Silicon fusion bonding for fabrication of sensors, actuators and microstructures

A mining machine is provided with a lock for the starting device, the lock being withdrawn by a piston and cylinder operated by a bleed from the dust suppression fluid supply, and a restriction is provided in the bleed for causing a delay in the withdrawal of the lock from the moment when the dust suppression fluid is turned on, whereby the machine cannot be started before the dust suppression fluid has been supplied to the cutting head for a period sufficient to warn away any personnel working on or in the region of the cutting head.