An object of this invention is to provide a ball mill in which the material to be ground is cir- 5 shown in Fig. 1. culated through the mill, is sifted, and the overs are continuously fed back to the entering end of the mill for further grinding, thereby continuously effecting removal of the finely ground material from the coarser which speeds up the grinding operation, This and other objects, as will hereinafter appear, are accomplished by this invention which is fully described in the following specification and shown in the accompanying drawings in which:

Figure 1 is a longitudinal vertical section through a machine embodying the invention; Figs. 2 and 3 are vertical transverse sections on the lines 2-2 and 3-3 respectively on Fig. 1; Fig. 4 shows a fragmentary end elevation of the receiving end of the machine; and Fig. 5 is a fragmentary view similar to that of Fig. 4 showing certain details thereof,Chrome Ore Crusher. The embodiment illustrated comprises a framework 10, 12 of wood or the like having legs 14, 16 for supporting the machine on the floor. A shaft 18 is suitably journaled in bearings 20, 22 which are carried by the main frame, this shaft being driven by means of a sprocket 24 and chain 26 from a sprocket 28 and through a suitable gear reduction 30 operated by a motor 32.

Spiders 40, 42 are keyed on the shaft 18 and their peripheries 44 and 46 respectively are preferably circular in shape. These spiders also carry through-bolts 48 on which are secured clips 50 about which are secured bands 52 of the same general ccnfigurat’on as the peripheries 44, 46.A su’table screen 54 of any well known type is then secured about the peripheries 44, 46 and the bands 52.The ends of the machine are c’osed by means of v-afls CO, G2 and plates 64, 68. The wall C0 carries an angular strip 70 which lies inside a shoulder 72 within the periphery 44. A feed chute 76 feeds material to be ground through the spider 40 and into the space enclosed by the screen 54.