Magnetic separation processing of garnet minerals

Abstract

A system for separating garnet from a feed, the system comprising a first separation stage comprising an electromagnetic separator.

Description

Magnetic separation processing of garnet mineralsField of the Invention

[0001] The invention relates to processing of minerals using high intensity electro-magnetic separation.Background

[0002] The following discussion of the background art is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge as at the priority date of the application.

[0003] The beneficiation of minerals and in particular, heavy minerals from sand deposits has historically involved dry mining (for example, by mechanical excavation) and the upgrading of these mineral sands using screening and gravity concentration techniques. The way in which these processes have been utilized within the mineral sands industry has fundamentally remained unchanged from its inception. Historically, mineral sand operations upgraded the run-of-mine ore at the wet concentrator prior to the transport of a heavy mineral concentrate to a mineral separation plant for further upgrading.

[0004] The wet concentrator plant serves to recover and concentrate the heavy mineral. The process relies on the varying density differences and magnetic susceptibilities that exist between the valuable and waste materials.

[0005] Deposits generally, and including mineral sands deposits, have become more challenging from a capital investment, mining and beneficiation perspective due to deposits becoming lower in grade and higher in unwanted materials.

[0006] Known techniques for upgrading garnet laden feeds in the rougher stage are expensive and require a complicated array of multiple stages to achieve a certain performance. This results in high capital cost, high ongoing cost, frequent stoppages, and performance limitations on the separation that can be achieved.

[0007] Improvements in overall efficiency are sought to make mining operations viable, which may be achieved by any of; lower capital and / or ongoing cost, improved reliability, reduced complexity, or improved performance, and it is against this background that the present invention is presented.

[0008] Throughout the specification unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[0009] Throughout the specification unless the context requires otherwise, the word "include" or variations such as "includes" or "including", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

[0010] Throughout the specification unless the context requires otherwise, the term electro-magnetic separator or electro-magnetic separation will be understood to include wet high intensity magnetic separator "WHIMS" and high gradient magnetic separator "HGMS" which are industry terms or descriptions for commercially available equipment.

[0011] Throughout the specification unless the context requires otherwise, where it is stated that a mineral "reports" or is "directed to" a location or apparatus, it is recognised that this is not absolute, and that a lower portion or concentration of said mineral may report, or be directed to, another output. The term is intended to mean the greater portion of said mineral.Summary of Invention

[0012] According to a first aspect of the invention, there is provided a system for separating garnet from a feed, the system comprising a first separation stage comprising an electromagnetic separator.

[0013] According to a second aspect of the present invention, there is provided a system for separating garnet from a feed, the system comprising an electromagnetic separator configured to separate the feed into a first portion and a second portion, wherein material of the feed having a sufficiently high magnetic susceptibility is directed to the first portion by an electromagnetic field, and wherein material of the feed having insufficient magnetic susceptibility to be directed to the first portion is directed to the second portion, and wherein garnet reports to the first portion.

[0014] In an embodiment, the electromagnetic separator operates at a sufficiently high magnetic field strength and magnetic gradient to attract garnet from the feed to the first portion.

[0015] According to a third aspect of the present invention, there is provided a mineral processing plant comprising an electromagnetic separator, wherein the electromagnetic separator receives a feed comprising garnet, wherein the feed is from either mineral sands or a hard rock deposit, and wherein the electromagnetic separator is configured to separate garnet from the feed.

[0016] Unless the contrary is apparent, embodiments of the above-described principal aspects, and any of those described below, may comprise or incorporate, either individually or in combination, any of the following features.

[0017] In an embodiment, the feed does not comprise iron.

[0018] In an embodiment, iron is absent from the feed.

[0019] In an embodiment, the feed comprises less than 1% iron.

[0020] In an embodiment, the feed comprises less than 1% ferrous minerals.

[0021] In an embodiment, the electromagnetic separator is a wet high intensity magnetic separator (WHIMS).

[0022] In an embodiment, the electromagnetic separator is a high gradient magnetic separator (HGMS).

[0023] In an embodiment, the electromagnetic separator is configured to direct garnet to a magnetic, or first, portion.

[0024] In an embodiment, the electromagnetic separator is configured according to properties of the feed, alone or in combination.

[0025] In an embodiment, the electromagnetic separator is configured by setting the magnetic field strength.

[0026] In an embodiment, the electromagnetic separator is configured by setting the magnetic gradient.

[0027] In an embodiment, the electromagnetic separator is configured by setting both the magnetic field strength and the magnetic gradient.

[0028] In an embodiment, the properties include magnetic susceptibility of garnet in the feed.

[0029] In an embodiment, the properties include concentration of garnet in the feed.

[0030] In an embodiment, the properties include particle size of garnet particles in the feed.

[0031] In an embodiment, the properties include composition of garnet in the feed.

[0032] In an embodiment, the properties include consideration of minerals other than garnet in the feed.

[0033] In an embodiment, the properties of the feed are measured and the measurements are used to configure the electromagnetic separator.

[0034] In an embodiment, the configuration of the electromagnetic separator is adjusted based on measurement of the outputs from the first and / or second, or magnetic and / or non-magnetic portions.

[0035] In an embodiment, the system comprises a cleaner stage following the electromagnetic separator.

[0036] In an embodiment, a magnetic, or first, portion of the electromagnetic separator reports to the cleaner stage.

[0037] In an embodiment, the cleaner stage comprises at least one re-cleaner spiral.

[0038] In an embodiment, the cleaner stage comprises a cleaner electromagnetic separator.

[0039] In an embodiment, the cleaner electromagnetic separator is of smaller capacity and / or magnetic field strength and / or gradient, than the electromagnetic separator of the rougher stage.

[0040] In an embodiment, the system comprises a cyclone separator, wherein an underflow of the cyclone separator becomes the feed to the electromagnetic separator.

[0041] In an embodiment, the cyclone separator is configured to separate higher density / larger particle size garnet from lower density / smaller particle size waste material.

[0042] In an embodiment, the system comprises a screening stage, wherein a fine output of the screen reports to the cyclone separator.

[0043] In an embodiment, the system comprises a screening stage, wherein a fine output of the screening stage becomes the feed to the electromagnetic separator.

[0044] In an embodiment, the screening stage is configured to separate garnet having a particle size smaller than 1.0mm from waste materials.

[0045] In an embodiment, the feed is a mineral sands feed.

[0046] In an alternative embodiment, the feed is from a hard rock deposit.

[0047] In an embodiment, the electromagnetic separator is configured to receive a garnet laden slurry.

[0048] In an embodiment, the garnet laden slurry comprises between 1% and 30% garnet.

[0049] In an embodiment, the garnet laden slurry comprises between 5% and 15% garnet.

[0050] In an embodiment, the feed is a garnet laden slurry in which the garnet content in the solid is between 1% and 30%.

[0051] In an embodiment, the feed is a slurry with a pH substantially the same as water.

[0052] In an embodiment, the feed is a slurry with a pH of between 6 and 8.

[0053] In an embodiment, the feed is a slurry having undergone no chemical treatment.

[0054] In an embodiment, the feed is received directly from any one of: a screen, a cyclone, or a protection filter.

[0055] In an embodiment, the feed has been beneficiated according only to particle size.

[0056] In an embodiment, the electromagnetic separator comprises a matrix configured to process garnet laden slurry.

[0057] In an embodiment, the electromagnetic separator comprises a matrix configured with spacing between 0.5mm and 5mm.

[0058] In an embodiment, the electromagnetic separator has a magnetic field strength and magnetic gradient sufficient to attract garnet particles.

[0059] In an embodiment, the electromagnetic separator has a magnetic field strength and magnetic gradient of sufficient magnitude to attract the garnet particles.

[0060] In an embodiment, the electromagnetic separator has a magnetic field strength of at least 10,000 Gauss (1.0T), preferably at least 15,000 Gauss (1.5T).

[0061] In an embodiment, the electromagnetic separator has a magnetic field strength of between 15,000 Gauss (1.5T) and 25,000 Gauss (2.5T).

[0062] In an embodiment, the electromagnetic separator has a capacity of at least 100 tonnes per hour (tph), preferably at least 200 tph, more preferably at least 400 tph.

[0063] In an embodiment, the electromagnetic separator is configured to separate at least 80% of the garnet from the feed.

[0064] In an embodiment, the electromagnetic separator is configured to separate at least 90% of the garnet from the feed.

[0065] According to a fourth aspect of the present invention, there is provided a method of processing an ore feed containing garnet, the method comprising; using an electromagnetic separator at a first separation stage to separate garnet from the feed, and directing the garnet to another processing stage.

[0066] In an embodiment, the electromagnetic separator is configured to separate the feed into a first portion and a second portion, wherein material of the feed having a sufficiently high magnetic susceptibility is directed to the first portion by an electromagnetic field, and wherein material of the feed having insufficient magnetic susceptibility to be directed to the first portion is directed to the second portion, and wherein garnet reports to the first portion.

[0067] According to a fifth aspect of the present invention, there is provided a method of separating garnet from a feed, the method comprising; directing the feed through a screening stage configured to separate the feed into a garnet laden fine output and a waste coarse output, directing the fine output to an electromagnetic separator, wherein the garnet reports to a magnetic portion of the electromagnetic separator.

[0068] In an embodiment, directing the fine output of the screening stage to the electromagnetic separator via a cyclone stage comprising an overflow and an underflow, wherein the garnet reports to the underflow, and directing the underflow to the electromagnetic separator.

[0069] In an embodiment, where the magnetic portion of the electromagnetic separator comprises sufficient quantity of another mineral in addition to garnet, directing the magnetic portion for further processing.

[0070] In an embodiment, the further processing comprises gravity separation.

[0071] In an embodiment, the further processing comprises a spiral concentrator.

[0072] In an embodiment, the further processing stage comprises magnetic separation.

[0073] According to a sixth aspect of the present invention, there is provided a method of modifying a garnet beneficiation process, the method involving replacing a plurality of gravity concentrator spirals of a rougher stage of a multi-stage spiral beneficiation process with an electromagnetic separator.

[0074] In an embodiment, the method further comprises calibrating a matrix of the electromagnetic separator according to properties of garnet laden slurry feed.

[0075] According to a seventh aspect of the invention, there is provided a system for separating a paramagnetic mineral from a feed, the system comprising a rougher stage comprising an electromagnetic separator.

[0076] In an embodiment, the mineral comprises garnet.

[0077] According to an eighth aspect of the present invention, there is provided a system for separating garnet from a feed, the system comprising an electromagnetic separator configured to separate the feed into a magnetic portion and a non-magnetic portion, wherein the garnet reports to the magnetic portion.

[0078] In an embodiment, the electromagnetic separator operates at a sufficiently high magnetic field strength and magnetic gradient to attract garnet from the feed to the magnetic portion.Brief Description of Drawings

[0079] In order to provide a better understanding, embodiments of the present invention will be described, by way of example only, with reference to the accompanying drawings, in which:Figure la is flow sheet of a conventional mineral sands beneficiation process, showing an electromagnetic separator apparatus employed at a cleaner stage of the process.Figure lb is a flow sheet of a conventional iron ore beneficiation process, showing an electromagnetic separator apparatus employed at a rougher and as a cleaner stage of the process.Figure 2 is a flow sheet of a mineral sands beneficiation process according to an embodiment of the present invention, showing an electromagnetic separator apparatus employed at a first separation stage of the process.Description of Embodiments

[0080] The terms magnetic and non-magnetic are commonly used in industry to differentiate the two outputs of an electromagnetic separator. Throughout the specification, the term "first portion" is considered synonymous with the magnetic portion, or mag report, and the "second portion" is considered synonymous with the non-magnetic portion, or non mag report. It is acknowledged that the non-magnetic portion, or non mag report, is not necessarily without any magnetic field, and is not an absolute term. It is intended todifferentiate the two outputs, and non-magnetic may be understood to encompass low levels, for example negligible, magnetic field.

[0081] Referring to Figure la, there is shown an example of a conventional mineral sands process 100 in which the sands deposit is mechanically excavated and fed into a hopper 110 before being directed to a screen 120, which may be used to remove the coarse oversize material. The fine materials (including sand and heavy minerals) are processed through a series of spiral gravity concentrators 130 to further separate the heavy minerals from the unwanted material, which is then then directed to tailings 170.

[0082] Although the figure shows the spiral gravity concentrators 130 as a single unit, the stage(s) of spiral gravity concentrators 130 often comprise a large number of spirals, sometimes in excess of 200, arranged in various stages to achieve the target levels of separation. Stages may include primary, scavenger, middling, cleaner and re-cleaner spiral stages, and as such, the series of spiral gravity concentrators 130 forms a complex and costly component of the processing plant.

[0083] In some cases, the concentrate produced by the spiral gravity concentrators 130 is directed to an electromagnetic separator, a WHIMS 140 in this case, for further processing by magnetic fractionation. In such applications, the WHIMS 140 is used to separate magnetic material from the non-magnetic material, with one portion reporting to tailings, sold or sent for further processing, and the other portion dewatered using a combination of cyclone 150 and dewatering screen 160. The final product is stockpiled 180.

[0084] The separation into waste and concentrate portions is determined based on the desired outcome, for example where the concentrate final product is non-magnetic, for example rutile or zircon, the waste portion comprises the magnetic material, for example ilmenite.

[0085] Alternatively, where the final product concentrate is rich in product having a higher magnetic susceptibility, for example ilmenite, the WHIMS 140 may be used to separate the ilmenite from the unwanted non-magnetic material, with the waste portion comprising the non-magnetic material.

[0086] Ilmenite is a common example of a mineral to be separated, either as the concentrate product, or as a waste or secondary product. Ilmenite has a higher iron content than many of the minerals it is commonly found with and is therefore suitable for separation using WHIMS 140 or other magnetic separation means.

[0087] The WHIMS 140 used in such applications is of a capacity to handle the required feed, and the apparatus are therefore sized accordingly and conventionally have a capacity of less than 100 tph.

[0088] Furthermore, the magnetic field strength and gradient of WHIMS 140 apparatus in cleaner stages of mineral sands applications cannot be too high, the purpose of the WHIMS 140 in these applications is toseparate material of sufficient magnetic susceptibility from the feed, and the magnetic field strength of the apparatus is determined accordingly, typically between 0.5T and 1.0T.

[0089] These levels of magnetic field strength are suitable for separating ilmenite for example, but are not sufficient for attracting materials of lower magnetic susceptibility, including garnet.

[0090] In a garnet process, the garnet is of much lower magnetic susceptibility than ilmenite, and the purpose of the WHIMS 140 when used in a cleaner application is to upgrade the feed by separating the more magnetically susceptible minerals, such as ilmenite, from the garnet, with the garnet reporting to the nonmagnetic portion.

[0091] Referring to Figure lb, there is shown an example of a conventional iron ore process 200 in which the ore feed is processed through a hopper 210 and then screened 220 into different size fractions, for example lump ore (6-25mm), sinterfeed (l-6mm) and fines (-1mm). The size fractions are typically upgraded by means of gravity separation (dense media separation or jigs). The fines (-1mm) may be upgraded by means on WHIMS 240. This can be done in a single stage or as it is shown here in a rougher - cleaner configuration, which comprises a rougher WHIMS 240 and a cleaner WHIMS 250.

[0092] A concentrate from the WHIMS 250 is usually pumped to cyclone 260 and then gravitates onto a dewatering screen 270.

[0093] Iron ore operations are conventionally orders of magnitude larger than garnet operations, and the throughput of an iron ore process is therefore typically much greater. WHIMS apparatus 240 are known to be used in a rougher stage to separate the highly magnetically susceptible iron from the waste ore.

[0094] Due to the required throughput of iron ore operations, it is common that high capacity WHIMS 240 are used in the rougher stage, in combination with various feeds from different hoppers and screens.

[0095] In iron ore applications, the WHIMS 240 apparatus is required to be high capacity, many hundreds of tonnes per hour, and of high magnetic field strength, usually between 10,000 Gauss (1.0T) and 18,000 Gauss (1.8T), which are sufficient to attract the ferrous material, having a high level of magnetic susceptibility, to the magnetic portion. Such capacities are desirable in iron ore applications as the commonly deleterious elements in iron ore, such as silica and alumina are non-magnetic, meaning that they will not be separated along with the iron ore.

[0096] If garnet were present in an iron ore feed, the magnetic field strength of the WHIMS 240 apparatus would be selected to cause garnet to report to the non-magnetic portion along with the tailings, due to the magnetic susceptibility of garnet and the magnetic field strength of the WHIMS 240 apparatus.

[0097] To enable this functionality, the magnetic field strength must not be too high, or the garnet, being somewhat magnetically susceptible, would report to the magnetic portion along with the iron, and would therefore not be separated from the iron.

[0098] Referring now to Figure 2, there is shown a system 10 for separating a paramagnetic mineral, preferably garnet, from a feed, the system 10 comprising a first separation stage comprising an electromagnetic separator 40.

[0099] Also referring to Figure 2, there is shown a system 10 for separating garnet from a feed, the system 10 comprising an electromagnetic separator 40 configured to separate the feed into a magnetic portion and a non-magnetic portion, wherein the garnet reports to the magnetic portion.

[0100] According to an alternative embodiment, there is provided a mineral processing plant 10 comprising an electromagnetic separator 40, wherein the electromagnetic separator 40 receives a feed comprising garnet, and wherein the electromagnetic separator 40 is configured to separate garnet from the feed.

[0101] The electromagnetic separator 40 may be configured to operate at a sufficiently high magnetic field strength and / or magnetic gradient, to attract paramagnetic materials, in particular garnet, from the feed to the magnetic portion. An electromagnetic separator 40 of such magnetic field strength enables the garnet to report to the magnetic portion of the electromagnetic separator 40, in contrast to the conventional operation of electromagnetic separator 40 in garnet processes, in which the garnet reports to the non-magnetic portion.

[0102] The electromagnetic separator 40 may be configured depending on properties of the feed, the properties may include, alone or in combination, magnetic susceptibility, concentration, particle size and composition of garnet in the feed.

[0103] One deposit containing garnet may vary significantly from another, with a number of factors contributing to the effectiveness of an electromagnetic separator 40 apparatus to separate the garnet from a feed of the deposit.

[0104] The magnetic field strength and / or gradient required to separate garnet from a feed may therefore be adjusted according to the properties of the feed.

[0105] Given the large number of variables, it may be difficult to configure an electromagnetic separator 40 to perform as required, to separate garnet from the feed, without first determining the properties of the feed.

[0106] The electromagnetic separator 40 may be configured according to properties of the feed determined by measured data from the deposit. Measured data may be obtained in the form of samples.

[0107] Other minerals found in the feed may also be considered to effectively configure the electromagnetic separator 40.

[0108] The configuration of the electromagnetic separator 40 may be adjusted based on measured data from the outputs from the magnetic and / or non-magnetic portions.

[0109] The electromagnetic separator 40 may have a capacity of at least 100 tph, preferably at least 400 tph.

[0110] When used in a first separation stage, the capacity of the electromagnetic separator 40 stage may be higher than the capacity of the electromagnetic separator stage in the conventional garnet process, such as that depicted in Figure la.

[0111] The electromagnetic separator 40 may be configured to separate at least 80% of the garnet from the feed, preferably at least 90%.

[0112] In the examples shown in Figure 2, as with the conventional process shown in Figure la, the feed, in this example a mineral sands slurry, may be directed to cyclones used to remove the fine materials.

[0113] The system 10 may comprise a cleaner stage 50 following the electromagnetic separator 40. The magnetic portion of the electromagnetic separator 40 may report to the cleaner stage 50, and the cleaner stage 50 may comprise at least one re-cleaner spiral.

[0114] The system 10 may comprise a screen 30, wherein an underflow of the screen 30 reports to the electromagnetic separator 40. The screen 30 may be configured to separate smaller particle size garnet from larger particle size waste material. The screening stage 30 may be configured to separate garnet having a selected particle size from coarse waste materials, for example the particle size may be less than 1.0mm.

[0115] The electromagnetic separator 40 may be configured to receive a garnet laden slurry, which may comprise between 1% and 30% garnet.

[0116] Mineral sands slurries typically comprise 3% to 10% garnet, in contrast to iron ore which is typically between 20% Fe and 55% Fe.

[0117] Garnet particles in a mineral sands slurry tend to be between 0.1 and 1.4mm, which is the condition found in the mineral sands and does not require grinding. In comparison, iron ore is generally ground toachieve liberation before being fed to the electromagnetic separator, with the slurry having iron particle size less than 1.0mm, with oversize particles from a mill reporting to re-grinding to ensure this figure is met.

[0118] The electromagnetic separator 40 may comprise a matrix configured to process garnet laden slurry, the matrix may be configured with spacing between 0.5mm and 5.0mm.

[0119] Although garnet does not have a high magnetic susceptibility, when sufficiently liberated, for example in a mineral sands feed or when ground to a small enough particle size, testing has shown that it is feasible to direct the garnet particles from the feed to the magnetic portion of the electromagnetic separator 40. Doing so requires an electromagnetic separator 40 of sufficient magnetic field strength and gradient to attract the particles to the magnetic portion.

[0120] As the properties of garnet, including magnetic susceptibility, vary from one deposit to another, is it not practical to apply a fixed value of magnetic field strength and gradient, as the required value will most likely be determined based on the properties of the garnet in the deposit, which may be determined by testing, and may be further refined or adjusted based on the properties of the feed to the electromagnetic separator, and feeds from the magnetic and non-magnetic outputs.

[0121] Testing has showed unexpectedly high rates of separation, often in excess of 90% of the garnet being separated using the electromagnetic separator 40 in a single first separation stage for garnet. The results are unexpected as the garnet does not have particularly high magnetic susceptibility, but when easily separated from the waste material, for example in a mineral sands application, the electromagnetic separator 40 magnetic separation has been shown to be effective, and offers an alternative to the conventional process of an array of spiral concentrators.

[0122] The magnetic field strength required to separate garnet from mineral sands slurry is expected to be at least 10,000 Gauss (1.0T) and preferably in excess of 15,000 Gauss (1.5T). This is far in excess of the field strength of electromagnetic separator 40 used in conventional applications as shown in Figure la.

[0123] The electromagnetic separator 40 may preferably have a magnetic field strength of between 15,000 Gauss (1.5T) and 25,000 Gauss (2.5T).

[0124] With such rates of separation, the concentrate that is feed from the electromagnetic separator 40 requires significantly less subsequent processing that would otherwise be required in the wet concentrator and may only require a re-cleaner spiral stage.

[0125] For example, where the feed includes other magnetically susceptible materials that are at least as magnetically susceptible as garnet, this will also report to the magnetic portion of the electromagneticseparator 40 and must then be separated from the garnet. Ilmenite is a common example of such a material commonly found with garnet and one that is more magnetically susceptible than garnet.

[0126] Subsequent processing may therefore be undertaken, for example using a spiral concentrator 60 or similar, to classify the materials using differences in particle size and / or density.

[0127] Given the high rates of separation enabled by the electromagnetic separator 40, the volume of material to be subsequently processed is significantly reduced, and the downstream processing is simplified in comparison with conventional processes.

[0128] The simplified process using electromagnetic separator 40 in place of a number of an array of spiral concentrators also allows for simpler operation. The monitoring and adjustment of an array of spiral concentrators, to account for variations in the feed, is a complicated exercise, and requires the adjustment of rates of feed and re-directing the various reports, which can be onerous, time consuming and expensive.

[0129] In comparison, a single electromagnetic separator 40 can be adjusted from a control room at short notice by a single operator. It is envisaged that such control may also be able to be automated.

[0130] The skilled reader would readily appreciate the nature of the materials appropriate for making the components of the embodiments of the arrangements described herein. Modifications and variations as would be apparent to the skilled addressee are intended to be covered by the accompanying claims.

Claims

Claims1. A system for separating garnet from a feed, the system comprising a first separation stage comprising an electromagnetic separator.

2. A system for separating garnet from a feed, the system comprising an electromagnetic separator configured to separate the feed into a first portion and a second portion, wherein material of the feed having a sufficiently high magnetic susceptibility is directed to the first portion by an electromagnetic field, and wherein material of the feed having insufficient magnetic susceptibility to be directed to the first portion is directed to the second portion, and wherein garnet reports to the first portion.3 A system according to claim 1 or 2, wherein the electromagnetic separator is a wet high intensity magnetic separator (WHIMS).4 A system according to any one of the preceding claims, wherein the system comprises a cyclone separator, wherein an underflow of the cyclone separator becomes the feed to the electromagnetic separator.5 A system according to claim 4, wherein the system comprises a screening stage, wherein a fine output of the screen reports to the cyclone separator.6 A system according to any one of claims 1 to 3, wherein the system comprises a screening stage, wherein a fine output of the screening stage becomes the feed to the electromagnetic separator.7 A system according to any one of the preceding claims, wherein the feed is from either mineral sands or a hard rock deposit.8 A system according to any one of the preceding claims, wherein the feed is received directly from any one of: a screen, a cyclone, or a protection filter.9 A system according to any one of the preceding claims, wherein the feed has been beneficiated according only to particle size.10 A system according to any one of the preceding claims, wherein the feed is a slurry with a Ph of between 6 and 8.11 A method according to any one of the preceding claims, wherein the feed is a garnet laden slurry where the garnet content in the solid is between 1% and 30%.

12. A mineral processing plant comprising an electromagnetic separator, wherein the electromagnetic separator receives a feed comprising garnet, wherein the feed is from either mineral sands or a hard rock deposit, and wherein the electromagnetic separator is configured to separate garnet from the feed.

13. A method of processing an ore feed containing garnet, the method comprising; using an electromagnetic separator at a first separation stage to separate garnet from the feed, and directing the garnet to another processing stage.

14. A method according to claim 13, wherein the electromagnetic separator is configured to separate the feed into a first portion and a second portion, wherein material of the feed having a sufficiently high magnetic susceptibility is directed to the first portion by an electromagnetic field, and wherein material of the feed having insufficient magnetic susceptibility to be directed to the first portion is directed to the second portion, and wherein garnet reports to the first portion.

15. A method of separating garnet from a feed, the method comprising; directing the feed through a screening stage configured to separate the feed into a garnet laden fine output and a waste coarse output, directing the fine output to an electromagnetic separator, wherein the garnet reports to a magnetic portion of the electromagnetic separator.

16. A method according to claim 15, the method comprising directing the fine output of the screening stage to the electromagnetic separators via a cyclone stage comprising an overflow and an underflow, wherein the garnet reports to the underflow, and directing the underflow to the electromagnetic separator.

17. A method of modifying a garnet beneficiation process, the method involving replacing a plurality of gravity concentrator spirals of a rougher stage of a multi-stage spiral beneficiation process with an electromagnetic separator.

18. A method according to any one of claims 12 to 17, wherein the electromagnetic separator is a wet high intensity magnetic separator (WHIMS).

19. A method according to any one of claims 12 to 18, wherein the feed is from either mineral sands or a hard rock deposit.

20. A method according to any one of claims 12 to 19, wherein the feed is a garnet laden slurry comprising between 5% and 15% garnet.

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