RESEARCH OF GEOLOGICAL EXPLORATION AND ECONOMIC PARAMETERS OF THE TYUBEGATAN SYLVINITE DEPOSIT

ABSTRACT

The article considers geological and economic aspects of the development of the Tyubegatan sylvinite ore deposit in Uzbekistan. It analyzes global trends in the mining and processing of potassium salts and the place of Uzbekistan among the leading producing countries. Data on ore reserves, chemical composition of sylvinite and methods of extraction are provided. Technological features of the deposit development, including geodynamic risks and infrastructure limitations are considered. Prospects for increasing production volumes, expanding production capacities and export potential of potash fertilizers are assessed. The calculation of economic indicators of mining and processing of potassium salts is given, demonstrating a significant contribution of the deposit to the development of the agricultural and chemical sectors of the country’s economy.

АННОТАЦИЯ

В статье рассматриваются геологические и экономические аспекты освоения Тюбегатанского месторождения сильвинитовой руды в Узбекистане. Анализируются мировые тенденции добычи и переработки калийных солей, а также место Узбекистана среди ведущих стран-производителей. Приведены данные о запасах руды, химическом составе сильвинита и методах его добычи. Рассмотрены технологические особенности разработки месторождения, включая геодинамические риски и инфраструктурные ограничения. Оценены перспективы увеличения объемов добычи, расширения производственных мощностей и экспортного потенциала калийных удобрений. Приведен расчет экономических показателей добычи и переработки калийных солей, демонстрирующий значительный вклад месторождения в развитие аграрного и химического секторов экономики страны.

Keywords: Tyubegatan mining deposit, sylvinite ore, potassium salts, geological exploration, economic aspects, extraction of potash fertilizers, Uzbekistan, ore processing, mineral reserves, mineralogy, agricultural production, chemical industry, export of potash fertilizers.

Ключевые слова: Тюбегатанское месторождение, сильвинитовая руда, калийные соли, геологическая разведка, экономические аспекты, добыча калийных удобрений, Узбекистан, переработка руды, запасы полезных ископаемых, минералогия, аграрное производство, химическая промышленность, экспорт калийных удобрений.

The mining and processing of potash salts is predominantly undertaken in Canada, Belarus, Russia, China and Germany, which collectively account for approximately 81% of the global production of potash fertilizers. Approximately ten mines are operational in Canada, contributing to around 30% of the global potash salt production. Russian mining activities are primarily concentrated at the substantial Verkhnekamsk deposit in the Perm region. Russia's share in the world's production of potash fertilizers is approximately 16%, and the quality of Russian products generally corresponds to world standards. Israel and Jordan utilize the Dead Sea brines as a source of raw materials, while China's main source of potash raw materials is the brines of Lake Charhan. Except for China, all of the listed countries export the majority of their potash fertilizers [1,2].

Concurrently, Uzbekistan is positioned amongst the top ten global leaders in terms of reserves and resources of certain universal mineral types, including gold (3rd place), silver (8th place), copper (10th place), tungsten (8th place), and potash (4th place). The largest deposits of potash salts have been discovered in Uzbekistan, namely Tyubegatan in the Kashkadarya region and Khodjaikan in the Surkhandarya region. The projected income from the provision of potash salts is expected to exceed 100 years [3].

Figure 1. Dry riverbed of the Shor-Darya River in the territory of the sylvinite deposit

Geographically, the Tyubegatan potash deposit is located in the Dekhkanabad district of the Kashkadarya region of the Republic of Uzbekistan and partly in the Chardzhou district of the Republic of Turkmenistan. The border is delineated by the Darya River, which bisects the deposit into approximately equal segments [4]. The prevailing climatic zone is continental, characterized by protracted hot summers and brief cold winters. The primary waterway is the Shor-Darya River, which traverses the southern border of the Uzbek portion of the deposit (Fig. 1).

In the 1930s, V.A. Korvatsky discovered inclusions of sylvite in samples of pink rock salt from old salt mines in Southwest Gissar (Korvatsky, 1931). This finding enabled him to discuss the widespread development of sediments and potassium salts in this region, in particular. The initial hypothesis concerning the presence of potassium salts in the Tyubegatan area was proposed in 1931 by B.A. Bender noted the elevated content of potassium chloride in the water of the Khozhaipok spring. In 1950, sylvinite formations were discovered in the salt layer by three wells within the northwestern wing of the Tyubegatan anticline, and reserves of potassium salts of category C1 were calculated at 45 million tons.

Figure 2. Relief of the Tyubegatan deposit

The deposit extends from the southwest to the northeast for a total of 24 km, including 14 km within the borders of Uzbekistan, with the width of the Lalmikan anticline (Turkmenistan) reaching a maximum of 7 km. The width of the deposit within the Uzbek territory varies from 1.5 km to 3 km (Fig. 2). The topographical features of the deposit are highly complex, as evidenced by the absence of anthropogenic infrastructure such as settlements, roads, electrical networks, and assured water resources. The selection of the site for the mining of sylvinite ore on the territory of the deposit with very complex mining and geological conditions is shown in Fig. 3. It is also located in a zone with increased geodynamic activity processes [8].

The initial design capacity of the mine was set at 700 thousand tons per year. The deposit's development commenced with a combined method utilizing a chamber development system. Ore is transported from the face by self-propelled cars [4-9]. The Kashkadarya Geological Exploration Expedition of the Ministry of Geology of the Uzbek SSR conducted a detailed exploration and calculation of potassium salt reserves at the deposit between 1959 and 1966, and these reserves were approved by the USSR State Reserves Committee.

Figure 3. Location of the mining site at the Tyubegatan deposit

A comprehensive study of the deposits was conducted utilizing vertical core drilling wells, which traversed exploration profiles to the extent of the salt layer, extending between 700 and 2000 meters. The industrial horizon of the deposit (lower II layer) was traversed by 51 wells. Of these, 32 were conducted in the Uzbek segment of the deposit. The exploration network is uneven, with a distance between wells ranging from 250 to 2000 meters, and the average exploration density of this part of the deposit is approximately 1.1 wells per square kilometer (Fig. 4). In 2007, a recalculation and approval was undertaken of the reserves of sylvinite within the Uzbek part of the deposit. Consequently, the reserves were categorised as follows: category "A+B+C1" (198,127 thousand tons), category "C2" (49.5 million tons) [4].

Figure 4. Boundaries of the calculation of reserves of the Tyubegatan deposit in the territory of the Republic of Uzbekistan

It is important to note that in this instance, the reserves of potassium salts are calculated separately for the primary lower productive sylvinite layer and the upper sylvinite layer. The upper and lower sylvinite layers are separated by a rock salt layer with a thickness of 4-5 meters. The distribution of potassium salts in the lower layer has been the subject of extensive study, leading to the identification of 11 calculation blocks: IB, II-B, V-C1, III-C1, VI-C1, IX-C1, VII-C1, X-C1, IV-C1, VIII-C1, XI-C2.

The total industrial reserves of the Tyubegatan deposit, located on the border with Turkmenistan, have been estimated at 400.2 million tons of ore, with a potassium chloride content of 36.8%. The most promising part of the deposit, which contains reserves of 200 million tons of ore, is located on the territory of Uzbekistan. The designed capacity of the plant is to process 700 thousand tons of raw materials and produce 200 thousand tons of potash fertilizers. The commissioning of the plant will create over 1,300 new jobs and ensure the export of 90 thousand tons of potash fertilizers. In recent years, the capacity of the mine has been doubled and brought to 1,500 thousand tons per year, taking into account the expansion of the tailings storage facility for halite waste [4-6].The reserves of the Tyubegatan deposit amount to more than 198 million tons of ore (sylvinite), in terms of reserves of which Uzbekistan ranks 10th in the world. The ore contains an average of 34-35% potassium chloride and 63% sodium chloride. The selected site contains ore reserves of 44.5 million tons, which will provide the plant with raw materials for approximately 30 years.

This is the first documented instance of sylvinite being mined in Asia, and it is noteworthy for being one of the most challenging excavations in the annals of mining. The president of ZUMK has described the conditions as follows: "There was flooding, everyone was going through karst and sinkholes, there was clay and mud at once." In 2007, ZUMK was awarded the tender for the design, construction and equipment of the first stage of a potash mine with a capacity of over 700 thousand tons of ore per year. The first stage of the mining complex, valued at $56 million, was inaugurated in 2010 at the Tyubegatan potash salt deposit, followed by the commencement of operations at the Dekhkanabad potash fertilizer plant, which was valued at $123.7 million. It is anticipated that the processing capacity will be augmented to 400 thousand tons in the future.

In conclusion, it should be noted that the mineral resources of Uzbekistan, in particular, based on sylvinite ores, have the potential to fully satisfy the country's agricultural potash fertilizer requirements for a period over one hundred years. The geological studies of sylvite ores have established that the total reserves of the Tyubegatan deposit (categories "A + B + C1" and "C2") are 685905 thousand tons, and on the territory of Uzbekistan, respectively, 247604 thousand tons. With an average KCl content of approximately 37.0%, the deposit has the potential to yield 91613.48 thousand tons of potash fertilizers. The economic indicator of the products, as determined by the wholesale price of JSC "Uzkimyosanoat", is more than $23.0 billion, and when measured against global prices, this figure exceeds $36.7 billion. Ore mining is methodically organized by an underground combine-mechanized approach in a geodynamic active zone. The products are then transported by road for processing, with the resultant enrichment waste being returned to the tailings storage facility. Concerning the global trends in sylvinite ore reserves, Uzbekistan (excluding the Tyubegatan deposit, which is 198 million tons) is in the top 10, after Russia (17127 million tons), Canada (8726 million tons), Belarus (4648 million tons) and China (210 million tons). About the associated component, the reserves of bromine (designated "Br") in the categories "A + B + C1 + C2" amount to 200.8 thousand tons.

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