FIELD

[0001] This disclosure relates to a mill liner, and, in particular, a mill liner for use in an autogenous grinding mill. This disclosure also relates to a mill including one or more of the liners.

BACKGROUND

[0002] After iron ore is removed from a mine, there are a number of steps involved in processing the extracted ore. These steps may include screening the ore to separate fine particles and then crushing, grinding and separating the iron ore and other valuable metals or minerals out from the remaining waste materials, known as gangue. The process of reducing the ore in size and separating the valuable components from the undesired materials is known as ore beneficiation.

[0003] Grinding is normally a subsequent step after an ore crushing process, and is an important part of the preparation work for mineral sorting. Grinding has two main purposes: to break open the ore rock crystals so that the minerals inside can be accessed (and then separated from the mixture); and to produce mineral filler, which is fine inert mineral matter. Grinding can also be used to achieve a certain particle size or increase the surface area of a solid material.

[0004] Grinding requires a significant amount of energy. The grinding process accounts for approximately 45-55% of the energy consumption for a plant associated with the beneficiation.

[0005] There are a range of grinding mills that can be incorporated into a mining system. Autogenous grinding (AG) and semi-autogenous grinding mills (SAG) may be used when, for example, the feed material into the grinding mill is coarse ore. This is because the feed material forms, at least, part of the grinding media of the mill when an AG or SAG mill is used.

[0006] An AG mill consists of a rotating drum, which when spun, tosses around material fed into the drum. AG mills with a larger diameter are widely used in modern mineral processing plants for high grinding tonnage and lower operation cost. Ore in large fragmentation is directly fed into the AG mill and the larger rocks act as grinding media, which significantly save the operating costs. The impact of the ore particles crashing together breaks the larger particles open and grinds the particles into finer material. Conversely, the SAG mill contains both ore particles and other grinding media, typically balls. When the SAG mill is in operation, the ore particles and the balls crash together to produce the grinding effect.

[0007] Because of this set-up with the rotating drum, the motion of grinding media in an AG mill typically involves being lifted as the drum spins around until it reaches a falling point within the drum. At this point, the particles cascade down the surface of the other particles until they reach the bottom of this slope, called the toe of the mill. This is known as attrition comminution, which occurs when the AG mill is running at low speed or when a smaller shell liner lifter height with a greater face-angle is installed in the mill. When the mill is operated at a high speed, or when a larger shell liner lifter height with a steeper face angle is installed, the grinding media can be thrown on a parabolic path and the particles break on impact.

[0008] The inside of the rotating drum includes liners. The purpose of these liners is to protect the mill shell from damage and wear from the impact of the grinding media, and also to provide additional elevation to the contents of the rotating drum which assists in the grinding process. For example, to achieve higher impact forces, an AG mill is often built with a larger diameter and the rocks are thrown or cascade down the mill from a very high point. These liners include lifting plates, or lifters, that lifts the material inside the mill and increases the movement within the rotating drum. The force involved in this process is significant to break a hard ore with more than 380-500 MPa of uniaxial compressive strength. This force wears down the liners, requiring them to be replaced. Accordingly, the profile and wearability of the liners, in addition to the mill rotary speed, determine the motion of the charge and the performance of the mill.

[0009] The performance of liners used in an AG mill not only affects the effective operation rate of each production line, but also has a significant impact on the throughput of the AG mill grinding circuit. Issues can also arise when the AG mill liners are not fit for purpose. For instance, the mill liner can be too heavy for the AG mill which affects the mill capacity, leading to a lower filling rate of material and low grinding efficiency. Parts of the mill liners that are found within the high wear zones of the AG mill, such as the feed end and the discharge end can wear out too quickly, requiring regular replacement, while other liners are still productive and not at a stage that require replacement. This leads to greater mill downtime while these liners are being replaced. Other issues affecting productivity can include the steepness of the lifter face angle of the liner and the aperture size of the grates. [0010] With the above in mind, during a size reduction process, the particles that reach the critical size will sometimes build up in the mill. This can affect the grinding efficiency, until these particles can find their way to the grates found at the discharge end of the mill and into the pulp lifters. This process causes them to be discharged from the mill through the trunnion, an outlet channel for the mill. Both of the aperture size and open area of the grates and the profile and volumetric capacity of pulp lifters determine whether critical particles and slurry can be discharged effectively in an AG mill.

[0011] The filling rate also influences the motion of the particle load inside the AG mill, the power demand of the mill, the grinding efficiency and subsequent throughput of the mill. If the filling rate is too high, the rocks from the feed are thrown from a lower height onto the toe of the mill and the impact effect is weakened, resulting in reductions to the power output, grinding efficiency and throughput of the AG mill. If the filling rate is too low, the impact energy increases but the amount of larger grinding media (rocks of a larger size) in the mill reduces correspondingly (due to more rocks breaking on impact). This reduction increases the power draw of the AG mill and lowers the grinding efficiency.

[0012] A low filling rate can also lead to increased wear and damage to the liners, due to rocks of a larger size falling onto a liner directly and more regularly during the grinding process. For an optimal grinding efficiency during production of an AG mill, an appropriate filling rate must be selected, bearing in mind the profile of the liners, which reflects the relative balance of the feed, grinding and discharging speed of the load in the mill.

[0013] Bearing this in mind, the present inventor(s) have developed an improved lining system with higher efficiency for a grinding mill.

[0014] Any reference to or discussion of any document, act or item of knowledge in this specification is included solely for the purpose of providing a context for the present invention. It is not suggested or represented that any of these matters or any combination thereof formed at the priority date part of the common general knowledge, or was known to be relevant to an attempt to solve any problem with which this specification is concerned.

SUMMARY

[0015] In one form, a mill liner is disclosed including: a feed end liner configured to be connected to a feed end of a mill; a shell liner configured to be connected to a middle portion of the mill; a discharge end liner configured to be connected to a discharge end of the mill, wherein at least one of the feed end liner, shell liner or discharge end liner is different to one another.

[0016] In an embodiment, at least the shell liner and the discharge end liner are different to each other.

[0017] In an embodiment, at least the shell liner and the feed end liner are different to each other.

[0018] In an embodiment, at least the discharge end liner and the feed end liner are different to each other.

[0019] In an embodiment, each of the feed end liner, shell liner and discharge end liner are different to each other.

[0020] In an embodiment, the geometry and/or materials between at least one of the feed end liner, shell liner or discharge end liner is different to each other.

[0021] In an embodiment, at least one of the feed end liner, shell liner or discharge end liner includes a plurality of sections.

[0022] In an embodiment, at least one of the plurality of sections is different to one or more other sections.

[0023] In an embodiment, the at least one of the plurality of sections is longer than the one or more other sections.

[0024] In an embodiment, the plurality of sections includes two sections.

[0025] In an embodiment, the plurality of sections includes at least three sections.

[0026] In an embodiment, the feed end liner, shell liner or discharge end liner include one or more lifters extending from a plate.

[0027] In an embodiment, the one or more lifters are asymmetric.

[0028] In an embodiment, the one or more lifters are asymmetric in their height direction. In an embodiment, the height direction extends perpendicularly to the plate.

[0029] In an embodiment, the one or more lifters include an upper face and two side faces, the two side faces extending at different angles to each other. [0030] In an embodiment, one of the side faces varies between approximately 0° to 30° whilst the other side face varies between approximately 5° to 70°, relative to a longitudinal axis.

[0031] In a further embodiment, one of the side faces varies between approximately 0° to 10° whilst the other side face varies between approximately 10° to 60°, relative to a longitudinal axis.

[0032] In an embodiment, one of the side faces includes a first side portion and a second side portion, the first side portion and second side portion extending at different angles to each other.

[0033] In an embodiment, the first side portion extends between approximately 10° to 40° relative to the longitudinal axis. In another embodiment, the first side portion extends between approximately 20° to 40° relative to the longitudinal axis. In an embodiment, the second side portion extends between approximately 20° to 60° relative to the longitudinal axis.

[0034] In an embodiment, the one more lifters include a plurality of lifters whereby the angle(s) of at least one side face increase from one angle to another angle, between lifters, towards the discharge end.

[0035] In an embodiment, the one or more lifters associated with the discharge end liner include a curvature above 0° to approximately 40°.

[0036] In an embodiment, the one or more lifters include a rubber composite, chromoly steel (CrMo) and/or white iron.

[0037] In an embodiment, the one or more lifters include sets of lifters whereby the material of one set of lifters is softer compared to another set of lifters closer to the discharge end.

[0038] In an embodiment, the one or more lifters includes a wear block sandwiched between two wear plates.

[0039] In an embodiment, the one more lifters include a height of approximately 250mm to 550mm.

[0040] In an embodiment, the plate thickness varies between approximately 60mm to 140mm.

[0041] In an embodiment, the plate thickness increases towards the discharge end.

[0042] In an embodiment, a protrusion extends from the plate. [0043] In an embodiment, the protrusion extends in a transverse direction to a longitudinal direction of the one or more lifters.

[0044] In an embodiment, a height of the protrusion is smaller than a height of the lifter.

[0045] In an embodiment, one lifter extends from the plate.

[0046] In an embodiment, the plate associated with the discharge end liner includes a plurality of apertures. In an embodiment, the plurality of apertures provide an open area of approximately 8% to 15% in the plate.

[0047] In another form, a mill is disclosed, the mill including: a hollow body having: a feed end; a middle portion; and a discharge end; a mill liner having: a feed end liner connected to the feed end; a shell liner connected to the middle portion; a discharge end liner connected to the discharge end, wherein at least one of the feed end liner, shell liner or discharge end liner is different to one another.

[0048] In an embodiment, the mill is herein as described.

[0049] In an embodiment, the discharge end liner includes a grate portion that is angled at approximately 0° to 10° to the discharge end.

[0050] In an embodiment, the feed end liner includes a filler ring.

[0051] In an embodiment, the filler ring includes rubber.

[0052] In an embodiment, the filler ring includes a rubber composite material.

[0053] In an embodiment, the mill liner is connected to the hollow body with one or more fasteners including a tapered shank.

[0054] In an embodiment, the one or more fasteners connect the mill liner to the hollow body with the assistance of a seal and/or a washer. [0055] In a further form, a liner is disclosed, the liner including: a plate; and a lifter extending from the plate, wherein the lifter is asymmetric.

[0056] In an embodiment, the liner is herein as described.

[0057] In an embodiment, the liner forms a feed end liner, a shell liner and/or a discharge end liner.

[0058] In an embodiment, a protrusion extends from the plate. In an embodiment, a longitudinal direction of the protrusion extends transversely to a longitudinal direction of the lifter.

[0059] Further features and advantages of the present disclosure will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0060] By way of example only, embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying figures, wherein:

Figure 1 illustrates a schematic view of a mill, according to an embodiment of the invention;

Figure 2 illustrates a perspective view of part of a feed end liner, according to an embodiment of the invention, for use in the mill shown in Figure 1 ;

Figure 3 illustrates a top view of an inner liner of the feed end liner shown in Figure 2;

Figure 4a illustrates a top view of a middle and outer liner of the feed end liner shown in Figure 2;

Figure 4b illustrates a side section view of the middle and outer liner shown in Figure 4a;

Figure 5a illustrates a perspective view of part of a further feed end liner, according to an embodiment of the invention, for use in the mill shown in Figure 1 ;

Figure 5b illustrates a perspective view of part of an inner liner of the feed end liner shown in Figure 5a; Figure 6 illustrates a schematic view of a shell liner, according to an embodiment of the invention, for use in the mill shown in Figure 1 ;

Figure 7 illustrates a schematic view of a further shell liner, according to an embodiment of the invention, for use in the mill shown in Figure 1 ;

Figure 8 illustrates a schematic view of another shell liner, according to an embodiment of the invention, for use in the mill shown in Figure 1 ;

Figure 9 illustrates a perspective view of part of a further shell liner, according to an embodiment of the invention, for use in the mill shown in Figure 1 ;

Figure 10 illustrates a partial front view of a discharge end liner, according to an embodiment of the invention, for use in the mill shown in Figure 1 ;

Figure 1 1 illustrates a close up view of part of a grate portion, according to an embodiment of the invention, for use with the discharge end liner shown in Figure 10;

Figure 12 illustrates a partial front view of a further discharge end liner, according to an embodiment of the invention, for use in the mill shown in Figure 1 ;

Figure 13 illustrates a top view of part of an inner liner arrangement for the further discharge liner shown in Figure 12;

Figure 14 illustrates part of a grate portion for the further discharge liner shown in Figure 12;

Figure 15 illustrates a side view of discharge end liners on a discharge end, according to an embodiment of the invention;

Figure 16 illustrates a top view of part of a grate portion, according to an embodiment of the invention;

Figure 17 illustrates a top view of part of a further grate portion, according to an embodiment of the invention;

Figure 18 illustrates a top view of part of another grate portion, according to an embodiment of the invention;

Figure 19 illustrates a partial perspective view of another discharge end liner, according to an embodiment of the invention, for use in the mill shown in Figure 1 ;

Figure 20 illustrates a partial perspective view of a discharge outlet, according to an embodiment of the invention, for use with the discharge end liner; Figure 21 illustrates a side and top view of a fastener, according to an embodiment of the invention;

Figure 22 illustrates a section view of a seal, according to an embodiment of the invention; and

Figure 23 illustrates a section view of a part forming a washer, according to an embodiment of the invention.

DETAILED DESCRIPTION

[0061] Figure 1 illustrates a mill 10, according to an embodiment of the invention. The mill 10 can be, for example, an autogenous (AG) mill or a semi-autogenous (SAG) mill. The mill 10 includes a body 110. The body 110 is a hollow body. The body 110 forms a rotating drum. The body 110 includes a feed end 120, a middle portion 130 and a discharge end 140. The feed end 120 includes walls that taper towards an inlet where feed material 150 enters. The feed end 120 is connected to one end of the middle portion 130. The middle portion 130 is substantially cylindrical. The middle portion 130 sets an outer diameter for the feed end 120 (and the discharge end 140). The discharge end 140 is connected to the middle portion 130 at its other end. The discharge end 140 (like the feed end 120) includes tapering walls. The tapering walls form an outlet where processed material 160 leaves the mill 10.

[0062] The mill 10 includes a mill liner 20. As further detailed below, the mill liner 20 acts as a system and includes a feed end liner 200, a shell liner 300 and a discharge end liner 400. The liners 200, 300, 400 include a plurality of sections which assist in protecting the body 110. The liners 200, 300, 400 protect the body 110 and process the ore with the assistance of a lifter extending away from a plate, as discussed further below.

Feed End Liner

[0063] Figure 2 illustrates part of a feed end liner 200a. The feed end liner 200a is connected to the feed end 120 of the mill 10. That is, the feed end liner 200a forms a circular ring that conforms to the feed end wall 120. The feed end liner 200a includes a plurality of liners/sections. In this embodiment, the sections include inner liner(s) 210a, middle liner(s) 220a and outer liner(s) 230a.

[0064] The inner liners 210 each include a lifter in the form of feed end lifter 250aa, which extends from a plate 260aa. In this regard, the use of a reference numeral followed by a lower case letter typically indicates alternative embodiments of a general element identified by the reference numeral in this specification. Thus, for example, feed end lifter 250aa is similar to but not identical to the feed end lifter 250ba. Further, references to an element identified only by the numeral refer to all embodiments of that element. Thus, for example, a reference to feed end lifter 250 is intended to include both the feed end lifter 250aa and the feed end lifter 250ba.

[0065] The feed end lifter 250aa and plate 260aa are formed from a rubber composite. The feed end lifter 250aa extends transversely to the plate 260aa. The feed end lifter 250aa includes two side faces 252aa. The two side faces 252aa are angled towards one another. The faces 252aa converge towards an upper face 258aa. The height of the feed end lifter 250aa is approximately 450mm in this embodiment. This height is taken relative to a ground surface (as indicated in Figure 4b). The height of the plate 260aa is approximately 66mm. In this regard, the height of the lifter 250aa is relatively high and the height of the plate 260aa is relatively low, compared to traditional designs, but this embodiment has been found to dramatically increase the service life of this component despite using a rubber composite composition.

[0066] To further assist with increasing service life, a wear plate 270a and a wear block 274a are imbedded into the feed end lifter 250aa (see Figure 3). The wear plates 270a include wear resistant steel plates in the form of Hardox Wear Plates. The wear blocks 274a include white iron. To assist with removal and placement of the liner 210, protrusion portion(s) 278, which extend away from the plates 260aa, also extend between lifters 250aa. That is, the protrusion portions 278 extend laterally across the plates 260aa in a transverse direction to the longitudinal direction of the lifters 250aa.

[0067] In a similar manner to the inner liners 210a, each of the middle liners 220a include a lifter in the form of feed end lifter 250ab and a plate 260ab. The length of the middle liners 220a are greater than the length of the inner liners 210a. This assists in avoiding excessive wear of the outer edge of the feed end inner liner and inner edge of the outer liner, which is a common problem in traditional liners. This is an example of a high wear zone. The middle liners 220a are formed from a chromoly (CrMo) steel. The CrMo steel has a Cr content of approximately 5%. The height of the lifters 250ab, in this embodiment, are approximately 450mm. In a similar manner to the feed end lifter 250aa, the lifter 250ab includes two side faces 252ab that converge to an upper (transverse) face 258ab. The height of the plates 260ab are approximately 86 mm.

[0068] The outer liners 230a each include a lifter in the form of feed end lifter 250ac and a plate 260ac. In comparison to the inner and middle liners 210a, 220a, the lifters 250ac have a height of approximately 300mm. Furthermore, the height of the plates 260ac may vary depending on the higher wear zones. The outer liners 230a include a CrMo steel that has a Cr content of approximately 1%.

[0069] As shown in Figure 4a, the middle liners 220a and outer liners 230a may be integrated in further embodiments. The lifter/plate thickness of this liner is 450 mm/86mm in high wear zones and 280mm/70mm in low wear zones. Furthermore, in this embodiment, the width of liner 220/230 is approximately half of that shown in Figure 2. Accordingly, one lifter (as opposed to two) is associated with each plate. This can be beneficial for improving the stability of the heat treatment process and the quality of the liner. The liner 220/230 also includes an attaching portion 280 to assist with removal and placement of the liner 220/230.

[0070] A summary of the feed end liner 200a is shown below for ease of reference.

[0071 ] In another embodiment, Figure 5a illustrates a further feed end liner 200b according to an embodiment of the invention. The feed end liner 200b includes inner liner(s) 210b, middle liner(s) 220b and outer liner(s) 230b. The inner liners 210b each include a lifter in the form of feed end lifter 250ba. The feed end lifter 250ba is connected to a liner plate 260ba. The lifters 250ba are substantially rectangular or trapezoidal in shape. The lifters 250ba each include two wear plates 270b that sandwich a wear block 274b (as shown in Figure 5b). The wear plates 270b are preferably made from a material with a hardness of 400-600 HB. The wear block 274b comprises white iron, having a hardness of approximately 600 to 650HB. The feed end lifter 250ba also includes rubber as part of a weight/service life compromise. The feed end lifter 250ba is designed with a maximum height that is greater than the feed end lifter 250bc by approximately 50mm to 250mm. The liner plates 260ba are also thinner than the liner plates 260bb, 260bc by approximately 5 to 40mm. The different heights, thicknesses and materials of the lifters 250 and plates 260 are used to reduce the liner weight for grinding efficiency or to increase the liner service life. The feed end lifter 250ba also includes one or more forward face(s) 253ba and one or more rear face(s) 255ba. The forward face(s) 253ba and rear face(s) 255ba extend at different angles to increase service life and grinding efficiency.

[0072] The middle liners 220b are formed from a white iron (with a -600-650 HB hardness) or a bimetal with a white iron insert in a CrMo steel (with a -325-375 HB hardness). The lifters 250bb of the middle liners 220b are preferably 50 to 250mm higher than the feed end lifter 250bc. In this regard, in further embodiments, the middle liners 220b and the outer liners 230b may be integrally formed. However, in the embodiment shown in Figure 5a, they are separate and the outer liner comprises Cr-Mo steel (with a -325-375 HB hardness).

[0073] Testing found that the feed end liners 200, whilst having approximately the same weight as conventional feed end liners, had a service life increase allowing 3.0 million dry tons ( Mdt) to 5.0Mdt new throughput. This results in a greater duration between down times, which is critical in the mining industry. Furthermore, not having to compromise on weight allows the mill 10 to perform as normal. The combination of different materials and geometry has therefore allowed a longer service life without any substantive downside.

[0074] Separately, the feed end liner 200 also has a filler ring 240 that frames the outer end of the outer liner 230 (shown in Figure 2). In other words, the filler ring 240 extends around the perimeter of the outer liners 230. The filler ring 240 is formed by a plurality of sections. The sections of the filler ring 240 are formed from rubber and, in particular, natural rubber. This significantly reduces the weight of the filler ring 240 and, in comparison to other traditional designs using harder steels, increases the service life of the product in a counterintuitive manner.

Shell Liner

[0075] Figure 6 illustrates part of a shell liner 300a, according to an embodiment of the invention. The shell liner 300a is connected to the middle portion 130 of the body 1 10. The purpose of a shell liner 300a is to prevent packing of the material and to give lift to the particles so that there is efficient grinding during the rotation of the body 110. The shell liner 300a includes a plurality of sections being feed end shell liners 305aa, first section of middle shell liners 310ab', second section of middle shell liners 310ab" and discharge end shell liners 315ac. As discussed further below, the liners 305, 310, 315 are different to one another in order to optimise the grinding process and throughput of the mill 10. The shape of the liners 305, 310, 315 also avoids, for example, significant loss of throughput when new liners are installed after reline.

[0076] The feed end shell liners 305aa each include a shell plate 320aa and a lifter in the form of shell liner lifter 350aa. Each liner 305aa is formed from CrMo steel with a Cr content of approximately 1%. The liners 305aa are arranged around the middle portion 130 to provide protection thereof.

[0077] The shell plate 320aa is approximately 85mm thick in this embodiment. The shell liner lifter 350aa extends transversely away from the shell plate 320a. The shell liner lifter 350aa is approximately 360mm in height, relative to a ground plane. The shell liner lifter 350aa includes two side faces 352a. The side faces 352a are angled differently to one another relative to a longitudinal axis extending through the shell liner lifter 350aa. One of the side faces 352aa is angled at approximately 20° relative to the longitudinal axis. The parts of the shell liner 305aa also each include a protrusion 360aa that forms a hump. The protrusion 360aa is approximately 10mm in height and extends away from the surface of the shell plate 320aa. The protrusions 360aa assist in protecting the plate 320a from excessive wear and reduce the rock packing issues between lifters. In addition, as detailed further below, it has been discovered that (in a non-obvious manner) the relative thinner shell plate 320aa, and taller shell liner lifters 350aa, together with material choice, extends the service life of the feed end shell liner 305aa.

[0078] Like the feed end shell liner 305aa, the first and second middle shell liners 310ab', 310ab" are formed from CrMo steel with a Cr content of approximately 1%. The middle shell liners 310ab', 310ab" form one piece. The shape of the middle shell liners 310ab', 310ab" are however different to each other. The first middle shell liners 31 Oab' include a shell plate 320ab' that is approximately 90 mm in thickness. In contrast, the middle shell liners 31 Oab" include a shell plate 320ab" that is approximately 115 mm in thickness. This assists with increasing the service life towards the discharge end of the mill 10 which undergoes higher wear. The lifter height also varies between the lifters 350ab', 350ab". That is, the lifter height for the middle shell liner 31 Oab' is approximately 360 mm whilst the middle shell liner 31 Oab" is approximately 390mm. The face angles of side faces 352ab', 352ab" also vary therebetween with one side face 352ab' being inclined at approximately 24° (relative to the longitudinal axis through the lifter), whilst one of the side faces 352ab" is inclined at approximately 28°. The face angles are balanced between (amongst other things) wear and better grinding efficiency and throughput. The middle shell liners 310ab', 310ab" also respectively include a protrusion 360ab', 360ab" that assists with protecting the plates 320ab', 320ab" from excessive wear and reduce the rock packing issues between lifters (as noted in a similar manner above with respect to protrusion 360aa).

[0079] The discharge end shell liners 315ac are arranged around the middle portion 130 (closest to the discharge end 140), each liner 315ac having a shell plate 320ac and a shell liner lifter 350ac. The discharge end shell liner 315ac is substantially the same as the second middle shell liner 31 Oab", including having protrusions 360ac that are similar to protrusions 360ab". However, the discharge end shell liner 315ac includes a CrMo steel having a Cr content of approximately 5%.

[0080] In a further embodiment, the present invention includes shell liner 300b (as shown in Figure 7). The shell liner 300b includes feed end shell liners 305ba, first middle shell liners 31 Obb', second middle shell liners 310bb" and first discharge end shell liners 315bc' and second discharge end shell liners 315bc". The feed end shell liners 305ba and first middle shell liners 31 Obb' are substantially the same as feed end shell liners 305ab, having similar plates 320ba, 320bb', lifters 350ba, 350bb and protrusions 360ba, 360bb. In order to improve service life and reduce weight, the second middle shell liners 31 Obb" and discharge end shell liners 315bc', 315bc" are discussed further below. In a similar manner above, the middle shell liners 31 Obb', 31 Obb" form one piece of the middle shell liner.

[0081] The second middle shell liners 31 Obb" include a shell liner lifter 350bb" that extends away from the shell plate 320bb" having a thickness of approximately 115mm. The shell liner lifter 350bb" is approximately 400mm in height, relative to a ground surface. The shell liner lifter 350bb" includes side faces 352bb" that converge towards an upper face 358bb" that extends transversely to the side faces 352bb". One of the side faces 352bb" also includes a first (lower) side portion 354bb" and a second (upper) side portion 356bb" that are transversely angled to each other. That is, the first side portion 354bb" extends at a different angle to the second side portion 356bb". In this embodiment, the first side portion 354bb" extends at angle of approximately 20° to a longitudinal axis extending through the shell liner lifter 350bb". The second side portion 356bb" extends at angle of approximately 28° to a longitudinal axis extending through the shell liner lifter 350bb". Accordingly, the second side portion 356bb" extends at a larger angle, relative to the longitudinal axis extending through the shell liner lifter 350bb", compared to the first side portion 354bb". The other side face 352bb" of the shell liner lifter 350bb' extends at an angle that is substantially linear (towards the shell plate 320bb") with a radius transition towards its end. The parts of the shell liner 300b (like 300a) are therefore asymmetric. Outboard of the side faces 352bb" is protrusions 360bb".

[0082] The first discharge end shell liner 315bc' is substantially the same as the second middle shell liner 310bb" in geometry, having a similar shaped shell plate 320bc', shell liner lifter 350bc' and side faces 352bc' with upper and lower portions 354bc', 356bc'. However, in contrast to the second middle shell liner 310bb" (which is formed with CrMo steel having ~1% Or), the first discharge end shell liner 315bc' is formed from a CrMo steel having a Cr content of approximately 5%. The second discharge end shell liners 315bc" also include a CrMo steel having a Cr content of approximately 5%. However, in contrast to the first discharge end shell liners 315bc', the height of the shell liner lifter 350bc" for the second discharge end shell liners 315bc" is approximately 420mm. The side faces 352cc" of the shell liner lifter 350bc", which extend away from the upper face 358bc', include two portions 354bc", 356bc" with the same angles as the lifter 350bc' (ie, 20° and 28°). The protrusions 360bc" are also located outboard of the lifter 350bc". The geometry and materials of shell liner 300b have been found to increase its service life to 4.5 Mdt, with a reduction of weight to 496 tonne. This is a slight improvement over shell liner 300a which, whilst including fewer components, had a weight of approximately 511 tonnes with a service life of 4.2 Mdt.

[0083] Further improvements have also been unexpectedly uncovered in shell liner 300c, as shown in Figure 8. The shell liner 300c includes feed end shell liners 305ca, first middle shell liners 310cb', second middle shell liners 310cb" and discharge end shell liners 315cc. The first middle shell liners 310cb' and the second middle shell liners 310cb" form one piece in this embodiment. The feed end shell liners 305ca include a shell plate 320ca and a shell liner lifter 350ca. The shell plate 320ca is approximately 75 mm in thickness. The shell liner lifter 350ca is located to one side of the centre of the shell plate 320ca. Accordingly, the feed end shell liners 305ca are asymmetric. The shell liner lifter 350ca is approximately 290mm in height. The side faces 352ca are asymmetric with one face extending at approximately 20° to a longitudinal axis extending through the shell liner lifter 350ca. On the opposite side to the shell liner lifter 350ca, protrusion 360ca extends from an end of the shell plate 320ca. The protrusion 360ca assists with avoiding wear of the wear plate 320ca. [0084] The first middle shell liners 310cb' are substantially the same as feed end shell liners 305ca, having substantially the same shell plate 320cb', shell liner lifter 350cb' and protrusion 360cb'. The second middle shell liners 310cb" are different to the first middle shell liners 310cb'. The second middle shell liners 310cb" include a shell plate 320cb" with a thickness of 85mm. The shell liner lifter 350cb' is located substantially towards one side of the shell plate 320cb" (like the lifter 350cb' and 350ca). The shell liner lifter 350cb' includes two faces 352cb" that extend transversely to upper face 358cb". One side face 352cb" includes a first side portion 354cb" and a second side portion 356cb". The side portions 352cb", 354cb" are transversely angled to each other. The first side portion 354cb" is angled at approximately 20° to a longitudinal axis extending through the lifter 350cb". The second side portion 356cb" is angled at approximately 35° to a longitudinal axis extending through the lifter 350cb". The other side face 352cb" extends substantially parallel to the longitudinal axis, but has a large radius towards its lower end. A protrusion 360cb" is located outboard of the radius, on the other end of the shell plate 320cb".

[0085] The discharge end shell liner 315cc is substantially the same in geometry as the second middle shell liner 31 Ocb", having the same shaped plate 320cc, lifter 350cc, side faces 352cc (with first and second portions 354cc, 356cc) and protrusion 360cc. However, to further improve the shell liner 300c, the discharge end shell liner 315cc is formed from white iron having a Cr content of approximately 20-27%. This further improves the wear characteristics of the discharge end shell liner 315cc (bearing in mind material costs, weight and replacement downtime). Overall, the shell liner 300c has a reduced weight of 405 tonne with a service life of 4.0 Mdt. This design is approximately 18% lighter than traditional designs, and the service life is increased approximately 33% when operating in single direction.

[0086] A summary of the shell liners 300 is shown below for ease of reference.

[0087] Figure 9 illustrates a further shell liner 300d. The shell liner 300d includes feed end shell liners 305da, middle shell liners 310db and discharge end shell liners 315dc. The feed end shell liners 305da each include a shell plate 320da and a lifter in the form of shell liner lifter 350da. The feed end shell liners 305da comprises CrMo steel having a Cr content of approximately 1 % with white iron (~20-27%Cr) inserted in CrMo steel for liner lifter 350da. The shell liner lifter 350da includes faces 352da. The faces 352 have a front face angle (a1 ) that may vary between 20° to 30° (or 40° in other embodiments). The back face angle (pi ) is preferably between 0° to 10°. The liner lifter 350da height H1 increases from about 310mm at the feed end to about 330mm along the longitudinal direction towards the middle liners 310db, and the shell plate 320da height T1 is around 75mm.

[0088] The middle shell liners 31 Odb each include a shell plate 320db and a shell liner lifter 350db. The middle shell liners 31 Odb comprises CrMo steel having a Cr content of approximately 1 % with white iron (~ 20-27%Cr) inserted in CrMo steel for liner lifter 350db. The liner lifter 350db height H2 is about 330mm close to the feed end shell liners 305da, and the shell plate 320db height T2 is about 75mm close to the feed end shell liners 305da. The shell liner lifter 350db includes faces 352db. One of the faces 352 has a (front) face angle (a2) of about 20° to 30° close to the feed end shell liners 305da (this may vary between 5° to 70° in other embodiments). The other face 352 has a (back) face angle (P) which is preferably between 0° to 10° (or 0° to 30° in other embodiments). The face angles a2, [32 are different to each other to increase the service life and the grinding efficiency. In this regard, the height of the shell lifter 350db increases in a direction towards the discharge end shell liners 315dc by approximately 5 to 25mm, and the thickness of the shell plate 320db increases in a direction towards the discharge end shell liners 315dc by approximately 5 to 25mm. The face angle (a2) also increases by approximately 10°-25° along the mill 10 (and 10° to 50° in other embodiments), towards the discharge end 140. This assists in improving milling efficiency.

[0089] The discharge end shell liners 315dc include white iron (~ 20-27%Cr) to strengthen wear resistance. The discharge end shell liners 315dc include a plurality of components having a shell plate 320dc and lifter 350dc. Like the lifter 350cc, the lifter 350dc includes faces 352dc where one face has a plurality of angles. That is, one face 353dc includes a first side portion 354dc having a face angle a4 and a second side portion 356dc having a face angle a3. The face angle a3 is preferably between approximately 35°-55° and the face angle a4 is preferably between approximately 20°-30°. The face angle a3 may vary between 25°-60° in other embodiments together with face angle a4 varying between 10°-40°. The other face 353dc preferably includes a face angle 3 between approximately 0°-10°.

Discharge End Liners

[0090] As shown in Figure 10, the discharge end liner 400a is connected to the discharge end 140. The discharge end liner 400a includes a cover portion 402a, an interior lifting portion 404a and a discharge outlet 405a. A discharge filler ring 500a assist with bridging a gap between the discharge end liner 400a and the shell liner 300a.

[0091 ] The cover portion 402a includes an inner cover arrangement 408a and an outer grate portion 480a. The inner cover arrangement 408a includes an inner plate 410a and inner lifter arrangement 420a. The cover portions 402a cover the interior lifting portion 404a. The interior lifting portion 404a includes an inner lifting portion and an outer lifting portion having an outer plate 450a and an outer lifter arrangement 460a.

[0092] The inner plate 410a and outer plate 450a are approximately 136mm in thickness. The plates 410a, 450a comprise a rubber composite. The inner cover lifter arrangement 420a includes first lifter(s) 430a and second lifter(s) 440a. The lifters 430a, 440a are connected to the inner plate 410a. The lifters 430a, 440a extend substantially in a linear manner. The lifters 430a, 440a comprise a rubber composite. The lifters 430a, 440a are approximately 348mm high.

[0093] The outer lifter arrangement 460a of the interior lifting portion 404a includes outer lifter(s) 470a. The outer lifters 470a are connected to the outer plate 450a. The outer lifters 470a extend in a curve manner. That is, the outer lifters 470a curve away from the lifters 430a, 440a towards an outer area of the outer plate 450a. The outer lifters 470a comprise a rubber composite. In high wear zones, wear parts in the form of white iron blocks 472a are embedded in the rubber composite. The outer lifters 470a are approximately 620mm high. [0094] As indicated above, the outer lifter arrangements 460a are connected and covered by the grate portions 480a. This allows the grate portions 480a to categorise/filter material before it passes to the interior lifting portion 404a. In other words, the grate portions 480a are located further inward into the (hollow) body 110 in order to filter material before it passes to the interior lifting portion 404a. In response to material passing to the interior lifting portion 404a, it is configured to rotate and lift material towards and out of the discharge outlet 405a.

[0095] The grate portions 480a comprise a CrMo steel with a Cr content of approximately 1 %. The grate portions 480a include a plurality of apertures 482a. The apertures 482a are formed in a plate 481 a that is approximately 100mm to 110mm thick. The width of the apertures 482a range between 45 to 60mm. The length of the apertures 482a is approximately 100-180mm. The apertures 482a provide approximately 11 .74% of open area in the plate 481 a. The apertures 482a are arranged between grate lifters 483a. The grate lifters 483a are approximately 270-315mm high. The grate lifters 483a curve along the plate 481 a. That is, the grate lifters 483a extend radially. To extend the service life of the plate 481 a, protrusions 484a extend between the lifters 483a. The protrusions 484a are approximately 10mm in height. The protrusions 484a can also assist in adjusting the discharge rate of material. The protrusions 484a extend substantially parallel to a longitudinal direction of the apertures 482a. To connect the grate portion to the lifter portion 402a, holes 486a are used. The irregular shape of the grate portion 480 allows three bolts to one piece of the grate portion 480a, via the holes 486a in a triangular direction, which decreases the possibility of the bolts breaking.

[0096] The service life of the inner cover lifter arrangements 420a are approximately 8.4 Mdt when operating in single direction, which is 180% longer compared to more traditional designs. Furthermore, the service life of the grate portions 480a are approximately 4.2 Mdt. The discharge end liner 400a assists in avoiding backflow of solids in the mill 10 which causes excessive wear in the base and head-side corners of the (pulp) lifter 402a. The weight of the discharge end liner 400a is also approximately 239 tonne. This is approximately 35% lighter compared to other traditional designs. This improves the filling rate of material inside the mill 10. Furthermore, the size of apertures 482a also improves the pebble discharge efficiency and avoids overgrinding in the mill 10. The curved shape of the grate lifters 483a also improves the slurry discharge efficiency by starting the motion of the pulp inside the body 110 earlier in the rotation of the mill 10, resulting in a more complete discharge.

[0097] Figure 12 illustrates a further discharge end liner 400b. The further discharge end liner 400b is similar to the discharge end liner 400a. The further discharge end liner 400b includes cover portions 402b, an interior lifting portion 404b and a discharge outlet 405b. In this embodiment, the lifter portions include: i) an inner plate 410b and inner cover lifter arrangement 420b; or ii) an outer plate 450b and an outer lifter arrangement 460b. These components comprise a rubber /white iron composite material. The white iron is embedded into the high wear zones. For example, as shown in Figure 13, the second lifters 440b includes a first wear block 442b. The height of the second lifter 440b, with the wear block 442b, is approximately 348mm. A second wear block 444b is located next to the lifters 440b. The second wear block 444b is approximately 290 mm in height. The first lifters 430b are also located next to the second lifters 440b. The first lifters 430b include a taper towards one end but, at an upper height, are approximately 348mm in height. The inner plates 410b, supporting the lifters 430b, 440b and blocks 442b, 444b, are approximately 136mm in thickness.

[0098] The grate portions 480b, associated with the outer plate 450b and the outer lifter arrangement 460b, are further shown in Figure 14. The grate portion 480b includes apertures 482b. The apertures 482b are approximately 50 to 55mm in width and approximately 100 to 180mm in length. The apertures 482b extend through a plate that is approximately 110mm thick. This allows for an open area in the plate 481 b of approximately 12.36%. This improves the pebble discharge efficiency. The protrusions 484b, which extend along at or near the perimeter of the apertures 482b, also assist in increasing the service life of the grate portion 480b. The grate lifters 483b extend transversely to the protrusions 484b. The height of the grate lifters 483b is approximately 315mm. Based on these improvements, the service life of the grate portion 480b is approximately 4.5 Mdt. The service life improvements for the lifter portion 402b is approximately 8.4Mdt. Overall, the service life is improved over 200% compared to more traditional designs whilst the weight of discharge end liner 400b is reasonably maintained around 265 tonne.

[0099] In a further embodiment, a lighter version of discharge end liner 400b may be implemented by reducing the height of the lifters in the lifting arrangement 420b to 308mm. The grate lifters 483b are reduced to 270mm and the thickness of the plate 481 b is reduced to 80 to 95mm. In this embodiment, the weight of the discharge end liner 400b is approximately 253 tonne. In an unexpected manner, the service life of the lifter portion 402b for the modified discharge end liner 400b is approximately 12 Mdt. The service life of the modified grate portion is approximately 4 Mdt. A summary of these designs is summarised below.

[00100] Figure 15 illustrates optimising the angle between the discharge end liner 400 and the discharge end 140. By adjusting the angle to approximately 8°, for end liners 400a, 400b, a higher discharge efficiency is achieved, leaving less material in the material lifting chamber as material is discharged at a faster rate. The angle may adjusted to approximately 5° in the event the discharge rate is too high and further control over the system is required. The discharge rate of material through the discharge outlet 405 needs to be considered in the context of a mining system as a whole, meaning material rates should not, for example, exceed the capacity of a pebble crusher or vibrating screen.

[00101] Figures 16 to 18 illustrate further grate portions 480c-e. The further grate portions 480c-e illustrate the compromise between open area, discharge efficiency and service life. Uniquely, an optimum point is reached around a range of 8 to 15% (and particularly 10.5% to 12.5%) open area. In this regard, grate portion 480c illustrates a plate 481c with a thickness of approximately 80-95mm. The length of the apertures 482c, 482c' is approximately 180mm and their width is such that approximately 12.17% of the plate 481c is open area. The apertures 482c' extend transversely to the other apertures 482c. This allows a suitable open area to be maintained whilst a service life of 4-5Mdt is expected.

[00102] In Figure 17, the orientation of the apertures 482d is vertical relative to the movement of material on the lifters. This increases the top size/amount of pebbles/material as the probability of larger pebbles passing through the grates 480d reduces. The apertures 482d in grate portion 480d have a maximum length of 180mm and form a 1 1 .96% open area with an expected 4-5Mdt service life.

[00103] In Figure 18, the apertures 482e in the plate 481 e are orientated such that they are substantially parallel to the movement of material on the lifter. This reduces the amount of material passing through the grate portion 480e as the probability of material passing through the apertures 482d decreases. The apertures 482e have a maximum length of approximately 180mm and create a 1 1 .18% open area in the plate 481 e (whilst having an expected service life of 4-5 Mdt).

[00104] Figure 19 illustrates another discharge end liner 400f, according to an embodiment of the invention. The discharge end liner 400f includes a number of cover portions 402f and interior lifting arrangements 404f thereunder. The cover portions 402f and interior lifting arrangements 404f are located in an annular array around the discharge end 140.

[00105] The cover portions 402f include an inner cover arrangement 408f. The inner cover arrangement 408f includes an inner plate which is connected to an inner cover lifter arrangement 420f. The lifters of the lifter arrangement 420f include a rubber/steel composite material. This assists with reducing weight and improving grinding efficiency. The cover portions 402f are positioned such that the inner cover arrangement 408f and grate portions 480f create an angle y of approximately 5° to 10° with the discharge end 140.

[00106] The interior lifting portion 404f includes: i) one set of outer lifter portions comprising an outer plate 450f and lifter arrangement 460f; and ii) another set of inner lifter portions comprising an inner lifter plate 455f and an inner lifter arrangement 465f. The inner and outer plates 455f, 450f are connected to the discharge end 140. The inner lifter arrangement 465f includes lifters 475f. The lifters 475f extend substantially straight. The inner cover arrangement 408f is connected to the inner lifter arrangement 465f therebelow. The outer lifter arrangements 460f include outer lifters 470f. The outer lifters 470f are arranged in a curved manner. The outer lifters 470 have a curvature between approximately 5° to 40°. The outer lifter arrangements 460f are connected to the grate portions 480f.

[00107] The inner lifter arrangement 420f of the cover portion 402f includes a plurality of lifters 430f, 440f connected to plate(s) 41 Of. The lifters 430f, 440f form a plurality of arrays, which are separated from one another, around the discharge end 140. The grate portion 480f of the cover portion 402f includes a plate 481 f with a plurality of apertures 482f. The plate 481 f comprises a CrMo steel with a hardness of approximately 325 to 375 HB. The apertures 482f are sized to pass particles with a size of approximately 45 to 70mm. The apertures 482f provide an open percentage area of approximately 8% to 15% within the plate 481 f. The grate lifters 483f extend from the plate 481 f. The grate lifters 483f have a curvature between approximately 5° to 40°. The grate lifters 483f includes lifters of different length. The shorter (inner) grate lifters 483f white iron blocks embedded in rubber. The (longer) outer grate lifters 483f include a rubber/steel composite with white iron blocks, which includes two side wear plates. The side wear plates have a hardness of -400 to 600 HB. The side wear plates sandwich the rubber/steel composite with white iron blocks.

[00108] The discharge outlet 405f (shown in Figure 20) is configured to be connected discharge end 140 of the mill in order to allow the process material to leave the mill 10. The discharge outlet 405f extends radially inwards towards a central axis of the mill 10, from the lifter portion 402f, in order to assist in discharging the processed material 160. The discharge outlet 405f comprises hook plates without lifter bars.

[00109] Similar to the end liners 400a, 400b, advantages of the discharge end liner 400f include the use of curved lifters to enhance the discharge efficiency for overgrinding reduction, elimination of slurry pool and throughput improvement; the use of rubber/steel composite material to reduce liner weight for mill charge ratio improvements and hence the mill for milling efficiency improvement; the use of a lower lifter height and a larger face angle for the discharge end shell liners for milling efficiency improvement; use of white iron/CrMo steel bimetals to enhance the wear resistance and to reduce the liner costs; and the use of varied grades of material in different sections of the liners to allow even wear across the whole sets of liners.

Fasteners

[00110] As noted above, bolts are inserted through holes 486. Fasteners in the form of bolts are also inserted into the other liners. Failure of bolts commonly happens in mills. In order to assist in avoiding this problem, a fastener in the form of bolt 600 (shown in Figure 21 ) may be used with the liners 200, 300, 400. The bolt 600 includes a threaded portion 605. The threaded portion 605 is an M52. The threaded portion 605 is connected to a shank portion 610. The shank portion 610 is approximately 60mm wide. The shank portion 610 includes a tapered portion 612. The tapered portion 612 assists in reinforcing the shank portion 610. The tapered portion 612 tapers from approximately 52mm to 60mm in width. The shank portion 610 is connected to a fastener head 615. The fastener head 615 includes two flat sides and two rounded sides.

[0011 1] The bolt 600 is used with seal 700 shown in Figure 22. The seal 700 includes a hole that suitably fits with the threaded portion 605. The seal includes (outer) side wall(s) 710. The side walls 710 include two transverse faces. The side walls 710 substantially form a triangular outer surface. The bolt 600 is also used with a ring 800 in the form of a washer (shown in Figure 23). The ring 800 is substantially circular but may be other non-radial shapes. The ring includes a hole 805. The hole 805 includes a transverse wall 807 and an axial wall 809. The walls 807, 809 are substantially perpendicular to each other but they may be at other transverse angles.

Set of Liners

[00112] To give further appreciation of how the liners 200, 300, 400 work with each other, the following information is presented to provide additional details on the present invention. In some embodiments, the body 1 10 of the mill may be approximately 12.2m in diameter and 11 m long. This may require the following liners:

• Feed end liners (18x inner liners 210, 18x middle liners 220, 18x outer liners 230 and 27x filler rings 240) (or feed end liners (18x inner liners 210, 36x middle liners 220 / outer liners 230 and 27x filler rings 240);

• Shell liners (54x feed end shell liners 305, 54x middle shell liners 310, 54x discharge end shell liners 315); and

• Discharge end liners (36x grate portions 480, 36x outer lifter arrangements 460, 18x inner lifter arrangements 420, 27x discharge filler rings 500, 3x discharge outlets).

[00113] The following tables set out a summary of different liners working together. The average throughput of the mill 10, using the parameters in the table below, is approximately 1280 wt/h. This is approximately 11.3% higher than the throughput of more traditional designs (with radial discharge).

[00114] This configuration (with a smaller curve in the arc of the discharge end liner 400a (e.g., the grate lifters 483a have a curvature of -20°)) provides a low cost option with a good service life and weight.

[00115] In a further embodiment, the liners below are combined yielding a throughput of approximately 1300 wt/h, 13% higher than the throughput of more traditional designs.

[00116] This configuration (with a relatively larger curve in the arc of the discharge end liner 400b (e.g. the grate lifters 483b have a curvature of -30°)) provides relatively higher milling performance, standard-to-lower material costs, standard liner weight and longer service life.

[00117] In another embodiment, the liners below are combined yielding a throughput of approximately 1370 wt/h, 19.1% higher than the throughput of more traditional designs.

[00118] This configuration (with a larger curve in the arc of the discharge end liner 400b

(e.g., the grate lifters 483b have a curvature of -30°)) provides relatively higher milling performance (see, e.g., the lower shell lifter height and larger face angle of discharge end shell liners) but comes with a compromise of higher material cost (which do reduce liner weight) and reduced service life.

[00119] Other options are also available as shown below. The option below provides higher milling performance, wear resistance material/bimetal with white iron insert (higher material costs) with longer service life and reduced liner weight. [00120] In other embodiments, the following set of liners, in the table below, may be adopted. The service life for this arrangement is approximately 9 million tons of ore throughput for discharge end liners 400f (except grates portions 480f have a service life of 4.5 million tons of ore throughput) and a service life of 4.5 million tons of ore throughput for the other liners 200b, 300d. The total liner weight for this arrangement is approximately 880 tonne.

[00121] In further embodiments, the following set of liners, in the table below, may be adopted. The service life for this arrangement is approximately 12 million tons of ore throughput for discharge end liners 400f (except grates portions 480f have a service life of 4.0 million tons of ore throughput) and a service life of 4.0 million tons of ore throughput for the other liners 200b, 300d. The total liner weight for this arrangement is approximately 779 tonne.

[00122] In other embodiments, the following set of liners in the table below may be adopted. The service life for this arrangement is approximately 15 million tons of ore throughput for discharge end liners 400f (except grates portions 480f have a service life of 5.0 million tons of ore throughput) and a service life of 5.0 million tons of ore throughput for the other liners 200b, 300d. The total liner weight for this arrangement is approximately 801 tonne.

[00123] The present invention provides new mill liners 200, 300, 400 with optimised profile and liner weight, improving the grinding efficiency, filling rate of material, mill throughput and extending service life with unique configurations (e.g. bi-face angles on shell liner lifters, higher lifter/plate thickness in high-wear zone) and carefully selected materials.

[00124] Use of the varied material grade (normal 1%Cr CrMo steel, more wear resistant 5%Cr CrMo steel, further wear resistant 20-27%Cr white iron) and composite material (rubber steel composite, rubber steel composite with white iron insert and bimetal with white iron insert in 1%Cr CrMo steel) in zones with different wear rates will allow a desired liner profile for milling efficiency to be achieved together with a targeted service life that is consistent across sections, making full use of liners, saving liner cost, and reducing the liner weights.

[00125] In this specification, adjectives such as left and right, top and bottom, hot and cold, first and second, and the like may be used to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where context permits, reference to a component, an integer or step (or the alike) is not to be construed as being limited to only one of that component, integer, or step, but rather could be one or more of that component, integer or step.

[00126] In this specification, the terms ‘comprises’, ‘comprising’, ‘includes’, ‘including’, or similar terms are intended to mean a non-exclusive inclusion, such that a method, system or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed. [00127] The above description relating to embodiments of the present disclosure is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the disclosure to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present disclosure will be apparent to those skilled in the art from the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. The present disclosure is intended to embrace all modifications, alternatives, and variations that have been discussed herein, and other embodiments that fall within the spirit and scope of the above description.

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