RU2014454C1 - Method for heaping spoil-bank on undermined territory - Google Patents

Abstract

FIELD: mining industry. SUBSTANCE: method involves placing a layer of rock on undermined territory within boundaries of projected spoil-bank in the zone of expected or repeated development of strata displacement process. The height of said rock layer should be sufficient for stopping the development of displacement and caving processes on its surface. Said height is determined by a mathematical expression and the spoil-bank is heaped on said layer. EFFECT: higher efficiency. 4 dwg

Description

 The invention relates to mining, mainly to the joint development of iron deposits by open and underground mining systems with the collapse of the overlying rock strata and can be used to ensure the safety of landfill operations in the construction of a waste dump in the undermined area.

 The known method (1) dumping in the zone of influence of underground mining, including dumping of rocks in the area with an inactive development of the displacement process, where the underground mining of operational mineral reserves and the accompanying process of displacement and collapse of the rock mass stopped, and finally manifested on the surface topography In this process, the corresponding violations are: subsidence, cracks, funnels and dips. The disadvantage of this method is the limited application on the part of the mine, due to the fulfillment of the mandatory security requirements (1) prescribed by clauses 38, 39 of the mandatory conditions for maintaining safety during the production of dumping works. A prerequisite for the application of the method is the natural attenuation of the displacement process or the artificial elimination of existing voids. In the first case, the term for the start of use of the territory for dumping may be delayed, and in the second, additional costs are required for engineering activities to lay the worked out space or collapse the overlying strata.

 This drawback is eliminated in the method (2), in which an active displacement zone is used for storing waste rock, where underground mining of minerals is not stopped and there is a process of development of displacements and deformations of the overlying rock stratum.

 Dumping in a zone with active development of displacement, including visual and instrumental monitoring of the development of the displacement zone, a predictive assessment of the degree of danger of the developed area and dumping of rocks, is carried out from the working area of the dump-pioneer embankment constructed on a surface site located outside the collapse funnels in the zone of fixed smooth movements and minor cracks. To fill the rocks from the pioneer embankment into the crater of the collapse, suspension roads and special earth-moving machines are used, which allow performing the dumping operation at a distance from a safe place.

 The danger of the sudden formation of funnels in the underworked rock mass, especially while maintaining the voids and the need for special equipment, significantly limit and reduce the efficiency of dumping in the undermined area.

 The aim of the invention is to increase the safety and efficiency of landfill operations in the area of the expected active process of rock displacement.

, м, где m_эф - эффективная мощность условно отработанной залежи, м;
К_р.вт - вторичный коэффициент разрыхления пород, равный 1.10-1.15, после чего на указанные породы производят отсыпку отвала.This goal is achieved by the fact that in the proposed method, which includes dumping the blade onto the surface being mined by underground mining, in order to reduce the activity of the displacement process by self-winding up collapsed rocks before the underground mining starts, a layer of rock with a height determined from the expression is laid on the surface of the zone of the expected active displacement process
H =

, m, where m _eff is the effective power of a conventionally worked out deposit, m;
To _r.vt is the secondary coefficient of loosening of the rocks, equal to 1.10-1.15, after which the dump is dumped onto the indicated rocks.

 In Fig.1,2,3 shows sections along the strike of the exploited deposits of mineral deposits, showing open and underground mining; figure 4 shows a structural diagram of a model for calculating the required height of the safe base layer for the waste dump in the undermined area.

 As a result of underground excavation of geological deposits 1 of the exploited field, the development of the rock stratum 2 and its surface 3 occurs (see figure 1).

 Using the undermined territory 3 for storing waste rock, the dumping work within the design boundaries 4 of the constructed waste dump 5 is carried out taking into account the temporary and spatial position of the underground treatment work relative to the surface.

 It is assumed that in the developed territory 3 zones with a different degree of danger of the harmful effects of underground mining are distinguished. To the right of the geological axis VII, Figs. 1.2 and 3 show zone 6 with the inactive development of the rock displacement process, where the treatment works are stopped, and the displacement and collapse of the overlying rock 2 is in the attenuation stage. Zone 7 is shown to the left of the geological axis with the active development of the process of rock displacement caused by the ongoing development of reserves of deposits 1 of the exploited field.

 In the usual case, dumping of the waste dump 5 in the developed area 3 is carried out after mining of deposits 1 mainly in the zone with the inactive development of the process of moving rocks 6. In the zone with the active development of the process of moving rocks 7 it is allowed to fill the crash funnels that have come to the earth's surface from a safe place characterized by a lack of development capabilities.

 In this case, the basis of the constructed waste dump 5 is the earth's surface of the underworked rock mass 2.

 The stability state of the waste dump 5 being built on the undermined territory 3 and the safety of dumping operations can be seriously impaired by the development in the body of the dump itself of the processes of collapse 8 from voids 9, formed by secondary craters of collapse and failures (see figure 2).

 The formation of secondary craters of collapse and dips at the base of the rock dump 5 is due to the re-development of the processes of collapse 10.

 The reason for this is the appearance of new voids 11 in the underworked rock mass 2 from redistribution, filling the worked up spaces of the underlying horizons, as well as voids 12, the collapse of which was delayed.

 The described situation worsens the conditions of dumping and makes it impossible to carry out further work on dumping the waste dump, due to the threat of part-time work.

 Improving the safety and efficiency of dumping in the developed area using the proposed method is as follows.

 To eliminate the threat of underworking and ensuring the possibility of simultaneous work on dumping in areas with active and inactive development of the process of shifting rocks and funnel formation previously on the site of the developed territory 3, enclosed within the design boundaries 4 of the waste dump 5, fill the rock embankment with a height of 13, providing the amount of rock mass with a volume sufficient to fill the volumes of the voids of the collapse funnels formed at the base of the constructed waste dump 5. After the dump of the embankment 13 proceed to the construction of the dump 5 on the compensating base 13 (see figure 3).

 The safe height of the dumped embankment is determined by calculation using the formula obtained from the condition for comparing the volume of the conditional emptiness of the collapse funnels expected on the surface of the dumping site of the rock dump with the increased volume of the rock dump during secondary loosening as a result of the development of the displacement process in it. In this case, directly for the calculation of all the expected collapse funnels, a collapse funnel with a maximum formation depth is selected. You can also dump a rock embankment of variable height depending on the parameters of the funnels in each particular area.

 Figure 4 presents a diagram of a model for calculating the height of the safe foundation for the waste dump.

Let us determine the height of the safe base H, denoting the depth of the collapse funnel 9-h _b , the effective power (height) of the conditional void 14-m _eff , the height of the compensating rock layer 13 H _o.otv , taking as a basis the provision on the compensation of the resulting emptiness of the collapse funnel with the loosened rocks of the dumped rock layer 13 in the developed area 3.

From the ratio of the volumes of the funnel cone 9 and the equivalent cylinder 14, we find m _eff = 1/3 h _b . The depth of the funnel 15 is determined by the formula (2)
h _b = m - H _p (K _p - 1), m, (1) where m is the power of the worked out deposit, m;
H _{p is the} distance from the surface to the upper boundary of the worked out space, m;
K _p is the coefficient of loosening;
- depth of the collapse funnel, m.

 The condition of preserving the operational ability of the waste dump and the guarantee of safe conditions for dumping in the developed area should correspond to the surface condition of the foundation for the waste dump, when there are no damages that define the area of the crater collapse, dips, cracks with subsidence of the edges of more than 0.25 m.

Based on this, the condition for the safety of the surface of the base can be written as follows:
η = m _eff - H _o.otv (K _r.vt - 1) <0.25, m, (2) where η is the subsidence of the worked surface, m;
N _o.otv - the height of the rock layer, which serves as the basis for the rock dump, m;
To _r.vt - the secondary coefficient of loosening;
m _eff is the effective power of a conventionally worked out mineral deposit, taken equal to 1/3 of the maximum depth h _{b of the} collapse funnel, m;
0.25 - the allowable amount of deformation of the surface of the base of the blade, is used in practice, as a parameter that estimates the zone of smooth displacements in the trough of displacement, m

, м.From expression (2) we find the height of the safe base H
H = H _about. =

, m

Claims (1)

METHOD OF DUMP FORMATION IN THE PRODUCED TERRITORY, including dumping of the dump on the surface being mined by underground mining, characterized in that, in order to increase the safety of dumping operations in the area of the expected active process of displacement of rocks by reducing the activity of their displacement by self-winding of collapsed rocks, they are laid before underground mining on the surface of the zone of the active process of displacement, a rock layer of height H, determined from the expression
H =

,
where m _eff is the effective power of a conventionally worked out deposit, m;
K _r.vt = 1.10 - 1.15 - secondary coefficient of loosening of rocks,
after which dumping is performed on the indicated rocks.

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