slat processing techniques

Sawing:
After extraction, the heavy slate slabs are cut across the grain into set sizes which are a little larger than the finished face size, using a saw that dates back to 1929, when electricity first came to the mine. The material is so hard, that a blade lasts only 200 hours of cutting.

The remaining processes, all of which are required to produce traditional roof slates, are all carried out by hand, in the same way that they have been performed for centuries.

Docking:

Docking the slate is the original process of dividing the large, sawn pieces (clogs) to a thickness of four slates (about 32mm) ready to be rived. This cutting is achieved with the use of a small chisel and a 21 pound mallet, cutting with the grain.

Riving:

Once docked, the slate can be rived - splitting the sections, again by hand, with a mallet and broad bladed chisel, into four slices each. This produces slates of a thickness suitable for use. (The width of the chisel equals the total thickness of eight finished slates). Riving is carried out along the grain.

Dressing:

Having made the slates the correct thickness, dressing is the process that cuts them into the precise shape required. A series of blades revolve and chop off the edges and corners of the material, leaving a completed slate, ready for use.]

After inspection, the slates are stacked in size order, in preparation for packing into shipping crates. They are then ready to be despatched to their final destination, which may be anywhere in the world.