Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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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.
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[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.
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[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
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described below. Another embodiment of the sluice box is illustrated in FIGS.
4-6
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.
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[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-
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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.
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[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.
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[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",
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"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.
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