Abstract: A method and apparatus for horizon control in a mining operation where fresh product 3 is cut from a seam 1. The cutting exposes a fresh cut product face 25. The fresh cut product face 25 is observed at a position immediately adjacent a cutter 11. Any temperature contrast regions from an IR observation between an upper limit of observation and a lower limit of observation are noted. At least one height co-ordinate position of a temperature contrast region 33 is determined and an output signal provided of the determined height co-ordinate position so that the output signal can be used as a horizon datum for horizontal control.

Abstract: A communication system including: a first communication device located in a first zone; a second communication device located in a second zone for generating an optical carrier signal; and at least one optical fibre connected to the first communication device for supplying power for operation of the first communication device and for supplying the optical carrier signal from said second zone, wherein the first communication device includes: a user interface for inputting information; and an optical modulator for modulating the optical carrier signal to include information input with said user interface and forwarding the modulated signal via the at least one optical fibre to the second communication device.

Abstract: A method and apparatus for horizon control in a mining operation is provided. Fresh product 3 is cut from a seam 1. The cutting exposes a fresh cut product face 25. The fresh cut product face 25 is observed at a position immediately adjacent a cutter 11. Any temperature contrast regions from an IR observation between an upper limit of observation and a lower limit of observation are noted. At least one height co-ordinate position of a temperature contrast region 33 is determined and an output signal provided of the determined height co-ordinate position so that the output signal can be used as a horizon datum for horizontal control.

Abstract: A control system for a mining machine which moves in passes across a seam to be mined using absolute coordinates is disclosed. The machine is carried on rail and co-ordinates of the rail are measured along the length of rail. The rail is then moved to a new position for a next pass, and the distance of moving is determined from the co-ordinates previously measured. By knowing the co-ordinates, the rail can be moved to assume a desired profile, so that a desired profile of the seam can be achieved on the next pass. Co-ordinates of the up and down movement of a shearing head can also be measured and stored with the co-ordinates along the rail to provide a profile of the seam being cut, and so that on a next pass the intended position of the shearing head can be predicted and moved accordingly.

Abstract: A mining machine (7) is provided which moves from side-to-side in sequential passes across a seam of material to be mined. The machine (7) is carried on rail means (19) and co-ordinate positions of the rail means (19) are measured at locations along the length of the rail means. A trailing part of the rail means (19) is then moved by rail moving means (25) to a new position for a next pass, and the distance of moving is determined from the co-ordinates of the positions previously measured. By knowing the co-ordinates of the positions, the rail means (19) can be moved to assume a desired profile, so that a desired profile of the face of the seam can be achieved on the next pass of the machine (7). Desirably the profile is a straight line.