A blasting method for hanging roof treatment in underground mines

Abstract

The present application provides a kind of blasting method for underground mine overhang processing, comprising the following steps: step one: after the overhang is generated by blasting, the relevant parameters of overhang layer are obtained;Step two: according to the relevant parameters of overhang layer obtained, the relevant information of subsequent normal blast hole which needs to be layered is determined, and the relevant information of the blast hole which needs to be layered includes the number of layers and the layering position of the blast hole which needs to be layered;Step three: based on the relevant information of the blast hole which needs to be layered determined, the blast hole which needs to be layered is charged;Step four: after charging, set the initiation sequence, and perform layered millisecond initiation from the first row to the second row, from the lower layer to the upper layer in the rear of overhang.The present application gradually expands the overhang cavity and reduces the thickness of overhang layer by layered millisecond blasting of subsequent normal blast hole.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of mining, and particularly relates to a blasting method for processing a suspended roof in an underground mine. BACKGROUND

[0002] In a mine adopting a sublevel caving method without a pillar, a suspended roof phenomenon is prone to occur in the production process. This phenomenon is usually caused by the fact that a fan-shaped deep hole cannot effectively break the top to form a solid roof with a certain thickness, resulting in that the upper and lower sublevels cannot be connected, and a barrier is formed at the top of the sublevel and an empty space is formed at the lower part. If the suspended roof is not processed in time, it will cause the production to be interrupted, and if the processing effect is not good, it will also increase the ore loss rate.

[0003] At present, the main technical means for processing the suspended roof in the domestic mine include the following methods. For example, for the suspended roof that has occurred, no remedial measures and methods are taken, and a natural caving method is used to let it naturally caving. This method has no premonition and is not controlled by human beings. Although the cost is low, it lacks safety (Gold, 2010, 31(2): 31-33; Mining Research and Development, 1989(4): 54-57). In the case that the ore is relatively empty in the lower part of the suspended roof area and the size of the suspended roof is not large, a balloon with drug processing can be used. This method is limited by the amount of drugs, and has poor reliability (Mining Engineering, 2008, 6(4): 29-31). In the case that the suspended roof and the design height of the blast hole are not much different, a method of directly using a bamboo to bind a drug package to directly perform blasting processing is also used. This method is simple and direct, but has poor safety (Mining Technology, 2018, 18(1): 6-8). There are also mines that take a method of processing the suspended roof which is technically complex and efficient and safe. For example, the Dading Mountain mine area uses a lateral inclined hole to process the suspended roof, and good results are obtained, but there are disadvantages such as more large blocks after processing the suspended roof, and high requirements for construction precision (Metal Mine, 2013(1): 33-37; Metal Mine, 2015, 11: 20-22). There is also a chamber method for processing a large suspended roof. Although the success rate is high, this method has a long cycle, many procedures, and affects normal production (Mining Research and Development, 2016, 36(3): 64-67).

[0004] In view of this, there is still room for further improvement in how to process the suspended roof. SUMMARY

[0005] In order to overcome the defects and limitations in the prior art, the present application proposes a method of using a fan-shaped blast hole to process the suspended roof in an underground mine.

[0006] Based on the above purpose, the present application adopts the following technical scheme:

[0007] A blasting method for processing a suspended roof in an underground mine, comprising the following steps:

[0008] Step one: obtaining the related parameters of the hanging roof layer after the hanging roof is generated by blasting;

[0009] Step two: determining the related information of the blast hole which needs to be layered according to the obtained related parameters of the hanging roof layer, the related information of the blast hole which needs to be layered including the layering number and layering position of the blast hole which needs to be layered;

[0010] Step three: layering the blast hole which needs to be layered based on the determined related information of the blast hole which needs to be layered;

[0011] Step four: setting the detonation sequence after the layering is completed, and performing the layering millisecond detonation in the order of the first row to the second row and the lower layer to the upper layer from the rear of the hanging roof.

[0012] According to one embodiment of the present application, the related parameters of the hanging roof layer include the hanging roof layer height and the hanging roof layer thickness.

[0013] According to one embodiment of the present application, the step one includes: after the hanging roof is generated by blasting, scanning the hanging roof cavity by using a three-dimensional laser scanner to generate a three-dimensional model of the hanging roof cavity; and based on the position relationship between the generated three-dimensional model of the hanging roof cavity and the subsequent normal blast hole, obtaining the hanging roof layer height and the hanging roof layer thickness.

[0014] According to one embodiment of the present application, the step two includes: determining the layering number of the blast hole which needs to be layered according to the hanging roof layer thickness.

[0015] According to one embodiment of the present application, the layering number of the blast hole is determined according to the thickness of each layer being 4-5 m.

[0016] According to one embodiment of the present application, in each layer, the blast hole charging length is 3 m, and the tamping length is 1-2 m.

[0017] According to one embodiment of the present application, one detonating cartridge is placed at the upper end and the lower end of each blast hole in each layer, and the tamping is performed by using tamping clay.

[0018] According to one embodiment of the present application, the step two includes: determining the layering position of the blast hole which needs to be layered according to the hanging roof layer height.

[0019] According to one embodiment of the present application, in the step three, the blast hole which needs to be layered is layering charged in the two rows of blast holes behind the hanging roof.

[0020] According to one embodiment of the present application, in the step four, the millisecond time is set to 300 ms to 500 ms.

[0021] By using the above technical solution, the present application has at least the following beneficial effects:

[0022] In the present application, the overhang is treated by layered blasting, and the subsequent normal blast hole is layered and millisecond blasted to gradually expand the overhang empty area and reduce the thickness of the overhang layer. The method of the present application does not need to drill new blast holes for treating the overhang in underground mines, and fully utilizes the existing blast holes for layered blasting, increases the height of the overhang empty area and reduces the thickness of the overhang layer by layered blasting, and the upper and lower segments are connected through one or two treatments, and the overhang is eliminated. The method of the present application is simple, the operating personnel are safer during the treatment process, the cost is low, the treatment effect is good, the layered blasting technology is applied to the overhang treatment practice, the overhang treatment time and cost are greatly reduced, the ore loss caused by the overhang is reduced, and the achievement has important popularization and application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The layered schematic diagram of the blast hole involved in the method according to the present application is shown in the figure.

[0024] Figure 2 The I-I sectional view of Figure 1 .

[0025] Figure 3 The position relationship between the overhang empty area three-dimensional model and the subsequent normal blast hole is shown in the figure. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present application clearer and more apparent, the embodiments of the present application are further described in detail below with reference to the drawings.

[0027] The present application provides a blasting method for treating overhang in underground mines, comprising the following steps:

[0028] Step one: after the blasting produces the overhang, the related parameters of the overhang layer are obtained; step two: according to the obtained related parameters of the overhang layer, the related information of the blast hole which needs to be layered in the subsequent normal blast hole is determined, the related information of the blast hole which needs to be layered includes the number of layers and the layering position of the blast hole which needs to be layered; step three: based on the determined related information of the blast hole which needs to be layered, the blast hole which needs to be layered is charged; step four: after the charging is completed, the initiation sequence is set, and the layered millisecond initiation is carried out from the first row to the second row, from the lower layer to the upper layer behind the overhang.

[0029] In the above scheme of the present application, the obtained related parameters of the overhang layer at least include the overhang layer height and the overhang layer thickness. The overhang layer height refers to the vertical distance between the lower end face of the overhang and the ground surface of the roadway, that is, the height of the overhang empty area, for example, Figure 2 G in the figure. The overhang layer thickness refers to the vertical distance between the lower end face of the overhang layer and the upper end face of the overhang layer, for example, Figure 2 H in the figure.

[0030] In a preferred embodiment, the parameters of the overhang layer are obtained by the following method: after the overhang is generated by blasting, a three-dimensional laser scanner is used to scan the overhang empty area to generate a three-dimensional model of the overhang empty area; based on the position relationship between the generated three-dimensional model of the overhang empty area and the subsequent normal blast hole, the height and thickness of the overhang layer are obtained. Figure 3 The position relationship between the three-dimensional model of the overhang empty area and the subsequent normal blast hole is schematically shown. In another preferred embodiment, the height of the overhang layer is directly obtained by a range finder, and then the thickness of the overhang layer can be derived based on the difference between the depth of the blast hole and the height of the overhang layer. It can be understood that the present application is not limited thereto, and the parameters of the overhang layer can be obtained using methods commonly used in the art.

[0031] In the above scheme of the present application, the "subsequent normal blast hole" refers to one or more rows of blast holes that have not been blasted and belong to the same roadway as the row of blast holes that generated the overhang in the current blasting and are located immediately behind the row of blast holes that generated the overhang in the current blasting (based on the mining sequence). In a preferred embodiment, each row of blast holes is arranged radially in a cross section perpendicular to the extension direction of the roadway, also known as fan-shaped blast holes, as shown in Figure 1 and 3 . After the current row of blast holes is blasted to generate an overhang, the one or more rows of blast holes adjacent to the row of blast holes are subjected to layered blasting, which can avoid or reduce the continuous generation of overhangs in subsequent blast holes due to the limitation of free surface. One row of blast holes adjacent to the row of blast holes can be subjected to layered blasting at a time, or two to three rows of blast holes adjacent to the row of blast holes can be subjected to layered blasting at a time. As shown in Figure 2 , after the front row of blast holes is blasted to generate an overhang, the first and second rows of blast holes adjacent to the overhang blast hole are subjected to layered blasting.

[0032] In the above scheme of the present application, the relevant information of the blast holes that need to be layered in the subsequent normal blast holes according to the obtained parameters of the overhang layer includes: the number of layers of the blast holes that need to be layered is determined according to the thickness of the overhang layer. The "number of layers" referred to in the present application refers to the number of layers into which the blast hole will be divided. The number of layers of the blast hole is determined according to the thickness of each layer, which is 4-5 m. For example, if the thickness of the overhang layer is 10-12 m, the number of layers of the blast hole can be determined to be 2-3. Within each layer, the blast hole is divided into a charging section and a stemming section. In a preferred embodiment, the charging length of the blast hole is 3 m, and the stemming length is 1-2 m. One detonating cartridge is placed at the upper end and the lower end of each layer, and the stemming is filled with stemming. Two to three layers can be set for one blasting, and the upper layer detonation should fully consider the time of falling ore after the lower layer blasting, and the VCR blasting method theory is used, and the lower layer blasting provides a free surface for the upper layer blasting, finally achieving the effect of expanding the overhang empty area and reducing the thickness of the overhang layer. In Figure 1 and Figure 2In the shown embodiment, the number of layers of the borehole corresponding to the area of the hanging roof entity is 2, i.e. two layers, the lower layer is referred to as the first layer, and the upper layer is referred to as the second layer.

[0033] In the above scheme of the present application, the information about the borehole needing layering according to the obtained parameters of the hanging roof layer includes: determining the layering position of the borehole needing layering according to the height of the hanging roof layer. The "layering position" mentioned in the present application refers to the position from which the borehole starts to be layered, and no layering is set below the position. The layering position is usually selected to be at the height of the hanging roof layer, i.e. the area below the height of the hanging roof layer is not layered and initiated, and the area above the height of the hanging roof layer is layered and initiated.

[0034] In the preferred embodiment of the present application, the millisecond initiation time in step four is set to 300ms to 500ms. That is, the interval time between the two millisecond initiations of the layered borehole is 300ms to 500ms. Figure 2 In the shown embodiment, the initiation sequence is: the section corresponding to the hanging roof empty area of the first row of boreholes (i.e. the first response in the figure), the section corresponding to the first layer of the first row of boreholes (i.e. the second response in the figure), the section corresponding to the second layer of the first row of boreholes (i.e. the third response in the figure), then the section corresponding to the hanging roof empty area of the second row of boreholes (i.e. the fourth response in the figure), the section corresponding to the first layer of the second row of boreholes (i.e. the fifth response in the figure), and finally the section corresponding to the second layer of the first row of boreholes (i.e. the sixth response in the figure).

[0035] In the preferred embodiment of the present application, before the layering blasting construction (i.e. before step three), the borehole for layering needs to be measured to ensure that the depth and angle of the layering blasting borehole meet the requirements.

[0036] The above scheme of the present application can be applied to the situation of blasting in sublevel caving mining method without bottom pillar to produce a hanging roof.

[0037] The current several suspended roof processing methods are summarized as follows: (1) Bamboo pole binding medicine bag processing: the processing method is simple, the cost is low, if the suspended roof is high, the operation is difficult, if the suspended roof is thick, the effect is poor due to less medicine quantity of one blasting, at the same time, the processing personnel need to operate under the suspended roof layer empty field, the empty field has the possibility of falling rock or collapse at any time, the safety risk is great. (2) Lateral inclined hole processing: this method is to drill holes in the adjacent roadway of the suspended roof, and then drill holes from the adjacent roadway to the suspended roof area, and then charge and blast the holes in the suspended roof part in the adjacent roadway. This method is relatively safe in construction, but new holes need to be drilled, since the holes are drilled in the adjacent roadway, the hole depth is generally longer, the depth is generally more than 30 meters, the precision requirement is high, the holes are easy to cross and perforate, the hole forming rate is low, at least 15-20 new holes need to be drilled for processing one suspended roof, and the processing time usually needs 2 days. In addition, if the adjacent roadway is mined in advance of the suspended roof roadway, this method cannot be implemented, and other methods need to be used. Compared with the above methods, the method used in the present application has the following characteristics: ① low cost: compared with the supplementary hole blasting method, the suspended roof layer blasting method does not need to drill new holes, and can save more than 500 meters of new holes for processing and blasting the suspended roof once, saving 32,000 yuan of cost, the main work of the suspended roof layer blasting method is to charge, pack and sequentially perform micro-difference blasting through the fan-shaped holes; the layer blasting can charge 2 rows of holes at a time, the thickness of one layer is 4-5m, the whole processing process does not need to drill new holes, does not increase additional explosives, and the processing cost is low. ② Small impact on production: the layer blasting processing of the suspended roof does not need to drill new holes, only needs to use the original fan-shaped deep hole for layer charging construction, which has little difference with normal charging construction, the single construction time is 2 hours, and the impact on production is small. ③ Safe construction: the layer blasting processing of the suspended roof only needs to charge according to the normal blasting operation requirements, the intersection of the roadway and the suspended roof empty area can be closed by a small amount of slag, the operation is not affected by the suspended roof empty area, and the construction is safe.

[0038] Example 1

[0039] A blasting method for hanging roof treatment of underground mine, comprising: ① after the blasting produces the hanging roof, the three-dimensional laser scanner is used to accurately scan the hanging roof empty area; ② the three-dimensional entity model is generated through the point cloud data obtained by scanning, and the three-dimensional entity model is consistent with the position and size of the actual hanging roof; ③ the specific values of the hanging roof layer height and the hanging roof layer thickness are calculated through the original fan-shaped medium-length hole and the three-dimensional entity model; ④ after the depth and angle of the two rows of fan-shaped blast holes behind the hanging roof area are re-measured, the layer thickness is determined in combination with the three-dimensional model of the hanging roof, the layer thickness is usually 4-5 m, the charging length of the blast hole in the layer is 3 m, and the filling length is 1-2 m; ⑤ the blast hole is charged in the conventional charging mode by using the BQF-200 charger or the charging trolley, one detonating explosive package is placed at the upper end and the lower end of each layer, the filling is carried out by using the stemming, and the filling length is 2 m; the stemming should be tamped to prevent the detonating explosive package from separating from the explosive column; ⑥ each layer is charged and constructed in the same way in the order from top to bottom; ⑦ after the charging is completed, the detonation sequence is set, the differential detonation is carried out in the order from the first row to the second row, from the lower layer to the upper layer from the rear of the hanging roof, and the differential time is set to 300 ms to 500 ms; ⑧ after the layer blasting, the ore removal operation is carried out, the treatment effect is verified, and when the hanging roof appears again, the treatment is carried out again according to the above steps.

[0040] The above is the exemplary embodiment disclosed by the present application, and the sequence of the above-mentioned embodiments disclosed by the present application is only for description, not representing the advantages and disadvantages of the embodiments. However, it should be noted that the discussion of any of the above embodiments is only exemplary, and is not intended to imply that the scope of the embodiments disclosed by the present application (including claims) is limited to these examples, and various changes and modifications can be made without departing from the scope defined by the claims. The functions, steps and / or acts of the method claims described herein do not need to be performed in any specific order. In addition, although the elements disclosed by the embodiments of the present application can be described or claimed in singular form, they can also be understood as plural unless explicitly limited to singular.

[0041] It should be understood by those of ordinary skill in the art that the discussion of any of the above embodiments is only exemplary, and is not intended to imply that the scope of the embodiments disclosed by the present application (including claims) is limited to these examples; under the idea of the embodiments of the present application, the technical features of the above embodiments or different embodiments can also be combined, and there are many other changes of different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the embodiments of the present application shall be included in the protection scope of the embodiments of the present application.

Claims

1. A blasting method for hanging- roof treatment in an underground mine, characterized in that, The method comprises the following steps: Step one: obtaining the parameters of the hanging roof layer after the blasting, the parameters of the hanging roof layer including the height of the hanging roof layer and the thickness of the hanging roof layer; Step two: determining the information of the blast holes which need to be layered in the subsequent normal blast holes according to the obtained parameters of the hanging roof layer, the information of the blast holes which need to be layered including the number of layers and the layering position of the blast holes which need to be layered, wherein the subsequent normal blast holes are the blast holes which belong to the same roadway as the row of blast holes where the hanging roof is generated and are located immediately behind the row of blast holes where the hanging roof is generated, the number of layers of the blast holes which need to be layered is determined according to the thickness of the hanging roof layer, and the layering position of the blast holes which need to be layered is determined according to the height of the hanging roof layer; Step three: charging the blast holes which need to be layered based on the determined information of the blast holes which need to be layered; Step four: setting the detonation sequence after the charging is completed, and performing layered millisecond detonation from the first row to the second row and from the lower layer to the upper layer behind the hanging roof.

2. A blasting method for the benching of an underground mine according to claim 1, characterised in that, The step one comprises: scanning the hanging roof cavity by using a three-dimensional laser scanner to generate a three-dimensional model of the hanging roof cavity after the blasting generates the hanging roof; and obtaining the height of the hanging roof layer and the thickness of the hanging roof layer based on the position relationship between the generated three-dimensional model of the hanging roof cavity and the subsequent normal blast holes.

3. A blasting method for the benching of an underground mine according to claim 1, characterised in that, The number of layers of the blast holes is determined according to the thickness of each layer being 4-5 m.

4. A blasting method for the benching of an underground mine according to claim 3, characterised in that, The charging length of the blast holes in each layer is 3 m, and the tamping length is 1-2 m.

5. A blasting method for the benching of an underground mine according to claim 1, characterised in that, One detonating cartridge is placed at the upper end and the lower end of each blast hole in each layer, and the tamping is performed by using clay.

6. A blasting method for the benching of an underground mine according to claim 1, characterised in that, In the step three, the blast holes behind the hanging roof are layered and charged.

7. A blasting method for the benching of an underground mine according to claim 1, characterised in that, In the step four, the millisecond time is set to 300 ms to 500 ms.

Images