A transitional method for ore mining

Abstract

The present disclosure provides a transition method for ore mining, belonging to the technical field of mine mining. The transition method for ore mining includes the following steps: S1. Determine the upper wall rock movement angle, lower wall rock movement angle, and two end rock movement angles at different mining positions on the open-pit mine; S2. Determine the regional depth of the caving method mining area in each mining position; S3. Determine the transition method according to the actual situation of the open-pit mine; S4. Calculate the thickness of the interval ore pillar between the caving mining area and the filling mining area in a single mining position. The present invention makes full use of the existing conditions where the ground surface has been damaged. The upper caving method mining makes full use of the existing environment, realizing the characteristics of low cost and high efficiency, saving the early-stage infrastructure investment for the transition from open-pit to underground mining. The lower part adopts the filling method mining, which meets the requirements of mining policies. The waste rock mined from the underground is filled into the open-pit, saving the waste rock site and controlling the expansion of the rock movement range.

Description

Technical Field

[0001] The present disclosure relates to the technical field of mine exploitation, and particularly to a transition method for ore exploitation. Background Art

[0002] With the increase of the depth of open-pit mining, the production stripping ratio gradually increases, and the ore exploitation cost, transportation cost and the risk of high-steep slope landslide continuously increase. For the orebody resources outside the open-pit boundary, it should be planned to be converted to underground mining.

[0003] Currently, the commonly used open-pit to underground transition modes include the boundary pillar transition mode, the overburden transition mode and the wedge transition mode. Different transition modes have different applicable conditions and characteristics. For example, if caving method is selected for underground mining, the overburden transition method and the wedge transition method can be adopted to achieve a rapid transition from open-pit to underground; if filling method is selected for underground mining, generally the method of setting boundary pillars and artificial boundary crown pillars is chosen for transition. However, this transition mode is not conducive to the connection of production capacity, and filling mining requires advance planning and the simultaneous construction of a filling station, which not only increases the infrastructure investment and infrastructure time of the mine, but also is not conducive to the production capacity transition from open-pit to underground and the production operation of mining enterprises.

[0004] With the introduction of green mining and related policies, caving method is restricted in most regions, and filling method must be adopted. However, caving method has obvious advantages in terms of carbon emission index, mining cost and production efficiency. At the same time, large open-pits are formed by open-pit mining, causing damage to the surface. Therefore, a transition method that can meet the current policy requirements and quickly landfill and connect the open-pit is needed. Summary of the Invention

[0005] One technical problem to be solved by the present disclosure is: the existing transition modes cannot both meet the needs of environmental protection policies and quickly complete the mode conversion operation.

[0006] To solve the above technical problem, an embodiment of the present disclosure provides a transition method for ore exploitation, which includes the following steps:

[0007] S1. Determine the hanging wall rock movement angle, footwall rock movement angle and two end rock movement angles at different mining positions on the open-pit mine;

[0008] S2. Determine the regional depth of the caving method mining area at each mining position;

[0009] S3. Determine the transition method according to the actual situation of the open-pit mine;

[0010] S4. Calculate the thickness of the separating pillar between the caving mining area and the filling mining area at a single mining position;

[0011] Among them, the upper bench rock angle and the lower bench rock angle are located in the width direction of the open-pit mine, and the two end bench rock angles are located in the length direction of the open-pit mine.

[0012] In some embodiments, for the foregoing ore mining transition method, the calculation method of the regional depth in S2 includes the following steps:

[0013] S21. Determine the upper bench and the lower bench at different mining positions in the open-pit mine, and the two side benches of the open-pit mine;

[0014] S22. Take the positions of the upper bench and the lower bench as starting points, and respectively take the intersection points of the upper bench rock movement angle and the lower bench rock movement angle with the upper boundary and the lower boundary of the ore body as the upper mining point and the lower mining point, and obtain the two side mining points through the calculation method of the upper mining point and the lower mining point on the two side benches;

[0015] S23. Calculate the regional height of the caving method mining area at different mining positions in sequence;

[0016] S24. Compare the distances of each upper mining point, lower mining point and the two side mining points relative to the bottom of the open pit, and take the minimum distance as the regional depth of the caving method mining area.

[0017] In some embodiments, for the foregoing ore mining transition method, the positions of the upper bench, the lower bench and the two side benches in S21 all extend 5-10 m towards the center of the open-pit mine.

[0018] In some embodiments, for the foregoing ore mining transition method, the calculation method of the thickness of the barrier pillar in S4 includes the following steps:

[0019] S41. Take the gravity action of the caved or backfilled waste rock bulk after water absorption saturation in the open-pit mine as the upper load and establish a mechanical model;

[0020]

[0021] Among them, δ is the thickness of the barrier pillar;

[0022] W is the span length of the filling mining area, and the span length is the width size of the open-pit mine;

[0023] σper is the allowable tensile stress of the barrier pillar;

[0024] q is the load size on the barrier pillar;

[0025] γ is the bulk density of the ore and rock of the barrier pillar;

[0026] b is the unit calculation width of the barrier pillar, and its width is 1 m.

[0027] 5. A transition method for ore mining according to claim 4, characterized in that

[0028] The calculation method of σ allowance in S41 is as follows:

[0029]

[0030] Wherein, σ t is the tensile strength of the ore and rock in the interval ore pillar;

[0031] K is the safety factor, and the range is 1.5 - 3;

[0032] K c is the structural plane weakening coefficient, and the range is 7 - 10.

[0033] In some embodiments, for the aforementioned transition method for ore mining, the transition method in S3 includes the backfill cover layer method and the caving slope cover layer method.

[0034] In some embodiments, for the aforementioned transition method for ore mining, wherein

[0035] It further includes:

[0036] S5. Lift and transport the waste rock generated in the filling mining area to the open-pit mine to support the surrounding rock of the open-pit mine.

[0037] Through the above technical solutions, a transition method for ore mining provided by the present disclosure makes full use of the existing conditions where the ground surface has been damaged, determines the mining depth of the caving method at each mining position according to the rock movement angle of the slope and the ground surface. The upper caving method mining makes full use of the existing environment, achieving the characteristics of low cost and high efficiency, saving the pre-investment for the open-pit to underground infrastructure, and alleviating the pressure of production capacity connection from open-pit to underground; the lower part adopts the filling method for mining, meeting the requirements of mining policies; the waste rock mined from the underground is filled into the open-pit, saving the waste rock site and controlling the expansion of the ground surface movement range. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 It is a top view structural schematic diagram of an open-pit mine of a transition method for ore mining disclosed in an embodiment of the present disclosure;

[0040] Figure 2It is a schematic side view angle relationship diagram of an open-pit mine in a transition method for ore mining disclosed in an embodiment of the present disclosure;

[0041] Figure 3 It is a schematic position diagram of an intermediate pillar in a transition method for ore mining disclosed in an embodiment of the present disclosure.

[0042] Explanation of reference numerals:

[0043] 1. Open-pit mine; 2. Hanging-wall platform; 3. Side platform; 4. Hanging-wall boundary; 5. Footwall boundary; 6. Caving mining area; 7. Filling mining area; 8. Intermediate pillar; 9. Footwall platform. Detailed implementation manners

[0044] The following further describes in detail the implementation manners of the present disclosure with reference to the drawings and embodiments. The detailed description and drawings of the following embodiments are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms, not limited to the specific embodiments disclosed herein, but including all technical solutions falling within the scope of the claims.

[0045] The present disclosure provides these embodiments to make the present disclosure thorough and complete, and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that: unless otherwise specifically stated, the relative arrangements of components and steps, the components of materials, numerical expressions and values described in these embodiments should be construed as merely exemplary, rather than as limitations.

[0046] It should be noted that in the description of the present disclosure, unless otherwise stated, the meaning of "a plurality of" is greater than or equal to two; the orientation or positional relationships indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", etc. are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present disclosure. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0047] In addition, the "first", "second" and similar terms used in the present disclosure do not denote any order, quantity or importance, but are only used to distinguish different parts. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range. Terms such as "including" or "comprising" mean that the elements before the term cover the elements listed after the term, and do not exclude the possibility of also covering other elements.

[0048] It should also be noted that in the description of the present disclosure, unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances. When it is described that a specific device is located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0049] All terms used in the present disclosure have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as those, should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense, unless specifically defined as such herein.

[0050] Technologies, methods, and devices known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the specification.

[0051] Embodiment 1

[0052] This embodiment discloses a transition method for ore mining. The selected surrounding rock of an open-pit mine is moderately stable dense rock, the surface elevation is 0, the vertical average distance from the surface to the bottom of the open-pit is 135 m, the final slope angles of the upper and lower walls are 45°, as Figure 1 shown. The horizontal thickness of the ore body is 40 m, which is the width of the open-pit mine 1, and the strike length of the ore body is 960 m, which is the length of the open-pit mine 1. The bulk density of the ore is 32 kN·m -3 .

[0053] S1. Determine the upper-wall rock movement angle, lower-wall rock movement angle, and two-end rock movement angles at different mining positions on the open-pit mine 1. According to the table in the mining design manual, the upper-wall rock movement angle α, lower-wall rock movement angle β, and end rock movement angle ζ are determined to be 60°, 65°, and 75° respectively.

[0054] Table for determining the rock movement angle

[0055]

[0056] S2. Determine the regional depth of the caving mining area 6 among the various mining positions; determine the upper bench 2 and the lower bench 9 at different mining positions in the open-pit mine 1, as well as the two side benches 3 of the open-pit mine 1. Among them, the positions of the upper bench 2, the lower bench 9, and the two side benches 3 all extend 5 - 10 m towards the center of the open-pit mine 1, and this distance is used as the safety bench for backfilling or replenishing the overburden during the caving mining process; take the positions of the upper bench 2 and the lower bench 9 as the starting points, and respectively take the intersection points of the upper rock movement angle and the lower rock movement angle with the upper boundary 4 of the ore body and the lower boundary 5 of the ore body as the upper mining point and the lower mining point. Among them, calculate the regional height of each mining position, and obtain the two side mining points through the calculation methods of the upper mining point and the lower mining point for the two side benches 3; compare the distances of each upper mining point, lower mining point, and the two side mining points relative to the bottom of the open-pit, and take the minimum distance as the regional depth of the caving mining area 6, and finally take the final height of the caving mining as 50 m.

[0057] S3. Determine the transition method according to the actual situation of the open-pit mine 1;

[0058] Among them, the transition methods include the overburden backfilling method and the caving slope overburden method.

[0059] S4. Calculate the thickness of the partition pillar between the caving mining area and the filling mining area 7 in a single mining position; S41. Take the gravity action of the caved or backfilled waste rock loose body saturated with water in the open-pit mine 1 as the upper load, and establish a mechanical model;

[0060]

[0061] Among them, δ is the thickness of the partition pillar;

[0062] W is the span length of the filling mining area 7, and the span length is the width size of the open-pit mine 1;

[0063] σper is the allowable tensile stress of the partition pillar;

[0064] q is the load size on the partition pillar;

[0065] γ is the bulk density of the ore and rock of the partition pillar;

[0066] b is the unit calculation width of the partition pillar, and its width is 1 m.

[0067] The calculation method of σper in S41 is:

[0068]

[0069] Among them, σ t is the tensile strength of the ore and rock of the partition pillar 8;

[0070] K is the safety factor ranging from 1.5 to 3;

[0071] K c The weakening coefficient of the structural surface ranges from 7 to 10;

[0072] The span length W of the backfill mining area 7 is taken as the width of the open-pit ore body as 40m, and the ore rock bulk density γ is taken as 32kN·m -3 The load on the interval pillar 8 is the saturated force of the overburden layer and the waste rock from the slope collapse. The bulk density of the saturated overburden layer on the interval pillar 8 can be calculated by dividing the bulk density of the saturated rock sample by the loose coefficient of the rock to be 22 kN·m -3 According to the safety regulations for metal mines, the minimum cover thickness of the caving method is 40m. Based on this thickness, the load size q on the interval pillar 8 is about 0.88MPa, and the tensile strength of the ore rock is σ t Take 12.8MPa. Since the overlying saturated bulk body is affected by the friction of the slope, its entire gravity does not act completely on the isolation pillar. Therefore, the safety factor is taken as a minimum value of 1.5. According to the degree of joint development of the mine, Kc is taken as 8. Substituting the value into formula (2) to calculate σ Xu = 1066.7kPa, substituting the value into formula (1), it can be calculated that the thickness of the isolation pillar of the open-pit pit 1 is 24m. Therefore, when mining in this way, the ore with a thickness of 50m above the bottom of the open-pit pit 1 is mined by caving method, and the mining movement range is controlled within the boundary of the open-pit pit. A 24m thick interval pillar 8 is left at the bottom of the caving method, and the ore body below the interval pillar 8 is mined by filling method.

[0073] Specifically, it also includes: S5, lifting and transporting the waste rock generated in the filling mining area 7 to the open-pit mine 1 to support the surrounding rock of the open-pit mine 1. It can be understood that: the waste rock can be backfilled into the open-pit through a mobile belt conveyor to control the expansion of the scope of surface rock movement caused by underground mining.

[0074] According to the above, the present disclosure provides a transition method for ore mining. Through caving mining, backfill waste rock or collapsed slopes can be formed into a covering layer, and open-pit slopes and ramps can be used as open-pit to underground and temporary development transportation systems to form a rapid transfer transition of production capacity. During caving mining, the construction of the filling system and the development system can be saved, and sufficient time can be gained. In addition, the established fact that open-pit mining damages the surface is fully utilized. At the same time, the movement range of caving mining is within the open-pit boundary range. The upper caving mining fully utilizes the characteristics of low cost and high efficiency, saving the initial open-pit to underground infrastructure investment and alleviating the pressure of open-pit to underground capacity connection; the lower filling mining meets the requirements of mining policies; the waste rock mined from underground is filled into the open pit, saving waste rock sites and controlling the expansion of the rock movement range.

[0075] So far, the embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details well known in the art are not described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0076] Although some specific embodiments of the present disclosure have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified or equivalent substitutions can be made for some technical features without departing from the scope and spirit of the present disclosure. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way.

Claims

1. A transitional method for ore mining, characterized in that, It includes the following steps: S1. Determine the hanging-wall rock movement angle, foot-wall rock movement angle, and two end rock movement angles at different mining positions on the open-pit mine; S2. Determine the regional depth of the caving mining area at each mining position; Among them, the calculation method of the regional depth includes the following steps: S21. Determine the upper bench and lower bench at different mining positions in the open-pit mine, and the two side benches of the open-pit mine; S22. Use the positions of the upper bench and the lower bench as starting points, and respectively take the intersection points of the hanging-wall rock movement angle and the foot-wall rock movement angle with the upper boundary and lower boundary of the ore body as the upper mining point and the lower mining point, and obtain two side mining points through the calculation method of the upper mining point and the lower mining point with the two side benches; S23. Calculate the regional height of the caving mining area at different mining positions in turn; S24. Compare the distances of each upper mining point, the lower mining point, and the two side mining points relative to the bottom of the open-pit, and take the minimum distance as the regional depth of the caving mining area; S3. Determine the transition method according to the actual situation of the open-pit mine; S4. Calculate the thickness of the barrier pillar between the caving mining area and the filling mining area at a single mining position; Among them, the hanging-wall rock angle and the foot-wall rock angle are located in the width direction of the open-pit mine, and the two end rock angles are located in the length direction of the open-pit mine.

2. An ore mining transition method according to claim 1, characterized in that The positions of the upper bench, the lower bench, and the two side benches in S21 all extend 5-10 m towards the center of the open-pit mine.

3. An ore mining transition method according to claim 1, characterized in that The calculation method of the thickness of the barrier pillar in S4 includes the following steps: S41. Take the gravity action of the caved or backfilled waste rock loose body saturated with water in the open-pit mine as the upper load and establish a mechanical model; ； Where δ is the thickness of the barrier pillar; W is the span length of the filling mining area, and the span length is the width size of the open-pit mine; is the allowable tensile stress for the said rib pillar; q is the magnitude of the load on the said interval pillar; γ is the bulk density of the ore and rock of the barrier pillar; b is the unit calculation width of the barrier pillar, and its width is 1 m.

4. An ore mining transition method according to claim 3, characterized in that In S41 The calculation method is as follows: ； Among them, is the tensile strength of the ore and rock of the interval ore pillar; K is a safety factor with a range of 1.5-3; The weakening coefficient range of the structural plane is 7 - 10.

5. An ore mining transition method according to claim 1, characterized in that The transition method in S3 includes the backfill cover layer method and the caved slope cover layer method.

6. An ore mining transition method according to claim 1, characterized in that It further includes: S5. Lift and transport the waste rock generated in the filling mining area to the open-pit mine to support the surrounding rock of the open-pit mine.

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