CN104948190A - Method for caving top surrounding rock to form covering layer recovery stud - Google Patents

Abstract

The invention discloses a method for recovering intercolumns from the covering layer formed by collapsing surrounding rocks at the top. In the method, the middle section is divided into 3-4 layers. Firstly, the intercolumns and the top surrounding rocks of the uppermost layer are blasted at one time by differential blasting. Caving, so that it forms a covering layer on the layer immediately below it, under the covering layer, the caving method is used to recover the inter-pillars of other layers, and at the same time, the ore and the bottom structure of the caving under the covering layers on both sides of the inter-pillar are recovered. ore for recycling. The invention combines ore pillar recovery and goaf treatment and puts it in a complete system, which is suitable for mining when the inclined medium-thick ore body has thicker and large rock mass at the top and the open-field mining method is adopted. It is the first mine to mine the middle column, and the ore block has no top column and the bottom structure is complete. The invention can not only reduce the dilution rate of ore pillar recovery, but also effectively treat the goaf, eliminate the safety hazards caused by the excessively large exposed area of the goaf, and realize the upper and lower coordination between the surrounding rock on the top of the collapse and the recovered ore pillar .

Description

The method of recovering the intercolumn by forming the overburden on the top of the collapsed surrounding rock

technical field

The invention belongs to the technical field of mining, and in particular relates to a method for recovering an intercolumn from an overburden by collapsing surrounding rocks at the top.

Background technique

  Apply the open-field method for mining, divide the ore block into mine rooms and ore pillars, return to the mining room first, and then recover the ore pillars. When returning to the mining room, the stope exists in the form of an open space, and the stability of the open field is maintained by relying on the strength of the ore pillar and the surrounding rock itself. After mining in the mine house, it is necessary to recover the ore pillars and deal with the goaf in time. Under normal circumstances, recovering the pillars alone will increase the exposed area of the goaf, thereby increasing potential safety hazards; while processing the goafs separately will cause the ore to be mixed with the filling material filling the goaf when the pillars are recovered, increasing the ore dilution.

Contents of the invention

The purpose of the present invention is to solve the technical problems existing in the separate operation of ore pillar recovery and goaf treatment in the prior art, and to provide a method that combines ore pillar recovery and goaf treatment to realize collapsed top surrounding rock and recovery of ore pillars. A method of coordinating upper and lower caving top surrounding rocks to form an overburden recovery column.

In order to achieve the above object, the present invention adopts the following technical solutions: a method for caving top surrounding rock to form an overburden recovery column, the method comprising the following steps:

A. Layering: In order to ensure that the interstitial columns can be recovered safely under the covering layer, the middle section is divided into 3-4 layers with a height of 10-15m.

B. Estimate the volume of the space on both sides of the intercolumn: In order to make the scattered objects produced by the one-time blasting of the intercolumn on the uppermost layer and the surrounding rock on the top have sufficient space for scattering and form a covering layer of a certain thickness, the intercolumn Check the occurrence of empty areas on both sides, and estimate the volume of empty areas.

C. Calculation of the amount of overburden: a reasonable overburden thickness is the premise to ensure the safe recovery of intercolumns. The overburden thickness is determined according to the characteristics of ore drawing under the cover of caving rocks and the requirements of the open field method for the thickness of the safety buffer cushion. According to the determination The thickness of the overburden layer and the natural repose angle of the caving loose body are used as the accumulation slope line, the area of the overburden layer loose body is calculated, and then multiplied by the thickness of the inter-column to obtain the required amount of overburden layer loose body.

D. Determine the blasting area of the top surrounding rock: according to the required amount of overburden, combined with the drillability of the mine rock and the drilling depth of the medium and deep hole drilling rig, draw a circle with the rock drilling center as the center, and draw a circle with the boundary line of the mine rock. The enclosed range is used as the top surrounding rock blasting area.

E. Engineering layout: excavate rock-drilling roadways in the uppermost layer of the inter-column and the top surrounding rock, and excavate the cutting level roadway perpendicular to the rock-drilling roadway in the uppermost layer of the inter-column to connect with the goaf on both sides. The uppermost layer of the intercolumn and the middle of the top surrounding rock are excavated for the ventilation pedestrian patio, and vertical fan-shaped medium-deep holes are respectively arranged in the cutting level roadway, the uppermost layer of the intercolumn and the top surrounding rock drilling roadway. The characteristics of the project layout are as follows: One is that there are ventilated pedestrian patios inside and outside the vein, which ensures that there are two safety exits during the recovery process; the other is that the cutting of the surrounding rock on the top and the engineering for the formation of blasting compensation space are omitted.

F. Divide the blasting area and determine the blasting method: the uppermost layer of the inter-column is the first blasting area, and the rest of the partitions are divided according to the principle of "first lower the wall, then the upper wall and then the top". In the blasting area, the goaf on both sides of the inter-column is used as the free surface for blasting, and the other partitions in the inter-column are blasted with the cutting level entry and goaf as the free surface, and the space formed by the blasting of the top surrounding rock and the lower inter-column is the free surface. Blast face down. This zoning method omits the engineering done by the top surrounding rock to form the blasting compensation space, and has good flexibility.

G. Recovery of the lower intercolumn: The top layer of the intercolumn and the top surrounding rock are blasted to form a covering layer. Under the overburden layer, the layered caving method is used to recover the uppermost layer and the lower intercolumn layer by layer. From the upper wall to the lower wall, the entire section is recovered in a backward manner, and the ore is discharged from the upper layer to the lower layer in sequence according to the ore-breaking step, and from the upper wall to the lower wall, and each ore-breaking step is blasted After the completion, when the ore is drawn to the cut-off grade, it will be transferred to the next step to recover, so as to ensure that each step and each layer can recover as much ore resources as possible. Since the recovery of the intercolumn at the lower part of the uppermost layer is carried out under the ore overburden, it can effectively reduce the depletion of the ore.

H. Recover the ore and bottom structure that have collapsed under the covering layers on both sides of the intercolumn: After the uppermost layer of the intercolumn and the surrounding rock on the top have collapsed at one time, part of the ore in the intercolumn has collapsed to the bottom of the mines on both sides, using the caving method Recover the part of the ore and the bottom structure of the mine.

Further, the area of the scattered particles in the covering layer is smaller than the blasting area of the top surrounding rock, so that the amount of scattered particles avalanched by blasting is greater than the required amount of scattered particles in the covering layer, forming a covering layer with a safe thickness.

Further, the thickness of the covering layer in the step C is 14.5-15.5m.

Further, the YGZ90 type drilling rig is used for the construction of medium and deep hole blastholes in the step E, and the medium and deep hole blasting parameters are: when the unit explosive consumption and the blasthole density coefficient are constant, the minimum resistance line W is proportional to the aperture d , W=(25-40)d, the hole-bottom distance of the fan-shaped hole a=(1.1-1.5)W, where the blasting parameters in the surrounding rock at the top take a large value, take a small value in the cutting groove, and take the middle column for normal row value.

Further, during the blasting in the step F, a network of multiple detonating cord transmission and millisecond nonel detonator detonation is used.

Further, in the step F, the uppermost layer of the top surrounding rock and the inter-pillar is blasted once, and different differential blasts are used for different positions.

Further, in the surrounding rock of the top, differential blasting between rows of inner holes is adopted: multiple rows of blastholes with the same number and same section, and the sections in the blastholes on both sides of the fan shape increase sequentially upward.

Further, in the uppermost layer of the inter-column, differential blasting between rows of inner holes is adopted: multiple rows of blastholes of the same number and the same section, and the sections of blastholes in the direction away from the cutting groove increase in turn.

Further, in the uppermost layered cutting entry of the inter-column, differential blasting between rows of inner holes is adopted: multiple rows of blastholes of the same number are in the same section, and the sections of blastholes away from the empty areas on both sides increase in turn.

Compared with the prior art, the present invention has the following beneficial effects: the present invention aims at the shortcomings of the existing single operation of mine pillar recovery and goaf treatment in the prior art, and combines mine practice, and proposes a method of collapsing top surrounding rocks to form overburden recovery inter-pillars method, this method divides the middle section into 3-4 layers, firstly, the intercolumns and the top surrounding rock of the upper layer are collapsed at one time by differential blasting, so that a covering layer is formed on the layer immediately below it, and the The caving method is used under the overburden to recover other layered interpillars, and at the same time, the ores that have collapsed under the overburden on both sides of the interpillars and the ores at the bottom structure are recovered. The present invention combines ore pillar recovery and goaf treatment into a complete system, and adopts the form of double patios (ventilated pedestrian patios) and single cutting slots (cutting slots are formed by the uppermost layer of the intercolumns) in the engineering layout , ensuring two safety exits during the recovery process, omitting the cutting of the top surrounding rock and the engineering for the formation of the blasting compensation space, realizing the synergy between the space column recovery and the treatment of the empty area, and laying a foundation for the overburden The recovery of the inner column in the middle section of the first mining provides a new method. The present invention is mainly applicable to the ore bodies with inclined medium thickness or above, thicker large rock mass at the top, and the open-pit mining method is used to recover the intercolumn in the middle section of the first mining, and the ore block has no top column and the bottom structure is complete. . The invention can not only reduce the dilution rate of ore pillar recovery, but also effectively treat the goaf, eliminate the safety hazards caused by the excessively large exposed area of the goaf, and realize the upper and lower coordination between the surrounding rock on the top of the collapse and the recovered ore pillar .

Description of drawings

Fig. 1 is the schematic diagram of intercolumn recovery method of the present invention;

Fig. 2 is a schematic diagram of the project layout of the uppermost layer inter-columns of the present invention;

Fig. 3 is a schematic diagram of the top surrounding rock engineering layout of the present invention;

Fig. 4 is a schematic diagram of blasting in the present invention.

The meanings of the reference signs of the present invention are as follows: 1, intercolumn; 2, overburden scattered body area; 3, rock drilling center; 4, ore boundary line; 5, top surrounding rock blasting area; 6, rock drilling roadway; 7, cutting Level alley; 8, first layer; 9, second layer; 10, third layer; 11, accumulation slope line; 12, ventilation pedestrian patio; L, thickness of covering layer; b, natural repose angle.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Example:

The method for recovering the intercolumn of the covering layer formed by the collapsed top surrounding rock of the present invention is applied to the recovery of the No. 1 intercolumn in the middle section of the first mining of a certain lead-zinc mine. According to the ore block parameters of the segmented rock drilling stage open-field method adopted by the mine, the length of the ore block is 60m, the height is 50m in the middle section, the width is 42m in thickness of the ore body, the width of the inter-pillar is 15m, and the height of the bottom structure is 12m. The specific implementation is as follows:

1. Layering: As shown in Figure 1, in order to ensure that the intercolumn 1 can be recovered safely under the overburden layer, the middle section of the first mining is divided into three layers, namely the first layer 8, the second layer 9 and the second layer Three layers 10.

2. Estimate the volume of the empty area on both sides of the inter-column: In order to make the scattered objects produced by the one-time blasting of the inter-column and top surrounding rock of the third layer 10 have sufficient space for scattering and form a covering layer of a certain thickness, the Check the occurrence of the voids on both sides of the inter-column 1. The volume of the voids that can be formed after the mining of the stope is 86170m ³ , and the volume of the voids that can be formed on both sides of the inter-columns is 172340 m ³ .

3. Calculation of overburden bulk: A reasonable overburden thickness is the premise to ensure the safe recovery of intercolumns. According to the characteristics of ore drawing under the cover of caving rocks and the requirements of the open field method for the thickness of the safety buffer cushion and combined with the actual situation of the mine, determine this The thickness L of the covering layer when the secondary column 1 is recovered is 15m. As shown in Figure 1, the accumulation slope line 11 is made according to the determined thickness L of the covering layer and the natural repose angle b of the caving mass, where L is 15m and b is 39.5 °, use the area surrounded by the accumulation slope line 11 and the first layer 8 and the unrecovered inter-columns below the third layer 10 to calculate the area of the scattered body area 2 of the overburden layer, and then multiply it by the thickness of the inter-column 1 to obtain the required The bulk volume of the covering layer is 57318m ³ .

4. Determine the blasting area of the top surrounding rock: according to the required amount of overburden and the formation of a safe thickness of overburden, the amount of debris in the blasting caving should be greater than the required overburden volume of 57318m ³ , that is, the top surrounding rock blasting The area of area 5 should be larger than the area of area 2 of the overburden bulk, combined with the drillability of mine rocks and the rock drilling depth of medium and deep hole drilling rigs, as shown in Figure 1, draw a circle with the rock drilling center 3 as the center, and draw a circle with the ore rock boundary The range surrounded by 4 is used as the top surrounding rock blasting area 5. After estimation, after one-time blasting and avalanche of the top surrounding rock blasting area 5 and the inter-column of the third layer, the amount of loose matter in the avalanche is 66910m ³ , which is larger than the required amount of covering layer, and can form a covering layer of sufficient safety thickness. , to create favorable conditions for the recovery of the studs of the second layer 9 and the first layer 8.

5. Engineering layout: as shown in Figure 2 and Figure 3, the rock drilling roadway 6 is respectively excavated in the intercolumn and top surrounding rock of the third layer 10, to the boundary of the ore body hanging wall and the blasted surrounding rock and the lower intercolumn At the boundary corresponding to the boundary of the hanging wall, excavate the cutting level entry 7 perpendicular to the rock drilling roadway 6 in the intercolumn of the third layer 10, and penetrate the goaf on both sides. The ventilated pedestrian patio 12 is excavated in the middle of the top surrounding rock, and vertical fan-shaped medium-deep holes are respectively arranged in the cutting level entry 7, the inter-columns of the third layer 10, and the top surrounding rock rock-drilling roadway 6, and the medium-deep hole blasthole construction adopts YGZ90 type drilling rig, the medium and deep hole blasting parameters are: when the unit explosive consumption and the blast hole density coefficient are constant, the minimum resistance line W is proportional to the hole diameter d, W=(25-40)d, the bottom distance of the fan hole a = (1.1-1.5) W, when the ore is hard, the coefficient takes a small value, otherwise it takes a large value. According to the above calculation formula and following the principle of "small resistance line and large hole-to-bottom distance", the blasting parameters in the surrounding rock on the top take the large value, take the small value in the cutting groove, and take the middle value for the normal row of the inter-column.

6. Divide the blasting area and determine the blasting method: the 12-15m cutting level aisle 7 in the intercolumn of the third layer 10 is the first blasting area, and the remaining partitions are divided according to the principle of "first lowering the wall, then upper the wall and then the top", as follows: As shown in Fig. 4, the entire blasting area is divided into four zones, among which, the first blasting zone in zone I is the uppermost layered cutting drift 7 of the inter-column 1, and the blasting is initiated sequentially according to the blasting zones during the blasting, and the first blasting zone is divided into the inter-column 1 The gobs on both sides are used as free surfaces for blasting; Zones II and III are blasted with the cutting headway 7 and gobs as free surfaces; and the space formed by blasting the lower intercolumns in Zone IV is used as free surface downward blasting. That is to say, it collapses to Zone I, Zone II, Zone III and the goaf. The blasting adopts multiple detonating cord transmission and millisecond nonel detonator detonation network. The uppermost layer of the top surrounding rock and inter-column is blasted once, and different positions are used for different differential blasting. Differential blasting: Multiple rows of blastholes with the same number and same segment, and the segments on both sides of the fan-shaped blast hole increase in turn upward; the uppermost layer of the inter-column adopts differential blasting between rows of inner holes: multiple rows of blastholes with the same number and the same segment, away from the cutting The blasthole sections in the groove direction increase sequentially; in the uppermost layered cutting entry road 7 of the stud column, the differential blasting between the rows of inner holes is adopted: multiple rows of the same number of blastholes are in the same section, and the blasthole sections away from the empty areas on both sides increase in turn.

7. Recovery of the lower intercolumns: the interlayer 10 of the third layer and the surrounding rock on the top are blasted to form a covering layer, and the layered caving method is used to recover the second layer 9 and the first layer from top to bottom under the covering layer. For the intercolumns of layer 8, each layer is recovered from the upper wall to the footwall in a full-section retrograde manner, and the interpillars of the second layer 9 and the first layer 8 are produced from the upper layer to the lower layer in sequence according to the ore collapse step Delamination, from the upper wall to the lower wall, after the blasting of each ore-breaking step is completed, when the ore is drawn to the cut-off grade, it will be transferred to the next step for recovery. The distance is 2.4m, that is, two rows fall each time. Since the recovery of the intercolumns of the second stratum 9 and the first stratum 8 is carried out under the ore overburden, the depletion of the ore can be effectively reduced.

8. Recover the ore and bottom structure that have collapsed under the covering layers on both sides of the interstitial column: After the uppermost layer of the interstitial column 1 and the surrounding rock at the top have collapsed at one time, part of the ore in the interstitial column 1 has collapsed to the bottom of the mines on both sides. The caving method recovers this part of the ore and the bottom structure of the mine house.

Through the method of the present invention to recover the inter-column from the covering layer formed by the surrounding rock at the top of the collapse, a total of 71698t of ore was mined from the No. 1 inter-column in the middle section of the lead-zinc mine, and the mining grade: Zn5.12%, Pb1.43%, inter-column The comprehensive recovery rate is 78.5%, the comprehensive dilution rate is 18.5%, and the technical indicators are better than similar mines.

Claims (9)

1. avalanche top country rock forms the method that covering layer reclaims studding, it is characterized in that the method comprises the following steps:

A, layering: 3-4 layering stage casing being divided into height 10-15m;

The volume of B, estimation dead zone, studding both sides: the situation of depositing is composed to the dead zone of studding (1) both sides and verifies, the volume of dead zone is estimated;

C, calculate covering layer prose style free from parallelism amount: cover the feature of lower ore drawing and open-stope method to the requirement determination overburden cover (L) of safe buffering cushion thickness according to avalanche rock, natural repose angle (b) according to the overburden cover determined (L) and an avalanche prose style free from parallelism is done to pile up line of slope (11), calculate covering layer prose style free from parallelism region (2) area, then be multiplied with studding (1) thickness and draw the covering layer prose style free from parallelism amount of needs;

D, determine top country rock burst region: according to required covering layer prose style free from parallelism amount, in conjunction with the drillability of mine rock and the rock drilling degree of depth of medium-length hole rig, with rock drilling center (3) for circle is drawn in the center of circle, the scope surrounded with boundary line of ore bed and rock (4) is as top country rock burst region (5);

E, work arrangement: in the most higher slice, top country rock of studding (1), tunnel drilling drift (6) respectively, at the most higher slice driving of studding (1) perpendicular to the cutting gallery (7) of drilling drift (6), through with goaf, both sides, at most higher slice, top country rock medium position digging ventilation pedestrain raise (12) of studding (1), in most higher slice and top country rock drilling drift (6) of cutting gallery (7), studding (1), arrange vertical fan shaped medium length hole respectively;

F, divide burst region and determine blasting method: quick-fried district headed by most higher slice cutting gallery (7) of studding (1), all the other each subregions are divided by the principle of " coiling top again on after first lower wall ", detonate successively in order according to explosion subregion, Shou Bao district carries out explosion using the goaf of studding (1) both sides as the scope of freedom, other subregion is to cut gallery (7) and goaf is that explosion is carried out on the scope of freedom in studding (1), top country rock with the space formed after the studding explosion of bottom for the downward explosion in the scope of freedom;

G, reclaim bottom studding: after the most higher slice of studding (1) and top country rock explosion, form covering layer, slicing and caving method is adopted from top to bottom successively to reclaim most higher slice bottom studding under the cover, each layering is reclaimed to lower wall tunneling boring retrusive by upper dish, most higher slice bottom studding ore removal carries out successively according to ore caving interval from higher slice to lower leaf, from upper dish to lower wall, after each ore caving interval explosion completes, ore drawing is to proceeding to next step during cut-off grade again apart from reclaiming;

H, reclaim avalanche at the infratectal ore in studding both sides and polycrystalline substance: after the most higher slice of studding (1) and the disposable avalanche of top country rock, the part ore avalanche of studding (1), to the bottom of both sides mineral building, adopts Caving Method with Large Space to reclaim this part ore and mineral building polycrystalline substance.

2. avalanche top according to claim 1 country rock forms the method that covering layer reclaims studding, it is characterized in that: described covering layer prose style free from parallelism region (2) area is less than top country rock burst region (5) area.

3. avalanche top according to claim 1 country rock forms the method that covering layer reclaims studding, it is characterized in that: in described step C, overburden cover (L) is 14.5-15.5m.

4. avalanche top according to claim 1 country rock forms the method that covering layer reclaims studding, it is characterized in that: in described step e, the construction of medium-length hole big gun hole adopts YGZ90 type rig, Parameters of Moderate Longhole Blasting is: when powder factor and the timing of big gun hole close coefficient one, minimum burden W and aperture d is proportional, W=(25-40) d, bottom hole pitch a=(1.1-1.5) W of scallop hole, wherein in the country rock of top, each blasting parameter takes large values, get the small value in cutting groove, studding is normally arranged and is got median.

5. avalanche top according to claim 1 country rock forms the method that covering layer reclaims studding, it is characterized in that: adopt compound detonating fuse propagation of explosion, Millisecond Nonel Tube Detonator initiation net during described step F borehole blasting.

6. avalanche top according to claim 1 country rock forms covering layer and reclaims the method for studding, it is characterized in that: in described step F, the most higher slice of top country rock and studding (1) adopts onepull, and diverse location adopts different short-delay blasting respectively.

7. avalanche top according to claim 6 country rock forms the method that covering layer reclaims studding, it is characterized in that: Hole-hole short-delay blasting in the row of employing in the country rock of described top: arrange with the same section in gunfire hole, in fan-shaped two side gun holes, section upwards increases successively more.

8. avalanche top according to claim 6 country rock forms the method that covering layer reclaims studding, it is characterized in that: Hole-hole short-delay blasting in the row of employing in the most higher slice of described studding (1): arrange with the same section in gunfire hole more, increase successively away from big gun hole, cutting groove direction section.

9. avalanche top according to claim 6 country rock forms the method that covering layer reclaims studding, it is characterized in that: Hole-hole short-delay blasting in the row of employing in most higher slice cutting gallery (7) of described studding (1): arrange with the same section in gunfire hole more, increase successively away from big gun hole, dead zone, both sides section.