Separator-drum scraper-blade holder

Abstract

A separator-drum scraper-blade holder for holding scraper blades (12) of a multi-gravity separator for separating material. The holder comprises a scraper support arm (14) and a carrier (16) for securing a plurality of scraper blades (12) thereto. The carrier (16) is removably attachable to the scraper support arm (14) so that the plurality of scraper blades (12) can be removed together without removing the scraper support arm (14).

Description

[0001] Separator-Drum Scraper-Blade Holder

[0002] The present invention relates to a separator-drum scraper-blade holder for holding scraper blades of a separator drum for separating material, particularly that which is the product of mining. For example, the separator drum is for separating minerals from gangue. The invention further comprises separator drum scraper-blade system and a separator drum.

[0003] A component may need to be separated from a mixture of different materials. If the density of the component to be separated differs from those of others in the mixture, then a separator drum or multi-gravity separator can be used for this. Typically, a higher density valuable mineral may need to be separated from lower density gangue material. Common applications are for tin, tungsten, and free gold.

[0004] The separator drum or multi-gravity separator is set at an angle and is rotated and axially oscillated. Scraper blades rotate relative to the drum surface and scrape the surface of the drum. A slurry is formed of the mixture and is fed into a raised end of the drum. The slurry is washed down the sloped surface of the drum by a feed of water. Higher density material is washed down the slope more slowly than the lower density material. The higher density material can therefore be scraped forwards by the scraper blades, to be collected separately from the lower density material.

[0005] The scraper blades degrade and / or wear during use, which reduces their effectiveness at moving heavier material forwards. This reduces the efficiency of the separator drum over time.

[0006] It is desirable to maintain the efficiency of the separator drum whilst reducing the time which the separator drum may be out of use for maintenance.

[0007] The present invention seeks to provide a solution to this problem.

[0008] According to a first aspect of the present invention, there is provided a separator-drum scraper-blade holder for holding scraper blades of a separator drum for separating material, the holder comprising: a scraper support arm; and a carrier having a securing means for securing a plurality of scraper blades thereto; the carrier being removably attachable to the scraper support arm so that the plurality of scraper blades is removeable from the separator drum together, without removing the scraper support arm from the separator drum.

[0009] The carrier being removably attachable to the scraper support arm can allow for all the scraper blades of a given arm to be removed from the separator drum in a single action. That is, the individual scraper blades are not required to be separately detached from the scraper support arm via unfastening separate fasteners, which would be a timeconsuming and difficult process. This is particularly the case since it may be difficult and unsafe to access the fasteners of blades deeper inside the drum. The scraper blades can therefore be changed in a time-effective manner, and without disturbing other components inside the drum. As such, the separator drum would be out-of-action for maintenance for shorter durations than would be otherwise possible.

[0010] The securing means may also be referred to as a fastener.

[0011] Preferably, the securing means may be a releasable securing means. As such, the scraper blades can be released from the carrier and replaced.

[0012] Beneficially, the securing means may comprise a plurality of blade-receiving holes in the carrier, each blade-receiving hole for receiving a portion of the scraper blade.

[0013] Advantageously, the blade-receiving holes may be blade-receiving slots. The blades are thin or flat, and therefore a slot-shape receives the blades in a more effective manner.

[0014] In a preferable embodiment, the carrier may be elongate and the slots may be at an angle to a longitudinal extent of the carrier. This allows the scraper blades to be mounted at an angle to a longitudinal extent of the carrier, which allows for the scraper blades to scrape material forwards.

[0015] Optionally, the securing means may comprise an elongate element for extending through an aperture of each of the blades. The elongate element may alternatively be termed a rod or a retention rod. The use of the retention rod allows for all the scraper blades to be released simultaneously, upon removal of the rod. The elongate element may not be necessary to secure the blades in use whilst the separator drum is rotating, since the rotation of the drum may keep the blades in the carrier. The elongate element may therefore be principally useful for retaining the blades in place whilst transporting and handling the carrier. Preferably, the carrier may include at least one opening for receiving the elongate element, the opening having a releasable fastener for selectively securing the elongate element.

[0016] Additionally, the carrier may include two said openings, one at a front end of the carrier and one at a rear end of the carrier. This allows for the elongate element to be released from either end, depending on which is more convenient.

[0017] Preferably, the carrier has a side wall and the scraper support arm has a side wall, the scraper support arm configured to exert a driving force on the carrier via the side walls. The side walls preferably extend at least along a majority of a longitudinal extent of the carrier and the scraper support arm. Since the carrier can be driven by interengagement of the side walls, any attachment means of the carrier and the scraper support arm is not required to take a driving load.

[0018] Advantageously, the carrier may be attachable to the scraper support arm via a front attachment means at or adjacent to the front of the carrier and scraper support arm, and a rear attachment means at or adjacent to the rear of the carrier and scraper support arm. Front and rear attachment provides strong support for the carrier.

[0019] Beneficially, the carrier may be attachable to the scraper support arm via a fastener and a fastener receiving aperture in each of the carrier and scraper support arm.

[0020] Optionally, the fastener and the fastener receiving aperture in each of the carrier and scraper support arm may comprise the front attachment means. The fastener being at the front allows easier access for maintenance.

[0021] Preferably, the carrier may be attachable to the scraper support arm via an interference fit.

[0022] Additionally, the interference fit may comprise a tapering receiver in one of the carrier and scraper support arm, and a protrusion at the other of the carrier and scraper support arm, the protrusion being receivable in the tapering receiver.

[0023] In a preferable embodiment, the interference fit may comprise the rear attachment means. The interference fit may not require manual interaction, being usable by pushing or pulling from the other end. Therefore, the carrier may be attachable and detachable from a user positioned only at the front, allowing maintenance to be quicker and simpler. Beneficially, the scraper support arm includes an aperture for receiving a head of a tool for engaging and forcing the carrier so as to disengage from the scraper support arm. This can allow for sufficient force to be applied to overcome the interference fit.

[0024] Advantageously, the carrier may include a hole for receiving a head of a tool for engaging and forcing the carrier so as to disengage from the scraper support arm. This can allow for sufficient force to be applied to overcome the interference fit. The hole is preferably a recess.

[0025] Additionally, said aperture of the scraper support arm and said hole of the carrier may be alignable.

[0026] According to a second aspect of the invention, there is provided a separator-drum scraper-blade system comprising the holder of the first aspect of the invention, and a plurality of scraper blades attached to the carrier via the securing means.

[0027] Preferably, each scraper blade may have an aperture for receiving the elongate element of the securing means therethrough.

[0028] Preferably, each scraper blade has a mounting portion for receipt by one of the holes, a cross-section of the mounting portion being smaller than an opening of the hole so that the scraper blade has freedom of movement within the hole. This allows the scraper blades to have sufficient float to maintain contact with slightly eccentric drums.

[0029] According to a third aspect of the invention, there is provided a separator drum for separating material comprising the separator-drum scraper-blade holder according to a first aspect of the invention or the multi-gravity-separator scraper-blade system according to the second aspect of the invention.

[0030] According to a fourth aspect of the invention, there is provided a method of removing the scraper blades of a separator drum having the separator drum scraper-blade system according to the third aspect of the invention, the method comprising removing the carrier having the plurality of scraper blades from the scraper support arm.

[0031] Preferably, the method further comprises inserting the head of the tool through the hole to engage the carrier and forcing the carrier so as to disengage the interference fit.

[0032] According to a fifth aspect of the invention, there is provided a scraper blade preferably for the separator-drum scraper-blade holder when there is a plurality of blade-receiving holes in the carrier. The scraper blade has a mounting portion for receipt by one of the blade-receiving holes of the carrier. A cross-section of the mounting portion is preferably smaller than an opening of the hole so that the scraper blade has freedom of movement within the hole.

[0033] The scraper blade has a body which defines a scraping portion, for scraping the surface of the drum, and a mounting portion, for receipt by one of the blade-receiving holes in the carrier. The mounting portion may be smaller and / or have a smaller lateral extent than the scraping portion.

[0034] The scraper blade may be defined by two parts, each part defining a portion of the scraping portion and each part and / or portion of the scraping portion being at an angle to each other so that the scraping portion is non-linear. This allows for a non-linear scraping portion to be formed from various materials, including those which are hardwearing but which are brittle, have a low-workability and / or have low tensile strength, such as ceramics. The parts are preferably attachable to each other.

[0035] Each part may also have a portion of the mounting portion, and the portions of the mounting portion being at an angle to each other. The blade-receiving holes of the carrier may be similarly configured to receive the angularly off-set mounting portions.

[0036] It will be appreciated that optional and preferable features of the scraper blade of the first aspect of the invention may apply for the fifth aspect of the invention.

[0037] According to a sixth aspect of the invention, there is provided a carrier for securing scraper blades thereto preferably for the separator-drum scraper-blade holder according to a first aspect of the invention. The carrier may have blade-receiving holes, such as slots. Each hole or slot may have angularly off-set portions. It will be appreciated that preferable and optional features described for the carrier of the first aspect of the invention may apply for the fifth aspect of the invention.

[0038] According to a seventh aspect of the invention, there is provided a method of separating minerals from gangue using the separator-drum scraper-blade holder of according to a first aspect of the invention, the separator-drum scraper-blade system according to a second aspect of the invention, or the separator drum of the third aspect of the invention.

[0039] The terms front and rear used herein refer to axial ends of the separator drum. The terms may be reversed. The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which:

[0040] Figure 1 shows an embodiment of a separator drum in accordance with a third aspect of the invention, having a separator-drum scraper-blade system in accordance with a second aspect of the invention including a separator-drum scraper-blade holder in accordance with a first aspect of the invention;

[0041] Figure 2 shows the separator drum of Figure 1 with a first embodiment of a carrier according to a sixth aspect of the invention removed from a scraper support arm;

[0042] Figure 3 shows the carrier of Figure 1 with a plurality of scraper blades, each according to a fifth aspect of the invention, removed therefrom;

[0043] Figure 4 shows a rear attachment means of the separator-drum scraper-blade holder of Figure 1 in a disengaged condition;

[0044] Figure 5 shows the rear attachment means of Figure 4 in an engaged condition;

[0045] Figure 6 shows a front attachment means of the separator-drum scraper-blade holder of Figure 1 in a disengaged condition;

[0046] Figure 7 shows the front attachment means of Figure 6 in an engaged condition;

[0047] Figure 8 shows a second embodiment of a carrier according to a sixth aspect of the invention and a second embodiment of a second type of a blade according to a fifth aspect of the invention; and

[0048] Figure 9 shows a reverse view of Figure 8.

[0049] Referring firstly to Figure 1 there is shown a separator drum 10 having a separator-drum scraper-blade holder and a plurality of scraper blades 12 attached thereto to form a separator-drum scraper-blade system. The separator-drum scraper-blade holder comprises a scraper support arm 14 and a carrier 16. The carrier 16 may be alternatively termed as a cartridge.

[0050] In Figure 1 , the carrier 16 is engaged with the scraper support arm 14.

[0051] The separator drum 10 may have additional conventional components, which are not shown, for causing rotation of the drum and axial oscillation of the drum. There may also be a support structure or spider hub for mounting and rotating the scraper support arm 14. Although only one scraper support arm 14 and carrier 16 is shown, each separator drum 10 may have a plurality of pairs of such components, such as four pairs, each mounted to the support structure to engage a different part of a drum body 18 of the drum. For example, the four pairs of scraper support arms 14 and carriers 16 may be equiangularly spaced apart. The drum is set at an axial slope. The drum may be a singular or sole drum, which is to say that there is preferably no inner and outer drum in the arrangement.

[0052] The drum body 18 of the separator drum 10 is conventional. Therefore, detailed description of the drum body 18 is omitted.

[0053] Referring now to Figure 2, the carrier 16 is shown as disengaged and removed relative from the scraper support arm 14.

[0054] The scraper support arm 14 is elongate and is rotatably mounted relative to the drum body 18.

[0055] The scraper support arm 14 has a receiving portion at which the carrier 16 is receivable. The receiving portion has a side wall 20 for engaging a side of the carrier 16, and a base 22 for engaging a base of the carrier 16. The receiving portion is therefore L-shaped or substantially L-shaped. However, it will be appreciated that the receiving portion may define a full channel in alternative embodiments. The receiving portion preferably has a continuous or substantially continuous cross-section.

[0056] The scraper support arm 14 further includes a mounting portion, which may comprise a bracket 24 for attaching to a support structure of the separator drum 10. The bracket 24 here extends from the base 22 of the receiving portion of the scraper support arm 14. A brace 26, which may be triangular, preferably supports the bracket 24. The bracket 24 may comprise two bracket portions, each having at least one fastener receiving aperture 28 therethrough, as best shown in Figures 4 and 5, for allowing connection to a support structure of the separator drum 10.

[0057] The carrier 16 may be elongate and may have a block shape or substantial block shape. The carrier 16 may have a continuous or substantially continuous cross-section.

[0058] Referring now to Figure 3, the scraper blades 12 are removably attachable to the carrier The scraper blades 12 each have a scraper blade body having a scraping portion 30 or scraping edge, which engages with a surface of the drum body 18, and a mounting portion 32 or mounting tab. The scraping portion 30 and mounting portion 32 are at opposite ends of the scraper blade body to each other. A central portion of the scraper blade body may be apertured.

[0059] The blades may be formed from materials such as high carbon sheet steel, waterjet cut ceramic sheet, tungsten carbide or other sintered forms of tungsten.

[0060] There are preferably two types of blade, a first type 12a and a second type 12b, which may alternate along the longitudinal extent of the holder. The first type of the scraper blade 12a is preferably flat. However, it will be appreciated that non-planar scraper blades 12 may be considered, such as scraper blades 12 with two separate scraping portions 30 extending in parallel. A more three-dimensional blade could be considered to provide a ploughing-action.

[0061] The second type 12b will be described with reference to Figures 4 and 5.

[0062] The mounting portion 32 of each scraper blade 12 has a smaller width than the body. The mounting portion 32 includes an aperture 33 therethrough. The aperture 33 is preferably elongate, for example extending towards the scraping portion 30.

[0063] The attachment of the scraper blades 12 to the carrier 16 is here achieved via the carrier 16 having a plurality of holes, each hole for receiving a mounting portion 32 of one scraper blade 12. The holes are preferably slots 34, being elongate. The slots 34 are at an angle to a longitudinal extent of the carrier 16, which allows the blades to be mounted at an angle to the carrier 16.

[0064] Although a slot is preferred, it will be appreciated that other forms of hole may be provided. For example, instead of a single slot, there may be two spaced apart holes. The holes may be round. The mounting portion may be shaped to correspond with the slot or vice versa.

[0065] The carrier 16 includes a receiving portion for receiving an elongate element 36, which may here be termed a rod. The receiving portion for the rod 36 extends through the carrier 16 and at the locations where the mounting portion 32 of each scraper blade 12 is received. The receiving portion of the elongate element 36 includes an opening 38 in at least one of the ends of the carrier 16. Here there is an opening 38 at each end of the carrier 16. The or each opening 38 may include a fastener 40, such as a screw-threaded fastener, for example a grub screw, for securing the rod 36 in position.

[0066] For manufacturing reasons, the receiving portion may be an open channel for a majority of its length, having drilled holes at each end to form the openings 38. The channel may be open on a reverse side relative to the slots 34.

[0067] The mounting portion 32 of each scraper blade 12 is inserted into a corresponding slot 34. The rod 36 is then inserted through the carrier 16 and through the aperture 33 of the mounting portion 32 of each scraper blade 12. This retains the scraper blades 12 to the carrier 16. The or each fastener 40 can then be engaged to secure the rod 36 to the carrier 16.

[0068] Whilst removably attachable scraper blades 12 are preferred, it will be appreciated that single use carriers or cartridges may be considered, with the scraper blades permanently attached thereto.

[0069] Referring now to Figures 4 and 5, the carrier 16 is removably attachable to the scraper support arm 14 via a rear attachment means 42 or rear attachment, which is preferably an interference fit. The rear attachment means 42 is at or adjacent to the rear end of the carrier 16 and scraper support arm 14.

[0070] The interference fit is achieved via a tapering receiver 44 at the side wall of the carrier 16. There is preferably a tapering receiver 44 at or in each side wall of the carrier 16. The receiver 44 tapers in a longitudinal direction of the carrier 16. The end of the receiver 44 may be rounded. The or each tapering receiver 44 may be a hole, cut-out, channel, or groove.

[0071] The scraper support arm 14 includes a protrusion 46 for receipt by the tapering receiver 44. Here the scraper support arm 14 has a protrusion 46 on the side wall 20, and a protrusion 46 on a bracket 47 mounted to oppose the side wall 20. This allows for one protrusion 46 to be received in each tapering receiver 44. The protrusion may be circular.

[0072] The taper of the receiver 44 has a close fit with the protrusion 46 for providing a secure interference fit.

[0073] The second type of the blade 12b can be more clearly seen in Figures 4 and 5. The second type of the blade comprises two parts 47a, 47b which attach or connect to each other. One of the parts 47a has the mounting portion 32, and a portion of the scraping portion 30. The other part 47b defines another portion of the scraping portion 30. The two parts 47a, 47b are at an angle to each other so that material flow around the blades can be controlled to maximise performance. The two parts 47a, 47b preferably attach to each other by an interference fit and / or interdigitating fingers.

[0074] Referring now to Figures 6 and 7, the carrier 16 is also removably attachable to the scraper support arm 14 via a front attachment means 48, or front attachment. The front attachment means 48 is at or adjacent to the front end of the carrier 16 and scraper support arm 14.

[0075] The front attachment means 48 comprises a fastener 50 and a fastener receiving aperture 52 in the carrier 16 and in the scraper support arm 14. The fastener 50 may include a bolt and nut. The fastener receiving aperture 52 of the carrier 16 preferably extends through an entire width of the carrier 16.

[0076] The scraper support arm 14 may include at least one aperture 54 in a base 22 of the receiving portion. Similarly, the carrier 16 may include at least one hole, preferably a recess 56, in a base of the carrier 16. This is for allowing the head of a tool, such as a screwdriver, to engage the carrier 16 and force or lever the carrier 16 from the scraper support arm 14. This is particularly useful to disengage the interference fit of the rear attachment means 42.

[0077] Preferably, the recess and aperture 56, 54 are at an opposing end of the carrier 16 and scraper support arm 14 to the interference fit. Therefore, the recess and aperture 56, 54 are at a front end portion of the carrier 16 and scraper support arm 14. As such, the recess and aperture 56, 54 are at the same end as the front attachment means 48, allowing the front and rear attachment means 48, 42 to be conveniently disengaged from the same end.

[0078] The front and rear attachment means may be reversed.

[0079] The carrier 16 and the scraper support arm 14 may have a bevelled edge 58.

[0080] The design of the scraper support arm 14 and carrier 16 is simple, and does not require welding of steel parts, and so a wider range of materials can be considered. When scraper blades 12 are attached to the carrier 16, and the carrier 16 is attached to the scraper support arm 14, the separator drum 10 may be used in a conventional manner. That is, a slurry of material to be separated, which may include gangue mixed with valuable minerals, may be fed into a front end of the drum, with a feed of water. Lighter material of the slurry is washed down the slope more quickly, whilst heavier material, including the valuable minerals, of the slurry is scraped forward by the scraper blades 12. This allows for the heavier material, or minerals, to be collected separately from the lighter material, or gangue.

[0081] The carrier 16 is driven around the drum by the scraper support arm 14. A driving force applied from the side wall 20 of the scraper support arm 14 is applied to and / or along the side wall of the carrier.

[0082] After a period of time, and / or after deterioration of the scraper blades 12 has been determined by routine inspection, it is desirable to change the scraper blades 12.

[0083] To do so, the carrier 16 is removed from the scraper support arm 14.

[0084] First, the front attachment means 48 may be disengaged by loosening and removing the nut and removing the bolt. The rear attachment means 42 may then be disengaged by inserting the head of a screwdriver through the aperture 54 of the scraper support arm 14 and into the recess 56 in the carrier 16. The carrier 16 may then be forced or levered so that the interference fit of the rear attachment means 42 is disengaged. The carrier 16 can then be removed from the scraper support arm 14.

[0085] The used scraper blades 12 are now removed from the carrier 16. This is done by loosening the fastener 40 which holds the rod 36 of the carrier 16 in position. The rod 36 is removed, freeing the used scraper blades 12. The used scraper blades 12 can then be removed from their slots 34, and new scraper blades 12 inserted. The rod 36 is reinserted into the carrier 16, through the aperture 33 of the mounting portion 32 of each scraper blade 12, and secured into position via the fastener 40. The new scraper blades 12 are thus attached to the carrier 16.

[0086] The carrier 16 is next re-attached to the scraper support arm 14. To do so, the carrier 16 is pushed firmly along the scraper support arm 14 so as to engage the interference fit of the rear attachment means 42 tightly. The front attachment means 48 can then be secured by inserting the bolt through the fastener receiving aperture and tightening the nut.

[0087] Thus, the scraper blades 12 for the scraper support arm 14 are changed. This may be repeated for each of the scraper support arms 14 of the separator drum 10.

[0088] Referring to Figures 8 and 9, there is shown a second embodiment of a carrier 116 and a second embodiment of a second type of the blade 112b. As before, there are preferably first and second types of blade which alternate.

[0089] The second type of the blade 112b comprises two parts 147a, 147b. The parts 147a, 147b are at an angle to each other. Each part 147a, 147b has a mounting portion 132a, 132b. The mounting portions 132a, 132b are similarly at an angle to each other. As before, each part 147a, 147b defines a portion of a scraping portion 130.

[0090] The two parts 147a, 147b may attach via an interference fit. The two parts may slot together. One part 147a may define a hole for receiving a leg of the other part 147b therethrough.

[0091] In view of the angular offset mounting portions 132a, 132b, the slot 134 or hole for receiving the angular offset mounting portions 132a, 132b has at least two angular offset components. Here there are preferably two slots which are at an angle to each other. Preferably, the two slots intersect. In view of the alternating first and second types of blade, the slots preferably also alternative in type.

[0092] It is therefore possible to provide a convenient way of changing the scraper blades of a separator drum. The scraper blades are secured to a carrier or cartridge which can be removed from a scraper support arm. The scraper blades can thus be removed together and at the same time as each other.

[0093] The words ‘comprises / comprising’ and the words ‘having / including’ when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0094] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

[0095] The embodiments described above are provided by way of examples only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined herein.

Claims

Claims1. A separator-drum scraper-blade holder for holding scraper blades (12) of a separator drum (10) for separating material, the holder comprising: a scraper support arm (14); and a carrier (16) having a securing means for securing a plurality of scraper blades (12) thereto; the carrier (16) being removably attachable to the scraper support arm (14) so that the plurality of scraper blades (12) is removeable from the separator drum (10) together, without removing the scraper support arm (14) from the separator drum (10).

2. A separator-drum scraper-blade holder as claimed in claim 1, wherein the securing means is a releasable securing means.

3. A separator-drum scraper-blade holder as claimed in claim 1 or claim 2, wherein the securing means comprises a plurality of blade-receiving holes (34) in the carrier (16), each blade-receiving hole (34) for receiving a portion (32) of the scraper blade (12).

4. A separator-drum scraper-blade holder as claimed in claim 3, wherein the bladereceiving holes are blade-receiving slots (34).

5. A separator-drum scraper-blade holder as claimed in claim 4, wherein the carrier (16) is elongate and the slots (34) are at an angle to a longitudinal extent of the carrier (16).

6. A separator-drum scraper-blade holder as claimed in any one of the preceding claims, wherein the securing means comprises an elongate element (36) for extending through an aperture (33) of each of the blades (12).

7. A separator-drum scraper-blade holder as claimed in claim 6, wherein the carrier (16) includes at least one opening (38) for receiving the elongate element (36), the opening (38) having a releasable fastener (40) for selectively securing the elongate element (36).

8. A separator-drum scraper-blade holder as claimed in any one of the preceding claims, wherein the carrier (16) has a side wall and the scraper support arm (14) has a side wall (20), the scraper support arm (14) configured to exert a driving force on the carrier (16) via the side walls (20).

9. A separator-drum scraper-blade holder as claimed in any one of the preceding claims, wherein the carrier (16) is attachable to the scraper support arm (14) via a front attachment means (48) at or adjacent to the front of the carrier (16) and scraper support arm (14), and a rear attachment means (42) at or adjacent to the rear of the carrier (16) and scraper support arm (14).

10. A separator-drum scraper-blade holder as claimed in any one of the preceding claims, wherein the carrier (16) is attachable to the scraper support arm (14) via a fastener (50) and a fastener receiving aperture (52) in each of the carrier (16) and scraper support arm (14).

11. A separator-drum scraper-blade holder as claimed in claim 9 and claim 10, wherein the fastener (50) and the fastener receiving aperture (52) in each of the carrier (16) and scraper support arm (14) comprise the front attachment means (48).

12. A separator-drum scraper-blade holder as claimed in any one of the preceding claims, wherein the carrier (16) is attachable to the scraper support arm (14) via an interference fit.

13. A separator-drum scraper-blade holder as claimed in claim 12, wherein the interference fit comprises a tapering receiver (44) in one of the carrier (16) and scraper support arm (14), and a protrusion (46) at the other of the carrier (16) and scraper support arm (14), the protrusion (46) being receivable in the tapering receiver (44).

14. A separator-drum scraper-blade holder as claimed in claims 12 or 13 when dependent on claim 9, wherein the interference fit comprises the rear attachment means (42).

15. A separator-drum scraper-blade holder as claimed in any one of the preceding claims, wherein the scraper support arm (14) includes an aperture (54) forreceiving a head of a tool for engaging and forcing the carrier (16) so as to disengage from the scraper support arm (14).

16. A separator-drum scraper-blade holder as claimed in any one of the preceding claims, wherein the carrier (16) includes a hole (56) for receiving a head of a tool for engaging and forcing the carrier (16) so as to disengage from the scraper support arm (14).

17. A separator-drum scraper-blade holder as claimed in claim 15 and 16, wherein said aperture (54) of the scraper support arm (14) and said hole (56) of the carrier (16) are alignable.

18. A separator-drum scraper-blade system comprising the holder of any one of the preceding claims, and a plurality of scraper blades (12) secured to the carrier (16) via the securing means.

19. A separator-drum scraper-blade system as claimed in claim 18 when dependent on claim 6, wherein each scraper blade (12) has an aperture (33) for receiving the elongate element (36) of the securing means therethrough.

20. A separator-drum scraper-blade system as claimed in claim 18 or claim 19 when dependent on claim 3, wherein each scraper blade (12) has a mounting portion (32) for receipt by one of the holes, a cross-section of the mounting portion (32) being smaller than an opening of the hole so that the scraper blade (12) has freedom of movement within the hole.

21. A separator drum (10) for separating material comprising the separator-drum scraper-blade holder as claimed in any one of claims 1 to 17 or the multi-gravity- separator scraper-blade system as claimed in any one of claims 18 to 20.

22. A method of removing the scraper blades (12) of a separator drum (10) having the separator drum scraper-blade system as claimed in any one of claims 18 to 20, the method comprising removing the carrier (16) having the plurality of scraper blades (12) from the scraper support arm (14).

23. A method as claimed in claim 22 when dependent on claim 15 or 16, further comprising the step of inserting the head of a tool through the aperture (54) ofthe scraper support arm (14) or the hole (56) of the carrier (16) to engage the carrier (16) and force the carrier (16) so as to disengage from the scraper support arm (14).

24. A scraper blade (12) for the separator-drum scraper-blade holder as claimed in any one of claims 3 to 17 when dependent on claim 3, wherein the scraper blade (12) has a mounting portion (32) for receipt by one of the blade-receiving holes (34) of the carrier (16).

25. A carrier (16) for securing scraper blades (12) thereto for the separator-drum scraper-blade holder as claimed in any one of claims 1 to 17.

26. A method of separating minerals from gangue using the separator-drum scraperblade holder of any one of claims 1 to 17, the separator-drum scraper-blade system as claimed in any one of claims 18 to 20 or the separator drum of claim21.

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