US2053802A - Means for classifying materials - Google Patents

Description

SepLfS, 1936. J, M, NlcQL 2,053,802

MEANS FOR CLASSIFYING MATERIALS Filed March 12; 1954 INVENTOR-T JOHN MALCOLM N/COL ATT RNEY Patented Sept. 8, 10936 UNITED STATES PATENT OFFICE MEANS Fon oLAssIFYING MATERIALS John Malcolm Nicol, Mill Valley,r Calif. Application March 12, i934, serial No. 715,068

Claims.

Myy invention relates to ameans for and method of concentrating unclassied materials, and more particularly to devices embodying the methods of my invention` for use in placer and dredge 5 My invention more specically relates to the art of separating and saving, by; virtue o-f the difference in specific gravity, gold, platinum, free metallic particles and associated mineral particles and gems from the Worthless light sandV and fine gravel with which these products are customarily associated in natural deposits.

Among the objects of my invention are: to provide a method of concentratingunclassified materials; to providea method ofv classifying materials having different specificgravities; to provide a rotating riifle.; to providea method of abstracting concentrates from a stream of unclassified materiali at righ-t angles to the direction of ow of sai-'dl stream.; to provide a means and method for relieving a rile box of material tending to interfere with the action of the riles; to provide a new and unique revolving drum sluice box; to provide a revolving drum concentrator wherein concentrated material is continuously andI simultaneously removed at right angles to the direction of flo-wof the material in a circular path; and to provide a novel and eflicient sluice box;

Other objects ofmy invention will beapparent or will be specifically pointed out in the descrip 30. tion forming a part of' this specification, but I do not limit myself tothe embodiment'of-theinvention herein described, as Various forms may be adopted within the-scope of the claims.

In the drawing attached hereto and forming a 3 part of the specifica-tion:

Figure l is aV side View in elevation of the concentratorand classifier of my invention.

Figure 2 is a perspective view looking into the interior of the revolving drum. 1

40 Figure 3- is a section of the revolving drum ill-ustrating the action of the; device.

To more1 clearly indicate the scope of my invention, a summary ofthe present standard methods off saving', as presently practiced in placer mining or-dredges, will be helpful. Y

The sluice boxma-y be saidAk to'be the heart of all present devices, and no matter what'the: final form may be, it consists essentially of a trough or box set at some predetermined grade and lined along the `bottomwitlrv some formof'rifile. The

rifii'esare usuallytransverseto the line. ofow of the stream oimateriall passing through the device. The material from' which it is desired to concentrate certain portions, isY passed through the" sluice box; usually` mixed' "withu a relatively large volume of water, the entire stream havlng a relatively high velocity.

lThe function of the riilles is twofold. Firstly, there is an ascending boil or an upward classifying current in front of each rile contrasted with 5 the nearly horizontal flow of mostrof the mass of the stream. Secondly, the riilles form a pocket or catchment point for the heavier particles of the stream which are sufficient in Weight to settle downwardly against the classifying current of the 1U boil. Y

,Practically all forms of present apparatus, pans, rockers, llong toms, sluices, sand tables and innumerable other similar devices used in placer mining areI based on this fundamentalprinciple, 15'

and attempt to make-a one stage operation of the removal ofmetallic particles from the gravels. By one stage operation it is meant that theclassi-cation, as-far-asfthe concentrates are concerned, issupposed to be complete or nearly so. zo In otherI words, the concentrates are supposed to contain almost all of the materials sought for'and not a great deal of anything else. It is my opinion, however,` that the method as outlined is subject to certain grave defects. In the ordinary emzo bodimentA of such sluices, the separating action is usually continuous whereasv the cleaning of the riilles isiintermittent, andin many cases, due to the time lost in cleaning up the concentrates,

that step is left until the last possible moment. 3o

In fact it is quite customary in sluice box installationseto have the riille bars extend over a much longer length of stream than isA at rst necessary when the box is clean, and' as the riiile bars get filled up with` deposits and fail to operate, other 35l bars further d'own the line swing into operation. In many other commercial installations new riil'le bars areV added as prior ones fill up, and the process extended for as long a time as desirable. Furthermore,4 due tothe long intervals between 40 clean-up shut downs, it is necessary to change various other conditions as, for example, the height ofthe riilles, steepness of the grade, violencer of the boil or like conditions surrounding the sluice. ofthe stream orY classifying currents will boil-out material from prior lled rifes, and consequently a great Ydeal of associated ne, flaky, or spongy gold is completely washed over the riiile line and. lost. These conditions are greatly aggravated 50 in those placer installations where the proportion, of heavy black sands and other concentratable materials is abundant. A great deal of trouble has been encountered along these lines in tin placer installations, as a concrete example. 55

Many times the increase of velocity 4:5v

A careful examination of the defects in placers brings to light the fact that multiple stage operation is desirable, that is, to save in one crude or rough concentrating operation everything that is heavy, including black sand or similar materials, and subsequently, by more refined methods, to separate out the metallic particles from the associated heavy minerals. Many of the associated minerals have been shown to contain included valuable metals and other desirable byproducts. Furthermore, for eicient operation I have found that the rifles should be continuously cleaned or discharged while in operation, and one step in my method, in its broadest aspect, comprises removing the concentrates from a sluice box continuously in a direction approximately at right angles to the ow of the material. I realize that this particular step has long been recognized as fundamental in the best concentrating devices, such as the Wilfly table, various vibrating jigs and like apparatus. My invention goes further, however, and not only provides for the removal of the concentrate continuously in a direction at approximately right angles to the direction of iiow of the material, but also includes the steps of raising the material out of the stream and dumping it, by gravity, into a collector. A still further step may be desirable in case the unclassified material contains relatively coarse material too large and heavy either to be removed during the cleaning operation or to boil over the riliies. Such material is exemplified by certain rounded boulders or slate slabs. It is obvious that such large units, lodging against the riilles, will alter the riflle currents and impair the efcient operation thereof.

The apparatus embodying my methods, in broad terms, therefore, will include a rotating drum type of concentrator wherein parallel transverse ring rifes are positioned, means for passing the unclassified material through the concentrator, and longitudinal riffles between the various transverse riiiies to catch the concentrates, remove them at right angles to the ow of material, and as they rotate around the axis of the drum, I provide means for catching or collecting the raised material as it is dumped under the influence of gravity. In many cases where the concentrated material is adherent I may prefer to aid gravity by the use of water streams so that the washing action thereof will aid gravity in relieving the longitudinal riflles of their concentrates. Furthermore, in case there are in the unclassied material, boulders, slate or other materials which are liable to jam against the transverse riflles, and which are not easily ren moved therefrom by the moving longitudinal riiles or the force of the stream, I provide short gaps in my transverse riilles, preferably staggered in relation to each other, and in many cases it may be desirable to provide means between the transverse riflles for urging such interfering material toward the gaps. I thereby provide a complete ,path through the drum and the interfering materials quickly pass through.

My invention, in both of its aspects, may be more readily understood by reference to the gu res which illustrate a preferred embodiment of my invention, adapted to concentrate gold bearing materials from placer deposits. As the embodiment illustrated is of a semi-portable type, I prefer to mount the device on a foundation frame I. Bearing brackets 2 are positioned at one end of this frame, a drum frame 3 is attached thereto by means of pivots 4. The other end of the foundation frame is provided with a screw plate 5 adapted to receive the end of an adjusting screw 6 threaded in the drum frame 3. When the foundation frame I is placed upon the earth the grade of the device may be determined or changed by rotating the adjusting screw 6. Flanged rollers mounted on the drum frame 3 by means of roller brackets 8, support a rotating drum 9 through the medium of bearings rings I 0. The flanges on the rollers 'I maintain the drum in place even though the angle or grade of the drum may be considerable.

The drum is rotated through the medium of a power shaft II, terminating in a pinion gear I2, engaging a circumferential master gear I4 on the drum. Other suitable means of rotating the drum may obviously be applied thereto. A feed chute I5 is positioned at the higher end of the device and is adapted to feed unclassied material into the interior of the drum, and an output chute I6 is positioned at the other end, adapted to carry away the discharge waste from the drum.

The construction of the interior of the drum is shown in Figures 2 and 3. A series of parallel, circumferential, cross rifIles I1 are secured to the interior of the drum wall, projecting inwardly. I prefer to equally space these cross riles along the drum. The height of the cross riiles will, of course, be dependent upon various factors, such as the amount of water available in the incoming material, the type of incoming material, and the specific gravities existing in various particles of the material. Between the cross riles and between the end cross riffles and the end of the drum are positioned longitudinal riiles I8. These riles may either be fastened to the cross riflles I1 or to the inner wall of the drum. I prefer, however, to line the interior of the drum underneath the riflles with corrugated rubber matting I9 and so arrange this matting that the corrugations 2G thereof shall extend longitudinally of the drum and be parallel in extent with the longitudinal riifies. I also prefer to make the longitudinal riles of lesser height, that is, extending inwardly to a lesser extent than the cross riflles and to make the corrugations in the rubber matting substantially of lesser radial extent than the longitudinal riflles.

A stationary interior launder 2| in the form of a partition, longitudinally bisects the interior of the drum. While this launder may have variations in shape consistent with the operation thereof, I prefer to make the device slightly concave in order to assist received material to run to one end thereof where it may be led into a concentrate chute 22, the material being delivered thereby into a suitable concentrate receptacle 23. I prefer to support this launder on launder brackets 24 fastened to the drum frame. If desired, the discharge angle of the launder may be made variable.

It is usually desirable to turn up the lateral edges 25 of the launder and also to provide them with indentations 26 wherein the cross riles I'I may rotate, thus allowing the lateral edges of the launder to closely approach the inner edges of the longitudinal riflles I8.

I also prefer to leave gaps 2'I in each of the cross rifTIes I'I and to so stagger these gaps that there will be a complete, preferably spiral, path along the entire drum through which certain objectionable material may be passed, as will be described later; and I may desire, in certain cases, to place adjacent each of these gaps an angular bar 28, of substantially the same height as the f longitudinal rimes, positioned to direct such ob- .jectionable material through the gaps and thus eventually to cause it to pass from the machine. vIn operation, unclassified material, preferably mixed with a suitable amount Vof water, is continuouslyrun intothe drum through chute I5, the drum having been set at the proper grade. The drum is, at the samev time, slowly revolved, preferably at a speed between two and six R. P. M. The cross riies Il act in exactly the same Inanner, as they revolve, as the usualriilles in the ordinary sluice box, causing heavy materials to be deposited. Such materials, being in'between the longitudinal riles, are continuously carried away during the rotation of vvthe drum, and furthermore, at the same time, rare carried upwardly and out of the stream of mixed water and material.

I have shown in the drawing that the longitudinal riffles i8 are provided with a retaining lip 29'. This lip, however, which makes the riles somewhat the equivalent of a bucket, is not always necessary and its presence will depend, to a large extent, onthe packing and settling qualities of the concentrates.

As the loaded longitudinal riffles pass upward past the lateral edges of Vthe launder, they are tipped, due to their `radial positioning, toward the launder, and at some point as they pass over the launder they will discharge their contents, which, in falling, will be intercepted by the launder. In order to aid the discharge of material from the launder, I may desire to supply liquid, preferably water, through a suitable pipe 30, generally centrally located above the launder, which has washing jets 3| positioned to direct streams of water over thesurface of the launder, loosening the concentrates and washing them into the discharge chute 22. It may also be advisable to clean the longitudinal riles, and I may therefore provide a cleaning nozzle 32 positioned to direct a stream of water against the longitudinal riflles after they have reached a position above the launder. Such a stream tends to' loosen packed fines and aids gravity in the discharge of the material carried by the longitudinal rifles. It may also be desirable to direct a relatively gentle stream of water against the longitudinal riflles by means of a settling pipe 33 having a settling jet 34 adapted to direct a gentle flow only of water between the longitudinal riflles before they come to a position above the launder. The object of this gentle washing is simply t' clean out the small corrugations between the longitudinal riffies, and deposit all of the concentrates against the upper face of the rising longitudinal riffles, from which they may be readily dumped.

As the entire action is continuous, the cross and longitudinal riffles are freed from their deposits and enter the stream again on the opposite side clean and ready for efficient operation. My device will be completely operable in all respects without the use of the gaps 21, if there are no objectionable materials in the unclassified mass. It many times happens, however, that a boulder, piece of slate, or similar object lodges in front of a cross riflle and is too heavy to be washed over, and too large to be carried out of the stream by any of the longitudinal riiiles. This means, then, that the rifliing action would be destroyed, as far as that particular riiile is concerned, and if by any chance several of these obstacles should come along in the stream, pass over one or more of the riiiies but not all, it is conceivable that all the cross riiiies might, in the course of time, be-

come damaged in their action and necessitate -a shut-down. I have therefore provided for the elimination of these obstacles by the use of the gaps 21.

As the drum rotates there will come a time when a gap is immediately in front of the objectionable object, and the object will usually be forced through the gap by the stream to land against the nextv -riiile vAs the drumv rotates, however, the next gap immediatelyvpresents itself to the obstacle; it passes therethrough,` and so on through the entire drum until the obstacle passes completely out of the drum into the output chute. At the same time, by having the gaps staggered, I prevent the loss of valuable concentrates when the gap in one riflle is centered with respect to the stream, as the other gaps are either off center or out of the stream entirely. Yet within a short period of revolution, determined by the amount of gap offset, the obstructive material is completely passed along and through the drum. .l It sometimes happens, however, that the obstacle is of-such angular shape that it is not pushed by the force of the stream through the gaps but normally tends to stop before it reaches a cross riiiie. I have, therefore, to take care of such obstacles, positioned the angular bar 28 in front of each gap so that a blow may be struck to the obstructive material at least once every revolution, this blow being angularly applied and urging the obstacle toward the adjacent gap. I have found in practical operation that tramp iron, boulders, regularly shaped blocks such as bricks, or irregular shaped angular masses such as cracked boulders having a flat side tending to stabilize them in a certain position, are passed through the device with a minimum of disturbance of the rifliing action.

It will be seen, therefore, that my concentrator is continuous in the true sense of the word in its action. There are no shut-,downs for clean ups. A rough concentration is continuously performed and material which will tend to obstruct the action of the riiiie is continuously acted upon to pass it through the device with a minimum of disturbance of the action thereof. The concentrates collected in the receptacle 23 may be further treated in any convenient manner to recover the values therefrom, and nes in the form of flake gold, for example, are not lost during the sluicing process.

It is obvious, of course, that the mounting of the device may be varied to suit conditions, within the scope of the claims.

I claim:

1. In apparatus for classifying materials, a rotating cylindrical vessel, means for passing an unclassified material through said vessel, a plurality of parallel circumferential cross riflies arranged transversely within said vessel, longitudinal riiiies extending between sai-d cross riilles of lesser height than said cross riffles, means for collecting the material carried by said longitudinal rifiles, and means for preventing accumulation in front of said cross riffles of interfering` material too large to be carried by said longitudinal riiiles and too heavy to be forced over said cross riiles by the pressure of the unclassied material.

.2. In apparatus for classifying materials, a rotating cylindrical vessel, means for passing an unclassified material through said vessel, a plurality of parallel circumferential cross riiiles arranged transversely within said vessel, longitudinal riilles extending between said cross riles of lesser height than said cross riflies, said cross rimes each having a gap therein for passage of interfering material too large to be carried by said longitudinal riilles and too heavy to be forced over said cross riles by the pressure of the unclassified material.

3. In apparatus for classifying materials, a rotating cylindrical vessel, means for passing an unclassified material through said vessel, a. plurality of parallel circumferential cross riies arranged transversely within said vessel, longitudinal riies extending between said cross riles of lesser height than said cross riilles, said cross ritlles each having a gap therein for passage of interfering material too large to be carried by said longitudinal rifes and too heavy to be forced over said cross riiiles by the pressure of the unclassified material, the gaps in the cross riiiies being staggered each from the preceding to form a spiral path for said interfering material through said vessel.

4. In apparatus for classifying materials, a rotating cylindrical vessel, means for passing an unclassified material through said vessel, a plurality of parallel circumferential cross riles arranged transversely within said vessel, longitudinal riilles extending between said cross riflies of lesser height than said cross riiles, said cross rifiles each having a gap therein for passage of interfering material too large to be carried by said longitudinal riilles and too heavy to be forced over said cross riiiles by the pressure of the unclassied material, and means positioned between said cross riilies to urge said interfering material toward said gaps during the rotation of said vessel.

5. In apparatus for classifying materials, a rotating cylindrical vessel, means for passing an unclassified material through said vessel, a plurality of parallel circumferential cross riilles arranged transversely within said vessel, longitudinal riiiles extending between said cross riilles of lesser height than sai-d cross riles, said cross riilles each having a gap therein for passage of interfering material too large to be carried by said longitudinal riiles and too heavy to be forced over said cross rillles by the pressure of the unclassified material, and a diversion bar positioned between said cross riles to urge sai-d interfering material toward each of said gaps during the rotation of said vessel, said diversion bars being of a height not greater than that of the longitudinal riilles.

JOHN MALCOLM NICOL.

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