Pump and associated tank for underground mine

Abstract

A dewatering apparatus for use in underground mining operations includes a longitudinally extending tank having a sloping floor. The tank has an outlet at a deep end. The tank includes a hemicylindrical diverting wall having a diameter about 75% of the width of the tank. The diverting wall directs the flow of water towards the deep end, increasing turbulence and encouraging fines particles to remain in suspension.

Description

“PUMP AND ASSOCIATED TANK FOR UNDERGROUND MINE”Field of the Invention

[0001] The present invention relates to a pump and associated tank used in the extraction of water from underground mining operations.Background to the Invention

[0002] It is frequently necessary to remove local groundwater from underground mining operations in a process known as dewatering. Often, an efficient way of doing this is to collect ground water in a tank located underground, and then to periodically pump water from the tank to a discharge location on the surface.

[0003] Ground water collected during underground mining operations typically contains a relatively large quantity of particulate matter, ranging from fines particles (less than about 2mm in size) through to small rocks.

[0004] Larger particulate matter must be screened out, and disposed of separately. It is generally not practical to screen fines.

[0005] When groundwater containing fines is stored in a tank, the fines have a tendency to settle in the base of the tank, creating a sludge or slurry. A pump designed to pump relatively clear water is generally incapable of pumping such a sludge, and attempts to do so are likely to cause blockages and damage to the pump. Accordingly, another means must be found to remove the fines-containing sludge, such as flushing or draining of the tank.

[0006] Australian patent number 2016224126 presents a possible solution to this problem, creating a series of baffles within the tank which aim to induce turbulence within the tank and thus to maintain the fines in suspension.

[0007] The present application seeks to provide an alternative means of achieving a similar end.Summary of the Invention

[0008] According to one aspect of the present invention there is provided a tank for use in underground mining operations, the tank extending longitudinally between a first end and a second end, the tank having a floor which slopes downwardly towards the second end at least partially, the tank having an outlet at the second end, the tank including a first side wall opposed to a second side wall, the tank having a diverting wall which extends from the first side wall towards the second side wall, the diverting wall having a curved portion which is convex when viewed from the first end.

[0009] It is preferred that the diverting wall extends upwardly from the floor. In a preferred embodiment, the diverting wall extends upwardly about 90% of the distance from the floor to an upper edge of the tank.

[0010] It is preferred that the diverting wall is substantially prismatic; that is, has a constant cross sectional shape along its vertical extent.

[0011] It is preferred that the diverting wall is part-cylindrical. The diverting wall may have a radius of curvature which is less than half of the distance between the first side wall and the second side wall.

[0012] In a preferred embodiment the diverting wall is hemi-cylindrical, with a diameter being about 75% of the distance between the first side wall and the second side wall. It will be appreciated that a gap between the diverting wall and the second side wall represents about 25% of the distance between the first side wall and the second side wall.

[0013] The tank may have a diverting baffle extending from the first side wall to the diverting wall. The diverting baffle may be oriented such that its connection to the first side wall is closer to the first end of the tank than its connection to the diverting wall. In a preferred embodiment, the diverting baffle forms an angle of about 75° relative to the first side wall.

[0014] It is preferred that the diverting baffle is generally tangential to the diverting wall.

[0015] The tank may include a screen positioned between the first end and the diverting wall. The tank preferably includes locating members positioned along the first side wall and the second side wall, the locating members arranged to maintain a removable screen in position.

[0016] The tank may have a curved end wall at the second end, the curved end wall being concave when viewed from the first end.

[0017] It is preferred that the curved end wall extends upwardly from the floor. In a preferred embodiment, the curved end wall extends upwardly about 90% of the distance from the floor to an upper edge of the tank.

[0018] It is preferred that the curved end wall is substantially prismatic; that is, has a constant cross sectional shape along its vertical extent.

[0019] It is preferred that the curved end wall is part-cylindrical. The curved end wall may have a radius of curvature which is twice the distance between the first side wall and the second side wall.

[0020] According to a second aspect of the present invention there is provided a dewatering apparatus having a tank as discussed above and a pump, the pump being arranged to draw water from the tank outlet and to pump to a discharge pipe.Brief Description of the Drawings

[0021] It will be convenient to further describe the invention with reference to preferred embodiments of the present invention. Other embodiments are possible, and consequently the particularity of the following discussion is not to be understood as superseding the generality of the preceding description of the invention. In the drawings:

[0022] Figure 1 is a first perspective of a first embodiment of a dewatering apparatus in accordance with the present invention;

[0023] Figure 2 is a second perspective of the dewatering apparatus of Figure 1 ;

[0024] Figure 3 is a perspective of a tank from within the dewatering apparatus of Figure 1 ;

[0025] Figure 4 is a plan view of the tank of Figure 3;

[0026] Figure 5 is a perspective of a tank from within a second embodiment of a dewatering apparatus in accordance with the present invention;

[0027] Figure 6 is a plan view of the tank of Figure 5; and

[0028] Figure 7 is a cross sectional view through the tank of Figure 5.Detailed Description of Preferred Embodiments

[0029] Referring to Figures 1 and 2, there is shown a dewatering apparatus 10 arranged on a skid base 12 for ease of movement. The skid base 12 includes forklift pockets 14 via which the dewatering apparatus 10 can be moved.

[0030] The dewatering apparatus of Figure 1 has a pump 18 and a tank 20.

[0031] The tank 20 can be seen in greater detail in Figures 3 and 4.

[0032] An alternative embodiment of the dewatering apparatus has a tank 60, which can be seen in greater detail in Figures 5 to 7.

[0033] The tank 20 has a first end 22 spaced from a second end 24, with a first side wall 26 spaced from a second side wall 28. The tank 20 is generally rectangular, with the side walls 26, 28 being about three to four times longerthan the walls at the ends 22, 24. The tank 20 has a longitudinal direction parallel to the side walls 26, 28.

[0034] The tank 20 has a generally rectangular upper edge 30.

[0035] The tank 20 has a floor 32. The floor 32 has a main portion 34 which slopes downwardly from the first end 22 towards the second end 24, and a second portion 36 which is parallel to the upper edge 30. The second portion 36 abuts the second end 24. The main portion 34 extends through about 90% of the distance from the first end 22 to the second end 24, with the second portion 36 extending through the remaining 10%.

[0036] The main portion 34 is angled at about 30° to the horizontal.

[0037] An outlet 38 is located at the second end 24, slightly above the second portion 36 of the floor 32. The outlet 38 is arranged to be connected by a transfer pipe 64 to the pump 18.

[0038] The tank has a nominal fill line (not shown) about 90% of the distance from the second portion 36 of the floor 32 to the upper edge 30.

[0039] Each side wall 26, 28 includes an inlet port 40 located in an upper corner of the side wall 26, 28, close to the first end 22 and just below the nominal fill line. It will be appreciated that the slope of the floor 32 encourages the flow of liquid in the tank 20 from the inlet ports 40 to the outlet 38.

[0040] A screen 42 extends vertically from the floor 32 to the nominal fill line of the tank 20. The screen 42 is located approximately midway between the first end 22 and the second end 24. The screen 42 extends from the first side wall 26 to the second side wall 28, and is perpendicular to the first and second side walls 26, 28. It will be appreciated that the screen 42 is formed of a mesh having apertures sized to allow water containing fines to pass easily through, but which prevents the flow of larger particles from the first end 22 of the tank 20 to the second end 24.

[0041] In the embodiment of the drawings, each of the first side wall 26 and the second side wall 28 has a plurality of locating members 44 spaced vertically along the screen 42, the locating members 44 being on either side of the screen 42. The locating members 44 are fixed to the first and second side walls 26, 28 respectively. The arrangement is such that the screen 42 is retained in position by the locating members 44, but can be readily removed for cleaning purposes by sliding vertically upwards.

[0042] A diverting wall 50 is located in the tank 20, positioned about halfway between the screen 42 and the second end 24. The diverting wall 50 is curved, at least for a portion. In the preferred embodiment of the drawings the diverting wall 50 is hemi-cylindrical, being convex when viewed from the first end 22 and concave when viewed from the second end 24. The diverting wall 50 extends upwardly from the floor 32 to the nominal fill line of the tank 20, having a constant cross-sectional shape.

[0043] The diverting wall 50 has a diameter about 75% of the width from the first side wall 26 to the second side wall 28; that is, has a radius of curvature less than half of the width from the first side wall 26 to the second side wall 28. The diverting wall 50 is fixed to the first side wall 26. There is thus a flow gap 52 between an outer end of the diverting wall 50 and the second side wall 28. The flow gap 52 represents about 25% of the distance from the first side wall 26 to the second side wall 28.

[0044] It is considered that in other embodiments a diverting wall having a diameter of between 60% and 90% of the width from the first side wall 26 to the second side wall 28 is likely to be effective. This could result in a flow gap of between 10% and 40% of the distance from the first side wall 26 to the second side wall 28. It will be appreciated that the diverting wall 50 may be positioned such that a first flow gap exists between the diverting wall 50 and the first side wall 26, and a second flow gap exists between the diverting wall 50 and the second side wall 28, with the total width of the flow gap being between 10% and 40% of the distance from the first side wall 26 to the second side wall 28.

[0045] A cross bar 54 extends from the first side wall 26 to the second side wall 28 near the upper edge 30, with the diverting wall 50 fixed to the cross bar 54.

[0046] A diverting baffle 56 extends between the first side wall 26 and the diverting wall 50. The diverting baffle 56 is fixed to the first side wall 26 forward of the diverting wall 50, such that the diverting baffle 56 extends from the first side wall 26 at an angle of about 75°, partially oriented towards the second end 24. The diverting baffle 56 is arranged to be generally tangential to the diverting wall 50.

[0047] In use, water containing fines and larger particulate matter enters the tank 20 at the inlet ports 40. It passes through the screen 42, which removes the larger particulate matter. It is then caused to accelerate along the diverting baffle 56 and diverting wall 50 in order to pass through the flow gap 52, which acts like a nozzle. It will be appreciated that this induces turbulence in the region between the diverting wall 50 and the second end 24, which assists in maintaining fines in suspension and enabling them to be pumped by the pump 18.

[0048] The tank 60 of the second embodiment, shown in Figures 5 to 7, is similar in many respects to the tank of the first embodiment, with like numbers referring to like figures.

[0049] The tank 60 has a curved end wall 62. The curved end wall 62 is located in the tank 20, abutting the second end 24. The curved end wall 62 is part-cylindrical, being concave when viewed from the first end 22 and convex when viewed from the second end 24. The curved end wall 62 extends upwardly from the floor 32 to the nominal fill line of the tank 20, having a constant cross-sectional shape.

[0050] The curved end wall 62 has a radius of curvature equal to about twice the width from the first side wall 26 to the second side wall 28. In cross section, therefore, the curved end wall represents an arc through about 30°. Thecurved end wall 62 is fixed to the first side wall 26, the second side wall 28 and the second end 24, which is tangential to the curved end wall 62.

[0051] The curved end wall 62 is intended to increase the degree of turbulence created in the tank 60 of the second embodiment when compared to that in the tank 20 of the first embodiment.

[0052] The dewatering apparatus 10 includes supporting piping, including a transfer pipe 64 which connects the tank outlet 38 to the pump 18, a discharge pipe 66 which connects to an outlet of the pump 18 for taking water to the surface, an overflow pipe 68 open at the nominal fill line of the tank 20, and flushing pipes 70 for cleaning and flushing of the tank 20 if required. A screen discharge port 72 at the base of the screen 42 is connected to the flushing pipes 70.

[0053] Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention. For instance, multiple pumps 18 and / or tanks 20, 60 can employed in a pump station configuration.

Claims

Claims1. A tank 20, 60 for use in underground mining operations, the tank extending longitudinally between a first end 22 and a second end 24, the tank having a floor 32 which slopes downwardly towards the second end at least partially, the tank having an outlet 38 at the second end, the tank including a first side wall 26 opposed to a second side wall 28, the tank having a diverting wall 50 which extends from the first side wall towards the second side wall, the diverting wall 50 having a curved portion, the curved portion being convex when viewed from the first end.

2. A tank as claimed in claim 1 , wherein the diverting wall extends upwardly from the floor.

3. A tank as claimed in claim 2, wherein, the diverting wall extends upwardly about 90% of the distance from the floor to an upper edge 30 of the tank.

4. A tank as claimed in any preceding claim, wherein that the diverting wall is substantially prismatic; that is, has a constant cross sectional shape along its vertical extent.

5. A tank as claimed in claim 4, wherein the diverting wall is part- cylindrical.

6. A tank as claimed in claim 5, wherein the diverting wall has a radius of curvature which is less than half of the distance between the first side wall and the second side wall.

7. A tank as claimed in claim 6, wherein the diverting wall is hemi- cylindrical, with a diameter being about 75% of the distance between the first side wall and the second side wall.

8. A tank as claimed in any preceding claim, wherein the tank has a diverting baffle 56 extending from the first side wall to the diverting wall.

9. A tank as claimed in claim 8, wherein the diverting baffle is oriented such that its connection to the first side wall is closer to the first end of the tank than its connection to the diverting wall.

10. A tank as claimed in claim 9, wherein the diverting baffle forms an angle of about 75° relative to the first side wall.

11. A tank as claimed in any one of claims 8 to 10 wherein the diverting baffle is generally tangential to the diverting wall.

12. A tank as claimed in any preceding claim, wherein the tank includes a screen 42 positioned between the first end and the diverting wall.

13. A tank as claimed in claim 12, wherein the screen is removable, and wherein the tank includes locating members 44 positioned along the first side wall and the second side wall, the locating members arranged to maintain the screen in position.

14. A tank as claimed in any preceding claim, wherein the tank has a curved end wall 62 at the second end, the curved end wall being concave when viewed from the first end.

15. A tank as claimed in claim 14, wherein the curved end wall extends upwardly from the floor.

16. A tank as claimed in claim 14, wherein the curved end wall extends upwardly about 90% of the distance from the floor to an upper edge of the tank.

17. A tank as claimed in any one of claims 14 to 16, wherein the curved end wall is substantially prismatic; that is, has a constant cross sectional shape along its vertical extent.

18. A tank as claimed in any one of claims 14 to 16, wherein the curved end wall is part-cylindrical.

19. A tank as claimed in claim 18, wherein the curved end wall has a radius of curvature which is about twice the distance between the first side wall and the second side wall.

20. A dewatering apparatus 10 having a tank as claimed in any preceding claim and a pump 18, the pump being arranged to draw water from the tank outlet and to pump to a discharge pipe 66.

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