950s brought much steppe under the plow for the first time.

The human occupation of Central Asia dates back to the late Pleistocene Epoch, approximately 25,000 to 35,000 years ago, but the first identifiable human groups to live there were the Cimmerians and Scythians (1st millennium bce) in the west and the Hsiung-nu people (from 200 bce) in the east. In the 6th century ce the first Turkic people established an empire that lasted for two centuries and greatly influenced the regions subsequent ethnic character. Another Turkic people, the Uighurs, rose to dominance in the 8th century, and their rule in turn gave way to that of the Khitans and then to the Karakhanids, a Turkic people closely related to the Uighurs. The region was gradually Islamized beginning in the 11th12th century, a process that was virtually complete by the 15th century. The Mongols took over almost all of Central Asia in the 13th century, and their rule in the form of various independent khanates lasted until the conquests of Timur (Tamerlane) about 1400. Following the breakup of his dynasty, southern Central Asia became divided into several rival khanates that were ruled by his descendants. By the end of the 15th century all of these Timurid possessions had fallen into the hands of the Uzbek people.

Russias conquest of the region began in the 17th century and continued until the last independent Uzbek khanates were annexed or made into protectorates in the 1870s. Soviet rule replaced that of the Russian tsars after the Russian Revolution of 1917, and thereafter the region was increasingly integrated into the Soviet system through a planned economy and improved communications. In the 1920s and 30s the Soviet government created five Soviet socialist republics out of the region: the Kazakh S.S.R., the Uzbek S.S.R., the Kirgiz S.S.R., the Tajik S.S.R., and the Turkmen S.S.R. Under Soviet rule, southern Central Asia undertook the large-scale cultivation of cotton to supply the U.S.S.R.s textile industry with raw material. When the Soviet Union collapsed, all five Central Asian Soviet socialist republics obtained their independence in 1991, becoming the sovereign and independent nations of Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan, and Turkmenistan.

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