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Title:
MOVING WASTE IN A LANDFILL
Document Type and Number:
WIPO Patent Application WO/2016/205924
Kind Code:
A1
Abstract:
A system and method for moving waste in a landfill includes the use of one or more excavators to move waste from a receiving location to a destination location in a tip face of the landfill. Multiple excavators may operate in a relay team to move the waste. The excavators may have grapples especially configured for the grasping, carrying, and movement of waste.

Inventors:
FENNELL, Barry John (38 Sassanowsky Road, Suttontown, South Australia 5291, 5291, AU)
VANDERWYST, Peter Anthony (39438 Fingal Line, St. Thomas, Ontario N5P 3S5, N5P 3S5, CA)
Application Number:
CA2016/050379
Publication Date:
December 29, 2016
Filing Date:
April 01, 2016
Export Citation:
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Assignee:
FENNELL, Barry John (38 Sassanowsky Road, Suttontown, South Australia 5291, 5291, AU)
VANDERWYST, Peter Anthony (39438 Fingal Line, St. Thomas, Ontario N5P 3S5, N5P 3S5, CA)
International Classes:
B09B1/00
Domestic Patent References:
2014-01-03
Foreign References:
CA2179283A11995-06-22
US3367523A1968-02-06
JP2003175381A2003-06-24
Attorney, Agent or Firm:
MUELLER-NEUHAUS, Jason et al. (BORDEN LADNER GERVAIS LLP, World Exchange Plaza100 Queen Street, Suite 130, Ottawa Ontario K1P 1J9, K1P 1J9, CA)
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Claims:
WHAT IS CLAIMED IS:

1. A method of moving waste in a tip face of a landfill for deposit and compaction of the waste in the tip face, the method comprising:

providing an excavator in the landfill; and

using the excavator to move the waste from a receiving location of the tip face to a destination location in the tip face.

2. The method according to claim 1 , wherein using the excavator to move the waste comprises:

grasping a load of the waste at the receiving location using a grapple of the excavator;

rotating or swinging the excavator; and

releasing the load of the waste from the grapple of the excavator at a second location in the tip face.

3. The method according to claim 2, wherein rotating or swinging the excavator comprises rotating a house of the excavator atop an undercarriage of the excavator to move the grapple of the excavator above the second location.

4. The method according to claim 2 or 3, wherein using the excavator to move the load of the waste comprises maintaining the undercarriage of the excavator substantially stationary. 5. The method according to any one of claims 2 to 4, wherein the second location is the destination location.

6. The method according to any one of claims 2 to 4, wherein the grapple is configured to grasp, carry, and/or move at least 12 m3 of waste in each load of the grapple. 7. The method according to any one of claims 2 to 4, wherein the grapple is configured to grasp, carry, and/or move at least 20 m3 of waste in each load of the grapple.

8. The method according to any one of claims 2 to 7, wherein the load of the waste has a weight of about 2.5-7 tonnes.

9. The method according to any one of claims 2 to 8 further comprising after the grasping the load of the waste and before the releasing the load of the waste:

using the grapple to compress the load of the waste from a density of about 170-200 kg/m3 to a density of at least 235 kg/m3

10. The method according to any one of claims 2 to 9, wherein the grapple has a tare weight of about 3.5-4.5 tonnes. 11. The method according to any one of claims 2 to 10, wherein the grapple has a width of about 3.0 m.

12. The method according to any one of claims 2 to 1 1 , wherein the grapple has a height of about 2.2 m.

13. The method according to any one of claims 2 to 12, wherein the grapple has an upper fingers section joined at a hinge with an opposed lower thumb section, wherein the upper fingers section comprises a first number of tines and the lower thumb section comprises a second number of tines, the excavator further comprising a closure means to close the lower thumb section against the upper fingers section.

14. The method according to claim 13, wherein the closure means comprises a hydraulic ram.

15. The method according to claim 13 or 14, wherein the tines of the upper fingers section have a spacing of about 400 mm to about 500 mm. 16. The method according to any one of claims 13 to 15, wherein the tines of the lower thumb section have a spacing of about 400 mm to about 500 mm.

17. The method according to any one of claims 13 to 16, wherein the first number of tines is six.

18. The method according to any one of claims 13 to 17, wherein the second number of tines is five.

19. The method according to any one of claims 13 to 18, wherein the tines each have a thickness of about 25 mm.

20. The method according to any one of claims 13 to 19, wherein the upper fingers section is curved forming a concave space opposite the lower thumb section. 21. The method according to claim 20, wherein grasping the load of the waste comprises performing a pulling, raking motion with the grapple through the waste to collect and compact at least partly the waste in the concave space of the upper fingers section.

22. The method according to claim 21 , comprising repeating the pulling, raking motion to accumulate the load of waste in the grapple. 23. The method according to claim 22 further comprising, following each pulling raking motion, compacting the waste in the upper fingers section by closing the lower thumb section to compact further the waste in the upper fingers section.

24. The method according to any one of claims 2 to 23, wherein the grapple comprises a plurality of crosstubes.

25. The method according to claim 24, wherein the plurality of crosstubes comprises a first crosstube being solid and having a cylindrical shape with a diameter of about 60 mm, a second crosstube being solid and having a cylindrical shape with a diameter of about 90 mm, and a third crosstube being hollow and having a cylindrical shape with an outer diameter of 1 15 mm and an inner diameter of 75 mm.

26. The method according to any one of claims 2 to 4, wherein the excavator is a first excavator, the method further comprising:

providing a second excavator in the landfill; and

using both the first excavator and the second excavator to move the load of waste from the receiving location of the tip face to the destination location in the tip face. 27. The method according to claim 26, wherein the second location is an intermediate location in the tip face, wherein using both the first excavator and the second excavator to move the waste comprises: grasping a portion of the load of waste at the intermediate location using a grapple of the second excavator;

rotating or swinging the second excavator; and

releasing the portion of the load of waste from the grapple of the second

excavator at the destination location in the tip face.

28. The method according to claim 26 or 27, wherein the grapple of the first excavator and the grapple of the second excavator are each configured to grasp, carry, and/or move about at least 12 m3 of waste in each load of the grapple.

29. The method according to claim 26 or 27, wherein the grapple of the first excavator and the grapple of the second excavator are each configured to grasp, carry, and/or move about at least 20 m3 of waste in each load of the grapple. 30. The method according to any one of claims 26 to 29, wherein the load of the waste has a weight of about 2.5-7 tonnes.

31. The method according to any one of claims 26 to 30 further comprising after the grasping the load of the waste and before the releasing the waste:

using the grapple of the first excavator or the grapple of the second excavator to compress the waste from a density of about 170-200 kg/m3 to a density of at least 235 kg/m3.

32. The method according to any one of claims 26 to 31 , wherein the grapple of the first excavator and the grapple of the second excavator each have a tare weight of about 3.5-4.5 tonnes.

33. The method according to any one of claims 1 to 32, wherein the receiving location is located at an edge of the tip face, and the destination location is located within the tip face. 34. A method of moving waste in a tip face of a landfill for deposit and compaction of the waste in the tip face, the method comprising:

providing a plurality of excavators in the tip face;

receiving waste at a receiving location of the tip face;

using the plurality of excavators to move the waste to a destination location in the tip face, wherein the plurality of excavators operate in sequence to relay at least part of the waste from the receiving location to the destination location.

35. The method according to claim 34, wherein at least one of the excavators moves the at least part of the waste by:

grasping the at least part of the waste at a first location in the tip face using a grapple of the excavator;

rotating or swinging the excavator; and

releasing the at least part of the waste from the grapple of the excavator at a second location in the tip face.

36. The method according to claim 34, wherein each one of the excavators moves the at least part of the waste by:

grasping the at least part of the waste at a corresponding first location in the tip face using a grapple of the excavator;

rotating or swinging the excavator; and

releasing the at least part of the waste from the grapple of the excavator at a corresponding second location in the tip face.

37. The method according to claim 35 or 36, wherein for each one of the plurality of excavators, the grapple is configured to grasp, carry, and/or move at least about 12 m3 of waste in each load of the grapple.

38. The method according to claim 35 or 36, wherein for each one of the plurality of excavators, the grapple is configured to grasp, carry, and/or move at least about 20 m3 of waste in each load of the grapple. 39. The method according to claim 37 or 38, wherein the waste in each load of the grapple has a weight of about 2.5-7 tonnes.

40. The method according to any one of claims 35 to 39 further comprising after the grasping the waste and before the releasing the waste:

using the grapple of at least one of the excavators to compress the waste from a density of about 170-200 kg/m3 to a density of at least 235 kg/m3

41. The method according to any one of claims 35 to 40, wherein the grapple of each of the excavators has a tare weight of about 3.5-4.5 tonnes.

42. A method of spreading waste in a tip face of a landfill for deposit and compaction of the waste in the tip face, the method comprising using the method of any one of claims 34 to 41 to move waste received at at least one receiving location of the tip face to a plurality of destination locations in the landfill, whereby the waste is spread in the tip face of the landfill.

43. Use of an excavator to move waste in a tip face of a landfill for deposit and compaction of the waste in the tip face.

44. A grapple for use with an excavator to move waste in a tip face of a landfill for deposit and compaction of the waste in the tip face, the grapple configured to grasp a volume of waste of at least 12 m3 having a weight of about 2.5-7 tonnes and to compress the waste from a density of about 170-200 kg/m3 to a density of at least 235 kg/m3, the grapple having a tare weight of about 3.5-4.5 tonnes.

45. The use according to claim 43, wherein the excavator is equipped with the grapple according to claim 44, comprising using the grapple to move the waste.

Description:
MOVING WASTE IN A LANDFILL

FIELD

[0001] The present disclosure relates generally to moving waste in a landfill.

BACKGROUND

[0002] Landfills are commonly used for the disposal of residential and industrial waste including construction and demolition material. In a typical landfill, waste is received in a designated area sometimes called a 'tip face'. The waste may be received from tipper trailers, or dump trucks, walking floor trailers, or by any other means. The waste is discharged in or about the tip face, typically at the edge of the tip face, and is redistributed and spread over the tip face by means of heavy equipment such a bulldozers. The waste thus spread over the tip face is then compacted, conventionally by means of heavy equipment which drives or rolls over the spread waste. One such piece of heavy equipment is called a compactor, which in some cases has large, specially-designed wheels, and is provided with substantial weight, to compact the waste as the compactor drives or rolls over the spread waste repeatedly.

[0003] In a typical landfill operation illustrated in FIG. 1 , waste is discharged into the tip face 10 of a landfill by a tipper trailer 20 or a dump truck 30, as shown. Other means for waste discharge are possible, such as walking floor trailers. In some cases the amount of waste discharged is so great that it cannot all be discharged at once. For example, when a tipper trailer is tipped in order to discharge the waste carried therein, a pile of waste forms immediately facing a back opening of the tipper trailer and grows to such a height that it effectively blocks further discharge of waste from the tipper trailer. A similar development typically occurs with walking floor trailers. In order to discharge further waste, it is necessary first to remove at least a portion, and preferably all, of the pile of waste so as to allow further waste to pour out of the trailer.

[0004] Conventionally, bulldozers 40 are used to push the pile of waste, or a portion thereof, away from the back opening of the trailer into the tip face for this purpose, as illustrated by arrow 50. In some cases, it is preferable to use a compactor 60 for this purpose, as compactors are typically provided with a plough which is spaced apart from a cabin of the compactor by a distance greater than the spacing between a plough and cabin of the bulldozer. The additional space between the plough and cabin of the compactor, as compared to a bulldozer, is desirable to avoid the accidental spillage of waste into or onto the cabin which is discharged from the trailer once the waste pile or a portion thereof is removed to allow such further discharge. While using a compactor for this purpose solves a problem faced in using bulldozers, compactors are not typically intended for such use, and are typically more costly than bulldozers, and thus the practice represents a misallocation of resources.

[0005] Moreover, the process of using bulldozers to spread waste over the surface of the tip face is time consuming and inefficient. As the bulldozer pushes waste about the tip waste, waste invariably spills past the sides of the bulldozer plough blade, and typically the bulldozer must make numerous passes in order adequately to spread and to layer the waste. In this connection, following a forward ploughing movement, the bulldozer must reverse some distance in order then to make a repeated forward ploughing movement. This not only wastes time and resources, but also gives rise to operator strain and risk of accident.

[0006] Despite the above disadvantages of the use of bulldozers to move and spread waste in a tip face of a landfill, their use for this purpose is not merely conventional, but appears to be universal. Despite diligent research, the inventors have found no teaching or practical example of an exception to this practice. The use of bulldozers for this purpose appears to be an unquestioned and undisturbed practice in the field of landfill operations. [0007] It is known, however, to use excavators in connection with landfill operations for the digging and movement of dirt, in which case the excavator is typically equipped with a bucket. It is also known to use excavators for the movement of waste including for loading and unloading of waste from trucks or conveyors, and for this purpose to it is known to equip the excavator with a so-called Orange peel' grapple 600 illustrated in FIG. 2. In use, the open orange-peel grapple is lowered onto the waste from above, and it is then closed to grasp and hold therein a quantity of waste to be moved. It is also known to use conventional grapples to move waste other than loose, compressible waste, and such a conventional grapple 410 is illustrate in FIG. 3.

[0008] In general, however, conventional excavators, including those equipped with buckets, orange-peel grapples, or conventional grapples are not configured for the economical movement of loose, compressible waste such as is found in a typically tip face of a landfill.

[0009] There is therefore a material value in addressing the above deficiencies in conventional landfill operations, and in providing more efficient means for moving waste in landfills.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Embodiments will now be described, by way of example only, with reference to the attached Figures.

[0011] FIG. 1 illustrates a conventional landfill operation using bulldozers to spread waste over a tip face.

[0012] FIG. 2 is a drawing of a known orange-peel grapple for an excavator.

[0013] FIG. 3 is a drawing of a known conventional grapple for moving waste other than loose, compressible waste.

[0014] FIG. 4 is a drawing of an excavator having a grapple particularly configured for moving and spreading waste over a tip face of a landfill. [0015] FIG. 5 is a scale drawing comparing sizes of a conventional grapple and a grapple according to disclosed embodiments.

[0016] FIG. 6 is a drawing illustrating an enclosed volume of a closed grapple.

[0017] FIG. 7 is a drawing illustrating an enclosed volume of a partly closed grapple.

[0018] FIG. 8 is a front perspective view of a grapple particularly configured for moving and spreading waste over a tip face of a landfill.

[0019] FIG. 9 is a side perspective view of the grapple of FIG. 8.

[0020] FIG. 10 is a block diagram illustrating a landfill operation using excavators to spread waste over a tip face.

[0021] FIG. 1 1 is a flowchart of a method to move waste in a tip face.

DESCRIPTION

[0022] The inventive means described herein include the use of one or more excavators in the tip face of a landfill to move and distribute loose, compressible waste. The excavators may be equipped with grapples configured particularly for the efficient grasping, compaction, and movement of loose, compressible waste. In some embodiments loose waste is waste that has a density of less than 300 kg/m 3 when uncompressed, which in some embodiments is a density of about 170-200 kg/m 3 when uncompressed. In some embodiments, compressible waste is waste that, when subjected to a compaction pressure typically generated by known waste compactors, for example about 120 bars, or about 138 bars, a volume of the waste is reduced by at least 25%. In contrast, non-compressible waste is waste whose volume is reduced no more than 25%, and typically less than 25%, when subjected to compaction pressures typically generated by known waste compactors. The waste may be composed of different materials having non-uniform sizes.

[0023] In a landfill, a designated area of land for the deposit and compaction of waste is sometimes called a 'tip face'. A size of the tip face may be any desirable size. For example, a tip face may be rectangular and have dimensions of 77 meters long and 33 meters wide. Other shapes and sizes are possible.

[0024] An excavator 70 is illustrated in FIG. 4. Excavators are heavy construction equipment typically having an arm 477 including a boom 470 and a stick 471 , an implement 474 (such as a bucket or grapple 400), and a cab 473, together termed the "house", rotatably mounted atop an undercarriage 474 having a chassis 475 and tracks 476 or wheels.

[0025] As noted above, it is known to use excavators in landscape operations. In some cases, excavators are used to move dirt, in which case they are typically equipped with a bucket. Excavators are sometimes also used to move waste, which is sometimes loose waste, to load and unload the waste from trucks, and in such case the excavator is sometimes equipped with an orange-peel grapple 600 illustrated in FIG. 2. Excavators are sometimes also used to move waste other than loose, compressible waste, in which case they are equipped with a conventional grapple or bucket, such as the grapple 410 shown in FIG. 3.

[0026] When equipped with such implements, however - namely, a bucket, or orange-peel grapple, or conventional grapple - the use of excavators to move and distribute loose, compressible waste in the tip face of a landfill is not economical, for a number of reasons.

[0027] Specifically, in order for the use of excavators to move and distribute loose, compressible waste in the tip face of a landfill to be economical, it is desirable for the excavators to be capable of moving and distributing more such waste in a given period of time than can be done by bulldozers and compactors by the methods known and universally employed in the field. Since excavators move material in discrete loads, whether they be bucket-loads or grapple-loads, the rate at which an excavator can move waste depends upon: the weight of waste the excavator can move in each load; and the amount of time required to move each load, which together determine the weight of waste the excavator can move in a given period of time. The weight of waste that an excavator can move in each load is determined by a number of factors including the capacity, or volume, of the implement (e.g. bucket or grapple) used to move the waste, and the ability to compact the waste using the implement or otherwise. With respect to the latter factor, the ability to achieve a greater compaction of the waste enables a greater weight of waste to be moved per load.

[0028] In addition, when used to move and distribute loose, compressible waste over the tip face of a landfill, it is desirable for the excavator to be able to collect and release loads of waste at the full extension of the boom of the excavator, thus maximizing the area in the tip face that the excavator can operate.

[0029] There is generally a limit, however, to the weight of material a given excavator may safely move at the full extension of its arm, and in general the limit is determined by the size and weight of the excavator, the length of the arm, and the weight of the implement used to move the waste. With respect to this last factor, it is generally the combined weight of the implement and the load that must be kept below some safe total weight, and thus the weight of waste moveable per load reduces as the weight of the implement increases. For a given excavator, therefore, characterized by a maximum safe total weight of the implement and waste at full extension of the arm, it is desirable to minimize the weight of the implement in order to maximize the permissible weight of waste. Although it is known that larger, heavier excavators are capable safely of bearing a greater total weight at full arm extension, it is also known that such larger excavators move more slowly than smaller excavators, thus reducing the rate of movement of waste.

[0030] It is believed that the above, competing set of factors has caused the idea of using excavators specifically in the tip face of a landfill to move and distribute loose, compressible waste, to be generally unknown and counter-intuitive in the industry. As indicated above, the adaptation of a conventional excavator for such purpose gives rise to a number of problems which have generally led the industry away from any use of excavators in the tip face, and thus the conventional and universal method continues to employ bulldozers and compactors, as described above.

[0031] In view of all of the above considerations, the inventors have discovered that it is desirable to provide a grapple configured to maximize the weight of the waste moveable by the grapple in each load, including maximizing the volume and compaction of waste, while minimizing the weight of the grapple itself so as to minimize the total weight of the grapple and carried waste in each load, so as to enable the safe use of conventional, relatively faster-moving excavators economically to move and distribute loose, compressible waste in the tip face of a landfill. It is also desirable to provide techniques for the use of such excavators and grapples efficiently to compact the waste in the grapple in each load.

[0032] As noted above, in some cases the excavators used in landfill operations are equipped with buckets useful for the digging and movement of dirt. Such buckets are not suitable for the efficient movement of loose, compressible waste, however, as the bucket generally includes no mechanism to compact the waste to increase the weight of waste moved per bucket, and moreover the weight of the bucket renders the weight of uncompressed waste safely moveable at full extension of the boom insufficient and uneconomical.

[0033] As also noted above, it is known that an excavator may be provided with a grapple which may be useful for the movement of waste, but similar deficiencies render uneconomical the use of such grapples to move loose, compressible waste in the tip face of a landfill.

[0034] For example, conventional grapples such as the one shown in FIG. 3 are not generally provided with means to compact loose matter grasped in the grapple, and moreover are not configured to grasp and carry a sufficient volume of waste. By way of non-limited example, FIG. 5 shows a grapple 400 according to an aspect of the present disclosure, and alongside depicted at the same scale an example of a conventional grapple 410 used for moving timber or other non- compressible waste. As shown, the inventive grapple 400 is considerably larger than a conventional grapple 410. For example, conventional grapples used for loading waste from vehicles such as tipper trailers, dump trucks, and walking floor trailers are typically limited in size so as to enable clearance for insertion and removal of the grapple. In some cases, such grapples are configured to grasp and carry 3-4 m 3 of material. By contrast, a grapple 400 for moving waste in a landfill as contemplated herein may have in various embodiments a size and configuration suitable to grasp, carry, and move at least or about 12 m 3 , or at least or about 20 m 3 , or 12-20 m 3 , or 12-25 m 3 , or 20-25 m 3 of waste.

[0035] On the other hand, orange-peel grapples, discussed above and illustrated in FIG. 2, are at best configured to compress waste only by means of closure of the tines of the grapple which are widely spaced apart and thus undesirably allow passage of the waste between the tines. Moreover, inasmuch as such orange-peel grapples are configured to be lowered onto waste and then closed, it is not generally possible to achieve any amount of compaction of the waste until the grapple is already partly closed, and during this process much waste initially grasped falls out of the open bottom of the grapple before sufficient pressure is developed in the grapple to retain it.

[0036] The inventors have discovered, however, that the amount of loose, compressible waste moveable by a grapple can be increased by providing the grapple with means for compressing the waste in the jaws of the grapple, and further by loading the grapple in such a way as to facilitate such compaction.

[0037] Moreover, in addressing the problem of providing a lighter grapple which, when filled with compressed waste, remains sufficiently light to be lifted at full boom extension by an excavator of a size conventionally used in landfill operations, the inventors have discovered, surprisingly, that it is not necessary for the grapple to close fully, and the grapple may be lightened by have fewer tines more widely spaced as compared to conventional grapples. This finding is counter-intuitive, and contrasts with the requirements applicable in the conventional use of excavator grapples for other loose matter such as dirt which typically requires the grapple to close fully and further requires narrow spacing of the grapple tines to provide adequate support. The inventors have discovered that as dirt is generally granular, it breaks apart comparatively easily when grasped in a grapple and thus falls through the spacing between the tines, thus requiring a close spacing of the tines to provide adequate support for the soil. The inventors have discovered, however, that, in contrast, loose, compressible waste, when compressed, tends to be self-supporting, and resists passage through the tine spacings or the open jaws of the grapple. Thus, while conventionally a grapple 500 must be closed fully as shown in FIG. 6, thus enclosing a volume Vi 510, the inventors have discovered that, with loose, compressible waste, when compressed, the grapple 500 need not be fully closed, as shown in FIG. 7, thus enclosing a volume V 2 520 which is considerably greater than volume Vi 510. The compressed waste enclosed in volume V 2 520 is self-supporting, and thus the grapple 500 need not be fully closed.

[0038] This surprising discovery regarding the properties of loose, compressible waste in excavator grapples has enabled the inventors to increase materially the volume of waste carried per load and simultaneously reduce materially the weight of the grapple by reducing the number and thickness of tines and increasing their spacing, and to employ unconventional methods for using such grapples including grasping and compressing loose waste without fully closing the grapple jaws. One embodiment of such a grapple 400 is shown in FIG. 8. These improvements enable the use of a conventionally-sized excavator 70, as shown in FIG. 4, while maximizing the amount of waste grasped and moved by the grapple per movement of the excavator. The foregoing thus renders the use of conventional excavators for movement and distribution of waste in a tip face of a landfill both economical and advantageous. [0039] FIG. 4 shows an excavator 70 having a grapple 400 especially configured for moving and spreading waste in a tip face of a landfill. FIG. 8 shows a front perspective view of the grapple 400 alone, and FIG. 9 shows a side perspective view of the grapple 400. The grapple 400 may have in various embodiments a size and configuration suitable to grasp, carry, and move at least or about 12 m 3 , or at least or about 20 m 3 , or 12-20 m 3 , or 12-25 m 3 , or 20-25 m 3 of waste. This volume may be the volume Vi 510 wherein the grapple is fully closed, as shown in FIG. 6, or the volume V 2 520, wherein the grapple is only partly closed, as shown in FIG. 7. The grapple 400 may have fingers 420 having a length L1 of about 1200-3000 mm, which in one embodiment is about 2200 mm, and a width W1 of about 1500-4000, which is one embodiment is about 3000 mm. The fingers 420 are connected at a joint 430 (shown in FIG. 8) with a thumb 440 having a length L2 of about 1000-3000 mm, which in one embodiment is about 2040 mm, and a width W2 of about 1000-3000 mm, which in one embodiment is about 2400 mm. Other dimensions are possible. In some embodiments, L2 is 75%-100% of L1. In some embodiments, W2 is 75%-100% of W1.

[0040] The thumb 440 may be moveable rotatably about the joint 430 by any suitable means, which may include a hydraulic cylinder 450 (shown in FIG. 4), or ram. In some embodiments, the hydraulic cylinder 450 is configured to function in the grapple 400 to close the thumb 440 toward the fingers 420 with such force so as to compact loose, compressible waste grasped in the grapple 400 from a density of about 170-200 kg/m 3 to a density of at least 235 kg/m 3 , which in some embodiments is about 235-335 kg/m 3 . The hydraulic cylinder 450 may have a bore size of 1 10-145 mm, and may have a 65 mm shaft. The hydraulic cylinder 450 may be configured to generate a hydraulic pressure of 185-315 bars. In some embodiments the hydraulic cylinder 450 and grapple 400 generate a compression ratio of at least or about 2: 1. The grapple 400 may be attached to the excavator 70 using 90 mm pins. Other dimensions and numbers are possible. [0041] The grapple 400 may have any desired number or spacing of tines. As shown in FIG. 8, the grapple 400 may have fingers 420 including 4-10 tines 460, and in some embodiments has 6 tines as shown, and a thumb 440 including 4-10 tines 460, and in some embodiments has 5 tines as shown. The tines 460 may have a spacing T1 of 250-700 mm, which in some embodiments is about 600 mm. The tines 460 of the thumb 440 may have a spacing T1 that is the same as the spacing of the tines 460 of the fingers 420, or they may have a different spacing. The tines 460 may be formed of bisalloy 80 tempered steel plate, or any other suitable material. The tines 460 may have a thickness T2 of 12-40 mm, which in some embodiments is about 25 mm.

[0042] The grapple 400 may have any suitable number of crosstubes, and in some embodiments has at least three crosstubes including first crosstubes 480, second crosstubes 482, and third crosstubes 484. The first crosstubes 480 may be solid and cylindrical, and have a diameter C1 of 40-100 mm, which in some embodiments is about 65 mm. The second crosstubes 482 may be solid and cylindrical, and have a diameter C2 of 65-130 mm, which in some embodiments is about 90 mm. The third crosstubes 484 may be hollow and cylindrical, and have an outer diameter C3 of 90-150 mm, which in some embodiments is about 1 15 mm, and an inner diameter (not shown) of 25-50 mm, which in some embodiments is about 75 mm. The fingers 420 may have fourth crosstubes 486 which in some embodiments are substantially similar in construction and dimensions to the third crosstubes 484. Other numbers and configurations are possible.

[0043] In some embodiments, the grapple 400 is configured to grasp and move 2.5-7 tonnes of waste per load, which in some embodiments is about 3.5-5 tonnes per load. In some embodiments, the grapple 400 has a tare weight of about 3.5-4.5 tonnes, which in some embodiments is about 4 tonnes. [0044] In some embodiments, the excavator 70 has a weight of about 45-48 tonnes, and when configured with the grapple 400 is operable to lift about 9-10 tonnes, including the weight of the grapple 400, at full extension of the arm 477.

[0045] With reference to FIG's 10 & 1 1 , a method 300 of moving waste in a tip face 10 of a landfill includes providing (step 310) and using at least one, and in some embodiments at least two, excavators 70 configured with the grapple 400 to move the waste from a receiving location 80 in the tip face 10 to a destination location 90 in the landfill (step 320). The waste moved to the destination location 90 may then be compacted using compactors 60 in known ways.

[0046] The waste may be received in the tip face 10 from tipper trailers 20 or dump trucks 30, or any other means known in the art such as walking floor trailers. A first excavator 71 may be positioned near a first receiving location 81 such that as waste is discharged into the tip face 10 at the receiving location 81 , the first excavator 71 is positioned to grasp and carry waste from the receiving location 81 for release in a second location 101 in the tip face, in a swinging or rotating motion as is known in the art of excavators. If the second location 101 is a destination location 91 , then only a single excavator is required 71. If, however, the destination location 92 is different from the second location 102, then a second excavator 72 is provided to grasp and carry the waste from the second location 102 to a third location 103, which may be the destination location 92, again by a swinging or rotating motion of the excavator 72. In such swinging or rotating motions, the house of the excavator 70 rotates about the undercarriage which may remain substantially stationary. In this way, a relay team of excavators 70 may operate in sequence to move the waste from the receiving location 80 to the destination location 90 in the tip face 10.

[0047] A system for moving waste in a tip face 10 of a landfill may include the excavator 70 or excavators 70, as the case may be, which may be configured and positioned to perform the above method. [0048] As noted above, the excavators 70 may be provided with grapples 400 specially configured for grasping, compacting, carrying, and moving loose, compressible waste. While grapples for use with excavators are known, the grapples 400 for use in moving loose, compressible waste in landfills will generally be larger, but nevertheless lighter, and configured especially to grasp and carry loose, compressible waste material commonly received in landfills.

[0049] In particular, and as shown especially in FIG. 9, the grapple 400 may be provided with fingers 420 which are curved forming a concave interior hollow 455 having a depth D1 , or space, opposite the thumb 440. The depth D1 may be 1200- 3000 mm, and in some embodiments is 1700 mm. In use, the grapple 400 may be dragged face-down with the thumb 440 open, through waste from a first extension of the excavator arm to a second, lesser extension of the excavator arm, and by this pulling, raking motion waste may be gathered and partly compressed or compacted in the interior hollow 455 formed by the fingers 420 of the grapple 400 before the thumb 440 is closed further compressing such waste. This raking motion may be repeated, as the waste thus compressed may be at least partly self-supporting within and held in the interior hollow 455 allowing opening of the thumb 440 while retaining substantially all of such waste in the interior hollow 455, thus enabling a further such raking motion gathering further and partially compacting more waste in the interior hollow 455 of the fingers 420 of the grapple 400 to be further compacted by closure of the thumb 440.

[0050] The methods and systems described above provide numerous advantages over conventional systems and methods. Fewer, if any, bulldozers may be required in the landfill operation, and thus may be dispensed with saving cost and material. The operation of the excavators to move, spread, and layer the waste over the surface of the tip face may be much faster and more efficient than with the use of bulldozers given the inherent inefficiencies resulting from their use as described above. In particular, the use of excavators as described herein enables an increased and more even distribution and layering of waste which enables a better and more even compaction by compactors or otherwise. Moreover, given that an excavator may quickly and efficiently remove any pile which has formed behind a discharging conveyance delivering waste to the tip face, such as a tipper or walking floor trailer, or dump truck, the time for complete discharge of all waste may be reduced, thus reducing waiting time and associated cost of such conveyances. Moreover, since the time to move and spread the waste over the tip face may be reduced, the waiting time of compactors to proceed to compact the waste may be reduced, again resulting in a cost savings.

[0051] In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments. However, it will be apparent to one skilled in the art that these specific details are not required. In particular, it will be appreciated that the various additional features shown in the drawings are generally optional unless specifically identified herein as required. The above-described embodiments are intended to be examples only. Alterations, modifications and variations can be effected to the particular embodiments by those of skill in the art. The scope of the claims should not be limited by the particular embodiments set forth herein, but should be construed in a manner consistent with the specification as a whole.