ANALYSIS OF THE DEEP QUARRY DEVELOPMENT SYSTEM

ABSTRACT

This article examines existing classifications of mineral development systems and establishes the relationship between the development systemsand the type of equipment used. A combined development systemsis proposed, which considers not only the direction of the mining front and the mutual arrangement of dumps and the mining zone but also the interconnection of equipment within the quarry. An analysis of the development systems of the "Muruntau" and "Kalmakyr" quarries was conducted, identifying their deficiencies and providing recommendations for optimizing the development systemsfor the "Kalmakyr" quarry. Specifically, the recommendations aim to improve efficiency and productivity through more rational use of equipment and improved organization of work within the quarry by implementing a cyclic-flow transport system, which significantly reduces the transportation distances of the mined material, thereby increasing the productivity of dump trucks and the quarry as a whole.

АННОТАЦИЯ

В статье рассматриваются существующие классификации систем разработки полезных ископаемых и устанавливается взаимосвязь системы разработки с типом применяемого оборудования. Предложена комбинированная система разработки, которая учитывает не только направление фронта горных работ и взаимное расположение отвалов и добычной зоны, но и взаимосвязь оборудования внутри карьера. Проведен анализ систем разработки карьеров «Мурунтау» и «Кальмакыр», выявлены их недостатки и предложены рекомендации по оптимизации системы разработки для карьера «Кальмакыр». В частности, рекомендации направлены на улучшение эффективности и производительности за счет более рационального использования оборудования и улучшения организации работ внутри карьера за счет внедрения циклично-поточной транспортной системы, которая в разы уменьшает расстояния транспортировки горной массы, тем самым увеличив производительность автосамосвалов и карьера в целом.

Keywords: mineral development system, open-pit mining technology, elements of the development system, classification of open-pit mining technologies, deep quarry.

Ключевые слова: система разработки полезных ископаемых, технология открытой разработки, элементы системы разработки, классификация технологий открытой разработки полезного ископаемого, глубокий карьер.

Introduction

The mining industry plays a crucial role in the economies of many countries by providing raw materials for various sectors and meeting the growing needs of humanity. As the population increases and industrial development accelerates, the demand for metals and minerals rises, leading to the necessity of deepening quarries and increasing extraction volumes. This process, in turn, results in higher costs for mineral resource development.

One of the main challenges in modern mining is the significant increase in the cost of extraction in deep quarries. This is due not only to technical difficulties and higher equipment costs but also to growing environmental and social risks. In these conditions, the search for rational and optimal development systems that can reduce costs and increase production efficiency becomes particularly relevant.

To determine a rational development system, let us consider the most well-known definitions of the concept «Development system». A mineral deposit development systemsis a set of methods and technologies used to extract minerals from the earth. The open-pit development systemsincludes the procedure for forming the working area of the quarry, which determines the sequential and balanced development of mining operations. The elements of the development systemsinclude benches, the working front of the bench, the working front of the quarry, the working area of the quarry, working platforms, transport, and safety berms. To fully evaluate quarry development systems, it is necessary to conduct a fundamental analysis of the classifications of development systems that have been used for several decades.

Research methods

Currently, there are several classifications:

Professor E.F. Sheshko's classification focuses on the method of overburden movement and dump placement. [1].

Academician N.V. Melnikov's classification shares the same defining criterion as the previous one. [2].

Academician V.V. Rzhevsky's classification is based on multiple criteria, including changes in the working area during deposit exploitation, type of mining front, direction of excavation and extraction in plan and profile, and the mutual arrangement of the working area and dumps. [3].

Analyzing these classifications reveals that the development systemsis classified based on specific elements of mining operations. For instance, Professor E.F. Sheshko justified the application of various extraction technologies based on the location of overburden dumps. Meanwhile, Academician V.V. Rzhevsky's classification suggests that technology selection for excavation is guided by the orientation of the working front relative to the dumps.

Based on the analyzed data, it can be concluded that the development systemsdepends on specific elements of open-pit mining.

In [4], it is explored that the open-pit development systemsfor mineral extraction comprises interdependent preparatory, overburden removal, and extraction operations, which evolve over time within the quarry field to extract geological materials from the Earth's crust.

Figure 1. Scheme of interdependence of elements in the mineral development system

The main parameters of the development systemsinclude bench advancement rates, bench slope movement rates, quarry floor deepening rates, new lower horizon preparation time, operational losses and ore extraction, as well as daily, monthly, and annual productivity in ore extraction, overburden removal, and total rock mass. These metrics concurrently serve as production characteristics of open-pit mining technologies [4].

Extracting geological materials from pre-prepared workings involves various types of mining operations, including pre-mining, overburden removal, and extraction works. Thus, the aggregate of these mining operations forms the basis for implementing mineral extraction technologies. In other words, the development systemsprovides an environment where extraction technologies efficiently operate. This distinction clearly delineates between the concepts of "development system" and «Mineral extraction technology».

Open-pit mining technology, encompassing pre-mining, extraction, and overburden removal works, constitutes a critical component of overall mining technology. It covers principles and methods for phased quarry field development, management of mining operation regimes, quality control of extracted products, and management of temporal progress in extraction and overburden removal to optimize space use and enhance interaction between technological processes. Optimal selection of overburden removal and extraction technologies, considering development systemsspecifics and equipment technical characteristics, ensures optimal operational outcomes. Open-pit mining technology structurally consists of two primary elements: mining-loading and transportation operations, as depicted in Figure 2 [5].

Figure 2. Structural diagram of open-pit mining technology

Considering the components of excavation-loading and transportation operations, B.R. Rakishev proposed categorizing open-pit mining technologies into cyclic non-transport, cyclic, cyclic-flow, flow-cyclic, flow and combined technologies.

Search for an optimal development systemsfor deep quarries with complex mining engineering conditions

Special attention should be drawn to the continuing decrease in the quality of valuable minerals at developed and most newly exploited deposits over the past several decades, along with significant complexities in mining-geological, natural-climatic, and economic-geographical conditions for developing deposits, particularly new ones, due to increasing environmental protection requirements. This situation underlies a stable trend towards substantial growth in operational and capital expenditures in the mining industry [6].

According to the aforementioned study, one of the factors influencing the development systemsis the type of open-pit mining technology used. The type of equipment used sets clear boundaries for the maximum allowable depth of the quarry. Hence, it follows that a particular development systemsis rational up to a certain depth.

In study [7], the efficiency of railway transport systems, road transport systems, and cyclic-flow technology, including steeply inclined conveyors with a clamping belt, on deep quarries is examined. It is shown that the application of cyclic-flow technology, including steeply inclined conveyors, improves the economic and environmental situation of the enterprise.

As demonstrated by practical experience, the development systemsclassification proposed by Academician V.V. Rzhevsky proves to be the most rational for deep quarries. However, analyzing existing quarries reveals that the maximum allowable depth already exceeds 500 meters (650 meters for the "Muruntau" quarry and 600 meters for the "Kalmakyr" quarry). In such quarries deeper than 500 meters, transportation distances exceed 10 kilometers in one direction, making transportation operations the primary cost factor in mine development.

Upon studying the technology and system of open-pit mining, it has been identified that one of the ways to optimize mining systems for quarries deeper than 500 meters is through a combination of classifications by Academician V.V. Rzhevsky and B.R. Rakishev. A combined development systemswould consider not only the evolution of the working area during mining operations, types of work fronts, and the direction of excavation in terms of plan and profile, but also the internal transportation distances within the quarry and the interaction between the equipment used.

Kalmakyr Quarry Mining System

During the development of the quarry, changes in mining and transportation conditions result in varying degrees of efficiency for different types of transportation. Therefore, to ensure optimal parameters for the quarry's transportation system, periodic updates with the introduction of new types of transportation are necessary [8,9].

The Kalmakyr quarry has a pear-shaped form with a widening in its eastern part. Horizons above the 680 m mark have an L-shape with parallel advancement of the faces, while horizons below 680 m have a U-shape. Currently, 24 benches have been cut at the mine, with 16-17 benches in constant operation. The height of the working benches ranges from 15 to 22.5 meters. The minimum width of the working platforms is 40-60 m, and the length of the working front of the excavator on the upper horizons is 800-1000 m, and on the lower horizons, it is 600-800 m. The height of the benches from the top mark to the 670 m horizon is 22.5 m, and below it is 15 m, determined by the loading equipment used.

The project adopts a development transportation system with overburden removal to external dumps. The movement of the work front in the quarry is parallel, and when transitioning to a permanent spiral exit, it is fan-shaped with a turning point for the bench paths near the exit trench.

Currently, the quarry deepens by 5-6 m per year, and the rate of work front advancement is 90-100 m.

The average transportation distance of overburden from the bottom of the quarry to the dumps is 10 km. In the future, within the next 10 years, a large-scale merger of the Kalmakyr quarry and the Yoshlik I quarry is planned. Considering this fact, the average transportation distance of overburden will increase significantly, which could make further quarry development impractical.

Using a combination of classifications to optimize the current development system may be the most rational for the Kalmakyr quarry. For example, the Muruntau quarry solved the problem of increasing transportation distances by implementing a steeply inclined conveyor. Thus, to optimize the current development system, a continuous technology for the development of mineral resources for the transportation of rock mass can be introduced.

Currently, the technological chain at the Kalmakyr quarry is as follows (Fig. 3):

Figure 3. Cyclic Technology of Mineral Development

The use of cyclic-flow technology for the development of mineral resources for the transportation of rock mass is proposed.

Figure 4. Proposed Cyclic-Flow Technology for Mineral Development

Discussion.

As of today, the Kalmakyr quarry employs 25 BelAZ dump trucks for mining operations. Considering the expansion and merger of the two quarries in the near future, the demand for an increased number of dump trucks for rock mass transportation will be relevant.

As practice has shown with the use of a steeply inclined conveyor at the Muruntau quarry, the implementation of cyclic-flow technology (CFT) will allow for the decommissioning of 14 dump trucks with a load capacity of 130 tons. Additionally, it will enable the quarry depth to increase to 1000 meters with steeper slope angles, due to the reduction of transportation berms for dump trucks that flatten the quarry slope. Moreover, the application of CFT at the Muruntau quarry has increased the productivity of dump trucks by 30% by reducing the transportation distance and lowering the height of cargo lifting.

Conclusion

The classical development system is the most effective for the Kalmakyr quarry. However, there are ways to optimize the development system by applying a combination of classifications. For the Kalmakyr quarry, the development system will include a transportation system with the use of cyclic-flow technology for mineral development and the removal of overburden to external dumps.

The implementation of cyclic-flow technology (CFT) for mineral development can address the issue of high transportation costs for rock mass.

Economically, CFT based on conveyor transport (KNK) is preferable even in the short term. For example, current operating expenses for large-capacity dump trucks are significantly higher compared to the costs of maintaining a CFT production line. Additionally, the vehicle fleet will require substantial investments for renewal in seven years, whereas the CFT complex does not require such capital investments since its maintenance is included in current expenses. Further savings are achieved through technological advantages that eliminate the need for additional mining preparatory work.

The Kalmakyr quarry is a significant object of the mining industry in Uzbekistan. For this reason, finding the optimal development system for the Kalmakyr quarry and the future combined Oliy-Ziyo quarry is a priority task that affects not only the economy of Almalyk but also the country's economy as a whole.

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