Fluid sprinkling – spraying – and diffusing – Flexible flow line or outlet storage or retrieval means – Reel and ground supported frame
Reexamination Certificate
1999-11-30
2001-04-17
Scherbel, David A. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Flexible flow line or outlet storage or retrieval means
Reel and ground supported frame
C239S726000, C239S736000
Reexamination Certificate
active
06216962
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for distributing fluid to a leach field in the practice of the art of hydrometallurgy.
The art of hydrometallurgy is described in some detail in U.S. Pat. No. 5,005,806, the disclosure of which is hereby incorporated herein by reference. In essence, hydrometallurgy is the art of recovering metals from ores by separating a solution of the metal in the form of a salt from the ore, then decomposing the metallic salt in such a way to cause precipitation of the metal from the solution. The leaching solution, or lixiviant, used depends on the particular metal being leached from the ore. For example, gold and silver are typically reclaimed from low grade ore using lixiviants generally constituting aqueous solutions of sodium cyanide mixed with oxygen to convert the metal to a soluble salt from which the metal can be recovered by precipitation. Leaching solutions of sulfuric acid or sulfuric acid-sulfate are typically used for leaching copper from an ore.
In the commercial practice of hydrometallurgy, a bed of run-of-mine or granular low grade ore, known as a heap, is spread over an impervious base or pad which may comprise sheets of plastic film, asphalt and/or compacted clay. Crushed ore is normally heaped onto the pad to a depth to 10 to 30 feet and leveled off at the top of the heap. The ore is typically pre-crushed to a desired size. For example, for copper mining, the ore may be crushed to one quarter inch granular size.
After the heap has been prepared, the target metal is leached from the ore by circulating the leaching solution through the heap in a process commonly known as percolation. To effect percolation, the solution is distributed over the top of the heap and permitted to seep down through the heap to the impervious pad. The impervious pad is typically sloped toward a drain pipe or channel for recovering the metal laden solution. The liquid that is distributed over the top of the heap may be a leaching solution comprising water mixed with a leaching agent, or a leaching agent may be premixed with the ore before the ore is spread onto the heap and relatively pure water is percolated through the heap. For example, in copper ore mining, sulfuric acid is mixed with one quarter inch crushed copper ore before the ore is spread onto the heap, and pure water is percolated through the heap to mix with the sulfuric acid and leach the copper from the ore.
Various systems have been used for distributing water over a leach field. For example, sprayers or sprinklers may be positioned at various locations on the heap to spray and distribute water or leaching solution over the top of the surface. Liquids distributed in such a manner are prone to rapid evaporation and degradation by exposure to air and ultra violet rays, and in addition, can be prone to freezing in cold weather operations. In addition, spraying techniques can result in surface puddling and run-off, raising the threat of channeling problems and potentials for blowouts.
U.S. Pat. 5,005,806 discloses a liquid distribution system which includes main line pipes extending longitudinally along a side of the heap and header pipes extending at spaced intervals from the main line pipe transversely across the heap generally parallel to one another. Extending in both directions across the heap from the header pipes are a plurality of generally parallel, closely spaced tubes. Liquid flows from the main line pipes, into the header pipes and into the tubes, and each tube has a plurality of spaced emitters secured thereon for directing the leaching solution onto the ore bed.
The general layout of a conventional copper ore leaching operation is shown in FIG.
1
. The lay-out of the leach field
10
is generally that of an oval track having a first straight portion
12
a second straight portion
14
and first and second turning areas
20
,
22
. To make such an operation commercially viable, it is typically necessary that such a field be extremely large. For example, in commercial operations, each of the straight portion
12
and
14
may be up to 400 meters wide and 1.6 kilometers long, and the depth of the heap may be six meters.
In the leach field operation shown in
FIG. 1
, heaps are formed along the first and second straight portions
12
and
14
by a traveling stacker conveyor system
32
, and spent ore is removed from the straight portions by traveling cleaner conveyer system
24
. Copper laden ore mixed with sulfuric acid is brought into the field from a remote crusher and mixer along an underground inlet conveyer
16
. The stacker conveyer assembly
32
branches off the inlet conveyer
16
. Stacker conveyer system
32
includes a stacker conveyer
34
extending transversely across the straight portion
12
or
14
from the inlet conveyer
16
. The stacker conveyer system
32
travels clockwise on the leach field shown in
FIG. 1
supported on a plurality of endless track crawlers
36
which are typically power by electrically powered hydraulic systems. A stacker mechanism (not shown) travels back and forth along the stacker conveyer
34
and distributes ore from the conveyer
34
onto the heap. The rate of movement of the stacker conveyer system
32
about the leach field
10
and the rate of movement of the stacker along the stacker conveyer
34
are preferably set so as to create a relatively evenly distributed heap of about
6
meters in depth. The heap is formed only on the straight portions
12
and
14
from the beginning
11
of straight portion
12
to the end
13
thereof and from the beginning
17
of straight portion
14
to the end
15
thereof.
In a conventional hydrometallurgy operation, such as that previously described, water is distributed to the heap to effect the leaching percolation in a manner similar to that disclosed in U.S. Pat. No. 5,005,806. That is, main pipes
40
and
38
bring fluid from a remote source to the leach field
10
, a plurality of header pipes (not shown) extend transversely from the pipes
38
and
40
across the leach fields, and pluralities of closely spaced, generally parallel hoses (not shown) extend from the header pipes in both directions across the top of the heap. Rather than using specially designed emitters, however, the hoses are typically perforated at numerous locations along their respective lengths so as to allow fluid to leak therefrom onto the heap. The copper laden solution is directed by the impervious pad beneath the heap toward recovery pipes
42
and
44
which direct the solution to a facility at which the copper can be precipitated from the solution.
After the ore has been sufficiently leached, the spent ore is removed from the field by a traveling cleaner conveyer system
24
. Cleaner conveyer system
24
comprises a conveyer
30
supported for clockwise translation about the leach field
10
on a plurality of endless track crawler mechanisms
28
. A cleaner mechanism
26
, typically comprising a rotary shovel device, travels up and down the cleaner conveyer
24
, scooping spent ore from the heap onto the conveyer
30
, which directs the spent ore towards the central underground conveyer and away from the leach field
10
through an outlet conveyer
18
. Accordingly, as shown in
FIG. 1
, the area to the right of the cleaner conveyer system
24
is a cleaned area from which spent ore has been removed, and the area to the left of the conveyer system is a heap of spent ore or ore which is presently undergoing a percolation procedure.
It can be appreciated that the stacker conveyer system
32
and the cleaner conveyer system
24
follow each other about the leach field
10
, the stacker conveyer system
32
distributing a heap of ore, and the cleaner conveyer system
24
removing the spent ore after percolation has been performed on the ore. The turning areas
20
and
22
are provided so as to permit the continuous forward translation of the stacker conveyer system
32
and cleaner conveyer system
24
.
The previously described method of distributing water over the leach fields suffers
Bocanegra Jorge
Pillsbury & Winthrop LLP
Scherbel David A.
LandOfFree
Method and apparatus for distributing fluid to a leach field... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for distributing fluid to a leach field..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for distributing fluid to a leach field... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2493869