Ecological restoration equipment and method for metal mine collapse pit
By adopting skateboard and sliding rod structures in metal mine collapse pit repair equipment, rack and worm drive driven by servo motors, dynamically adjusting the motion trajectory of bulldozer and compaction rollers, the problems of earth accumulation and compaction blind spots are solved, and efficient ecological restoration of collapse pits is achieved.
Patent Information
- Application Number
- CN202510910188.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-02
- Publication Date
- 2025-08-12
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Traditional metal mine collapse pit restoration equipment lacks morphological adaptability in the earth backfilling process, resulting in uneven earth accumulation, making compaction equipment difficult to fit complex terrain, forming compaction blind spots, and insufficient compaction of deep clay layer.
The fixed slide plate and sliding rod structure are adopted, combined with the gear rack, worm transmission and threaded rod design driven by the servo motor, to realize dynamic adjustment of the L-shaped bulldozer and the elliptical movement of the compaction roller, to adapt to the depth and slope of the collapse pit, form a stepped earth structure and accurately compact.
It achieves uniform backfill and precise compaction of the earthwork, avoids earthwork accumulation and compaction blind spots of traditional equipment, and improves the quality and safety of the collapsed pits.
Smart Images
Figure CN120465544A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of ecological restoration, and in particular to an ecological restoration device and method for a metal mine subsidence pit. Background Art
[0002] As the scale of mineral resource development expands, geological disasters such as ground collapse and cracks caused by underground mining areas occur frequently, resulting in desertification of land resources, vegetation destruction and soil erosion. Taking my country's non-ferrous metal mines as an example, collapse pits in karst landform areas not only threaten the safety of life and property of surrounding residents, but also aggravate regional ecological degradation due to problems such as acidic wastewater leakage and heavy metal pollution.
[0003] Traditional metal mine subsidence pit repair equipment has obvious shortcomings during operation. In the earth backfilling stage, its linear bulldozer method lacks adaptive adjustment to the pit shape and can only advance in a fixed direction. As a result, under the dual action of gravity and mechanical thrust, a large amount of earth accumulates in the center area of the pit. Due to the lack of effective earth filling, the edge area forms a loose void layer, which lays hidden dangers for subsequent settlement and collapse. In the compaction stage, fixed rollers or linear vibrating rollers are limited to a single motion trajectory and are difficult to fit the undulating and deep terrain of the collapse pit bottom. The corner areas are prone to compaction blind spots, and the deep clay layer is insufficiently compacted. Therefore, it is necessary to propose a metal mine subsidence pit ecological restoration equipment and method. Summary of the Invention
[0004] The purpose of the present invention is to solve the problem in the prior art of earth backfilling, in which its linear bulldozer method lacks adaptive adjustment to the pit shape and can only advance in a fixed direction. As a result, under the dual action of gravity and mechanical thrust, a large amount of earth accumulates in the central area of the pit, while the edge areas lack effective earth filling, forming a loose void layer, which lays hidden dangers for subsequent settlement and collapse. In the compaction link, fixed rollers or linear vibrating rollers are limited to a single motion trajectory and are difficult to fit the undulating and deep terrain of the collapse pit bottom. The corner areas are prone to become compaction blind spots, and the deep clay layer has insufficient compaction. Therefore, a metal mine collapse pit ecological restoration equipment and method are proposed.
[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A metal mine collapse pit ecological restoration equipment, including a fixed slide and a sliding rod, the fixed slide and the sliding rod are slidably connected, the fixed slide and the sliding rod are jointly provided with a collapse pit repair component, the collapse pit repair component includes a first servo motor fixedly connected to the fixed slide, a gear fixedly connected to the end of the output shaft of the first servo motor, and a rack and a fixed plate provided on the sliding rod, a second servo motor and a worm provided on the upper part of the sliding rod, an L-shaped bulldozer plate movably connected to the fixed plate, and a rolling roller movably connected to the outer side of the L-shaped bulldozer plate. The start-up of the first servo motor will drive the two sets of gears to rotate, and the rotation of the gear will drive the rack to rotate on the fixed slide. The inner side slides, and the start-up of the second servo motor will drive the worm to rotate, and the rotation of the worm will drive the L-shaped bulldozer plate and the rolling roller to perform circular motion. The sliding rod is provided with a repair and compaction assembly, and the repair and compaction assembly includes a third servo motor and a threaded rod symmetrically arranged on the sliding rod, a telescopic motor and a push plate arranged on the threaded rod, and a third fixed rod and a compaction roller movably connected on the inner side of the sliding rod. The start-up of the third servo motor will drive the threaded rod to rotate, and the rotation of the threaded rod will drive the movable plate to move in the horizontal direction. The start-up of the telescopic motor will drive the push plate to squeeze the outer side of the compaction roller in the vertical direction, and the compaction roller will move in an elliptical shape along the third fixed rod to compact the collapsed pit.
[0006] The above technical solution further includes: The upper portion of the sliding rod is fixedly connected to the rack, and the rack is meshed with the gear. The rotation of the gear drives the rack to move in the horizontal direction.
[0007] The outer sides of the sliding rod are respectively fixedly connected with an L-shaped plate and a T-shaped plate, the upper part of the L-shaped plate is fixedly connected to the first servo motor, the output shaft end of the first servo motor is fixedly connected with a rotating rod, the end of the rotating rod away from the first servo motor is rotatably connected to the T-shaped plate, the outer side of the rotating rod is fixedly connected to the two sets of gears, and the L-shaped plate mainly serves to connect and fix the sliding plate and the first servo motor.
[0008] The sliding rod is fixedly connected to the side close to the gear and the second servo motor. There are two groups of second servo motors. The output shaft end of the second servo motor is fixedly connected to the worm. Starting the second servo motor will drive the worm to rotate.
[0009] The upper part of the sliding rod is fixedly connected to the fixed plate. There are two groups of fixed plates. A worm gear is movably connected to the outer side of the fixed plate. The worm gear and the worm are meshed. The fixed plate is mainly used to connect the worm gear and the sliding rod.
[0010] The end of the worm wheel away from the fixed plate is fixedly connected to a lifting rod, and the end of the worm wheel away from the worm wheel is fixedly connected to a first fixing rod. The outer side of the first fixing rod is fixedly connected to the L-shaped bulldozer plate. When the worm wheel rotates, it will drive the lifting rod to rotate, and the lifting rod will make a circular motion along the worm wheel.
[0011] The outer side of the L-shaped bulldozer blade is symmetrically fixedly connected with a connecting plate, and the opposite sides of the two groups of connecting plates are commonly fixedly connected with a second fixing rod. The outer side of the second fixing rod and the rolling roller are movably connected, and the rolling roller rotates on the outer side of the second fixing rod. The main function of the connecting plate is to connect the second fixing rod and the L-shaped bulldozer blade.
[0012] A sliding groove is symmetrically provided on the upper part of the sliding rod, the inner side of the sliding groove is fixedly connected to the third servo motor, the output shaft end of the third servo motor is fixedly connected to the threaded rod, and the threaded rod is threadedly connected to the movable plate. The rotation of the threaded rod will drive the movable plate to move on the inner side of the sliding groove.
[0013] The upper part of the movable plate is fixedly connected to the telescopic motor, the output shaft end of the telescopic motor is fixedly connected to the push plate, the opposite sides of the two sets of sliding rods are fixedly connected to the third fixed rod, the outer side of the third fixed rod is movably connected to the compaction roller, the third fixed rod and the compaction roller are not on the same axis, and the compaction roller will move in an elliptical shape along the third fixed rod to compact the sand in the collapsed pit.
[0014] The present invention has the following beneficial effects: 0. In the present invention, by setting up a collapsed pit repair component, the first servo motor drives the sliding rod to linearly move along the fixed slide through the engagement of the gear rack, so that the L-shaped bulldozer blade can dynamically adjust the shoveling position according to the depth and slope of the collapsed pit. The second servo motor drives the worm to drive the L-shaped bulldozer blade to swing in a circle, which can not only efficiently backfill the pit to form a stepped earthwork structure, but also use its arc-shaped trajectory to perform preliminary paving and leveling of the backfill soil, avoiding the problem of uneven earthwork accumulation caused by linear bulldozers of traditional equipment.
[0015] 1. In the present invention, further, by setting up a repair and compaction component, the third servo motor drives the threaded rod to rotate, and the horizontal position of the movable plate can be dynamically adjusted according to the depth of the collapsed pit and the soil characteristics, so that the compaction roller can accurately fit the bottom of the pit or the undulating area of the slope, avoiding local insufficient compaction or excessive disturbance caused by blind pressing of traditional equipment. The vertical linkage design of the telescopic motor and the push plate makes the compaction roller move along the elliptical trajectory of the third fixed rod, achieving the dual effects of horizontal rolling and vertical downward pressure. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1This is a schematic diagram of the overall structure of a metal mine subsidence pit ecological restoration device and method proposed by the present invention; Figure 2 It is a schematic diagram of the overall top view structure of the present invention; Figure 3 This is a schematic diagram of the overall bottom-up structure of the present invention; Figure 4 for Figure 1 A schematic diagram of the structure at center A; Figure 5 for Figure 2 A magnified schematic diagram of the structure at point B in the middle; Figure 6 for Figure 3 A magnified schematic diagram of the structure at point C in the middle; Figure 7 for Figure 3 Enlarged schematic diagram of the structure at point D in the middle.
[0017] In the figure: 1. Fixed slide; 2. Sliding rod; 3. Rack; 4. L-shaped plate; 5. First servo motor; 6. Rotating rod; 7. Gear; 8. T-shaped plate; 9. Second servo motor; 10. Worm; 11. Fixed plate; 12. Worm gear; 13. Lifting rod; 14. First fixed rod; 15. L-shaped bulldozer blade; 16. Connecting plate; 17. Second fixed rod; 18. Roller; 19. Sliding groove; 20. Third servo motor; 21. Threaded rod; 22. Moving plate; 23. Telescopic motor; 24. Push plate; 25. Third fixed rod; 26. Compacting roller. DETAILED DESCRIPTION
[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0019] Example 1 like Figure 1-Figure 7As shown, the present invention proposes a metal mine collapse pit ecological restoration equipment, including a fixed slide 1 and a sliding rod 2, which are slidably connected to each other, and a collapse pit repair component is commonly provided on the fixed slide 1 and the sliding rod 2, and the collapse pit repair component includes a first servo motor 5 fixedly connected to the fixed slide 1, a gear 7 fixedly connected to the output shaft end of the first servo motor 5, and a rack 3 and a fixed plate 11 provided on the sliding rod 2, a second servo motor 9 and a worm 10 provided on the upper part of the sliding rod 2, an L-shaped bulldozer 15 movably connected to the fixed plate 11, and a rolling roller 18 movably connected to the outside of the L-shaped bulldozer 15. The start-up of the first servo motor 5 will drive the two sets of gears 7 to rotate, and the rotation of the gear 7 will drive the rack 3 to slide on the inner side of the fixed slide 1. The start-up of the second servo motor 9 will drive the worm 10 to rotate, and the rotation of the worm 10 will drive the L-shaped bulldozer blade 15 and the rolling roller 18 to perform circular motion. A repair and compaction component is provided on the sliding rod 2, and the repair and compaction component includes a third servo motor 20 and a threaded rod 21 symmetrically arranged on the sliding rod 2, a telescopic motor 23 and a push plate 24 arranged on the threaded rod 21, and a third fixed rod 25 and a compaction roller 26 movably connected on the inner side of the sliding rod 2. The start-up of the third servo motor 20 will drive the threaded rod 21 to rotate, and the rotation of the threaded rod 21 will drive the movable plate 22 to move in the horizontal direction. The start-up of the telescopic motor 23 will drive the push plate 24 to squeeze the outer side of the compaction roller 26 in the vertical direction, and the compaction roller 26 will move in an elliptical shape along the third fixed rod 25 to compact the collapse pit.
[0020] The upper portion of the sliding rod 2 is fixedly connected to the rack 3 , and the rack 3 is meshed with the gear 7 . The rotation of the gear 7 drives the rack 3 to move in the horizontal direction.
[0021] The outer sides of the sliding rod 2 are fixedly connected with an L-shaped plate 4 and a T-shaped plate 8, respectively. The upper part of the L-shaped plate 4 is fixedly connected to the first servo motor 5. The output shaft end of the first servo motor 5 is fixedly connected with a rotating rod 6. The end of the rotating rod 6 away from the first servo motor 5 is rotatably connected to the T-shaped plate 8. The outer side of the rotating rod 6 is fixedly connected to the two sets of gears 7. The L-shaped plate 4 mainly serves to connect and fix the slide plate 1 and the first servo motor 5.
[0022] The sliding rod 2 is fixedly connected to the side close to the gear 7 and the second servo motor 9. There are two groups of second servo motors 9. The output shaft end of the second servo motor 9 is fixedly connected to the worm 10. The start-up of the second servo motor 9 will drive the worm 10 to rotate.
[0023] The upper part of the sliding rod 2 is fixedly connected to the fixed plate 11. There are two groups of fixed plates 11. The outer side of the fixed plate 11 is movably connected with a worm gear 12. The worm gear 12 and the worm 10 are meshed. The fixed plate 11 is mainly used to connect the worm gear 12 and the sliding rod 2.
[0024] The end of the worm gear 12 away from the fixed plate 11 is fixedly connected to the lifting rod 13, and the end of the worm gear 12 away from the worm gear 12 is fixedly connected to the first fixing rod 14. The outer side of the first fixing rod 14 is fixedly connected to the L-shaped bulldozer plate 15. When the worm gear 12 rotates, it will drive the lifting rod 13 to rotate, and the lifting rod 13 will make a circular motion along the worm gear 12.
[0025] The outer side of the L-shaped bulldozer blade 15 is symmetrically fixedly connected with a connecting plate 16, and the opposite sides of the two groups of connecting plates 16 are commonly fixedly connected with a second fixing rod 17. The outer side of the second fixing rod 17 is movably connected to the rolling roller 18, and the rolling roller 18 rotates on the outer side of the second fixing rod 17. The main function of the connecting plate 16 is to connect the second fixing rod 17 and the L-shaped bulldozer blade 15.
[0026] In this embodiment, the specific implementation method is as follows: pour sand into the opposite sides of the two sets of fixed slides 1, start the first servo motor 5, and the rotation of the output shaft of the first servo motor 5 will drive the rotating rod 6 to rotate. The rotation of the rotating rod 6 will drive the two sets of gears 7 to rotate at the same time. Because the gear 7 and the rack 3 are meshed, the rotation of the gear 7 will drive the rack 3 to move in the horizontal direction, and the movement of the rack 3 will drive the sliding rod 2 to move. The L-shaped plate 4 mainly serves to connect the fixed slide 1 and the first servo motor 5. The sliding rod 2 will slide on the inner side of the fixed slide 1. During the sliding process of the sliding rod 2, the second servo motor 9 will be started. The start of the second servo motor 9 will drive the worm 10 to rotate. Because the worm 10 and the worm wheel 12 are meshed, the rotation of the worm 10 will drive the worm wheel 12 to rotate. It will rotate on the outside of the fixed plate 11. The fixed plate 11 is mainly used to connect the worm gear 12 and the sliding rod 2. When the worm gear 12 rotates, it will drive the lifting rod 13 to rotate, and the lifting rod 13 will make a circular motion along the worm gear 12. The circular motion of the lifting rod 13 will drive the first fixed rod 14 to make a circular motion, thereby driving the L-shaped bulldozer blade 15 to make a circular motion. When it is necessary to push sand to repair the collapsed pit, the L-shaped bulldozer blade 15 needs to be rotated to be perpendicular to the ground. At this time, as the sliding rod 2 slides, the L-shaped bulldozer blade 15 will be driven to move, and the movement of the L-shaped bulldozer blade 15 will push the sand. During the movement of the L-shaped bulldozer blade 15, the rolling roller 18 will continue to flatten the sand, and the rolling roller 18 rotates on the outside of the second fixed rod 17. The main function of the connecting plate 16 is to connect the second fixed rod 17 and the L-shaped bulldozer blade 15.
[0027] Example 2 like Figure 1-Figure 7As shown, based on the first embodiment, a sliding groove 19 is symmetrically opened on the upper part of the sliding rod 2, the inner side of the sliding groove 19 is fixedly connected to the third servo motor 20, the output shaft end of the third servo motor 20 is fixedly connected to the threaded rod 21, and the threaded rod 21 and the movable plate 22 are threadedly connected. The rotation of the threaded rod 21 will drive the movable plate 22 to move on the inner side of the sliding groove 19.
[0028] The upper part of the movable plate 22 is fixedly connected to the telescopic motor 23, the output shaft end of the telescopic motor 23 is fixedly connected to the push plate 24, the opposite sides of the two sets of sliding rods 2 are fixedly connected to the third fixed rod 25, the outer side of the third fixed rod 25 is movably connected to the compacting roller 26, the third fixed rod 25 and the compacting roller 26 are not on the same axis, and the compacting roller 26 will move in an elliptical shape along the third fixed rod 25 to compact the sand in the collapse pit.
[0029] In this embodiment, the specific implementation method is that during the movement of the sliding rod 2 in the horizontal direction, the third servo motor 20 will be started, and the start of the third servo motor 20 will drive the threaded rod 21 to rotate. Because the threaded rod 21 and the movable plate 22 are threadedly connected, the rotation of the threaded rod 21 will drive the movable plate 22 to move on the inner side of the sliding groove 19, and the start of the telescopic motor 23 will push the push plate 24 to move back and forth in the vertical direction. The start of the rack 3 will drive the push plate 24 to squeeze the outer side of the compacting roller 26 in the vertical direction. It is worth noting that the compacting roller 26 rotates on the outer side of the third fixed rod 25, but the third fixed rod 25 and the compacting roller 26 are not on the same axis. The compacting roller 26 will move in an elliptical shape along the third fixed rod 25 to compact the sand in the collapse pit.
[0030] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.
Claims
1. A metal mine subsidence pit ecological restoration device, comprising a fixed slide plate (1) and a sliding rod (2), characterized in that: The fixed slide (1) and the sliding rod (2) are slidably connected, and a collapse pit repair component is commonly provided on the fixed slide (1) and the sliding rod (2). The collapse pit repair component includes a first servo motor (5) fixedly connected to the fixed slide (1), a gear (7) fixedly connected to the output shaft end of the first servo motor (5), a rack (3) and a fixed plate (11) provided on the sliding rod (2), a second servo motor (9) and a worm (10) provided on the upper part of the sliding rod (2), an L-shaped bulldozer (15) movably connected to the fixed plate (11), and a rolling roller (18) movably connected to the outer side of the L-shaped bulldozer (15). When the first servo motor (5) is started, the two sets of gears (7) are driven to rotate, and the rotation of the gear (7) drives the rack (3) to slide on the inner side of the fixed slide (1). When the second servo motor (9) is started, the worm (10) is driven. The worm (10) rotates, and the rotation of the worm (10) drives the L-shaped bulldozer plate (15) and the rolling roller (18) to perform circular motion. The sliding rod (2) is provided with a repair and compaction assembly, and the repair and compaction assembly includes a third servo motor (20) and a threaded rod (21) symmetrically arranged on the sliding rod (2), a telescopic motor (23) and a push plate (24) arranged on the threaded rod (21), and a third fixed rod (25) and a compaction roller (26) movably connected on the inner side of the sliding rod (2). The start-up of the third servo motor (20) drives the threaded rod (21) to rotate, and the rotation of the threaded rod (21) drives the movable plate (22) to move in the horizontal direction. The start-up of the telescopic motor (23) drives the push plate (24) to squeeze the outer side of the compaction roller (26) in the vertical direction. The compaction roller (26) moves in an elliptical shape along the third fixed rod (25) to compact the collapsed pit.
2. The metal mine subsidence pit ecological restoration equipment according to claim 1, characterized in that: The upper portion of the sliding rod (2) is fixedly connected to the rack (3), and the rack (3) is meshed with the gear (7).
3. The metal mine subsidence pit ecological restoration equipment according to claim 1, characterized in that: The outer sides of the sliding rod (2) are respectively fixedly connected to an L-shaped plate (4) and a T-shaped plate (8); the upper part of the L-shaped plate (4) is fixedly connected to the first servo motor (5); the end of the output shaft of the first servo motor (5) is fixedly connected to a rotating rod (6); the end of the rotating rod (6) away from the first servo motor (5) is rotatably connected to the T-shaped plate (8); and the outer side of the rotating rod (6) is fixedly connected to the two sets of gears (7).
4. The metal mine subsidence pit ecological restoration equipment according to claim 1, characterized in that: The sliding rod (2) is fixedly connected to the side of the gear (7) and the second servo motor (9). The second servo motor (9) is provided in two groups. The output shaft end of the second servo motor (9) is fixedly connected to the worm (10).
5. The metal mine subsidence pit ecological restoration equipment according to claim 1, characterized in that: The upper portion of the sliding rod (2) is fixedly connected to a fixed plate (11), and the number of the fixed plates (11) is two. A worm wheel (12) is movably connected to the outer side of the fixed plate (11), and the worm wheel (12) and the worm (10) are meshed.
6. The metal mine subsidence pit ecological restoration equipment according to claim 5, characterized in that: One end of the worm wheel (12) away from the fixed plate (11) is fixedly connected to a lifting rod (13), and one end of the worm wheel (12) away from the worm wheel (12) is fixedly connected to a first fixing rod (14), and the outer side of the first fixing rod (14) is fixedly connected to the L-shaped bulldozing plate (15).
7. The metal mine subsidence pit ecological restoration equipment according to claim 1, characterized in that: The outer side of the L-shaped bulldozer plate (15) is symmetrically fixedly connected to a connecting plate (16), and the opposite sides of the two groups of connecting plates (16) are commonly fixedly connected to a second fixing rod (17), and the outer side of the second fixing rod (17) is movably connected to the rolling roller (18).
8. The metal mine subsidence pit ecological restoration equipment according to claim 1, characterized in that: A sliding groove (19) is symmetrically formed on the upper portion of the sliding rod (2), the inner side of the sliding groove (19) is fixedly connected to the third servo motor (20), the output shaft end of the third servo motor (20) is fixedly connected to the threaded rod (21), and the threaded rod (21) is threadedly connected to the movable plate (22).
9. The metal mine subsidence pit ecological restoration equipment according to claim 1, characterized in that: The upper portion of the movable plate (22) is fixedly connected to the telescopic motor (23), the output shaft end of the telescopic motor (23) is fixedly connected to the push plate (24), the opposite sides of the two groups of sliding rods (2) are fixedly connected to the third fixed rod (25), and the outer side of the third fixed rod (25) is movably connected to the compacting roller (26).
10. A method for ecological restoration of a metal mine subsidence pit, using the metal mine subsidence pit ecological restoration equipment of claim 1, characterized in that: The steps include: Step 1: Pour sand into the opposite sides of the two sets of fixed slides (1), start the first servo motor (5), and the rotation of the output shaft of the first servo motor (5) will drive the two sets of gears (7) to rotate simultaneously. The rotation of the gears (7) will drive the rack (3) to move in the horizontal direction, and the movement of the rack (3) will drive the sliding rod (2) to move; Step 2: The start of the second servo motor (9) drives the worm (10) to rotate, and the rotation of the worm (10) drives the L-shaped bulldozer (15) to perform circular motion. When the sliding rod (2) moves, it drives the L-shaped bulldozer (15) to move in the horizontal direction. The movement of the L-shaped bulldozer (15) pushes the sand to repair the collapsed pit. The movement of the L-shaped bulldozer (15) drives the rolling roller (18) to move, and the rolling roller (18) flattens the sand. Step 3: The activation of the third servo motor (20) drives the threaded rod (21) to rotate, and the rotation of the threaded rod (21) drives the movable plate (22) to move in the horizontal direction. The activation of the rack (3) drives the push plate (24) to squeeze the outer side of the compaction roller (26) in the vertical direction. The compaction roller (26) moves in an elliptical shape along the third fixed rod (25) to compact the sand in the collapse pit.