Gold Mining Equipment for Sale

The roll mill 5 is in closed circuit with th( eight-mesh screen 2, and that portion of the rol: mill product in excess of eight-mesh is returnee to the bin 3. In view of the fact that the space between the rolls is so much greater than the screen openings, there is a large percentage ol screen over-size reject to be returned to the rolls and cnnpnsrunftly a hoeavsr c nir l o*~4.i f drJ A through the roll mill 5.The foregoing operation results in the reduction of the ore to a minus eight-mesh size,gold milling equipment and at the same time the formation of fines is held at a minimum and the addition of iron impurities is inhibited.

As indicated in Figure 1, the under-size from screen 2 is passed to bin 4, which feeds the ore to a twenty-mesh screen 6. The plus twentymesh material from screen 6 is choke-fed to pebble mill 7. This pebble mill departs from the conventional type in certain respects, and in Figure 2 there is diagrammatically shown a mill that is particularly well adapted for use in our process. The mill 7 is for the purpose of reducing the size of the plus twenty-mesh material, but at the same time is designed to avoid, or minimize, the production of fines and the incorporation of ferrous impurities into the ore being treated.

Referring more particularly to Figure 2, the mill may be formed with a casing 8 of conventional construction, and provided with a feed trunnion 9 and a discharge trunnion 10 of such a size as to permit of a heavy and rapid circulating load. A grating 11 is located in the mill adjacent the discharge trunnion in order to retain the pebbles in the mill but permit the discharge of the ground ore.The casing 8 is lined with a non-ferrous material 12, such as silex, and the grinding media are non-ferrous pebbles 13. These pebbles are preferably pieces of the ore that is being treated, and initially may be from 4 to 6 inches in size.Of course, as these pebbles are broken down during the course of operation, they may be replenished....