OA17427A - Mobile ore slurrying apparatus. - Google Patents

Abstract

A mobile ore slurrying apparatus comprising: a feeding unit; a processing unit; and a pumping apparatus, wherein the processing unit is separated into a slurry tank section and a water tank section, such that ore may be passed from the feeding unit to the slurry tank where it is contacted with water from an overflow of the water tank to produce a slurry stream, the slurry stream is then transferred from the processing unit by way of the pumping apparatus.

Description

[0001] The présent invention relates to a mobile ore slurrying apparatus. More particularly the mobile ore slurrying apparatus of the présent invention is intended for use in respect of dry mining. A method of use of the mobile ore slurrying apparatus of the présent invention is also disclosed.

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

[0003] The processing of dry minerais from deposits typîcally involves the use of dry mining (for example, by mechanical excavation) and the upgrading of the ore at a separate wet plant concentrator.

[0004] Due to the requîrements of the wet plant concentrator, separate processing of the dry ore to form a slurry of a spécifie density is required. Typîcally, the associated slurrying unit is stationary and will be positioned close to the dry mining operation to reduce the distance the ore has to be transported prior to the slurrying step. However, as the mining operation progresses in a certain direction, this distance increases, signifïcantly reducing the processing rate.

[0005] Altematively, the wet plant concentrator may also process a primary feed stream from another source, for example a primary dredging unit. The primary dredging unit provides a feed stream at a desîgnated processing rate which allows the wet plant concentrator to operate at an efficient rate. However, as a resuit of certain dredging conditions, the feed is not always delivered at this rate, which results in the plant operating at a less than optimal process rate, which negatively impacts production time and costs.

[0006] The présent invention seeks to overcome, or at least ameliorate, one or more of the deficiencies of the prior art mentioned above, or to provide the consumer with a useful or commercial choice.

[0007] Throughout this spécification, 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.

SUMMARY OF INVENTION [0008] In accordance with the présent invention there is provided a mobile ore slurrying apparatus comprising:

A feeding unit;

A processing unit; and

A pumping apparatus, wherein the processing unit further comprises a slurry tank section and a water tank section, such that ore may be passed from the feeding unit to the slurry tank where it is contacted with water from an overflow of the water tank to produce a slurry ₁₀ stream, the slurry stream is then transferred from the processing unit by way of the pumping apparatus.

[0009] Preferably, the slurry tank section and the water tank section are separated by way of a dividing wall.

[0010] Preferably, the feeding unit further comprises an automatic drive unit to ¹⁵ control feed rate.

[0011] In one form of the présent invention, the feeding unit further comprises a boil box to slow the feed material’s speed prior to being passed to the slurry tank. Preferably, the boil box further comprises distribution bars. Still preferably, the boil box further comprises spray bars.

[0012] Preferably, the processing unit further comprises a f lu s h valve. Actuation of the flush valve will preferably rapidly release the water in the water tank to the slurry stream in order to rapidly reduce the slurry density.

[0013] In one form of the présent invention, the pumping apparatus further comprises _>5 an inline density meter. More preferably, the inline density meter allows for the détection of a slurry density above a first predetermined value in order to raise an alarm, such that the feeding rate of the feeding unit may be altered to maintain a desired slurry density. Still preferably, the inline density meter allows for the détection of a slurry density above a second predetermined value in order to effect _D the release of the flush valve.

[0014] In one form of the présent invention, the pumping apparatus further comprises an inline flow rate meter. More preferably, the inline flow rate meter allows for the détection of a slurry flow rate relative to a first predetermined value whereby a remédiai step may be implemented, in order to maintain a slurry flow rate at the predetermined value. Still preferably, the inline flow meter allows for the détection of a slurry flow rate below a second predetermined value in order to effect the release of the flush valve.

[0015] Preferably, the remédiai step involves the alteration of the speed of the pumptng apparatus, alteration of the speed of the feeding unit or actuation of a control valve in order to alter the volume of slurry passing through the pumping apparatus.

[0016] Preferably, water is pumped from an external source into the water tank to maintain the required water level.

[0017] In one form of the présent invention, the mobile ore slurrying apparatus further ¹⁰ comprises a screening plant, wherein the ore is screened to remove coarse oversize material in order to provide a slurry tank stream. More preferably, the screening plant comprises a two-stage screening process.

[0018] Preferably, the slurry tank stream material has diameter of less than 40mm. Still preferably, the slurry tank stream material has diameter of less than 10mm.

[0019] In accordance with the présent invention there is further provided a slurrying method comprising the steps of:

Mining an ore body to provide a dry ore stream; Directing the dry ore stream to a mobile slurry tank; Contacting the dry ore stream with water from a mobile water tank to provide 2U a slurry stream; and

Transferring the slurry stream to a primary processing plant.

[0020] In one form of the présent invention, the dry ore stream is directed to the slurry tank section of the mobile ore slurrying apparatus of the présent invention, where it is contacted with water from the water tank section of the mobile ore slurrying apparatus of the présent invention to form a slurry, prior to being transferred to the primary processing plant.

[0021] In one form of the présent invention, the dry ore stream is subject to a screening process prior to being transferred to the mobile ore slurrying apparatus. Preferably, the screening process comprises a two stage screening process.

[0022] Preferably, the screening process will remove particles with a diameter of greater than 40mm. Still preferably, the screening process will remove particles with a diameter of greater than 10mm.

[0023] In one form of the présent, should the înline density meter of the mobile ore slurrying apparatus set off an alarm, the feeding rate of the feeding unit may be altered to maintain a desired slurry density. Preferably, should the slurry density remain above the first predetermined value, the inline density meter may effect the release of the flush valve.

[0024] In one form of the présent, should the inline flow rate meter of the mobile ore slurrying apparatus detect a slurry flow rate relative to a first predetermined value, a remédiai step may be implemented, in order to maintain a slurry flow rate at the predetermined value. Preferably, the remédiai step involves the alteration of the speed of the pumping apparatus, alteration of the speed of the feeding unit or actuation of a control valve in order to alter the volume of slurry passing through the pumping apparatus.

[0025] In one form of the présent invention, should a slurry flow rate below a second predetermined value be detected, the inline flow rate meter will preferably actuate the release of the flush valve.

[0026] In one form of the présent invention, should a slurry flow rate below the 15 second predetermined value be detected for an extended period of time, the inline flow rate meter will preferably stop the pumping apparatus.

[0027] As the mining of the ore body progresses, the mobile ore slurrying apparatus preferably moves with the moving face of the mine. The mobility of the mobile ore slurrying apparatus is understood to minimise the distance between the mining unit and the mobile treatment plant as the mining operation progresses.

[0028] Preferably, the mobile ore slurrying apparatus may be lifted and transferred to a vehicle to allow mobility. Altematively, the mobile ore slurrying apparatus may be provided with skids, wheels or tracks to further allow mobility.

[0029] Preferably, the upgraded minerai stream may be transferred to the primary processing plant by any means known in the art. More preferably, the slurry is pumped by way of pipeline to the primary processing plant.

[0030] It will be appreciated that the slurry stream may not be transferred directly to the primary processing plant and may be stockpiled by any means known in the art prior to treatment at the primary processing plant.

[0031] In accordance with the présent invention there is still further provided a method of supplementing a primary feed at a wet plant concentrator, comprising the steps of:

Mining an ore body to provide a dry ore stream

Directing the dry ore stream to the mobile ore slurrying apparatus described above;

Contacting the dry ore stream with water to provide a slurry stream; and Transferring the slurry stream to a wet plant concentrator to supplément the primary feed.

[0032] In one form of the présent invention, the dry ore stream is subject to a screening process prior to being transferred to the mobile ore slurrying apparatus. Preferably, the screening process comprises a two stage screening process.

[0033] Preferably, the screening process will remove particles with a diameter of greater than 40mm. Still preferably, the screening process will remove particles with a diameter of greater than 10mm.

[0034] As the mining of the ore body progresses, the mobile ore slurrying apparatus preferably moves with the moving face of the mine. The mobility of the mobile ore slurrying apparatus is understood to minimise the distance between the mining unit and the mobile ore slurrying apparatus as the mining operation progresses [0035] Preferably, the mobile ore slurrying apparatus may be lifted and transferred to a vehicle to allow mobility. Alternative^, the mobile ore slurrying apparatus may be provided with skids, wheels or tracks to further allow mobility.

[0036] The upgraded minerai stream may be transferred to the wet plant concentrator by any means known in the art. Preferably, the slurry is pumped to the wet plant concentrator by way of pipeline.

[0037] It will be appreciated that the slurry stream may not be transferred directly to the wet plant concentrator and may be stockpiled by any means known in the art prior to treatment at the wet plant concentrator.

BRIEF DESCRIPTION OF THE DRAWINGS [0038] Further features of the présent invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplîfying the présent invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:

Figure 1 is a schematic représentation of a mobile ore slurrying apparatus in accordance with a first embodiment of the présent invention;

Figure 2 is a plot of the slurry density during a 24 hour operation period of the a mobile ore siurrying apparatus of the présent invention;

Figure 3 is a plan view of a method of supplementing a primary feed at a wet plant concentrator in accordance with a further embodiment of the présent ⁵ invention; and

Figure 4 is plot showing the feed into a Wet Plant Concentrator, split into the feed from a primary dredging operation and the supplément feed provided by the mobile ore siurrying apparatus of the présent invention.

DESCRIPTION OF EMBODIMENTS ¹⁰ [0039] In Figure 1 there is shown a mobile ore siurrying apparatus 10 in accordance with a first embodiment of the présent invention. The mobile ore siurrying apparatus 10 comprises a feeding unit 12, a processing unit 14 and a pumping apparatus 16. [0040] The feeding unit 12 further comprising a sériés of screens 18 and a feed means, for example a variable speed belt feeder 20. During operation, material from ¹⁵ a dry mining operation 22 is passed through the screens 18 to the feeder 20. The sériés of screens 18 remove substantiaîly ail coarse materials with a diameter of greater than mm.

[0041 ] The material is first screened through a 200mm grizzly screen. It is then passed to a woven 40mm screen. Depending on the material being mined, a third 10 mm screening stage may also be implemented. The screened ore 22 is then transferred to the processing unit 14.

[0042] The processing unit 14 is defined by a bottom surface 24, two longitudinal walls 26 and two transverse walls 28. The processing unit 14 is separated into two discrète sections, the slurry tank 30 and the water tank 32. The slurry tank 30 and water tank 32 are separated by a dividing wall 34 which extends vertically from the bottom surface 24.

[0043] The screened ore 22 is transferred to the slurry tank 30 through a boil box 36. The boil box 36 is positioned to be partially submerged in the slurry and stops the ³⁰ screened feed material 22 contacting directly with the slurry initially. This slows the speed of the feed material 22 immediately prior to contacting the slurry and stops air bubbles being drawn into the pumping apparatus 16. The bottom of the boil box 36 ₇ 17427 may also be provided with distribution bars (not shown) that siow the material and encourage more even distribution in order to aid the slurrying process and avoid solids build up at the bottom of the slurry tank 30. The boil box 36 may also hâve water spray bars (not shown) attached thereto in order to remove build up on the boil box 36 itself.

[0044] Water is pumped into the water tank 32 by way of the water feed line 38 from an extemal water source 40 at a constant rate, such that the water in the water tank 32 overflows into the slurry tank 30 at a constant rate. Further provided in the slurry tank 30 is an agitation apparatus 41 which utilises the water from the external location 40 to further assist mixing and prevent solids settling.

[0045] The pumping apparatus 16 comprises in part a suction inlet 42 and an outlet pipe 44. The suction inlet 42 draws the slurry from the slurry tank 30 to the outlet pipe 44 by way of a pumping means 46. The outlet pipe 44 then directs the slurry out of the processing unit 14.

[0046] Leading from the water tank 32 is a flushing line 50 which feeds directly into the outlet pipe 44. The flushing line 50 allows for the slurrying apparatus 10 to be put into a flushing mode. In flushing mode, water is transferred directly from the water tank 32 into the outlet pipe 44 by way of a flushing valve 51, at an increased rate in order to quickly lower the density of the slurry stream to prevent solids settling and blockages in the pumping means 46. The water tank 32 provides a reserve of water so the slurrying apparatus 10 can be put into “flushing mode even if there is a failure in the pumping of water by way of the water line 38.

[0047] A slurry density control system 52 is provided in line with the outlet pipe 44 The sîurry density control system 52 comprises a density meter 54, a screen feeder motor 56 and a programmable logic controller (PLC) (not shown). The density meter 54 allows for the détection of a slurry density above a first predetermined value and the PLC raises an alarm so operators can reduce the rate of the feeder 20. If the slurry density is detected at a second higher predetermined value, the PLC will automatically stop the screen feeder motor 56. If this second higher slurry density condition continues for a predetermined length of time, the PLC will automatically put the apparatus 10 into flushing mode în order to rapidly reduce the slurry density and prevent solids build up în the outlet pipe 44.

[0048] A slurry flow control system 58 is further provided în line wîth the outlet pipe

44. The slurry flow control system 58 comprises an inline flow meter 60, the pumping means 46, the screen feeder motor 56, a shut off valve 64 and the PLC. Détection of a slurry flow below a desired rate in the inline flow meter 60 automatically switches off the screen feeder motor 56. Should the inline flow rate meter 60 detect a slurry flow rate sufficiently above or below the desired flow rate, the pumping speed of the pumping means 46 will be automatically altered to maîntain the desired slurry flow rate. If a slurry flow rate below a second predetermined flow rate is detected, the PLC will put the apparatus 10 into flushing mode and close the shut off valve 64. If this condition continues for a predetermined time, the control system turns off pump 46. At détection of a slurry flow above a particulariy high level, the PLC switches off pump 46 and screen feeder motor 56, as this may indicate burst pipeline.

[0049] In Figure 1 there is further shown a mobile slurrying method in accordance with a second aspect of the présent invention. By way of example, the method of the présent invention is described in the context of the treatment of heavy minerai deposîts, although such should not be seen as limiting the generality ofthe foregoing description. The method of the présent invention may be applied to any mining operation which requires the transport of materials from a mining stage to a primary processing stage.

[0050] Dozers (not shown) will deliver and deposit the run of dry ore material onto stockpiles 22 located in close proximity to the feeding unit 12. These dry materials 22 are reclaimed by front-end loader/s (not shown) and fed into the feeding unit 12. [0051] The ore materials 22 are then passed through the screens 18 to the variable speed belt feeder 20. The sériés of screens 18 remove ail coarse materials with a diameter of greater than 10 mm from the material. The screened material 54 is then passed into the slurry tank 30 of the processing unit 14 by way ofthe variable speed belt feeder 20 where it is contacted with water from the water tank 32.

[0052] Water from an extemal location 40 is pumped into the water tank 30 at a constant rate, with the overflow being passed into the slurry tank 30 where it contacts the screened material stream 22.

[0053] In the slurry tank 30, the formation ofthe slurry is aided by the agitation apparatus 41 which utilises the water from the external location 40 to further assist the mixing and to prevent solids settling. The agitation apparatus 41 can be turned off via a manual valve 65 if not required.

[0054] The slurry is then transferred out of the slurry tank 30 and into the outlet pipeline pipe 44 to the primary wet processing facility 66 by way of the pumping means 46.

[0055] The mobile ore slurrying apparatus 10 opérâtes at a nominal feed rate of 400 tph, though it has the capacity to operate at up to 500 tph. When operating at a 400 tph solids feed rate, the slurry flow rate is nominally 800 m³/hr, with a slurry spécifie gravity of 1.35 (40% solids by weight).

[0056] As would be understood by a person skilled the art, the density of the slurry is of course depended on the percentage of heavy metals (HM) in the ore to be processed. In standard grade zones this is typically 10% HM, giving a spécifie gravity of approximately 2.8. Under such conditions the flow rate of the water into the slurry tank will preferably be above ~393m³/hr. with this a stable slurry flow rate of ~573m³/hr through the mobile ore slurrying apparatus may be achieved. This equates to a maximum slurry solids by weight to water of 55% Cw. Accordingly, the maximum slurry density should always be between 1.04 and 1.6, assuming 10% maximum HM at any point in time. This is best seen in Figure 2, which shows the slurry density through the mobile ore slurrying apparatus 10 over an extended time period. Table 1 below describes the system parameters during normal operation.

Table 1

Spécifie Gravity Solids (S) 10% HM

Spécifie Gravity Water (Sw)___

Solid Conc. Desity (Cwj ___i

Spécifie Gravity Slurry (Sm) J

2.80 _ LP⁴

55.0%

1.590 [0057] In the event that mining proceeded in high grade zones of approximately 50% HM, the spécifie gravity of the ore is increased to around 3.4, causing the slurry density to increase. Slurries with a % solid by weight content of above 70% will cause clogging of the pump and pipes, resulting in the requirement of the system flush. Table 2 below describes the system parameters in which clogging is likely.

Table 2

Spécifie Gravity Solids (S) HM		2.80
Spécifie Gravity Water (Sw)		1.04!
Solid Conc. Desity (Cw)		70.0%i
Spécifie Gravity Sluny (Sm)		1.857

[0058] In Figure 3 a method 100 of supplementing a primary feed at a wet plant concentrator 102 in accordance with a third aspect of the présent invention is shown. u/~

Again, by way of example, the method of the présent invention is described in the context of the treatment of heavy minerai deposits, although such should not be seen as limiting the generality of the foregoing description. The présent invention may be applied to any mining operation where the primary minerais feed from a dredge operation may need to be supplemented at certain time in order for the primary processing stage to operate a full capacity.

[0059] As a resuit of certain dredging conditions, a primary feed 104 of the wet plant concentrator 102 is not always delivered at a full rate, this results in the wet plant concentrator 102 operating at a lower mining rate than might otherwise be achieved. The method of the présent invention acts to supplément the primary feed 104 at such times to ensure that the wet plant concentrator 102 opérâtes at maximum efficiency.

[0060] As can be seen in Figure 3, dozers 106 will deliver and deposit the run of dry ore material onto stockpiles (not shown) located in close proximity to the feeding unit

112. These dry materials are reclaimed by front-end loaders 114 and are fed into the mobile ore slurrying apparatus 116 of the présent invention.

[0061] The slurry output will then be transferred by way of pipeline 118 to an inlet 120 of the primary processing plant 102. In use, as the supplément mining operation continues the mobile ore slurrying apparatus 116 will be transported in concurrence with the movement of the mining operation.

[0062] In Figure 4 there is shown a plot of the total head feed being transported into a Wet Plant Concentrator (WPC). This feed has been separated into the contributions of both the primary feed from a dredging operation and the feed supplemented by the mobile ore slurrying apparatus 10 of the présent invention. Of note are the times in which the primary feed is non-operational, for sometimes weeks at a time, in which the feed being transported to the WPC is solely from the mobile ore slurrying apparatus of the présent invention. This allows the WPC to remain operational and production to continue.

[0063] As can be seen from the above description, the mobile ore slurrying apparatus and the methods of the présent invention can be implemented to more fully utilise processing capacity and enhance flexibility of operations through the combination of dry mining techniques with conventional dredge mining operations. This provides a contingency against further delays to the commissioning program. Due to the size of the mobile ore slurrying apparatus, it is a portable and versatile solution available to a mining site in the event of the need to supplément the feed of a primary dredge. This allows for shorter and more economically viable set up time resulting in decreased down time and delay in production.

[0064] The Applicants believe that it is one advantage of the présent invention to provide a mobile ore slurrying apparatus with as small a footprint as possible such that it may be easily moved as required.

[0065] Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the présent invention, u/^

Claims (10)

1. A mobile ore slurrying apparatus comprising:

Afeeding unit;

A processing unit; and

A pumping apparatus, wherein the processing unit is separated into a slurry tank section and a water tank section, such that ore may be passed from the feeding unit to the slurry tank where it is contacted with water from an overflow of the water tank to produce a slurry stream, the slurry stream is then transferred from the processing unit by wayofthe pumping apparatus.

2. An apparatus according to claim 1, wherein the processing unit is separated into the slurry tank section and the water tank section by way of a dividing wall.

3. An apparatus according to claim 1 or 2, wherein the processing unit further comprises a flush valve.

4. An apparatus according to claim 3, wherein actuation of the flush valve will rapidly release the water in the water tank to the slurry stream in order to rapidly reduce the slurry density.

5. An apparatus according to any one of the preceding claims, wherein the pumping apparatus further comprises an inline density meter.

6. An apparatus according to claim 5, wherein the inline density meter allows for the détection of a slurry density above a first predetermined value in order to raise an alarm, such that the feeding rate of the feeding unit may be altered to maintain a desired slurry density.

7. An apparatus according to claim 6, wherein the inline density meter allows for the détection of a slurry density above a second predetermined value in order to effect the release of the flush valve.

8. An apparatus according to any one of the preceding claims, wherein water is pumped from an external source into the water tank to maîntain the required water level.

9. A slurrying method comprising the steps of:

5 Mining an ore body to provide a dry ore stream;

Directing the dry ore stream to the mobile ore slurrying apparatus of claims 1 to 8;

Contacting the dry ore stream with water to provide a slurry stream; and Transferring the slurry stream to a primary processing plant.

10.A method of supplementing a primary feed at a wet processing plant, comprising the steps of:

Mining an ore body to provide a dry ore stream

Directing the dry ore stream to the mobile ore slurrying apparatus of claims 18;

Contacting the dry ore stream with water to provide a slurry stream; and

Transferring the slurry stream to a wet processing plant to supplément the primary feed.