Abstract: Apparatus for transmitting data relating to a mining machine in a longwall mining operation, comprising a data collection device mountable on a mining machine for collecting data relating to the machine, a data transmission device also mountable on the mining machine for transmitting the data in the form of a remote signal, and a plurality of receiving devices each mountable on one of a plurality of mine roof supports past which the machine is arranged to travel. The apparatus also includes a data conveying device for conveying the data away from the mine roof supports.