The Slate Industry of North and Mid Wales

A glossary of some slate industry terms

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Adit  The entrance to a tunnel
Back filling Using waste rock to fill underground workings
Bad rock Unproductive rock found during working
Balanced incline  Incline with 2 tracks where the descent of the loaded wagons drew up empty wagons
Barracks Accommodation block used by quarrymen during the week
Black powder A primitive form of explosive
Block Large piece of quarried slate 
Blondin  A wire rope across a pit with a carriage for wagons to attach to, enabling them to be raised and lowered
Chain incline Suspended incline using a wire rope instead of rails and an inclined plane
Chamber The underground working area - up to 70 foot wide
Chwarel Welsh name for a quarry
Cowjian Plug chisel used for block splitting
Crimp The top edge of an incline
Cupboarding Dangerous practice of cutting into roofing pillars to get cheap slate
Cyffell Long wide knife used to trim roofing slates to size
Drum Horizontal drum around which the ropes of a balanced incline were wound
Firesetting Old practice of loosening slate by using fire
Flat rods Horizontal hinged wooden rods used to convey the power of a water wheel over a distance
Floor working level of a quarry, usually numbered or lettered
Hunter Large circular saw with replaceable teeth
Jwmpah Long weighted rod used to manually bore a hole
Launder Trough for carrying water
Llechi General term for slate
Mill building where slate is reduced using machinery
Pelton Wheel Advanced form of water wheel
Pillar Column of slate left underground to support the area above it
Pillar robbing Thinning of the pillars to get "free" slate (see also cupboarding)
Pillaring line A line of weakness in rock allowing blocks to be removed
Planer Machine used to smooth the surface of a slab
Powder house Purpose built building used to store explosives
Pric Mesur Serrated stick with a nail in the end used to mark out roofing slate sizes
Rhys Large mallet used to break slate blocks
Rubbish Waste rock from the quarrying process
Sinc A pit working
Slideway An unrailed incline where the rock was pushed down
Strike A tunnel bored horizontally into the slate vein
Terrace Working level of an open quarry, usually numbered or lettered
Trimmer Machine used to trim roofing slates to size
Twll A pit working
Untopping Removing the earth and rock from above underground workings to remove the pillars
Waliau Open fronted sheds where slate was hand trimmed and dressed
Water balance Type of incline where the weight of water is used to raise wagons
Winding House Structure where the drum of an incline is housed


Next page: Traditional names and sizes of slates

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