Abstract: Laser welding apparatus, in which a laser beam is impinged upon a component to be welded at a laser beam impingement point, wherein a plasma suppressor is arranged to impinge a jet of gas on the component at an angle to its surface, flowing towards the laser beam impingement point.

Abstract: Small cooling holes, e.g. 0.25-0.9 mm diameter, in cast hollow turbine blades are provided by delivering successive pulses of laser energy to the surface of the blade until penetration of the blade is complete. By leaving the ceramic casting core in situ within the blade during drilling, the laser beam is prevented from striking through to the far wall of the cavity defined by the ceramic core within the blade. The ceramic core is subsequently removed by leaching techniques common to the art.

Abstract: Mobile mineral processing apparatus comprising at least one module having a base, frame structure and a roof. The base is mounted on skids or the like whereby the module can be moved from place to place at will. Also, each module is demountable for convenient transport from one site to another and for convenient reassembly at the new site. In a basic form of the apparatus there is a preliminary separation module having an inclined screen for separating feed material into waste and treatment components, and a concentrator module having several banks of spiral concentrators which receive the treatment component and process that component to achieve a satisfactory level of recovery of the mineral of interest. Water and power distribution systems together with ancilliary equipment such as pumps and motors are provided as an integral part of the apparatus. The apparatus is therefore self contained and fully operational subject only to connection of external sources of water and power.