It is important' to note in this connection that the capacity of a battery of stamps depends very largely upon the construction of the used.
Battery or mortar screens are usually made of genuine Russia iron, or of the best quality of cold rolled homogeneous steel. They are of various patterns —"roundhole screens" with charge type, designed for copper lining plates in the back and front, the former bolted through the mortar, and the latter attached to a block under the screen frame. The copper plates are coated with mercury. The ore is fed through the opening in the back near the top and is dis tributed under the stamps by their own action, peculiar to the order of their drop. The water enters at the top against each stamp and carries the crushed ore or "pulp" through the screen as fast as it becomes fine enough, by being perforations ranging from 3/4 to 1 millimeter in diameter; "needle slot screens" perforated with diagonal or horizontal slots usually 15/32 of an inch in length, and ranging from 12 to 70 mesh; and °indented-slot screens.° Fig. 14 illustrates an example of each type. In addi tion to these regular patterns, most of the large manufacturers are always prepared to furnish screens punched according to any specifica the lower for the neck of the shoe, and the upper for the tapering end of the stamp-stem, which requires no other fastening than the wedging action of its taper to bind it firmly to the head. Slots arc cut from the side of the head into the sockets, through by means of wedges the stem and the shoe can be forced out when necessary.
- -- tions that may be may be required for use with particular ores.
Stamp dies are made of very hard and tough material, usually the same as that used for the body of the shoe. Fig. 15 shows six of the principal forms.
The tappets are collars fastened to the stamp stems. They bear against the revolving cams and thus alternately lift and drop the stamps. Each tappet is fitted with a gib which, being pressed against the stem by cross keys behind, binds the tappet on the stem as firmly as pos sible, and at the same time admits of a quick adjustment to another portion of the stem when ever necessary. As shown by Fig. 18, they are Stamp shoes are made in a variety of regu lar and special patterns. Fig. 16 shows one of
the usual pattern. In wet crushing mills it is attached to the stamp-head by means of strips of wood placed in the space between the neck of the shoe and the socket of the head. The wooden strips are swelled by the water and thus hold the shoe and head firmly together. In dry crushing mills strips of iron are used for this purpose.
are made the same diameter as the stamp shoes. As shown by Fig. 17, the stamp-head has a tapering socket at each end made with either two or three keys, and are counterbored to prevent slipping on the stem.
Cams are being made in a variety of patterns depending upon the height the stem is lifted and dropped, and the necessary distance be tween the centre of the cam-shaft and the centre of the stamp-stem. They are made both right-handed and left-handed, and are either keyed onto the cam-shaft, or attached by means of taper-bushings which give a self-tightening effect. Fig. 19 shows side and edge views of both types, and the method of applying the taper-bushings.
Fig. 20 shows their positions on the cam shaft so as to give the most general order of a drop for a 10-stamp battery, when driven from either end of the shaft.
The other essential parts of the battery are the °cam-shaft boxes," gcam-shaft pulley" and the °stamp guides." These are illustrated by Figs. 21, 22, 23, respectively. The cam-shaft boxes are made of metal and in the improved forms are provided with an oil drip launder which extends around the two ends the front of the box and thus prevents the lubricat ing grease from dripping into the mortar and onto the amalgamating plates. Standard cam shaft pulleys are built up of well-seasoned pine, properly laid in oil and spiked. The face and sides are turned and thoroughly covered with oil paint The hub is of cast-iron, the through sleeve and one flange being cast in one piece. The sleeve is bored to fit the cam-shaft and Tube Mills.—These are used for the purpose of reducing ores to a fineness up to 200 mesh. Fig. 24 is an example of the cylinder type. Another favorite form is conical or double conical. With the demand for extreme fineness in the cyaniding and flotation processes, as well FIG. 19.- Cams.