Vol 52 Iss. 1

When designing and planning quarry operations, the parameters of mining systems are usually based on annual production limits, which naturally depend on the quarry's productivity, initial position and the size of the front on the benches. The consequence of annual production limits is annual limits and volumes of overburden. Lack or excess of the front of mining works, dispersion of equipment and transport communications on many benches, periodic stops of the front on one of the sides or a group of benches and concentration of the majority of mining excavators on one or two benches with a small length of blocks - complicate the work of transport at the quarry and along with other organizational and technological reasons are the result of insufficient justification of the parameters of systems within adjacent benches of the deposit.

The article considers variants of stripping opening and development systems with longitudinal preparation of the mining front in conditions of achieving the highest productivity of the open pit Aₚ. The calculations are based on the length of deposits Lₚ, their horizontal thickness t, the length lₑ and the number of blocks nb on the ledge, the annual productivity of the excavator Ab

The most common way of determining the boundaries of open pit operations is to determine whether the contour stripping ratio is equal to the economically acceptable one, which is found by comparing open pit and underground mining. However, in the case of significant overburden thickness, this methodology can lead to incorrect conclusions, since the boundaries determined according to this method do not take into account the volume of capital stripping required to put the open pit into operation, which depends on the overburden thickness ...

The labor costs of the main and auxiliary mining processes depend on the number of excavators on the ledge, which determines the length of the blocks and the intensity of the front movement. By the length of the block is meant the length of the front of work per excavator, which provides independent and productive operation of mining transportation equipment. The length of the block is determined by the conditions of rational technology of adjacent production processes - loosening, loading and transportation - in accordance with the “Standard projects of development systems and transportation at quarries." When designing the length of the block is taken according to practice, norms or standard projects ...

When developing deposits by the open-pit method, the parameters of the panels are usually determined by the productivity of the quarry, the conditions of occurrence, the equipment used, the technology of excavation and transportation works, the qualitative composition of the mineral, the water content of the deposit and the method of draining it, the depth of frost and other factors ...

High trenching speeds are necessary to reduce construction time and increase the production capacity of open pits. During normal operation, the speed of trenching depends on the intensity of mining, the length of the mining front, the direction of front movement in relation to the occurrence of the ore body, the height and number of mining benches that are in simultaneous mining, the width of working benches and other factors and can be determined by the formula ...

The Kingisepp phosphate rock deposit is a horizontal stratum-shaped deposit with an average thickness of 2.5 meters and is characterized by significant water cut (in 1964, the average water inflow was 150 m3/h). Due to the pit's high ore output, the strip of exposed reserves exceeds 200 meters. During the winter months, the phosphorite bed freezes and its mining is associated with drilling and blasting operations. It is well known that the depth of freezing of rocks depends largely on their moisture content. The groundwater level can be reduced by a number of measures using the excavator available at the quarry ...

When designing a quarry with a given annual productivity of a mineral, the question arises of determining the amount of waste rock removed annually. Since the volume of waste rock is generally much greater than the amount of mined minerals, proper planning of stripping operations by year of development is extremely important. The solution of this issue affects the scale of the mining enterprise and the size of its industrial base, which in turn determines the efficiency of capital investment in the national economy ...

In the process of quarry operation, landslides and collapses of the sides and benches often lead to a violation of the mode of operation of the quarry and require significant funds and time for their elimination. With special technology of overburden rock development, cave-ins can acquire a qualitatively different character and be used to increase the efficiency of open pit operations. The possibility of using caving as a method of overburden development has been repeatedly mentioned in the literature. The experience of hydromechanized development shows that the use of caving as a method of development of mineral deposits composed of weak rocks is promising.

Variability of geological structure, hydrogeological conditions and physical and mechanical properties of rocks is characteristic of open-pit mine fields of many mineral deposits. Often the thickness of the rocks to be excavated also varies significantly. All this leads to variability of rock stability conditions in the slopes of mine workings in one open-pit field. In such cases, based on the analysis of natural conditions to justify the design solutions of open-pit mining, it is advisable to subdivide (zone) the quarry field into areas with similar engineering and geological conditions that determine a unified approach to the design and organization of mining operations. Let's consider such zoning in connection with the assessment of rock stability using the example of quarry fields of the Tikhvin mining district ...

The question of artificial strengthening of rock slopes is becoming more and more urgent, both in hydraulic engineering and road construction, and in open-pit mining - to strengthen unstable areas of the sides of the limiting contour of quarries. The expediency of strengthening the unstable section is determined by the need to maintain the continuity and the specified width of the transport berms and cleaning berms, as well as the side profile adopted in the development project during the entire life of the excavation ...

In the Tikhvin mining district in the open-pit mining method in the sides of the quarries are exposed mainly sandy and clayey rocks of the Carboniferous and overlying Quaternary boulder loams. In a number of quarries of the region, landslides of the sides and rock ledges are observed, and less frequently their slides. During snowmelt or as a result of precipitation, the Quaternary rocks are overmoistened, and their bearing capacity is sharply reduced. Decrease in bearing capacity of boulder loams adversely affects the working conditions of walking excavators: their maneuverability decreases, the base of the excavator often sinks into the ground up to 0.4–0.5 m, sometimes the bearing capacity of the over-moistened soil is insufficient and excavators without additional measures (sand and gravel-pebble cushions, scaffolding under the timber, etc.) cannot work at all ....

At Apatit mines, as a rule, the upper part of ore deposits is exposed at the day surface. During the underground development of blocks of upper horizons, self-collapse of the massif, freezing of the beaten ore, and scattering by explosion are often observed. This leads to large losses of ore ...

Coal loading at many large open-pit coal mines is carried out by excavators directly into the rolling stock of the Ministry of Railways (for example, at Irsha-Borodinsky, Irtyshsky, etc.). The conditions of management of mining operations at these mines differ from those existing at open-pit mines when using their own rolling stock. In the latter case, transportation ensures the operation of excavators. Reducing the turnover time of trains leads to an increase in the productivity of the open pit. Therefore, the shift productivity of the quarry depends on the quality of dispatch control of excavation and transportation processes and can serve as one of the indicators to assess the operational management ...

Operational management (OM) deals with issues that require immediate intervention in the course of the technological process. In open-pit mining operations it is necessary to manage a single technological process of excavation and transportation of rock mass. OM is part of the overall management process of mining enterprises and ensures the operation of the enterprise for a period of time no longer than a shift or a day. OM tasks differ sharply from the planning or design tasks by the small time interval during which it is necessary to make a decision. So, if solving the problems of OM takes at least 1 min, then for a large quarry (for example, Magnitogorsk) it is equivalent to the loss of one working week a year. This difference results in special requirements for OM methods and technical means for their realization. Therefore, it is advisable to separate the issues of OM into a special section of the management of mining enterprises ...

Mechanical drilling of boreholes in granite quarries of the Karelian Isthmus due to high strength and abrasiveness of rocks is an expensive and insufficiently productive method. To determine the possibility of application at granite quarries of fire drilling of boreholes by the department of open pit and drilling and blasting works of the Leningrad Mining Institute, the drillability of granites of several deposits of the Leningrad area (Rovnoe, Erkil, Vozrozhdeniya and Kamennogorsky) was investigated. The studies were carried out with the use of small-scale jet burners (RGR-2, RTB-V5, MIRGEM), operating on oxygen-kerosene and benzine-air mixtures. Their technical characteristics are as follows ...

Quarries of Pervomayskiy and Aleksandrovskiy stone-crushing plants develop granites with a coefficient of strength on the scale of M. M. Protodyakonov 12-14 and volumetric weight 2,6-2,7 t/m3. The complex structure of granites and their poor explosiveness essentially influence technical and economic indicators of drilling and blasting works ...

Theoretical characteristics of workability of explosives are: specific energy F and specific potential energy ...

The rocks of the oil shale formation of the Baltic basin, of which the Estonian deposit is a part, are characterized by three features that complicate both the determination of physical and mechanical properties of rocks and the study of the process of destruction of the massif by the action of explosion: 1) oil shale is not an isotropic body, but finely layered media; 2) the high clay content and porosity of both oil shale and some limestone interlayers make them highly plastic; 3) the presence of moisture and limestone inclusions in oil shale layers makes it necessary to regard oil shale as a multicomponent medium...

It is known that in the near zone of the explosion, a significant part of the energy of the explosive charge is spent. Determination and calculation of energy expenditure in this zone are important because they make it possible to control the action of the explosion. In this paper, two methods of determining the energy expenditure are considered - calorimetric and computational-experimental. The calorimetric method considered here, in contrast to the existing ones, is developed for rocks and makes it possible to determine the energy expenditure for the formation of the free surface and to estimate the energy expenditure in the near zone (plastic deformation zone). The computational-experimental method is based on the determination of shock compressibility of rocks and requires the use of relatively complex equipment, either a high-speed photoregister to determine the speed of propagation of the shock wave, or piezometric sensors and cathode oscilloscopes to measure high pressures ...

During the explosion of borehole charges in underground workings at the initial moment of the explosion (before the beginning of rock detachment) the explosion products and the stemming from the borehole are ejected. The main reason for the formation of shock air waves is expanding gaseous products of the explosion. In the initial stage of expansion of the products of the explosion, the wave front has the shape of a hemisphere, somewhat distorted toward the axis of the borehole due to the axial dispersion of the products of the explosion and the stemming. In the subsequent stages, as the wave front interacts with the walls of the excavation, a plane wave is formed. Its intensity is determined by the energy that the expanding products of the explosion impart to the air.