US2311414A - Apparatus for concentration of min - Google Patents

Description

Feb. 16, 1943. F, c, PETERSON 2,311,414

APPARATUS FOR CONCENTRATION OF MINERALS AND LIKE MATERIALS Filed March 12, 1940 2 Sheets-Sheet 1 INVENTOR. M/mm/ (17 mm 1 m 7 ATTORNEY.

Feb. 16, 1943. c PETERSON 2,311,414

APPARATUS FOR CONCENTRATION OF MINERALS AND LIKE MATERIALS Filed March 12, 1940 2 Sheets-Sheet 2 A II F 6.5.

I I" I B um W -T o I l .B I 27 1 1 11 n 27 l I I g I i 8 u i" C 2 .D I E INVENTOR.

ATTORNEY.

Patented ,Feb. 16, 1943 ERALS ANDLIKEMAT Frank 0. Peterson, Oakland, Calif.

' Application March 12, 1940, Serial No. 323,553

6 Claims.

This invention relates to an apparatus for concentration of minerals and like materials by jig operation.

A pulsating type of jig is not a new device. It has been used for many years in coal classifying, tin concentration, and other material separations. In recent years it has been adapt-.- ed to gold mining operations, replacing the riille and table in many instances.

The jig most extensively used in the gold mining industry consists of a displacement diaphragm mounted in the bottom or sides of a square or rectangular tank, the top of which is covered with a coarse wire screen basket called the grid. This basket is from two to six inches deep and is partially filled with steel shot from A; to 4 inch in diameter. The tank is mounted in the sluice circuit with the top of the basket level with the bottom of the sluice, and has no grade. Water is admitted to the tank from an outside source, flowing upwardly through the shot bed, which gives an undercurrent effect. As the diaphragm is moved, the water velocity is increased on the up-stroke, and suction is applied to the bed on the down-stroke. The diaphragm displacement is greater than the amount of water admitted. This action gives first a loose and then a tight bed condition, moving the heavier material from the overflowing gangue into the tank by progressive steps. The greatest disadvantage of this method is that the bed is held closed not only by its own weight but by added suction as well, for a period of fifty per cent of the time, thus causing the bed to solidify itself to a density prohibiting the lodging of other material which is continuously flowing over it and thereby obviously reducing efliciency.

The mechanical connection of the diaphragm usually consists of a cam, crank or eccentric with a connecting rod which is guided with a cross head. As the load of water and sand is heavy, a great deal of power is required for rapid oscillation, with resultant wear on the connecting devices. Some manufacturers have mounted two diaphragms on a rocker or walking beam to lessen the power demand. This however does not lessen the load on the connecting rods, bearings and cross heads. They must be heavily constructed and well lubricated, it reasonable durability is to be expected.

The type of jig just described is commonly known as a rougher or low ratio" concentrator, operating from one hundred to two hundred strokes per minute. The stroke length varies from inch to 1 inches, depending upon the requirements of the operation.

The material from this Jig is delivered to a second jig operating at a faster speed and shorter stroke, which reconcentrates to a higher ratio,

and is termed a cleaner or finishing jig."

Fromhere the material goes to a polishing device, if coated or rusted gold is present, then itgoes to an amalgamator. The entire transaction requires at least three, and many times four and five, operations to recover the gold from the gangue. As the rougher jig is the only unit in the circuit having contact with the goldcarrying gangue, the main recovery rests with the rougher jig. If the rougher jig permits gold to pass, there is no way to prevent its loss. Furthermore, the successive steps following the rougher jig are not eflicient.

In handling certain materials a large percentage of the gold content is of a minute and flaky type. This prevails high in the gangue and is resistant to concentration. It is these values which cause heavy losses in many mining operations.

During several years of continuous experimentation many factors have been revealed which have heretofore been unknown, or at least unrecognized. These are as follows: i

(1) Materials of different specific gravities and size respond to different vibrations or pulsations of the water passing through the grid bed.

(2) Impact delivered to the gangue by the pulsating water promotes concentration.

(3) Water dilution must be varied to gain the greatest recovery.

(4) The points at which gold and other values will synchronize with the pulsation of water are much higher than two hundred strokes per minute.

(5) The grid bed must be loose and receptive to the heavier materials at all times, and not held tightly closed by weight and suction action half of the time.

(6) Water must flow upwardly through the grid bed in suflicient quantity to classify, and little if any must be drawn'irom the overflowing sluice in a reverse direction through the grid bed.

('7) Impact delivered to equal speeds in all directions, thus determining the shape of the hutch ortank as round.

(8) The greatest velocity of flow of material in a sluice is in the center, and it accordingly requires a round recovery bed for maximum efiiciency.

the water travels atpression B and below which are mounted the hutchesC, D and E of three iigswhich are identical in construction and operation. Bach hutch is cylindrical in shape and is provided with a sloping bottom section I, at the lower end-of which is mounted a discharge spigot which permits intermittent or continuous discharge of concentrates. The jig or concentrating bed of each hutch is formed in the depressed portion of the sluice, and is substantially identical to jig beds in common use,-as the bottom of the bed consists of a coarse screen or grid, on to'p of whichis placed steel shot varying in diameter from V; inch to V inch. The depth of the bed may vary from two to six inches, depending on the type and quantity of material to be handled.

The water fiow through the bed is in several respects diil'erent from common practice, as the now is substantially continuous in a direction upwardly through the bed, and at the same time an impulse of comparatively high frequency is imparted to the water by impact action. The frequency of the impact will, however, vary in the dlflerent hutches, as the frequency in the first hutch will be the lowest and that in the last hutch will be the highest.

The mechanism whereby impact or'pulsating movement is imparted to the water is identical in each hutch, andis best illustrated in Figs. 1

and 2. 1 It comprises a stationary piston rod 0, secured by a coupling I to the upper end of a tube I which extends through the bottom of the hutch. Secured to the upper end of the rod 8 is a cup leather 9, snugly fitting the interior of a cylinder it which is free to reciprocate with relation to the stationary cup leather androd. The cylinder is provided with an upper head li'and a lower head l2, said cylinder and heads normally assuming the position shown in Fig. 1 due to valve l'l whereby an air inletport II and an exhaust' port I. are intermittently opened and closed.

Secured to the upper cylinder head is a hanger II, and extending through said hanger and the valve is a threaded rod 2|, the upper end of which is provided with a head 2!. Springs, 23 and 24 are interposed between the head and hanger and the valve, respectively, to insure 'seatpressureinstantly capes, andasthespring llisundereom pro-ion, thecylinderisforceddownwardlytoitslonm.

ation is repeated.

Thediameterofthecylinderemployedislo smallthattheareapresente'dtothewaterintbe hutchwouldnotbemfiicienttoimpartthedesired impact or pulsating movement For this reason a cone-shaped head I! of comparatively large diameter is secured to the head of the cylinder, and in order that water may be excluded from the mechanism, an annular diaphragm made of rubber is secured to a flange 21a of the headand to a similar flange II which in turn is secured to the stationary piston rod. By providing a head such as shown at 21, any desired area and impact action may be obtained. The rapidity or frequency of the impact action depends entirely upon the length'of stroke and the air pressure employed. A short stroke and high air pressure give the highest frequency and impact action. Conversely, a lower presure and a longer stroke will give a lower frequency and impact. The air pressure or speed with which the air is admitted may be controlled by various means, for instance by a valve ll. The stroke is regulated by inserting; screwdriver and rotating the threaded rod which extends through the valve. By rotating the rod to raise the head 22 in the hanger, the stroke is lengthened, and by lowering the head in the hanger the stroke is shortened. Also, it is possible to produce a comparatively slow upward stroke by the slow admission of air or reduction of pressure. and to insure a rapid return stroke by use of the spring I.

In actual practice, I prefer to employ two or more hutches, as shown in Fig. 3, and to supply each hutch with water from a pipe such as shown at II in Fig. 2. Each pipe is provided with a valve Ii, and the fiow of water upwardly through each hutch and the concentrating bed disposed above the same may thus be separately controlled. The pulsating mechanism in each hutch is also separately adjustable and may be regulated so that the first hutchoperates with the lowest frequency and the last with the highest frequency. The frequencies employed may range from two'hundred pulsations per minute to one thousand or more, depending upon the character of the material being handled, the size and specific gravity of the concentrates, etc.

Sufiice it to say that I have discovered that materials-of different size and specific gravity respond to different vibrations or pulsations, and

it is for this reason that I employ a series of Jigs operating at different frequencies. By placing the impact or pulsating mechanism high in the hutch, just below the grid bed, power demand ther, by being placed close to the bed, the impact is delivered directly to the gangue, and no excess water is moved. As all hutches are independently controlled, water dilution increases with each jig.

Due to the high pulsations and the rapidity of the down-stroke, the water fiow is not only pulsating but the direction of flow is upwardly, thereby maintaining a jig bed which is soft and permeable to permit rapid settling of the concentrates. The impact delivered to the water travels at equal speeds in all directions,thus determining the cross sectional shape of the hutches as round. The hutches are close together and are covered with one continuous jig bed with a grade down stream. This grade is formed into steps by the cross partition plates 40 employed, and I thereby obtain the well known riflle effect.

While certain features of the present invention have been more or less specifically described and illustrated, I nevertheless wish it understood that various changes may be resorted to within the scope of the appended claims; and similarly that the materials and finish of the several parts employed may be in accordance with the experience and judgment of the manufacturer.

Having thus described and illustrated my invention, what I claim and desire to secure by Letters Patent is:

1. In a jig of the character described, a hutch having a jig bed disposed over the same, means for feeding water into the hutch and for discharging it up through the bed, a head member disposed below the bed in close proximity thereto, a cylinder secured to the head, a stationary piston within the cylinder, and a valve for admitting and exhausting air under pressure from the cylinder to impart a reciprocal movement to the cylinder-head.

2. In a'jig of the character described, a hutch having a jig bed disposed over the same, means for feeding water into the hutch and for discharging it up through the bed, a head member disposed below the bed in close proximity thereto, a cylinder secured to the head, a stationary piston within the cylinder, a valve for admitting and exhausting air under pressure from the cylinder to impart a reciprocal movement to the cylinder head, and means actuated by movement of the cylinder for opening and closing the valve.

3. In a jig of the character described, a hutch having a jig bed disposed over the same, means for feeding water into the hutch and for discharging it up through the bed, a head member disposed below the bed in close proximity thereto, a cylinder secured to the head, a stationary piston within the cylinder, avalve for admitting air under pressure to impart movement to the cylinder in one direction, and a spring for returning the cylinder.

4. In a jig of the character described, a hutch having a jig bed disposed over the same, means for feeding water into the hutch and for discharging it up through the bed, a head member disposed below the bed in close proximity thereto, a cylinder secured to the head, a stationary piston within the cylinder, a valve for admitting air under pressure to impart movement tothe cylinder in one direction, a spring for returning the cylinder, means actuated by movement of the cylinder for opening and closing the valve, and an exhaust port actuated by the valve.

5. In a jig of the character described, a hutch having a jig bed disposed over the same, means for feeding water into the hutch and for discharging it up through the bed, a head member disposed below the bed in close proximity thereto, a cylinder secured to the head, a stationary piston within the cylinder, a valve for admitting and exhausting air under pressure from the cylinder to impart a reciprocal movement to the cylinder head, and an annular, flexible diaphragm connecting the piston and head to exclude water from the piston and cylinder.

6. In a jig of the character described a hutch having a bottom and a jig bed disposed over the same, means for feeding water into the hutch and for discharging it up through the bed, a tube extending through the bottom and upwardly into the hutch, a flanged member secured on the upper end of the tube, a head member covering the tube and flange, an annular flexible diaphragm secured to the head and the flange to exclude water, and means for imparting a vertical reciprocal movement to the head.

FRANK C. PETERSON.

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