use of magnets 72 does not enhance the effectiveness of the machine and they may be eliminated the shaft 30 of horizontal auger 14 is preferably of ferromagnetic material except for the outer end portion 30a which is of low permeability material the flight of auger 14 itself is preferably of low permeability material such as stainless steel in this way magnet flux is concentrated and distributed by the shaft 30 except for the outer end portion 30a the importance of providing the outer end portion 30a of low permeability material is so that any ferromagnetic cutting chips or parts such as a lost wrench bolt or nut which may inadvertently get in machine cuttings does not cling by magnetic attraction to the outer end of the horizontal auger 14 but freely falls off and down onto the inclined auger 16 referring to fig7 9 and 10 a system is illustrated which improves the safety and performance of the separator hydraulic pump 64 driven by motor 76 see fig1 and 10 moves fluid from reservoirs 66 through a flow control valve 78 to an auger control valve 80 the auger control valve has three positions one port of the valve 80 is connected to the source of fluid pressure provided by pump 64 another part is connected to reservoir 66 and the outlet ports connected to a hydraulic motor 82 which drives the horizontal auger 14 and a hydraulic motor 84 which drives the inclined auger 16 a pressure relief valve 86 is set to limit the pressure provided by pump 64 as for example at 1 000 psi so that a substantially constant fluid pressure source is applied to control valve 80 valve 80 has three positions and is spring loaded.