Histogram Method for Determining the Location of the Internal Dump in Coal Open Pits

With the deepening of open pit mining, the volume of worked out space increases and, along with it, the potential capacity for storing overburden. At the same time, the pits completely allocated for the internal dumps are used only by the end of the period of the open pit operation. The known theoretical approaches to determining the location of the internal dump are little implemented in the practice of surface mining, which is explained by two reasons. First, standard design solutions are based on wellknown theoretical provisions; secondly, a formalized template approach to substantiating certain design developments in the field of dumping of internal dumps prevails, which pushes them towards their fragmentary rather than integrated implementation. With regard to the conditions of the Kuzbass open-pit mines, the article proposes a modernized interpretation for the formation of structural schemes of the sequence of quarry fields on the basis of constructive-and-parametric studies of a multivariate adaptation of the internal dumping mode.

Experimental mining of three coal seams by transportless technology

In conditions of market economy and competition it is of great importance to reduce the cost of coal mining. It is especially important when mining coal at the complicated deposits of Kuzbass. In these conditions it is important to choose the technology of stripping and winning works, providing a minimum cost for them. There are two essential factors for achieving this goal: reduction of expenses on transportation of overburden and expenses connected with alienation of lands for external dumps and their reclamation. Therefore, promising technologies are those that ensure the placement of the maximum amount of overburden in the internal dump. This condition sets the task of expanding the scope and boundaries of application of transportless technology, which is used in Kuzbass both independently and in combination with transport technology. In particular, the combined technology is used at Chernigovets open pit mine, where the upper part of the quarry field, containing Kemerovsky seam, is mined using transport technology. The lower part up to 70 m high, which includes three flat seams: Volkovsky, Podvolkovsky I, Podvolkovsky II, on an experimental basis is mined by transportless technology (the volume of stripping works is 5-10 % of the total volume). A distinctive feature of the experiment is the performance of stripping and winning operations with a single dragline excavator, which eliminates the cost of maintaining the rope shovel and bulldozer. Therefore, the experience of using this technology is of practical interest for other open pits in the basin, as well as for any other quarries with similar mining and geological conditions.

Rational parameters of the transportless technological scheme for the development of strata with maximum permissible dip angle

In this article the rational value of overburden cut width and thickness of transportless overburden at mining of two dispersed flat seams IV-V and VI at Kureinsky section of Sibirginsky open pit mine are presented, which makes it possible to minimize the volume of rock re-excavation under the condition of the planned annual productivity of coal on the open pit and to ensure reduction of stripping costs. This task is complicated by the fact that the dip angle at the section is close to the limit on the condition of the possibility of spoiling of internal dump, and since the overburden rocks of the section are represented mainly by large-block sandstones on the clay cement and siltstones and their compressive strength is 60-80 MPa, then it is required to use a drilling and blasting method of their preparation for excavation. Under such conditions, optimizing the parameters of the transportless excavation scheme is of special importance for effective mining of the section.

Parameters of Transition from Deepening Longitudinal to Continuous Lateral Surface Mining Methods to Decrease Environmental Damage in Coal Clusters

The present paper deals with an original way to reduce the environmental damage caused to land and air resources by surface coal mines with external dumping, due to the transition to internal dumping with filling the worked out space of the surface mine with overburden. The basic principle of the proposed idea is the transition from the deepening longitudinal mining method for the development of inclined and steep coal seam strata to lateral ones. This article substantiates the choice of technology for a block-and-layer continuous lateral mining method, including the construction of a first-stage pit, the use of a combined transport and direct dumping technology for moving overburden to an internal dump when mining blocks using draglines. The advantage of the presented technology, along with filling the internal capacity of the surface mine field with overburden, is the possibility of leveling the relief within the boundaries of the pit allotment and the implementation of reclamation as the mining front moves forward, without waiting for the dump to be completely filled in the boundary contours. Attention is also paid to the economic benefits of block-layer technology and the continuous lateral mining method, in the transition to which the overburden transporting costs can be significantly reduced, while the limitations of the proposed method’s implementation concern specific coal deposits that make up a small part of the fields being developed today by surface mining.

Justification of multi-section clay storage parameters on the pit internal dump during the integrated use mining of placer deposits

Purpose is an establishment of efficient parameters of a multi-section man-made deposit at the pulp clays storage on the surface of internal pit dumps during the development of placer deposits. The analytical research method was used to establish the main parameters of man-made deposits sections depending on their width and depth. A graphical research method was used to establish the downtime duration between formation of the first and second sections of the man-made deposit. It is established that division of the man-made deposit into five sections parallel to the mining front reduces time period till start of its operation from 8 to 5 years for it thickness 10 m and from 7 to 5 years at thickness 20 m. However, a significant disadvantage is the increassd number of sections in the man-made deposit from 2 to 5 is an increase in the volume of construction work from 0.27 to 1.11 million m3 at thickness 10 m, and from 0.53 to 2.15 million m3 at thickness 20 m, which confirms the necessity to find an effective number of sections in the man-made deposit and their parameters. The dependence between beginning of the works on filling the man-made deposit and the width of its first section delays start of the filling works, but too small width causes downtime at transiting from the first section to the second one. Efficient width of the man-made deposit first section is established, in which downtime is reduced from 7 years to 5.8 years, and volume of raw materials located outside the pit is reduced by 0.1 - 0.5 million m3 depending on the width of the first section. A method is proposed for determining an effective width of the first section in a two-section man-caused deposit, in which occurs while filling the sections. It is established that effective width of the first section oin the two-section man-made deposit with thickness of 10 m and with parameters of a typical pit development at mining of titanium-zirconium deposit is 241 m.

Influence of the flooding speed of former lignite open pits on the stability of final slopes

Flooding the residual gaps of former lignite open pits is often applied worldwide, offering opportunities for the use of the lake and the reclaimed land, as well as many benefits, ranging from the restoration of ecosystems to the development of the local economy. The flooding process is conditioned by the available quantities of water from natural and/or artificial sources. Flooding can be done either by natural methods (underground water inflow plus intake of water from rainfall and superficial drainage), or by natural and artificial methods (water adductions from superficial collectors). Unlike artificial flooding, natural flooding has the advantage of reduced costs, but it is a long-lasting process. Depending on the flooding speed, as a result of rising water level and saturation of rocks from the final slopes, geotechnical phenomena such as landslides may occur. The paper aims at establishing the dependence between the rhythm of raising the water level in the lake and the geotechnical behavior of the rock in the internal dump. Depending on this, there is a need to accelerate the flooding process through adductions, as the hydrostatic pressure manifested on the final slopes determines the increase of their stability reserve.

Management and engineering solutions to improve stripping equipment efficiency in Chernogorksy open pit mine

Chernogosky open pit mine integrates truck-and-shovel system of mining with overburden rehandling to internal dump with a set of walking excavators for rehandling of overburden to mined-out area of the pit. It is possible to improve efficiency of stripping in the conditions of Chernogorsky OPM by reducing percentage of stripping with more expensive handling system. The relevant research and solutions to this effect are presented in this article. Comparative characterization of mining conditions and parameters of mining systems applied is given for open pit mines Chernogorsky, Turnui, Nazarovsky, Vostochno-Beisky and Izykh. The comparative analysis points at the need to account for difficulty of mining and process sites in comparison of equipment productivity. High concentration of mining machines, which is conditioned by narrow mining front and simultaneous operation of five faces, as well as blasting operation implemented every 1-2 days, are recognized as the main constraints of excavator capacity in mining with direct dumping in Chernogorsky open pit mine. The management and engineering solutions implemented in the mine and resulted in higher efficiency of draglines are described.