УДК 622.271

Conducting research to improve the parameters of drilling and blasting operations in the appointment of underground mining operations on the conditions of the Nurkazgan deposit

Кариполла Авдол – магистрант кафедры Разработки месторождений полезных ископаемых Карагандинского технического университета имени Абылкаса Сагинова (Республика Казахстан).

Абай Ырысбек Асылбекұлы – магистрант кафедры Разработки месторождений полезных ископаемых Карагандинского технического университета имени Абылкаса Сагинова (Республика Казахстан).

Abstract: To date, one of the reported problems of mining is the destruction of the rock mass. The efficiency of rock destruction, the efficiency of the entire mining industry and the further possibilities of the entire industry using the results of the work of mining enterprises. At high horizons of workings, increased requirements are imposed on drilling and blasting operations in terms of the necessary collapse of the rock after the explosion and its high-quality crushing, high stability of workings and their completion in accordance with the project, as well as economic indicators. First of all - cost reduction for blasting. It is possible to ensure the fulfillment of the specified requirements by calculating the optimal calculations of the parameters of drilling and blasting, preliminary results of the specified separations and the quality of crushing of the rock mass during penetration. The following source materials were used in the research work.

Аннотация: На сегодняшний день одной из известных проблем горного дела является разрушение массива горных пород. Эффективность разрушения горных пород, эффективность всей горнодобывающей промышленности и дальнейшие возможности всей отрасли по использованию результатов работы горнодобывающих предприятий. На высоких горизонтах выработок предъявляются повышенные требования к буровзрывным работам с точки зрения необходимого обрушения породы после взрыва и ее качественного дробления, высокой устойчивости выработок и их завершения в соответствии с проектом, а также экономических показателей. Прежде всего - снижение затрат на дробеструйную обработку. Обеспечить выполнение указанных требований можно путем расчета оптимальных параметров буровзрывных работ, предварительных результатов указанных сепараций и качества дробления горной массы при проходке. В исследовательской работе были использованы следующие исходные материалы.

Introduction

The birthplace of Nurkazgan is located in the Bukhar-Zhyrau district of the Karaganda region at a distance of about 50 km north of the city of Karaganda and about 8.5 km north of the city of Temirtau. The Nurkazgan mine, which develops the Western section of the deposit, is administratively part of the Production Association "Karagandatsvetmet" Mining and production complex of the LLP branch Kazakhmys Corporation.

The Astana-Karaganda railway line runs 6 km northeast of the field. At a distance of 2.5 km to the north-west of the site, the Temirtau-Aktau highway with asphalt concrete pavement passes.

The industry of the region is well developed. In the city of Temirtau, enterprises of metallurgy of the ferrous industry, chemical industry cover the territory in the republic, in the settlement of Aktau, located 7.0 km from the north-eastern deposit, there is a cement plant.An overview of the occurrence of the Nurkazgan field is shown in Figure 1.

1

Figure 1. The Nurkazgan field.

The climate of the region is sharply continental with long cold winters, stable snow cover and hot summers. Sharp observations of sunny days, and yearly. the maximum value of extreme temperature indicators is 80°С (from 38°С in June to minus 42°С in January). The average annual air temperature is 2.3°C; average monthly air temperatures in January - from minus 14.2 to 16.9°C, in January - from 17.5 to 20.5°C.

The warm period with an average monthly temperature of zero lasts 200-220 days, frost-free days are higher than 112-130 per year.

The average is the annual rainfall of 250-300 mm. The largest number of changes occurs in summer, but at the same time, precipitation is vegetative and has a shower character. This precipitation is mainly used for evaporation.

The average long-term duration with a stable snow cover is 130-150 days, the snow cover disappears at the end of March, the average duration of snowmelt is 15 days. Snow accumulation proceeds gradually, reaching a maximum by the end of winter (February-March). The average long-term snow cover height is 20-30 cm.

Field observations of compliance with the parameters of drilling and blasting operations during clearing and tunneling operations

At the Nurkazgan field, the excavation of mine workings is carried out automatically using a Sandvik drilling rig. The working is drilled to a depth of 2.7 m, the diameter of the crown is 40.0 mm.

The following types of explosives are used in the construction of mine workings: ammonite 6ZhV (cartridge diameter 32 mm), petrogen (cartridge diameter 34 mm), DSHE-12, ED-3-N, NSV and UISh-5. Of these, I spent ammonite 6ZhV and petrogen containing patronized explosives.

The quality of the explosion is evaluated by the following indicators: the coefficient of use of holes (CUH), the coefficient of excess section (CES), the granulometric composition of the blasted rock and the dispersion of the rock along the working.

According to the results of field observations of the state of underground mine workings of the horizon +44.0 m (block No. 1 scraper ort No. 4, loading No. 2 scraper ort No. 2, horizon +60.0 block No. 8 chamber No. 3) of the Nurkazgan mine, it should be distinguished a number of the following problems associated with drilling and blasting:

  1. The actual CUH is lower than the design one, which significantly affects the bottomhole advances per cycle. The depth of the glasses in tunneling faces is 0.3-0.6 m with a hole depth of 2.7 m.

The value of CUH depends on the physical and mechanical properties of the rocks, the depth of the holes, the specific consumption of explosives, the cross section of the mine working, the type of cut, the layout of the holes, the location of initiation, the type and length of the stemming, and other factors.

The degree of influence of these factors on the value of CUH depends on the specific conditions for the construction of a mine working, as well as the interaction of these factors in the overall complex of drilling and blasting.

Under certain conditions, the following influence of individual factors on the value of CUH was established:

  • an increase in the diameter of the explosive cartridges usually leads to an increase in the value of the CUH by 6-8%, which is explained by the concentration of the explosion energy in the hole;
  • with an increase in the strength of the rocks, the value of the CUH decreases.

The layout and depth of the cutting holes are important, providing a second exposed surface, which increases the value of the CUH.

In the general case, in order to increase the value of CUH, it is necessary to optimize the consumption of explosives and the depth of holes, use an increased diameter of explosive cartridges, correctly select the type and depth of the cut, as well as the layout of holes, in accordance with geological conditions. The optimal value of these parameters is selected depending on the technical and geological conditions for the construction of a mine working by conducting a series of experimental explosions.

  1. The actual value of the CES exceeds the normative, that is, the rock selection is 15-20% of the design section in the rough.

The main reasons for sorting out the breed:

  • incorrect location of the contouring holes, which go beyond the design contour of the working;
  • laying a charge of a large mass or high power in the contouring holes;
  • location of the zone of disturbed, unstable rock, which collapses after the explosion, into the working (in this case, the contouring holes must be located at a distance of 0.3-0.5 m from the design contour).

The main measure to reduce "brute force" is the use of contour blasting. In conventional rock blasting, in order to reduce “overkill”, it is necessary to correctly position contouring holes with a reduced charge value.

  1. The spread of blasted rock along the length of the working has a significant impact on all types of tunneling operations. A heap of rock breakage at the face improves loading performance and reduces the likelihood of damage to lining and communications. Reducing the spread of rock is achieved by using prismatic cuts.
  2. The output of substandard pieces of rock mass (oversized) during the cleaning operations

References

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