CONSTRUCTION OF LOG CABINS AND SCHEMES OF DEVELOPMENT OF THE LOG STRIP

ABSTRACT

Today, one of the fundamental problems of mining production is the destruction of the mountain range. The efficiency of rock destruction determines the efficiency of the entire mining industry and further the capabilities of the entire industry using the results of mining enterprises. When carrying out horizontal workings, increased requirements are imposed on drilling and blasting operations in terms of ensuring the necessary collapse of the rock after the explosion and its high-quality crushing, ensuring the stability of the workings and outlining them in accordance with the project, as well as low cost of work.

AННОТАЦИЯ

На сегодняшний день одной из основополагающих проблем горного производства является разрушение горного массива. Эффективность разрушения горных пород определяет эффективность всего горного производства и далее возможности всей промышленности, использующей результаты работы горнодобывающих предприятий. При проведении горизонтальных выработок к буровзрывным работам предъявляются повышенные требования в части обеспечения необходимого развала породы после взрыва и качественного ее дробления, обеспечения устойчивости выработок и оконтуривание их в соответствии с проектом, а также низкая себестоимость работ.

Keywords: mining workings; drift; hole; log; drilling; explosion; rock; perforator; contour; face; construction; compensatory hole.

Ключевые слова: горных выработок; штрек; шпур; вруб; бурения; взрыв; горных пород; перфоратор; контур; забой; конструкция; компенсационные шпур.

Introduction

Currently, one of the main indicators of the effectiveness of blasting operations during underground mining is considered to be the utilization factor of the hole, reflecting the ratio of the magnitude of the movement of the face for the explosion to the depth of the drilled holes. Thus, it is necessary to identify a number of factors affecting this value. One of the directions of improving the technology of drilling and blasting operations (DBO) when sinking workings is the use of sets of deep holes (up to 1.6-2 meters or more) [2].

The efficiency of DBO production in this case primarily depends on the chosen design of the log cabin. Currently, when sinking workings, the following log structures have become the most widespread: two straight lines with one compensating hole; four straight lines with one compensating hole; four straight lines with two compensating holes and six straight lines with three compensating holes, are shown in Fig. 1.

There are different points of view in assessing the effectiveness of the presented log structures and determining the conditions for their rational use.Based on the criteria of the cost of the formation of a 1m³ cut-in cavity, the maximum efficiency of slot cut-ins has been proven, while the worst results are noted when using sectional and wedge cut-ins. When evaluating the effectiveness of slit and prismatic cuttings according to the criterion of the specific consumption of explosives necessary for the formation of 1 m³ of the cut-in cavity, proof of their equivalence was obtained.

а –  is the distance between the centers of the charged straight and compensation holes; d –  is the diameter of the charged holes, m; D –  is the diameter of the compensation holes, m; H_i,j,k – is the distance between the charged straight holes, m; h – is the distance between the centers of the compensation holes. a) two straight lines with one compensation hole, б) four straight lines with one compensation hole, в) four straight lines with two compensation holes, г) six straight lines with three compensation holes.

Figure 1. Log cabin structures and the scheme of the development of the log cabin cavity with an increase in exposure from the initial to the final size

Methods

According to the experience of using sectional cuttings, their advantage in comparison with prismatic cuttings is emphasized, moreover, the total volume of drilling of boreholes and compensatory boreholes is taken as the criterion of efficiency. The inconsistency of the conclusions is explained by the following. The application of various criteria and the selection of one of them as the main one leads to simplification of the task and in some cases inadequate results.

The different methodological basis used in the calculations of log cabins without taking into account the degree of their reliability does not allow for a reliable comparison of the conclusions and recommendations obtained.

A methodology has been developed for evaluating the effectiveness of log cabin structures based on the principles of multi-criteria optimization with ranking criteria by their significance. A unified methodology has been adopted to calculate the structures of the log cabins. According to this method, the construction of log cabins is such a technical solution for drilling holes. As the explosive sequence develops, the output of a second outcrop with a length of at least 1 m is provided, which is necessary and sufficient for the subsequent operation of jackholes with a constant LRS.

The scheme of the development of the cut-in cavity with an increase in exposure from the initial size H_i,j,k to the final size Н_n =1m. It is noteworthy that the coefficient of proportionality n between the exposure of H and the value of a characterizes the explosiveness of rocks, since under the condition Н_к=1m, n is numerically equal to a of jackholes, by the value of which, related to the diameter of the hole d, the real resistance of the array to the destructive action of the explosion is estimated.

Results and discussion

According to the above provisions, an experimental test was carried out of the methods of formation of cavities at the mine "Kauldy" and during the drift + mountains 860 m. The following log cabin designs have been tested: pyramidal-straight log cabins with compensating holes. For each design, 5 series of tests were carried out in workings with a cross section of 12 m². The comparison was carried out with the workings in a rock similar in strength (andesite-dacite and porphyries). The number of holes and the magnitude of the Almanite charges remained unchanged. Only their mutual arrangement changed. Initiation was carried out by detonators of the EDZN with 5 series of decelerations (1st series-2 pcs., 2nd series-4 pcs., 3rd series-2 pcs., 4th series-6 pcs., 5th series-16 pieces of electric detonators). All constructions of log cabins give an average of 0.90-0.93 in the log cavity, and an average of 0.89-0.90 in the face. the specific consumption of explosives in the log holes is minimal compared to similar mining and geological conditions of the mines of the Republic of Uzbekistan.

The optimal depth of holes for a pyramidal log is 1.6 ≤ l ≤ 2.0 m. The performed experiment allows us to conclude that for complex mining and geological conditions, preliminary conclusions are confirmed that after the formation of the cut-in cavity and removal of the destroyed rock from it by an additional explosive charge placed in the bottom of the compensation hole, for the first state of the LNS is W = 0.7 m.

The formation of the total destruction zone occurs under the action of the separation mechanism (90-95% of the destruction volume). In the second state, W = 0.6 m, and the mechanisms of separation and shear are almost equally responsible for the final result of the explosion. In the third state, the destruction volumes increase in comparison with the conditions of hydrostatic compression, and the dominant mechanism of destruction is a shift (70-80% of the destruction volume), and the value W = 0.65 m, i.e. occupies an intermediate value between the optimal LNS of the first and second states. The excavation is carried out according to the relevant DBO passports. The analysis of the DBO passports of the Kauldy mine is given in Table 1.

The above research results make it possible to make a reasonable choice of rational schemes for the arrangement of a set of boreholes in the pipe cavity, taking into account the specific VAT of the array, and also to obtain results no worse than when using traditional compensation boreholes of increased diameter. They take into account various aspects and features of mining-geological and mining-technical factors affecting the quality of drilling and blasting operations.

When drawing up DBO passports, it is necessary to take into account all the main mining, geological, mining and economic factors that ensure high efficiency of work during underground horizontal mining. As is known, the fluctuation of the required number of holes in the current DBO passport entails a change in the specific consumption of explosives. In this case, it is necessary to use a minimum number of holes, which ensures the required separation and crushing of the rock mass.

Table 1.

Drilling and blasting data of the DBO  passport for 31 holes

Table 2.

Comparison of the results of the applied (1-3-5-7-9-11) and the proposed (2-4-6-8-10-12) variants of the DBO passport

Table 3

Comparison of the results of the applied (1-3-5-7-9-11) and the proposed (2-4-6-8-10-12) variants of the DBO passport

The distances between the contouring and auxiliary holes are not maintained, the average deviation from the design was 20 cm. The design of the explosive frame does not correspond to the design. According to the results of the explosion, the average depth of the "glasses" is 15.0 cm. The utilization factor of the holes is 0.90, shown in Figure 2.

Figure 2. The average value of the "glasses" in the development of the drift

From the experimental and industrial verification of the developed technological solutions, experimental results of studies of blasting operations during the sinking of mine workings, it can be concluded that today there are a large number of different methods for calculating the parameters of the DBO.

Conclusion

As a result of the performed analysis, the following main conclusions can be drawn:

1. The analysis of the practice of mining operations at the underground mine "Kauldy" showed that the dominant number of DBO passports involves the use of pyramidal-straight cuttings with compensating holes.

2. The use of this type of log cabin allows for a high intensity of mining operations without reducing the quality of the DBO.

3. This will reduce the total volume of drilling and the consumption of explosives, thereby ensuring an increase in the efficiency of DBO when conducting underground horizontal mining.

References:

1. Lukyanov V.G., Gromov A.D., Pinchuk N.P. Technology of mining and exploration workings. - Tomsk.: Publishing House of Tomsk Polytechnic University, 2004. - 246 p.
2. "Improving the efficiency of mining technology in difficult mining and geological conditions" Kan.of Technical Sciences. abstract // Ignatiev E.R. -S. 8. Access mode – http://kazneb.kz/site/catalogue/view ?br=1123137
3. Akbarov T.G., Toshtemirov U.T. Analysis of mining technology at mining enterprises of the Republic of Uzbekistan // Materials of the XIV International Scientific and Technical Conference on the topic: "Resource-reproducing, low-waste and environmental technologies of subsurface development". - Moscow, 2015. - pp. 89-91.
4. Lykhin P.A. Technology of drilling and blasting operations during mining operations in the twentieth century. Part 2. / Lykhin P.A. - Perm: Presstime Publishing House 2007,– - 351 p.
5. Masaev Yu.A. Influence of the parameters of drilling and blasting operations on the state of a structured array of mining workings // Bulletin of the Kuzbass State Technical University, 2000, No. 5. - pp. 85-87.
6. Toshtemirov U.T. Analysis of methods for calculating rational parameters of drilling and blasting operations during the transition of mining solder // The international interdisciplinary research journal ACADEMICIA, published by the South Asian Academic Research Journals CDL College of Education. - India, 2020. - Volume 10, Issue 11, November. - pp. 1923-1930. (SJIF 2020=7,13).
7. Toshtemirov U.T., Raimkulova S., Mahkamova Kh. Современные методы оценки устойчивости пород и расчета анкерной и набрызг-бетонной крепей горных выработок // Central Asian Journal of Theoretical and Applied Sciences. - India, 2021. - Vol. 2, Issue 5, May. -Pp. 29-37.
8. Akbarov T.G., Toshtemirov U.T., Solikhov J.T., Abduvohidov J.U. Determining the Length of Anchors for Vertical Works // IJARSET. «International Journal of Advanced Research in Science, Engineering and Technology». - India, 2019. - Vol. 6, Issue 11, November. -Pp.11849-11854.
9. Ilmuratov U.H Shamaev M.K., Toshtemirov U.T. Selection and Substantiation of the Method of Exploiting the Tebinbulak Deposit // IJARSET» International Journal of Advanced Research in Science, Engineering and Technology». - India, 2019. - Vol. 6, Issue 11, November. -Pp.11828-11833.
10. Akbarov T.G., Toshtemirov U.T., Nurkhanov Kh. Khojakulov A. Recommended Support Structures for Excavations in Difficult Mining and Geological Conditions // IJARSET. «International Journal of Advanced Research in Science, Engineering and Technology». - India, 2020. - Vol. 7, Issue 2, February. -Pp. 12798-12802.
11. Ilmuratov U.H Shamaev M.K., Toshtemirov U.T. Selection And Justification Of Methods For Opening The Southbay Field // IJARSET» International Journal of Advanced Research in Science, Engineering and Technology». - India, 2020. - Vol. 7, Issue 2, February. -Pp.12849-12853.
12. Toshtemirov U.T., Raimkulova S., Mahkamova Kh. Analysis of the stress state in the rock mass around the horizontal productions // Asian Journal of Multidimensional Research (AJMR). - India, 2020. - Vol. 9, Issue 11, November. -Pp. 245-251.