A method for controlling the strength of cemented filling bodies in high-stage subsequent stopes

Abstract

The present invention provides a method for regulating the strength of a cemented filling body in a high-stage subsequent stope, wherein the filling structure is divided from bottom to top into a bottom layer (1), a lower layer (2), a regulating layer (3), an upper layer (4) and a top layer (5), and a cemented filling body is used for layered filling from bottom to top; the cemented filling body is a mixture of cementitious material and aggregate in a weight percentage of 1:4-12; the regulating layer (3) uses a cementitious material and aggregate in a ratio of 1:4-10, and the ratio of the height of the regulating layer to the height of the filling structure is 1-3:10. According to the strength requirements of the filling stope, the present invention layers and adds an intermediate regulating layer on the middle weak layer, thereby improving the stability of the first-step stope and the safety of the subsequent filling body during the high-stage subsequent stope mining process, reducing the loss and depletion of ore recovered from the second-step stope, reasonably improving the use rate of aggregates, reducing the proportion of cementitious materials and the filling cost, and realizing safe and efficient production of mines.

Description

Technical Field

[0001] The invention relates to the technical field of mining filling, and in particular to a method for regulating the strength of cemented filling bodies in a high-stage subsequent stope. Background Art

[0002] The mine goaf is backfilled with cemented tailings consisting of cementing materials, tailings, water and admixtures through automatic flow or pumping to the underground goaf or stope. Backfilling with cemented tailings not only eliminates the risk of collapse, but also handles a large amount of solid waste such as tailings. In order to save costs, most mines use layered filling mining, that is, filling the top and bottom layers with high-cementing ratio filling slurry, and the middle layer with low-cementing ratio filling slurry.

[0003] In the above backfilling method, since the strength of the middle layer of cemented tailings is low, and in actual mining, as the height of the mining area increases, the vertical exposure height of the mining pillars or cemented filling bodies in the high-stage mining area increases and even reaches 100m, and the lateral exposure area increases. During the two-step backfilling process, the production and ground pressure activities of the large-structure mining area will cause the filling body of the first step to break and fall off, threatening the safety and stability of the mining area.

[0004] At present, the middle layer of layered glued tailings backfill is still the most vulnerable area, and there are no more effective measures to improve the mechanical properties of the middle layer filling body. Summary of the invention

[0005] The purpose of the present invention is to solve the deficiencies of the prior art and provide a method for controlling the strength of cemented filling bodies in a high-stage subsequent mining area by layering on an intermediate weak layer and adding an intermediate control layer to optimize mine filling parameters and processes.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for controlling the strength of cemented filling bodies in a high-stage subsequent mining field, which divides the filling structure from bottom to top into a bottom layer, a lower layer, a regulating layer, an upper layer and a top layer, and uses a cemented filling body to fill the layers from bottom to top; the cemented filling body is a mixture of cementitious material and aggregate in a weight percentage of 1:4-12; the regulating layer uses a cementitious material and aggregate in a ratio of 1:4-10, and the ratio of the height of the regulating layer to the height of the filling structure is 1-3:10.

[0008] Furthermore, the bottom layer adopts a cementitious filling body with a ratio of cementitious material to aggregate of 1:4-8, and the ratio of the bottom layer height to the filling structure height is 1-2:10.

[0009] Furthermore, the lower layer and the upper layer respectively use cementitious filling bodies with a ratio of cementitious material to aggregate of 1:7-12, and the ratio of the height of the lower layer and the upper layer to the height of the filling structure is 1.5-3.5:10.

[0010] Furthermore, the top layer adopts a cementitious filling body with a ratio of cementitious material to aggregate of 1:4-8, and the ratio of the bottom layer height to the filling structure height is 1-2:10.

[0011] Furthermore, the aggregate includes one or more of tailings, coal gangue, crushed stones, etc.

[0012] Furthermore, the cementitious material includes cement and one or more of silica fume, fly ash, blast furnace slag, metakaolin and the like.

[0013] Beneficial effects of the present invention:

[0014] The present invention divides layers into layers and adds an intermediate regulating layer on the middle weak layer according to the strength requirement of the filling mine, optimizes the mine filling parameters and processes by the proportion of layer height of each layer and the proportion of aggregate and cementitious materials in each layer, replaces the method of directly increasing the ash-sand ratio of the middle layer, improves the stability of the first-step mine during the subsequent mining process of the high-stage mine and the safety of the subsequent filling body, reduces the loss and depletion of ore recovered from the second-step mine, reasonably increases the utilization rate of aggregates, reduces the proportion of cementitious materials and the filling cost, and realizes safe and efficient production of mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram comparing an original filling structure and a filling structure using the control method of the present invention;

[0016] Among them, 1-bottom layer, 2-lower layer, 3-regulating layer, 4-upper layer, 5-top layer, and 6-middle layer. DETAILED DESCRIPTION

[0017] The content of the present invention is further described below in conjunction with the accompanying drawings and embodiments. Example 1

[0018] A method for regulating the strength of cemented filling bodies in a high-stage subsequent mining field, which divides the filling structure from bottom to top into a bottom layer 1, a lower layer 2, a regulating layer 3, an upper layer 4 and a top layer 5, and uses a cemented filling body to fill the layers from bottom to top; the cemented filling body is a cementitious material of ordinary silicate cement and an aggregate of mine tailings, which is prefabricated by a ground filling station and transported to an underground mine room to be filled by a pipeline for use.

[0019] The bottom layer 1 is used as the top column when the next middle top layer is mined. In order to ensure the safety of the roof when the next middle top layer is mined and increase the strength of the filling body, the ratio of cementitious material to aggregate is 1:4, and the height ratio is 2:10;

[0020] The lower layer 2 needs to meet the safety requirements during upper mining, and the ratio of cementitious material to aggregate is 1:11, and the height ratio is 2.5:10.

[0021] The regulating layer 3 is used to regulate the mechanical properties of the layered cementitious filling body, and the ratio of cementitious material to aggregate is 1:8, and the height ratio is 1:10;

[0022] The upper layer 4 needs to meet the safety requirements during upper mining, and the ratio of cementitious material to aggregate is 1:11, and the height ratio is 2.5:10;

[0023] The top layer 5 is used as the last mining area to support the upper area. To ensure safety and increase the strength of the filling body, the ratio of cementitious material to aggregate is 1:4, and the height ratio is 2:10; Example 2

[0024] A method for regulating the strength of cemented filling bodies in a high-stage subsequent mining field, which divides the filling structure from bottom to top into a bottom layer 1, a lower layer 2, a regulating layer 3, an upper layer 4 and a top layer 5, and uses a cemented filling body to fill the layers from bottom to top; the cemented filling body is a cementitious material of ordinary silicate cement and an aggregate of mine tailings, which is prefabricated by a ground filling station and transported to an underground mine room to be filled by a pipeline for use.

[0025] The bottom layer 1 is used as the top column when the next middle top layer is mined. In order to ensure the safety of the roof when the next middle top layer is mined and increase the strength of the filling body, the ratio of cementitious material to aggregate is 1:4, and the height ratio is 2:10;

[0026] The lower layer 2 needs to meet the safety requirements during upper mining, and the ratio of cementitious material to aggregate is 1:11, and the height ratio is 2:10.

[0027] The regulating layer 3 is used to regulate the mechanical properties of the layered cementitious filling body, and the ratio of cementitious material to aggregate is 1:8, and the height ratio is 2:10;

[0028] The upper layer 4 needs to meet the safety requirements during upper mining, and the ratio of cementitious material to aggregate is 1:11, and the height ratio is 2:10;

[0029] The top layer 5 is used as the last mining area to support the upper area. To ensure safety and increase the strength of the filling body, the ratio of cementitious material to aggregate is 1:4, and the height ratio is 2:10; Example 3

[0030] A method for regulating the strength of cemented filling bodies in a high-stage subsequent mining field, which divides the filling structure from bottom to top into a bottom layer 1, a lower layer 2, a regulating layer 3, an upper layer 4 and a top layer 5, and uses a cemented filling body to fill the layers from bottom to top; the cemented filling body is a cementitious material of ordinary silicate cement and an aggregate of mine tailings, which is prefabricated by a ground filling station and transported to an underground mine room to be filled by a pipeline for use.

[0031] The bottom layer 1 is used as the top column when the next middle top layer is mined. In order to ensure the safety of the roof when the next middle top layer is mined and increase the strength of the filling body, the ratio of cementitious material to aggregate is 1:4, and the height ratio is 2:10;

[0032] The lower layer 2 needs to meet the safety requirements during upper mining, and the ratio of cementitious material to aggregate is 1:11, and the height ratio is 2:10.

[0033] The regulating layer 3 is used to regulate the mechanical properties of the layered cementitious filling body, and the ratio of cementitious material to aggregate is 1:10, and the height ratio is 2:10;

[0034] The upper layer 4 needs to meet the safety requirements during upper mining, and the ratio of cementitious material to aggregate is 1:10, and the height ratio is 2:10;

[0035] The top layer 5 is used as the last mining area to support the upper area. To ensure safety and increase the strength of the filling body, the ratio of cementitious material to aggregate is 1:4, and the height ratio is 2:10;

[0036] Comparative Example 1: Filling method of the original filling structure of the prior art

[0037] A method for controlling the strength of cemented filling bodies in a high-stage subsequent mining field, wherein the filling structures are respectively a bottom layer 1, a middle layer 6 and a top layer 5, and the filling is performed in layers from bottom to top; the cemented filling body is a cementitious material of ordinary silicate cement and an aggregate of mine tailings, which is prefabricated by a ground filling station and transported to an underground mine room to be filled by a pipeline for use.

[0038] The bottom layer 1 is used as the top column when the next middle top layer is mined. In order to ensure the safety of the roof when the next middle top layer is mined and increase the strength of the filling body, the ratio of cementitious material to aggregate is 1:4, and the height ratio is 2:10;

[0039] The middle layer 6 only needs to meet the safety of the top layer 5 during mining, and the ratio of cementitious material to aggregate is 1:8, and the height ratio is 6:10;

[0040] The top layer 5 is used as the last mining area to support the upper area. To ensure safety and increase the strength of the filling body, the ratio of cementitious material to aggregate is 1:4 and the height ratio is 2:10.

[0041] Comparative Example 2: Filling method of the original filling structure of the prior art

[0042] A method for controlling the strength of cemented filling bodies in a high-stage subsequent mining field, wherein the filling structures are respectively a bottom layer 1, a middle layer 6 and a top layer 5, and the filling is performed in layers from bottom to top; the cemented filling body is a cementitious material of ordinary silicate cement and an aggregate of mine tailings, which is prefabricated by a ground filling station and transported to an underground mine room to be filled by a pipeline for use.

[0043] The bottom layer 1 is used as the top column when the next middle top layer is mined. In order to ensure the safety of the roof when the next middle top layer is mined and increase the strength of the filling body, the ratio of cementitious material to aggregate is 1:4, and the height ratio is 2:10;

[0044] The middle layer 6 only needs to meet the safety of the top layer 5 during mining, and the ratio of cementitious material to aggregate is 1:10, and the height ratio is 6:10;

[0045] The top layer 5 is used as the last mining area to support the upper area. To ensure safety and increase the strength of the filling body, the ratio of cementitious material to aggregate is 1:4 and the height ratio is 2:10.

[0046] According to the cementing filling body parameter settings in Examples 1 to 3 and Comparative Examples 1 to 2, cementing filling body specimens were prepared. The cementing material, aggregate and water were mixed in a mixer and fully mixed for more than 5 minutes. After mixing evenly, the fresh slurry was cast into an acrylic glass cylindrical mold with a height of 100 mm and a diameter of 50 mm, and the fresh slurry was vibrated with a vibration table to eliminate bubbles. The prepared cementing filling body specimens were placed in a curing box with a temperature of 20°C ± 2°C and a relative humidity of 95% ± 5%, and the cementing filling body was tested at 3, 7, and 28 days, respectively. The results are shown in Table 1.

[0047] Table 1 Test results of cemented filling specimens in Examples 1-3 and Comparative Examples 1-2 at 3, 7 and 28 days

[0048]

[0049] It can be seen from Table 1 that the compressive strength of the cemented filling body prepared in Example 1 is similar to that of the cemented filling body prepared in Comparative Example 2 at 3, 7, and 28 days, indicating that the same compressive effect can be achieved by changing the structure of the cemented filling body. The compressive strength of the cemented filling body prepared in Example 3 is improved compared with that of the cemented filling body prepared in Comparative Example 2 at 3, 7, and 28 days, indicating that the addition of the regulating layer can improve the compressive strength of the cemented filling body. The compressive strength of the cemented filling body prepared in Example 2 is improved compared with that of the cemented filling body prepared in Example 1 at 3, 7, and 28 days, indicating that increasing the height of the regulation can improve the compressive strength of the cemented filling body. The compressive strength of the cemented filling body prepared in Example 3 is improved compared with that of the cemented filling body prepared in Comparative Example 1 at 3, 7, and 28 days, indicating that the proportion of the cemented filling body containing the regulating layer is better, which can reduce the cost while the compressive strength is higher than that of the cemented filling body with an overall increase in the ash-sand ratio of the intermediate layer.

[0050] During the filling process of various areas underground, the filling material ratio, that is, the ratio of cementitious materials to aggregates, can be adjusted according to the actual strength requirements of the filling body in each area, and the filling structure of the cemented filling body can be adjusted, that is, the layer ratio can be adjusted, the aggregate consumption ratio can be increased, and the amount of cementitious materials used can be reduced. All ratios are not limited to the above ratios. According to the actual strength requirements, strength calculations are carried out to design the filling body structure and ratios.

[0051] Unless otherwise specified, the percentages described herein are percentages by weight.

[0052] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made within the scope of the present invention still fall within the scope of the present invention.

Claims

1. A method for controlling the strength of cemented filling bodies in a high-stage subsequent stope, characterized in that: The filling structure is divided into a bottom layer (1), a lower layer (2), a regulating layer (3), an upper layer (4) and a top layer (5) from bottom to top, and a cemented filling body is used to fill the filling layer by layer from bottom to top; The height ratio of the bottom layer (1) is 2:10, and it is used as the top column when the next middle top layer is mined, and is filled with a cementitious filling body with a ratio of cementitious material to aggregate of 1:4; The height ratio of the lower layer (2) is 2.5:

10. In order to ensure the safety of the upper part during mining, a cementitious filling body with a ratio of cementitious material to aggregate of 1:11 is used; The height ratio of the regulating layer (3) is 1:10, which is used to regulate the mechanical properties of the layered cementitious filling body, and the cementitious filling body is filled with a ratio of cementitious material to aggregate of 1:8; The height ratio of the upper layer (4) is 2.5:

10. To ensure the safety of the upper part during mining, a cementitious filling body with a ratio of cementitious material to aggregate of 1:11 is used; The height ratio of the top layer (5) is 2:10, and it is used as the upper area of ​​the support of the final mining area, and is filled with a cementitious filling body with a ratio of cementitious material to aggregate of 1:

4.

2. A method for controlling the strength of cemented filling bodies in a high-stage subsequent stope according to claim 1, characterized in that : The aggregate includes one or more of tailings, coal gangue, and crushed stones.

3. A method for controlling the strength of cemented filling bodies in a high-stage subsequent stope according to claim 1, characterized in that The cementitious material includes cement and one or more of silica fume, fly ash, blast furnace slag and metakaolin.

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