OCR Text |
Show covered with lengths of railroad Iron. Thla drum in to be revolved at a speed from one to three thomand revolutions revolu-tions pr minute. Outside thla drum, and bearing upon Its upper circumference, circum-ference, is a large drum, the Inside of which waa, according to original specifications, speci-fications, covered with railrond iron. However, practice has shown that the armoring of the outside drum Is unnecessary un-necessary and In the future the grinding grind-ing surface of the outer drum will be left srnooth. Motion Is Imparted to the other drum by the fricHon of the smaller drum within, which la geared directly to the engine', the outer drum thus traveling at a considerably slower rate than the one within. The ore I3 fed into the larger drum and the rate of revolution of the entire machine ia sufficiently great to throw the material ma-terial between the drums at their r.olnt of contact. Besides being thrown between the drums the major portion of the rock la finely ground before coming In contact with tho rollers by impinging npon other rock in the revolving receptacle. At one end of the outer drum Is a fine mesh screen through which tho ground material ma-terial will pass. The passage is facilitated fa-cilitated and the mechanism cooled at the same time by the passing through the outer cylinder of a current cur-rent of water. That portion of the gold, or concentrate, which does not pass through tho screen will, because It is of greater weight than the rougher rough-er material, be found In the coating of the outer drum and can be secured by the removal of the outer cylinder. Thla finely ground matter also furnishes fur-nishes a grinding surface after the machine has been in operation for about one minute by forming a deposit de-posit on the metal inside surfaces and thus preserving them from any wear or friction. It Is estimated that the new contrivance, con-trivance, equalling in capacity a 100-starop 100-starop mill, can be operated by a 30-b.oursepower 30-b.oursepower gasoline engine; since after af-ter tho full speed Is once attained the Inertia of the heavy drums tends to continue the revolution and very little power is required to maintain the speed. In development work the machine may prove of especial value since they are to be made of ony one size, a large one having been found to be no more expensive to manufacluro than one of smaller capacity. By running a shorter or longer time the new invention can be economically adapted to the needs of any property prop-erty which requires from 10 to 100 stamps. A small plant can thus Increase Its milling capacity without any increase of expenditure of money other than that required to keep the machinery In motion. The assembling of the contrivance con-trivance Is complete 'and it can be seperated Into a number of small parts, thus making Its freighting comparatively easy. A mechanism is provided which automatically regulates regu-lates the feed and while in operation the machine requires very little attention. ARIZONA MAN HAS A NEW ORE MILL Produces New Device for Treatment in Place of Stamp Mill. New inventions are being made every day for tho treatment of ore and among the latest la that of Julius Ju-lius Johnson of Mesa, Ariz. His machine ma-chine had been covered by many patents pat-ents during the past two years and the machinery Is now being given a tryout as to its advantages. The model machine, which was built by Mr. John-1 John-1 son, is being usod by the Sbattuckj-Nirnmo Sbattuckj-Nirnmo company in its work at the Dull Dog mine, near Goldfield. Ariz., and is said to be giving satisfaction. It is declared to be much cheaper and more effectual thau the stamp mill. The new machine differs radically in principle from the prevailing stamp mills, the grinding forces being tho centrifugal force impaVted to the ore by the revolution of the cylinder In which it is contained and the action of a rapidly revolving smaller drum placed inside the cylinder Into which the ore jg fed. The new machine may be briefly described de-scribed as follows: A small circular drum filled with concrete or some solid material to prevent Its being crushed by the impact of the heavy ore la placed on a horizontal bearinc. The outside surface of this drum is |