CA2873528C - Vortex-inducing sluice box - Google Patents

Abstract

A sluice box includes a pair of spaced-apart elongated rails and a plate disposed between the pair of rails, the plate having a plurality of vortex- inducing wells to separate a heavy metal, such as gold, from a metal-containing aggregate slurry. The wells may be disposed in a plurality of rows that are substantially orthogonal to the rails. The vortex-inducing wells may each have an internal spiral. Counterclockwise spiralled wells may be provided for a first set of rows and clockwise-spiralled wells for a second set of rows. The first set of rows may alternate with the second set of rows. A plurality of transverse troughs may be interspersed between each pair of adjacent rows of wells.

Description

VORTEX-INDUCING SLUICE BOX
TECHNICAL FIELD
[0001] The present invention relates to sluice boxes for recovering heavy material, such as gold, from an aggregate.
BACKGROUND

[0002] The mining of gold or other precious metals or heavy metals aggregated in alluvial deposits is known generally as placer mining. Placer gold deposits are found in areas where veins and lodes of gold have been exposed and eroded due to such forces as glaciers, water and rock slides. Such deposits are found, for example, in the Yukon and in British Columbia, Canada.

[0003] Several different techniques have been developed for separating placer gold from the surrounding aggregate. Prospectors historically used gold pans in creek beds. More recently, placer mining is performed typically with a sluice box.
The sluice box includes a channel placed on an incline and having riffles on the bottom. The riffles are blocks or bars for catching the gold. The riffles are commonly placed on top of matting, which traps the finer gold particles. In operation, a stream of water flows along the sluice and gold-bearing aggregate is added to the sluice.
The gold particles are trapped by the riffles and matting, while the remaining aggregate and water are discharged at the end of the sluice.

[0004] Due to the high price of gold, it has become increasingly important to improve the recovery efficiency of gold from sluice boxes. The devices used in early years were relatively inefficient and a considerable amount of gold, particularly fine material and gold flour, was discharged from the sluice boxes. For example, in the device disclosed in Canadian Patent 1,074,263, a superfine recovery section has been added to the lower portion of the fine recovery channels to attempt to recover fine material not recovered by the upper portion of the device. Various other improvements in sluice boxes have been disclosed in the prior art. For example, a portable sluice box is disclosed in US Patent 4,592,833. A collapsible sluice box is disclosed in US Patent 8,322,536. A vibrating sluice box is disclosed in US
Patent 4,860,874. A method for cleaning sluice boxes is disclosed in US Patent 4,962,858.

[0005] An improved sluice box capable of efficiently recovering gold or other heavy metal remains highly desirable.
SUMMARY

[0006] The present invention provides a sluice box having vortex-inducing wells that enhance the separation or recovery of a heavy metal such as gold from a metal-containing aggregate slurry that is sluiced over the wells. The sluice box includes a pair of spaced-apart elongated rails and a plate disposed between the pair of rails.
The plate includes a plurality of the vortex-inducing wells that are geometrically configured to promote separation of a heavy metal, such as gold, from a metal-containing aggregate slurry. The wells may be disposed in a plurality of rows that are substantially orthogonal to the rails. The vortex-inducing wells may each have an internal spiral. Counterclockwise spiralled wells may be provided for a first set of rows and clockwise-spiralled wells for a second set of rows. The first set of rows may alternate with the second set of rows. A plurality of transverse troughs may be interspersed between each pair of adjacent rows of wells.

[0007] Accordingly, one inventive aspect of the present disclosure is a sluice box having a pair of spaced-apart elongated rails and a plate disposed between the pair of rails, the plate having a plurality of vortex-inducing wells for separating a metal from a metal-containing aggregate.

[0008] Another inventive aspect of the present disclosure is a method of separating a heavy metal from a metal-containing aggregate slurry. The method entails inclining a sluice box having a pair of spaced-apart elongated rails and a plate disposed between the pair of rails, the plate having a plurality of vortex-inducing wells and sluicing the metal-containing aggregate slurry over the vortex-inducing wells of the plate of the sluice box to induce vortices in the aggregate slurry that separate the heavy metal from the aggregate slurry.

[0009] Yet another inventive aspect of the present disclosure is a sluice plate for use in a sluice box, the sluice plate including a plurality of vortex-inducing wells for separating a metal from a metal-containing aggregate slurry.

[0010] This summary is provided to highlight certain significant inventive aspects but is not intended to be an exhaustive or limiting definition of all inventive aspects of the disclosure. Other inventive aspects may be disclosed in the detailed description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Further features and advantages of the present technology will become apparent from the following detailed description, taken in combination with the appended drawings, in which:

[0012] FIG. 1 is an isometric view of a sluice box in accordance with an embodiment of the present invention;

[0013] FIG. 2 is a top view of the sluice box of FIG. 1;

[0014] FIG. 3 is a side view of the sluice box of FIG. 1;

[0015] FIG. 4 is an isometric view of a sluice box in accordance with another embodiment of the present invention;

[0016] FIG. 5 is a top view of the sluice box of FIG. 4;

[0017] FIG. 6 is a side view of the sluice box of FIG. 4;

[0018] FIG. 7 is a top view of a sluice plate having vortex-inducing wells for use in a sluice box;

[0019] FIG. 8 is a cross-sectional view of the sluice plate of FIG. 7;

[0020] FIG. 9 is an isometric view of a vortex-inducing well for use in the sluice plate of FIG. 8;

[0021] FIG. 10 is a cross-sectional view of the vortex-inducing well of FIG. 9;

[0022] FIG. 11 is a top view of another version of a sluice plate having vortex-inducing wells for use in a sluice box;

[0023] FIG. 12 is a cross-sectional view of the sluice plate of FIG. 11;

=
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[0024] FIG. 13 is an isometric view of a vortex-inducing well for use in the sluice plate of FIG. 12;

[0025] FIG. 14 is a cross-sectional view of the vortex-inducing well of FIG. 13;

[0026] FIG. 15 is an isometric view of a vortex-inducing well for use in the sluice plate of FIG. 12; and

[0027] FIG. 16 is a cross-sectional view of the vortex-inducing well of FIG. 15.

[0028] It will be noted that throughout the appended drawings, like features are identified by like reference numerals.
DETAILED DESCRIPTION

[0029] In general, the present invention relates to a sluice box and a method of using the sluice box to separate gold or another heavy metal from an aggregate slurry.

[0030] SLUICE BOX

[0031] FIGS. 1-3 depict a sluice box in accordance with an embodiment of the present invention, in which FIG. 1 is an isometric view, FIG. 2 is a top view and FIG.
3 is a side view.

[0032] The sluice box is generally denoted by reference numeral 10.
The sluice box includes a pair of spaced-apart elongated rails 12 which are substantially parallel to each other as shown by way of example in these figures. Between the rails are one or more vortex plates 14 (or sluice plates) over which the metal-containing aggregate slurry sluices. The plate(s) and rails may be connected together by threaded fasteners, e.g. screws, or by any other suitable mechanical connecting means. Together the rails and vortex plate(s) constitute a sluice channel or conduit. In operation, the sluice box is inclined to permit a metal-containing aggregate slurry to sluice (i.e. flow or wash) over the vortex plate(s). The one or more vortex plates of the sluice box include a plurality of vortex-inducing wells for separating a metal from a metal-containing aggregate slurry as will be further described below. Another embodiment of the sluice box is illustrated in FIGS.

in which FIG. 4 is an isometric view, FIG. 5 is a top view and FIG. 6 is a side view.

[0033] An aggregate slurry, for the purposes of this specification, is any mixture of water and aggregate. An aggregate, for the purposes of this specification, is any mixture of streambed deposits of sand, sediment, silt, soil, clay, gravel, pebbles, stones, etc. that contain particles, flakes, bits or specks of gold or other heavy metals.

[0034] In the embodiments illustrated by way of example in FIGS. 1-6, each vortex plate 14 includes a plurality of vortex wells 20. The vortex wells are spiral or helical structures that induce vortices in the water flow to enhance separation of the heavy metal particulate from the aggregate slurry.

[0035] In the illustrated embodiments, the vortex-inducing wells 20 are disposed in a plurality of rows 30. The wells may be connecting, adjoining, adjacent or partially overlapping as shown in the illustrated embodiments. Although the illustrated embodiments provide excellent results, other variants may be possible in which the wells are disposed in a different layout or configuration.

[0036] The rows 30 may be substantially orthogonal to the rails 12 as shown by way of example. Although a configuration with rows substantially orthogonal to the rails is believed to provide the best performance, other variants may be possible with one or more rows that are angled or non-orthogonal.

[0037] Further details of the sluice plates (also referred to herein as vortex plates) and vortex-inducing wells are depicted by way of example in FIGS. 7-16.

[0038] In addition to the vortex-inducing wells, the vortex plate 14 in the embodiment illustrated by way of example in FIGS. 7-8 includes a plurality of spaced-apart transverse troughs 40 that function as riffles to trap heavier gold particles as water washes them and the other material or aggregate over the sluice box. The sluice box may include a plurality of transverse troughs interspersed between each pair of adjacent rows of wells. Each transverse trough may be, as shown by way of example in the embodiment of FIGS. 7-8, a single continuous trough extending completely between the pair of rails.

[0039] In the illustrated embodiment, the troughs 40 are substantially parallel to each other and to the rows of wells. The troughs 40, as shown in this embodiment, are substantially orthogonal to the rails. In the illustrated example of FIGS.
7-8, the troughs 40 extend completely from one rail to another rail (i.e. they extend entirely from one side of the vortex plate to the other opposite side of the vortex plate). In the embodiment illustrated by FIGS. 7-8, the number of troughs (eight) is less than the number of rows of wells (nine) although this may be varied in other embodiments. The troughs 40 may be chamfered on one side. The chamfer 45 may be a 45-degree chamfer as illustrated or any other suitable angle.

[0040] In the embodiments illustrated in FIGS. 7-8, some of the wells are counterclockwise spiralled wells (i.e. for a first set of rows) while others are clockwise-spiralled wells (i.e. for a second set of rows). Best performance is believed to be obtained when the first set of rows alternates with the second set of rows. In other words, the first, third, fifth, seventh and ninth rows have counterclockwise-spiralled wells while the second, fourth, sixth and eighth rows have clockwise-spiralled wells. Although the number of rows in this example is nine, it will be appreciated that variants of the design may have a different number of rows. In this example, there are more rows having counterclockwise-spiralled wells than rows having clockwise-spiralled wells. In other words, the number of rows having counterclockwise-spiralled wells may be greater than the number of rows having clockwise-spiralled wells. In a variant, the number of rows having clockwise-spiralled wells may be equal to the number of rows having counterclockwise-spiralled wells. In yet another variant, the number of rows having clockwise-spiralled wells may be greater than the number of rows having counterclockwise-spiralled wells.

[0041] Each vortex-inducing well 20 may be designed as shown by way of example in FIGS. 9 and 10, which are isometric and cross-sectional views of the vortex-inducing well. The well 20 depicted by way of example in FIGS. 9 and 10 has an internal spiral (or helical ramp-like structure) that spirals two and a half revolutions from a top surface to a bottom surface. Each well creates a vortex that agitates the slurry to cause the gold or other heavy metal to settle in the bottom of the well where it can be recovered. In the specific embodiment shown in FIGS. 9-10, the diameter of the well at the top of the well is 1.05 inches and the diameter of the well at the bottom of the well is 0.375 inches. The depth of the well is 0.410 includes. These dimensions are solely presented to illustrate one specific implementation. These dimensions may be varied without departing from the inventive concept.

[0042] In another embodiment, the vortex plate 14 may be constructed as shown by way of example in FIGS. 11-12. Interspersed between the rows of wells are troughs. Unlike the troughs in FIGS. 9-10 which extend completely from one rail to another rail (i.e. from one side to another side of the vortex plate), the troughs in FIGS. 11-12 are formed as two side-by-side troughs 41 which are spaced apart from each other and which are also spaced apart from the sides of the plate (i.e.
spaced apart from the rails). In the specific embodiment of FIGS. 11-12, the gap G
between the left trough 41 and the left side is equal to the gap G between the right trough 41 and the right side. This gap G is also equal to the gap G between the troughs 41. For example, for a plate having a width of 48 inches, the gap G
may be 0.5 inches. These dimensions are presented solely to convey a sense of the size of the gap for one specific implementation. These dimensions may be varied without departing from the inventive concept.

[0043] In the embodiments illustrated in FIGS. 13-16, the vortex-inducing wells 30 each have an internal spiral that is formed as a helical ramp spiralling three revolutions from a top surface to a bottom surface. The internal spiral creates a vortex as the slurry sluices over the wells to enhance separation of the metal from slurry. In the specific embodiment depicted in FIGS. 13-16, the diameter at the top of the well is 2 inches and the diameter at the bottom of the well is 0.75 inches. The depth of the well is also 0.75 inches. The thickness of the plate is 1 inch.
These dimensions are solely presented to illustrate one specific implementation.
These dimensions may be varied without departing from the inventive concept.

[0044] In the embodiment of FIGS. 13-16, the sluice box further includes a central post 44 inside each vortex-inducing well. In the illustrated embodiment, the top of the post is flush with the top of the vortex plate. The post may be 0.25 inches in diameter and 0.75 inches high. These dimensions may be varied without departing from the inventive concept.

[0045] The sluice box may be scaled to different sizes. For example, the sluice box of FIGS. 1-3 has fourteen rows of wells over a total length of 53 inches (including rails) with rails that are three inches high. The sluice box is, in this particular embodiment, six inches wide. As another example, the sluice box of FIGS. 4-6 has 27 rows of wells over a total length of 82.5 inches (again including the rails which are also three inches high). The sluice box is twelve inches wide in this second example. These dimensions are solely presented to illustrate specific implementations of the sluice. These dimensions may be varied without departing from the inventive concept.

[0046] The sluice box is primarily designed for separating gold from aggregate although it may also be used for other heavy metals such as platinum and silver.

[0047] METHOD

[0048] Another inventive aspect of the disclosure is a method of separating a heavy metal from a metal-containing aggregate slurry. The method entails inclining a sluice box having a pair of spaced-apart elongated rails and a plate disposed between the pair of rails, the plate having a plurality of vortex-inducing wells and sluicing the metal-containing aggregate slurry over the vortex-inducing wells of the plate of the sluice box to induce vortices in the aggregate slurry that separate the heavy metal from the aggregate slurry.

[0049] In one embodiment, the method involves sluicing the aggregate slurry over a plurality of rows of wells which may be, in the illustrated embodiment, substantially orthogonal to the rails. The method is best performed by inducing vortices by internal spirals in the vortex-inducing wells. The vortex-inducing wells may be counterclockwise spiralled wells for a first set of rows and clockwise-spiralled wells for a second set of rows. The method is best performed using a sluice box in which the first set of rows alternate with the second set of rows.

[0050] Metal separation is enhanced when the method employs a sluice box having a plurality of transverse troughs interspersed between each pair of adjacent rows of wells. In one embodiment, the method is performed with well whose internal spirals comprise two and a half revolutions and wherein each transverse trough is a single continuous trough extending completely between the pair of rails.

[0051]
Alternatively, the method may be performed with a sluice box having internal spirals that each comprises three revolutions and wherein the troughs comprise pairs of spaced-apart side-by-side troughs which are furthermore spaced from each rail. Metal separation from the aggregate may be enhanced using a central post inside each of the vortex-inducing wells. This method is useful to extracting gold from aggregate but may also be used, or adapted for use, with other heavy metals.

[0052] In operation a metal-containing aggregate slurry enters the top end of the sluice box. As the slurry flows down the sluice box it passes over first a row of interconnected helical/spiral vortex-inducing wells. As the slurry passes over the wells it enters a low-pressure area. The heavy particles in the slurry are pulled down into the vortex wells where they stay in a swirling section of fluid created by the helix/spiral. As particles collide in the vortices created by the wells, heavier particles release some of their energy into the lighter particles driving them up and out of the vortices. After the slurry passes over the first row of vortex-inducing wells it then passes over a drop riffle (i.e. the trough). As the slurry passes over the drop riffle (trough) the heavy particles are pulled down into the drop riffle (trough) where these particles are caught in turbulence that further helps separate the heavy material from the lighter material. As the slurry leaves the drop riffle it then passes over another row of vortex-inducing wells that are offset from the row above it, and which have an opposite rotation from the row above it. This opposite rotation further enhances the separation of the heavy material from the lighter materials. This process is continued down the length of the sluice box as the slurry passes over rows of vortex-inducing wells and troughs (drop riffles). Each row of vortex-inducing wells further separates heavy materials from lighter materials capturing even finer materials. The slope or angle of the sluice box may vary with the volume of water flow for best results.

[0053] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising", "comprise(s)", "having", "has", "have", "including", "include(s)", "containing", "contain(s)", "entailing", and "entail(s)" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. The term "connected" is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided herein, is intended merely to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0054] The embodiments of the invention described above are intended to be exemplary only. As will be appreciated by those of ordinary skill in the art, to whom this specification is addressed, many obvious variations, modifications, and refinements can be made to the embodiments presented herein without departing from the inventive concept(s) disclosed herein. The scope of the exclusive right sought by the applicant(s) is therefore intended to be limited solely by the appended claims.

Claims (36)

CLAIMS:

1. A sluice box comprising:
a pair of spaced-apart elongated rails; and a plate disposed between the pair of rails, the plate having a plurality of vortex-inducing wells for separating a metal from a metal-containing aggregate slurry wherein each of the vortex-inducing wells comprises an internal spiral.

2. The sluice box of claim 1 wherein the vortex-inducing wells are disposed in a plurality of rows.

3. The sluice box of claim 2 wherein the rows are substantially orthogonal to the rails.

4. The sluice box of claim 1 wherein the internal spiral of the vortex-inducing wells comprise counterclockwise spiralled wells for a first set of rows and clockwise-spiralled wells for a second set of rows.

5. The sluice box of claim 4 wherein the first set of rows alternate with the second set of rows.

6. The sluice box of claim 5 further comprising a plurality of transverse troughs interspersed between each pair of adjacent rows of wells.

7. The sluice box of claim 6 wherein the internal spiral comprises two and a half revolutions and wherein each transverse trough is a single continuous trough extending completely between the pair of rails.

8. The sluice box of claim 6 wherein the internal spiral comprises three revolutions and wherein the troughs comprise pairs of spaced-apart side-by-side troughs which are furthermore spaced from each rail.

9. The sluice box of claim 8 further comprising a central post inside the vortex-inducing well.

10. The sluice box of any one of claims 1 to 9 wherein the heavy metal is gold.

11. The sluice box of claim 6 wherein the internal spiral comprises two or more revolutions and wherein each transverse trough is a single continuous trough extending completely between the pair of rails.

12. The sluice box of clam 6 wherein the internal spiral comprises two or more revolutions and wherein the troughs comprise pairs of spaced-apart side-by-side troughs which are furthermore spaced from each rail.

13. A method of separating a heavy metal from a metal-containing aggregate slurry, the method comprising:
inclining a sluice box having a pair of spaced-apart elongated rails and a plate disposed between the pair of rails, the plate having a plurality of vortex-inducing wells; and sluicing the metal-containing aggregate slurry over the vortex-inducing wells of the plate of the sluice box to induce vortices in the aggregate slurry that separate the heavy metal from the aggregate slurry wherein the sluicing comprises inducing vortices by internal spirals in the vortex-inducing wells.

14. The method of claim 13 wherein sluicing comprises sluicing the aggregate slurry over a plurality of rows of wells.

15. The method of claim 14 wherein sluicing comprises sluicing the aggregate slurry over rows of wells that are substantially orthogonal to the rails.

16. The method of claim 15 wherein inducing vortices comprises using counterclockwise spiralled wells for a first set of rows and clockwise-spiralled wells for a second set of rows.

17. The method of claim 16 wherein the first set of rows alternate with the second set of rows.

18. The method of claim 17 further comprising a plurality of transverse troughs interspersed between each pair of adjacent rows of wells.

19. The method of claim 15 wherein the internal spiral comprises two and a half revolutions and wherein each transverse trough is a single continuous trough extending completely between the pair of rails.

20. The method of claim 15 wherein the internal spiral comprises three revolutions and wherein the troughs comprise pairs of spaced-apart side-by-side troughs which are furthermore spaced from each rail.

21. The method of claim 20 further comprising a central post inside the vortex-inducing well.

22. The method of any one of claims 13 to 21 wherein the heavy metal is gold.

23. The method of claim 15 wherein the internal spiral comprises two or more revolutions and wherein each transverse trough is a single continuous trough extending completely between the pair of rails.

24. The method of claim 15 wherein the internal spiral comprises two or more revolutions and wherein the troughs comprise pairs of spaced-apart side-by-side troughs which are furthermore spaced from each rail.

25. A sluice plate for use in a sluice box, the sluice plate comprising:
a plurality of vortex-inducing wells for separating a metal from a metal-containing aggregate slurry wherein the vortex-inducing wells each comprises an internal spiral.

26. The sluice plate of claim 25 wherein the vortex-inducing wells are disposed in a plurality of rows.

27. The sluice plate of claim 26 wherein the rows are substantially orthogonal to a longitudinal axis of the sluice plate.

28. The sluice plate of claim 25 wherein the internal spiral of the vortex-inducing wells comprise counterclockwise spiralled wells for a first set of rows and clockwise-spiralled wells for a second set of rows.

29. The sluice plate of claim 28 wherein the first set of rows alternate with the second set of rows.

30. The sluice plate of claim 29 further comprising a plurality of transverse troughs interspersed between each pair of adjacent rows of wells.

31. The sluice plate of claim 30 wherein the internal spiral comprises two and a half revolutions and wherein each transverse trough is a single continuous trough extending from a first side of the plate to a second side of the plate.

32. The sluice plate of claim 30 wherein the internal spiral comprises three revolutions and wherein the troughs comprise pairs of spaced-apart side-by-side troughs which are furthermore spaced from first and second sides of the plate.

33. The sluice plate of claim 32 further comprising a central post inside the vortex-inducing well.

34. The sluice plate of any one of claims 25 to 33 wherein the heavy metal is gold.

35. The sluice plate of claim 30 wherein the internal spiral comprises two or more revolutions and wherein each transverse trough is a single continuous trough extending from a first side of the plate to a second side of the plate.

36. The sluice plate of claim 30 wherein the internal spiral comprises two or more revolutions and wherein the troughs comprise pairs of spaced-apart side-by-side troughs which are furthermore spaced from first and second sides of the plate.