US1343266A - Ore-concentrating table - Google Patents

Description

B. A. HUGHES.

ORE CONCENTRATING TABLE.

Patented June 15, 1920.

2 SHEETS-SHEET 1.

awuwnt a E5. H. HUGHES B. -A. HUGHES. v ORE CONCENTRATING TABLE. APPLICATION FILED MAR. 17, I917. RENEWED MAR. 22, I920- Patented June 15, 1920.

2 SHEETS-SHEET 2.

ESSS Eg amen 601 5. Fl. HUGHES NIT ORE-CONCENTRATING TABLE.

Specification of Letters Patent. Patented June 15, 1920.

Application filed March 17 1917, Serial No. 155,539. Renewed March 22, 1920. Serial No. 367,828.

To all whom it may concern:

Be it known that I, BENJAMIN A. HUGHEs,

a citizen of the United States, residing at Colorado Springs, in the county of El laso and State of Colorado, have invented certain new and useful Improvements in Ure- Goncentrating Tables, of which the following is a specification, reference being had to the accompanying drawings.

This invention relates to ore concentrating tables of the reciprocating type, and particularly to the manner of riflling these tables.

The general object of this invention is to secure a better concentration of the ore than is possible with tables as ordinarily rifilcd and in this connection to provide for a scientific ore dressing-and the separation of one mineral from another and to provide for as large a head tonnage as is required to properly load the separating zones into which th table is divided.

A further object of the invention is to provide in connection with a table of this character a feed stratifying zone in which the material is. first Stratified in vertically disposed strata in the order of the specific gravities of the components of the material and to further so'riflle the table that the min eral discharged from the feed stratifying zone will be eventually discharged upon a final or mineral stratifying zone in strata disposed across the table in correspondence with the specific gravities of the minerals.

A further object of the invention is to provide an initial rifiled zone so constructed that it will uniformly distribute the material and feed water and counteract, any underwashing tendency whereby fine mineral would be carried over into the tailings before such fine mineral could sink under the coarse mineral and be protected in its travel to th final stratifying zone.

A further object in this connection is to provide a third, relatively long zone in which the riflies are disposed in a direction at an angle to the direction of inclination of the table and the direction of reciprocation of the table, these angularly disposed riflies acting to check the speed of the mineral and bank it up against the upper sides of the an-' gularly disposed riiiies in this zone to thereby compact the ore bed and permit the line ma- ,terial to sink under the coarser material.

Another object is to provide a fourth zone into which the angularly riflied zone ill-S- charges, this fourth zone havingrifiles so disposed that the mineral will move forward more rapidly than in the angularly disposed zone and permit the freerer longitudinal movement of the mineral and in this connection to provide a further riflied zone into which the last named zone discharges having riiiles so disposed as to again check the speed of the mineral, these ritfies being so placed and directed as to provide for a final separation of the minerals and to secure a final pressure on the material which will force out the lighter particles therefrom so that these lighter particles will be carried downward across the table to lower rililes and will be r orrics.

discharged upon the final stratifying zone at the proper point. g

Other objects of the invention will be more specifically stated after the specificarrangement of the riffies on the table have been described.

My invention is illustrated in the accorn- I I panyi'ng drawings, in which Figure 1 is a plan view of aconcentrat'ing table having riiiles disposed thereon, in accordance with my invention;

Fig. 2 is a longitudinal section of the concentrating table on the line'22 of Fig; 1;

Fig. 8 is a fragmentary transverse section of the table to show the transverse increase in the height of the riflies from the upper side edge of the table toward the opposite side edge; and

Fig. 4 is a diagrammatic plan view to show the general proportlons-of'rthe table and the proportions of theseveral zones.

Referring to the drawings, andv particularly to Fig. 1, lOdesignatesa concentrating table of the usual or ordinary form, this table being mounted for longitudinal reciprocation in any suitable manner, which 'reciprocation is given to the table by any suitinstance the edge 00, is higher than the edge 2. An end board 121s disposed at the head end of the table for retaining vthe material on the table. At the upper or feed side of :th6 I table, at the receiving end, is disposed the feed box 13' of any suitable construction adapted to receive the material to be concentrated, together with feed water, and to distribute it over the receiving end of the table at the upper side thereof. A water box 14 extends the full length of the table along its upper edge by which washing water is discharged upon the face of the table. The surface of the table is a plane surface and the table is preferably of wood c overedwith linoleum to which the riflles 15 are secured in any suitable manner. These .riffles 15 have a uniform width but taper ironi the head end of the table to the discharge end-thereof, as-will be later stated. and these riffies gradually increase in height from the upper edge of the table to the lower edge thereof as will K be later stated So far as described, the concentrating table is of common and ordinary form and my invention cons1sts in providing an initial stratifying zoneA, a final classifying or separating zone F, and providing a plurality of. rilile'zones B, O, D and E, between the initial stratifying zone and the final stratifying or classifying zone. The stratifying zone A is relatively large and extends approximately somewhat more than threefourths of the length of the upper edge of the table and approximately one-third of the width of the table at its head end.

The rifile zone B is disposed below the stratifying zone A and has its riflles disposed in parallel relation to each other, to

the upper and lower edges of the table, and to the direction of reciprocation of the table. Also disposed below the forward portion of the zone A and forward ofthe zone B is the zoneO in which the ri liles are disposed at an. angle to the zone B, the rilfles extending upward and forward, the upper rililes on this zone extending forward and transversely across the zone A. For,- ward of the zone C thereis a zone D having parallel ritiles, which rifiles, however,

are disposed at an angle to the riflies in the zone C and at an angle to the longitudinal. axis of the table but at a less angle than the ritlies in zone C. This zone D at its upper end is disposed beneath the forward narrow portion of the zone A, and forward of the 1 zone D is a zone E having riffles whichextend upward and forward at a greater angle than the riifles D to the longitudinal axis of the table. In other words, the rifiies on zone E are disposed at an angle about the same as the rifiles in zone C. l

The line of demarcation between the riffles in zone B and those in zone O is inclicated in the drawing by the dotted line 71, z,

. and this line is approximately parallel with of zone D is indicated by the dotted line a, Z), this line starting about midway of the length of the table along its upper edge and extending down to the lower corner of the table at the discharge end. The riffles in zone E are about five inches in length in ordinary practice and terminate on the line 0, 0K extending from a point adjacent the water box 14 to a pointon the discharge end of the table 10 about one-fourth of the width of the table from the lower corner. The riflles in zone E between the point 0! and the point I), vof the lower corner of the table discharge at the extreme end of the table, but the rililes in zone E above the point d discharge onto the final stratifying or classifying zone F.- Below the lowermost and foremost riffie 16 of the zones C and D is a middlings zone G in which the riffies run parallel to the direction of reciprocation of the table and intersect with the lowermost riffies ofthe zone E. Along the lower edge of the table extend parallel riffles 17. These long rifiles 17 are arranged to catch any mineral which may be washed out of its proper'zone and cause the same to progress toward the discharge end of the table where it may be recovered for reconcentration. It is to be noted that the'ends of the ritfles in'the zone C which confront the long rifiles 17 are spaced from the uppermost of these long rifiles by a space which may be e" wide in practice.

All of the riflles are wlde and may have a uniform width for their entire the lines 0, (Z, Z): The uppermost riiile at the head end ofthe table is high and tapers uniformly to the discharge end of the table where it is, as before stated, high. The riflies increase progressively in height from the uppermost ritfies of the series to the lowermost rifiies of the series, along the line hi,- these lowermost rifiies at their head ends being, a" high. On the line a, b, the height of the riffles progressively decreases from 1:" at b to at a. the line ht' the rifiles increase in height downward across the table, while on the line ab, the riffles decrease in height downward across the table. On the line between the zones D and E the riflies'have an equal height and the extremities of the rifiies of the zone E are equal in height. Of course it is to be understood that these figures are purely illustrative as the relative heights Thus on i and spacing of the riflies may be varied depending on the character of the ore to be treated and the tonnage required. The number of rifiles may also be varied. In actual practice, I use from 48 to 52 riifles depending upon the angle of the riffles in the zone C and in ordinary practice I space the riffies 1" apart. Should, however, the spacing be more than 1 a less number of riffies will be used. Thus, for instance, the standard riflie which I have heretofore referred to is -3 high at the head end and tapers to -g high at the discharge end. This rifile is suited to an ore containing 20 to 40% mineral, but in treating a 5% ore a riflle depth of 3 1' at the head end and at the tall end,

' angle tothe riffles of zone B and theriffles of zones Dand E as being disposed at certain angles, I wish it understood that these angles will be varied depending upon the character of the ore, as will be more fully broughtout later. A

No means for separating and stratifying ore equals a smooth agitated surface upon which the ore is disposed. It is for this reason that I have provided an initial stratifying zone A having a relatively large area. "On this stratifyingzone, themineral is stratified according to its specific gravity before it enters onto either the "rifile zone l3 or the riffie zone C. In this zone A several actions take place. The heavy bottom stratum of ore which receives the impulse of the longitudinal thrust caused by light gangue from the zone A passes into zone B and the longitudinally extending parallel rifiies of zone B-distribute the material and the feed water uniformly over that zone and thereby prevent any undue washing tendency that would tend 'tocarry the fine mineral over into the tailings before such fine mineral could sink under the coarser mineral and be protected on its travel to the mineral stratifying zone F.

It will be understood that the stratifying zone Ais for the purpose of permitting all mineral to sink and engage the smooth surface and to become stratified in the order of itsspecific gravities. the heaviermineral moving forward and finding 'lodgment against the uppermost rifiie of zone 0. Meanwhile the lighter gangue and mineral have been carried. over into zone B, evenly distributed in this zone, and when the mineral reaches the first angular 'riffie in zone C. the separation of one'mineral from an-' other commences and at the same time the separation of all minerals from the gangue commerces- The longitudinal movement of the table forces the mineral particles for-,

ward against the angular riffiesin zone C with considerable force and-"inasmuch as these angular riffies impede the forward progress of the mineral particles, these angular riffies cause each, mineral bed to pack against the riflie just below, which has the effect of forcing out all particles of lighter specific gravity than the mineral properly accompanying or corresponding to the space above such riflle and this prevents the wash water coming from the wash box 14 from passing through the mineral bed. with adetrimental effect which it-would do were the irifflesin zone C disposed parallel to the longitudinal axis of the concentrating tablef Y The angularity of the riflies in zonewC,

which angularity may be anything from 1} per foot to 5 inches per foot, depending on the character of ore treated, is for the purpose of checking the speed of the min eral and causing it to bankagainst the up-' per side of the rifile, thus permitting the finer mineral tosink under the coarser min.- eral and force out all sihcious particles.-

The angularity of the .riflies in zone D may also be varied to meet the different conditions depending upon the. ores being treated. The object of having the "rifiies in zone D at a less angle thanthe riffies in zone C is that this permits the mineral mass to move more rapidly and allowsthe riffies in zone C to feed onto zone'D more readily.

.Zone Ehas riffies init of greater angularity' than the rifiies in zone D, the riflies in zone E checking the speed of forwardmovement of the mineraland causes a final washing and discharge onto the mineral stratifying zone F. i

. I have stated before that the mineral par-' ticles are forced against the riffles in zone C with considerable force and-"are packed by the rifiies thus forcing out all particles of lighter specific gravity than belongs in the particular space betweentwonriffles. Another effect also takes place in zonetC and also in zone E, this effectxbeing based upon the action of a natural law which may be termed the law of selection. If .dry granular material is placed upon a plane agitated surface, the particles of material will range themselves as follows :--The coarser particles will rise to the top-and the finer particles will sink to the bottom, with out respect to the relative specific gravities This, as above noted, is

specific gravity as the coarser particles from sinking downward through'the mineral bed of fine mineral.

to the deck: surface of the table and being thereby protected from'the heavy flow of wash water throughout zone C :and to less degree in zonesID and E. This action 'is not active to any appreciable extent, in concentrators having: deep longitudinally extending rifiies, that is riffles which are parallel to the direction of movement of the table, for the reasonthatthe bed of mineral is too light and buoyantand the mineral is notsufficientlyi packed; The Wash water penetrates the mineral beds between the longitudinally extending riffles and washes out the fines'and there is a resultant lossv F or example, in an ordinary. 16 foot table.

concentrating an ore ground tosa-y'a 20' mesh screen and having longitudinally extending rii'fles on itssurfaces, the time required for the .ore to be passed from end to end ofthe table is about one minute and five seconds. Assuming that the riffles in zone C areidisposed at an angle of15 t0 the direction of movement of the table, then these angular .r'iiiles .in zone (3- reduce the speed of the mineral one-sixth and further act to'compr ess the bed of mineral one-sixth above itsnormal state where the ore is moving between longitudinallyextending rifl'les and this compression in zones C, D and E will be in direct'proportion to the angles in the rifliesin these zones It will be seen, therefore, that the action of the rifi'les in zone C and to aless degree in zones D and properly occupying any particular space between two rlflies.

The angle of the riflies in'zone E is for the purpose ofefi'ecting final mineral separation,-.but-I do not wish to be limited to the 'use of t'his zone E as the use of this zone is necessary only where ores are being concentrated having a heavy gangue, which so closely approaches in specific gravity, the specific gravity of the mineral,- that a last final pressure is necessary to force out the lighter particles whether they are gue or mineral, so that these lighter particles may flow downward across thetable, find, their proper bed, and may enter the final classifying or stratifying zone E at a lower point and each at its proper place. e In the classifying zone F, the minerals are arranged in longitudinally extending lines .or stratas lying side by side in the order of their specific gravities, the heaviest mineral being of course at the upper portion of the zone F and the lightest mineral at the bottom of the zone. It will be seen that ma es;

Whereas in' zone A the strata of mineral are superimposed in the order of their relative specific gravities, in zone F the strata are; not superimposed, but are disposed or an ranged in what may be termed a horizontal relation instead of a vertical relation. The,

riflles which retain the relatively heavy particles of gangueitwill be seen discharge'at the-end of the table and .=not upon the classifying zone "F except,-of course, those rela tively-long riiileslTpreviously referred to. whichdischarge at the end of-the table. 1

The'zone G is a middlingf zonegand operates in conjunction. with the long vrifiles at the bottom of the deck; Material f'getsgintothis-zone G by flowing over the-last rifile of: zone C. The ,end'anglesactfjto'pass the lighter particlesovei' the top of the rifles to the next lower andtendtoplate all particles in their relative order of specificgravityso that the gangue may be more. easily cut out.

It is also necessary to take into consideraand by providing. a large 'mineral classify ing zone onto which the riffles .discharge, the

riiiles entering this final classifying zone in a direction sufficiently transverse to the longitu'dinalthrust of'the'table as to deliver the various mineral strata from the table without unduly mixing one strata or group with the other strata or group next lower in the zone and next lighter in'specific gravity.

I havefound by experiment that there is no definite angle at which therifilesin zones C, D and E must be placed forthe reason that no two ores are exactly similar in constitution. Someores can be crushed into coarseriparticles than others and can be dressed in that state, Whereas other ores re quire finer crushing to free themineral from the gangue and still other ores require a much finer. crushing not only. to free the mineral from the gangue but to free one mineral from the other. Each-ore to. be treated,'therefore, is a problem peculiar to, itself. The angularity of the rii'rles-C, D and E must therefore'be adjusted to the various ores as accurately as practical knowledge and experience render possible.

For instance, a coarsely crushed ore, the mineral of which may have-the size of 10 mesh,.will not pack as firmly against a there will be a variation of riffle angle in zones and E asv requirements may indicate. Some mlneral and gangue are so near alike in their specific gravities that a relatlvelygreat angle in zone C Wlll be necessary in order to bank the mineral, check its advance along the riflies and force the gangue to rise to the top and pass over to theneXt rifile below. Conversely if there is a wide difference in the specific gravities of themineral and the gangue,rthen the riffles in zone C may be'disposed at a less angle which will be suflicient to cause the gangue and the mineral to be washed apart and sufficient to clean the mineral. In this case, of course, the gangue and mineralwill travel faster toward the discharge end of the table and will be less compacted than where the riflles in zone C, are disposed at a relatively great angle. The same rule applies to the riffles in zone E. Some mineral will beso thoroughly cleaned when it enters the zone E that only a very low angle of the riflles in zone E will be required whileanother mineral may require a very high angle owing to the presence of a very heavy gangue. Under all circumstances, however, thelriffles are so I designed in accordance with my invention as mineral stratifying:

to cause the banking or compacting of the mineral by checking its travel and, furthermore, by causing the wash water to wash the gangue back toward the head of the. table which makes the gangue line run well down toward the discharge side of zone C.

IVhile I, of course, do not wish to be limited to any specific dimensions, I have illustrated a concentrating table having about the following proportions The table shown in Fig. 1 is supposed to be 15 feet, 8 inches over all, the upper end of the line w-b 1s supposed to be about 8 feet from the discharge end of the table, while the upper end of the line 0cl is supposed to be 4 feet, 9 inches from the end of the table. Thetable is 5 feet, 6 inches wide at its discharge end and the length of the zone B from the head of the table to the line 711 i is about2 feet, 5 inches. l/Vith this proportion of parts, the

distance between it and a would be-bjfeet,

while the'distance from 11 to the line wb along the riffle in zone U extendingfrom the point i would be 8 feet. .I merely glve these dimensions .in order that the pro- Q portions ,of the feed stratifying zone, the

zone and the several zones B, (I, D and may be understood.

I am aware that it has been proposed to table. I am not aware that it has been proposed to provide a relatively large stratifying zone for the purpose of disposing the ifferent component parts of the material in vertical strata corresponding to the relative specific gravities of the components, and before thematerial passes on to the longitudinal riffles of zone B.

In some forms of concentrator,:inclined rifiles are provided but these riffles are relatively wide apart, that is, the riffles in the inclined zone are wider apartthan the longitudinal riffles. This is not advantageous for thereason that the wider the space between the rifiies, the greater is the cascade of water over the riffle above the space. Now the material 'on the table or deck seeks to have alevel surface and in a relatively wide space the material above thelrilfle may not extend above the base of the riflle next above in whichv case the wash water will pour'over the riflle next above with a heavy washing effect. This is the case also where the riffles are longitudinal and not disposedat an angle to the line of reciprocation of the table. Now

if a short diagonal zone is interposed be tween the longitudinal riffles, withrelatively deep riflles and wide spacing, thistendency 7 of the wash water to cascade over .the riffles is reduced and there is an increased tendency of the washwater to flow down the channel and to produce a strong washingeffect rear H very short, the cleaning effect is produced by the strong back wash. Nere the spacings of the diagonal riflies and the height of said diagonal riflles such that the material would fill the space between the ri'lfles when operating at an ordinary table inclination, there would be a reduction of. this tendency to dis tribute the mineral bed and the washing effect would be confined to the surface of the material.

length of the diagonal zone and under these conditions, were the spaces between the riflles 1 filled.with arelatively solid compacted mass of mineral, there islittle orno back wash ng V In that case there would be a .banking effect just in proportion ,to the effect as the riffles are submergediin the bed v of material and the washing tendency is transversely across the deck and is not influenced by the diagonal rifilesf d In my system of riffling. the rifiles are uniformly spaced fromv each. other, whereas if the rifile channels arewider inthe zone C than intthe other zon'es, the packing" or compacting action of the inclined riflles'will that point, where there is not enough ma minerals collected inthesev lower beds and ,where, therefore, ,a longer action must be delicate separation.

p be reduced and the fines will be liable to be washed out.

In actual practice I have proven that there is no back 'washing'effect in my system of rifitling, by pouring asmall amount of black oil on the water at'the upper side of the zone C and I find that as the oil travels toward the lower side, the oil makes a small advance toward the discharge end of the table as far as the riflles are filled, but below on the mineral bed.

Again in my system of riffling less that 30% of the riffied suface has longitudinally extending riflies, while 70% has inclined riflles. Thus during 70% ofthe travel of the ore over the riflles', the ore beds are being compressed and the lighter particles of gangue, etc., are being squeezed out and carried away.

Again it will be noted that in my system, the uppermost riflle inizone C is relatively one-third shorter thanthat little of zone C which extends from the lowermost rifile of zone B and that the lengths of the rifiies in zone C increase progressively downward across the table. Thus in the upper mineral beds composed of very heavy minerals, the 1 compressive action is .of relatively shorter duration than in the lower beds where the light minerals collect and where the gangue approaches most nearly' the weight of the provided for in order to secure this more The line 0-Z defining the discharge ends of the riflies is disposed at an angle across the zone F in order to cause the wash water to wash backward and downward.

It will be understood that the zone D is absolutely essential to the proper working of zone C; Zone D is set. at a low angle in order to move the bed rapidly from the zone C owingto the rifiies having less depth than "the rifllesin zone'G. This allows zone C' to discharge its lead freely. Zone E is very essentialwhere ores are treated having a M heavyfganguejLOnly with ores of an extremely light gangue and a very heavy min.-

eral. do I contemplate using a relatively low 1 angle in zone B. On all ores of heavy gangue fIiwill use a high The zone Bis relat v'ely'of less importance than any zone of riflie. I

The object of these rifiies is to form beds my system, yet it is highly essential to proper operation of the remainder of the system. 'Zone 0 is the absolutely vital zone but each of the zones has an important specific function. I p p The banking and cleaning effect in" my system is due to the long angular zoneIC in conjunction with the angular riffles, the wash water flowing over the top of the riffles and over the beds of ore and acting directly on the top of the particles, there being no chance for the water to cascade over the top of the space, because the space or channels between the riflies are full to the top of the riffles and, therefore, all wash is transverse. angle of deck inclination may, of course, be changed depending upon the ore being treated, for instance, on lead carbonates, I use an angle of about t to per foot.

It will be seen that in its complete formmy system of riffiing includes the use of six riflle zones A, B, G, D, E, F. Eachzone has its separate and distinct function to perform, and at the same time, is dependent upon the The '80 correct action of all the zones acting conjointly, thereby forming a system of riflling, in which no. single zone is capable of producing results that equal the results obtained by the use of all zones working in harmony.

The initial zone A is the zone which receives-the feed, and is formed by the top rifHeQ In this zone'are placed, one or more short rifiies, spaced 8 to 10 inches apart,.so arranged as to form mineral beds; .These rities have less length than the feed box' with a depth nominally the same as the top of stratified mineral and also to hold the mineral atthe top of the riflie system and prevent it passing with the pulp down'to the middle of the table, as would occur. very largely were these riifles not'used. The riffle which forms this zone does not have holding capacity to prevent a large amount of the.

mineral from entering zone B.

The ob ect of zone A is to trap out and stratify the mineral ,into' vertical strata,

which is progressed forwardand the lighter strata, shaved off to a'lower position, wlthout disturbing or breaking up the various strata.-

as they pass through the various zones following' Zone intothe following angular zone C, andbe fore-the mineral can pass far down in zone 1 B. At this, point-two objects are sought: 1st

to stratify and, 2nd to retain all mineral as high up in the riflle system as possible, which B is ashort longitudinal zone, and is I ,so arranged for the purpose of forming a light buoyant bed ofmaterial, in which the mineral can settle quickly and be progressed in-th'e final efiort,prevents a heavy mineral f 7 from having to cross under the line of'lighter V tions, the tendency of the clean mineral is,

' ZOIIGS.

form of the mineral beds, these fines are protected from the cross wash and follow this bed to the point of delivery. This action is due to the natural law of selection.

Zone Cis arranged angular, for the purpose of forming a compact slow moving mineral bed, which receives the Stratified mineral from zones A and Band progresses the same in a compact form, constantly squeezing out all the lighter particles, andcon'stantly concentrates the mineral as it: advances, and as the riifle depth grows less, the top strata are sheared over to a lower position in'the transverse angle of the table; this action continues throughout the length of this zone.

The concentration made in zones AB- C, are only part of the final effort of all All material fromzone C passes to zone D which has less angularity than zone C. The object of this is to progress the material at a more rapid rate,and to produce more buoyancy to the mineral bed, while the top strata are being sheared over to a lower position, before entering the final riflle zone E, which has its greater angularity than any of the preceding zones.

The object of this, is to form a compact mineral mass such that no light particles can remain in the stratum notcomposedof particles of similar specific gravity. In other words, particles of dissimilar gravities cannot occupy the same stratum in zone E. i 7

All the mineral is completely concentrated and accurately stratified in the combination of riffle zones, and delivered into zone F, in clean lateral strata and quickly discharged from the table, before it is possible for v one stratum to climb another stratum due to the smooth surface and transverse angle of the table, together with the washing effect of the dressing water, as, under these condifor the heavy stratum to pass under the next lighter'stratum,'a nd therefore the overlap be-V tween each mineral stratum is proportionate to the length'of'the smooth zone, and the time required for the mineral to pass off the smooth zone. 7 r I V Zones E and C are both flexible zones, that is, their 'angularity governed by the character of the material which they are required A to treat, both as regards the nature of the ore, as wellv as the texture, or mesh to which the 1 table feed is crushed. In other words, the rifile system isadjusted to the requirements the old riffle' system, wherein an attempt is of the ore, and not'an arbitrary system, like thoroughly cleaned passes into made to makeithe ore fit the ri-iile' system, which is the direct cause of so many failures to the many different elassesof ores.

The angularity of zone E depends especially upon the relative gravities of the various particles ofboth the mineral and governed by the texture ormesh' of the table feed, in fact this system is arranged to meet the special requirements 'of the ore in every case. V

Itwill be'understood that the deck-plane of my concentrating table is all in one "plane with the entire surface from the waterbox to the lower edge of the" table lying at the same lateral inclination. It will also be seen that the zone A is approximately triangular 1n form, being large at the-head endand relatively wide, and very narrow where it joins zone F so that the zone F would be 'entirely cut off from zone A at the point 0 were it not for the water box and in order I gangue, while the angularity of zone C 1s' v to have the riflletips disposed for cleaning (in case of oxidized minerals'cementing to the deck when the table is stopped, which is a commondifliculty). This difficulty makes it desirable to keep the riifie tips all in the clear. Therefore, the riffie tip of the uppermost riflie does not touch the water box but at this point only clean, heavy mineral 7 smooth surface above, so that in fact zone A r I is a separate and closed zone and is not oined in action to zone F, in other words only the heaviest mineral which has been directly from the zone A. i

The action of the material in zone A isas follows The feed water and pulp pass across this zone toward the riflle zones B and C, with about three fourt'hs' of the feed of the pulp passing toward zone B.

the zone F Immediately'upon this smooth surface of the zone A, allthe particles are segregated and pass laterally down the inclined face of the zone A rapidly unt lthe uppermost bounda 'y riffle is reached, Here, the material is banked and formed into a bed some six or seven inches wide, and it is in this bed that the real Stratification takes place. This bed follows the upper riffie or boundary riffle with a varyingwidth to about one inch at the point c. Beyond the end of the feed'box l3there is no material in zone A exceptthat portion banked against the boundaryrifiie, and as "the table motionis su'ioothgand the mineral bed is advanced without disturbing the strata of thisbed and'as the rilfledepth is less as the bed advances, the top strata; of this rifiie bed. aresheared over the boundary ,riflle into zones Cand D, it being noted that the inclinedrimes of zones C inter- Y i riflies in the riflle zones C and D and E proother class or spread out so that the operator may see better how to separate the classes of mineral into separate launders. The angular boundary of zone A andthe angular duce separating results through the action A of compressing the mineral beds, squeezing effect.

out the lighter particles, and causing these lighter particles to shear over the rifiles as the mass is progressed forward along rifHes which decrease in height and which are placed on an inclined surface. The only zone which does not form a compressed bed is the zone B, Where the riflles extend parallel to the direction of motion of the table. This zone B forms a light and buoyant bed of material and only acts to sink all mineral quickly so that it may be later acted upon by the squeezing and compression action in zone C. It is also to be understood that my table is to be reciprocated by that" form of mechanism known as the toggle motion, which is quite commonly used in concentrating tables, which produces the same progressive movement as the bed of material moves forward and does not set up a remixing action as is produced by mechanism such as that used to produce a bumping motion. This commonly used toggle motion produces the forward movement of the material on the table by moving the table forward at such a ratethat all the particles follow the surface. This stroke starts slowlyand stops slowly without impact or disturbance of the mineral bed, and has its greatest velocity near mid-stroke. The return stroke is similar, except that its rate of speed is faster and the deck surface, therefore, is slipped under the material without disturbance or stirring This stroke is usually about %7 long and rarely over 1 long, so that this action can easily take place within the space between the angular rifiles, which are spaced about I apart and without any disturbance of the strata which may be formed from agitation by this motion. In the angular zone C' where the mineral beds are formed by compression, the angularly disposed riifles permit the fine mineral to sink and pass under the coarser minerals and in wet table concentration specific gravity acts to select the particles of like gravity so that only the heavy particles can enter a stratum of like gravity composed of coarser particles. This means that fine lead will enter the coarse lead stratum, fine iron will enter the iron stratum, and the fine zinc will enter the zinc stratum, and that the fine gangue particles of the .heaviestclass will enter the heavy gangue stratum on top of the zinc stratum. 7'

Vertical stratification will place the minerals in the order named in such arrangement or stratification, and thus if the mass is compressed into a compact, heavy bed, such as is produced by the inclined rifiles G and D ring, concentrating table having no lateral component in. its movement and having its upper surface disposed entirely in one plane, said table having a relatively large, smooth, initial stratifying zone at the'head'end of the table, the lower boundary of this stratifying zone extending upward and forward at an inclination to the direction of movement of the table, a relatively large,

smooth, flat, classifying zone at the discharge end of the table and extending transversely thereof from the upper sideitoward the lower side of the table, and a zone disposed between the stratifying zone and classifying zones and separating them from i each other having riffles inclined upward and toward the discharge end of the table and at such an angle to the line of motion of the table as to offer material resistance to the progress of the material, the channels defined by said inclined'zone of riffies all discharging upon the final classifying zone, and the uppermost rifile forming an upwardly inclined boundary to the lower edge of the stratifying zone against which mineral in the stratifying zone will bank.

2. A longitudinally horizontal but transversely inclined concentrating table having longitudinally reciprocating movement without lateral component and having its upper surface disposed in one plane, said table having a relatively large, smooth, inifying zone at the discharge end of the table and extending transversely thereof, and a zone disposed between the stratifying and classifying zones and separating the one from the other and having rifiles inclined upward and toward thedischarge end of the table and extending transversely to the stratifying zone, the uppermost riflie forming the uppermost boundary ofsaid riffled zone extending upward and forward at an inclination to the lineof motion of the table and forming the lower boundary of the stratifying zone, the channels defined by said inclined riffles all discharging upon the forward classifying zone, the ends of said riffies being disposed in a line extending downward and forward toward the discharge end of the table.

3. A transversely inclined concentrating table having longitudinal reciprocation without any lateral component, said table having a relatively large, smooth, initial stratifying zone at the head end 'of'the table, a relatively large, smooth, fiat classifying zone at the discharge end, and a pinrality of zones disposed between the stratifying and classifying zones having uniformly spacedrilfles inclined upward and toward the discharge end of the table and extending transversely to the stratifying zone, the riflies in the several intermediate zones having different relative angular relations to each other, the channels defined by said inclined rifiles discharging upon the. final classifying zone, said inclined. rifiles being disposed at such aninclination to the line of motion of thetable as to offer material resistance to the progress of the material being concentrated. a p

4. A longitudinally horizontal but transversely inclined concentrating table having its upper face disposed in one plane and having longitudinal reciprocation with no lateral component, said table having a relatively large, smooth, initial stratifying zone extending from the head end of the table along the upper margin thereof and being relatively wide at the head end of the table and narrowing toward the discharge end thereof, the table also having a relatively large, smooth, flat, classifying zone at the discharge end of the table extending downward from the upper margin thereof, and an intermediate zone extending downward from the stratifying zone to the lower edge of the table, and having riifles extending at an angle to the line of movement of the table and all discharging upon the final classifying .zone at an angle upward-and. toward the discharge end of the table, th riffles being uniformly spaced apart for their entire length, and the angle of the riifles relative to the line of motion of the table being such as to offer-material resistance to theprogress of the material being concentrated whereby to cause compression of the mineral beds formed between said rifiles and squeeze out the lighter particles therefrom, said uppermost, inclined.

stratifying zone from the final classifying.

zone.

5, A longitudinally horizontal transversely inclined concentrating table having a relatively large smooth initial stratifying zone extending from the head end of the table longitudinally along the upper margin thereof and a final classifying zone at the discharge end of the table extending downward from the upper margin thereof toward the lower margin thereof, the table'at its head end below the stratifying zone being formed with -a zone having parallel uniformly zone from the classifying zone, the dis-, I

charge ends of the'channels between. the

'riifles discharging upon theclassifying zone and being disposed on a line extending downward and; toward the discharge end of the table and extending transversely across the lower portion of the classifying zone, the lowermost inclined riflies extending to the extremity of the table.

inclined concentrating table having longitudinal reciprocation with no lateral component having at its head end a relatively large smooth initial stratifying zone extending longitudinally along the upper-margin of the table, the lower boundary of the stratifying zone extending upward and toward the discharge end of the table nearly to the upper margin of the table, an approximately'triangular classifying zone relatively large in area disposed at the discharge end of the table and extending from the forward end of the stratifying zone to the dischargeend of the table, the base of the trianglebeing at the upper edge of the 1 O 0 6. A longitudinally horizontal transversely table and the apex of the triangle extending ing parallel to thefline of movement of the table and forward of this zone with a zone having uniformly spaced riffles extending upward and toward the discharge end of the table at such an inclination to the line of motion of the table as to offer material resistance to the progress of the material heingconcentrated, said zone defining the lower forward boundary of the stratifying zone and said rifiles terminating on a line extending downward and toward the' discharge end of the table and defining the lower boundary of the classifying zone, the lowermost rifiles 'ofjthe upwardly inclined riffies extending to the extremity of the table. a

7. A longitudinally horizontal transversely inclined concentrating table having longitudinal reciprocation but no lateral component having at its head end a relatively.

' large smooth initial stratifying zone extending longitudinally along the upper edge" ofthe margin of thetable, the lower boundary of the stratifying zone extending upward and toward the discharge end of the table nearly to the upper -margin' of the table, an approximately triangular classifying zone relatively large in area disposed at the discharge end of the table and extending from the forward end of the stratifying zone to the discharge end of the table,'

7 the apex of the triangle being toward the lower edge of the table, the table being provided below the head end of the stratifying zone with a zone having longitudinally extending riffies parallel to the sides of the table and for-ward of this zone with a zone having rifiies extending upward and toward the discharge end of the table, said zone defining the lower forward boundary of the v the line of motion being such as will materially resist the forward progress of the material being concentrated.

8. A transversely inclined concentrating table having longitudinal reciprocation with no'lateralcomponent and having a feed box and a water box extending along its upper margin, the table having a relatively large feed stratifying zone at its head end and extending toward the discharge end of the table and a relatively large classifying zone at the discharge end of the table and extending downward from the upper margin thereof, the table below the rear end of the stratifying zone having a plurality of riffies extending parallel to each other and to the line of reciprocation of the table, the table forward of this last named zone being provided with riffles extending upward and toward the discharge end at an angle tending transversely across it, a third riffie zone disposed in advance of the last named riffie zone and having riflles extending up rifile'zone having rifl'les'extending upward" and toward the discharge end of the table at a greater angle than'in the second named:

riflie zone, the discharge'ends of the Chan-- nels defined by said last named-rifiles being disposed on a line toward the discharge end of the table at an angle to the line of reciprocation and from the upper margin of thetable to the discharge end thereof and intersecting said discharge end at a point. above the lower edge of thetable. 1

9. A transversely inclined concentrating table having longitudinal reciprocation with no lateral component and havinga feed box and a water box extending along its, upper margin for its entire length, said table having a flat smooth relatively large feed stratifying zone extending along the upper mar gin of the table from the head endtoward the discharge endand having a flat smooth relatively large classifying zone atthe dis' charge end and extending downward from the upper margin of the table nearly to the lower margin thereof, the table below the head end of the stratifying zone having a zone formed with longitudinally extending riflies parallel to the'line of motion of the table, said riflies at the lower edge of the table extending longitudinally the full length of the table, thetable in advance of the longitudinally rifiied zone being formed with a second riflied zone having upwardly and forwardly inclined uniformly spaced riflles extending at'a predetermined inclination to the line of motion of-the table and transversely of the stratifying zone, a third successively disposedriflied zone having riffies extending at a less inclination than in the second riflied zone and a fourth relatively short riffled zone having riffies disedge of the table, the line of juncture bea tween the riffies of the second named riffled zone and of the third named riflied zone ex tending downward and forward from the upper margin of the table to its lower forward corner at a greater angle than the angle of the line bounding the lower end of the classifying zone. i

10. A longitudinally horizontal trans c,

clined riffles discharging upon the final classifying zone, the uppermost riffie of the riffied zone forming the boundary of the lower margin of the stratifying zone, the rifiies 'being uniformly spaced along their entire extent and uniformly tapering from the head end to the discharge end of the riffles, but said riflies at the beginning of the inclined riflie zone progressively increasing in height from the upper margin of the table to its lower margin.

11. A laterally inclined concentrating table having longitudinal reciprocation with no lateral component, the table being formed at its head end and adjacent its highest margin with a longitudinally extending stratifying zone and below this zone with a longitudinal rifiied zone, the riflies for a portion of their length extending upward and toward the discharge end of the table at an angle to the line of motion of the table and forming an upwardly inclined boundary to the stratifying zone, the rilfies forming the boundary of this zone extending unbrokenly from the head endvof thezone to the discharge end thereof, means for discharging pulp upon the stratifying zone at the head end thereof andrcausing the pulp to flow transversely of the table, and means for discharging wash water upon the table along the upper margin thereof and in a direction transverse to the longitudinalaxis of the table. I

12. A reciprocating laterally inclined concentrating table moving in a right line direction with no lateral component, having means for supplying wash water along the upper margin of the table, and initial stratifylng zone, a final mineral classlfylng zone,

and riflies extending longitudinally of the table and defining ore channels, said riflies being uniformly spaced but being so disposed for a portion of the length of the table as to resist the forward movement of the ore along said channels to thereby compact the ore beds in the channels and squeeze out relatively light particles,the discharge ends of the channels being so formed as to exert a final compressing action on the ore in said channels just previous to its discharge upon the final classifying zone.

In testimony whereof I hereunto afiix my signature in the presence of two witnesses.

BENJAMIN A, HUGHES.

Witnesses MIKE WOLF, HENRY ELLIS.

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