Ballachulish Slate Quarry EarthCache
Ballachulish Slate Quarry
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The Ballachulish Slate Quarry is now a peaceful place, surrounded by magnificent mountains, with ducks swimming on the water and lots of other birds too. There are picnic tables here for you to enjoy a quiet sit… so very different to how it would have been back in the late nineteenth century when six hundred men worked here.
Please park at the Tourist Information Centre in Ballachulish, then head towards the published co-ordinates. This will take you to the quarry entrance, go through the gate to explore the main quarries, here you will find several information boards which tell the story of the quarries going back to 1693 when the West Quarry was opened and the East Laroch quarries, established just two years after the infamous Glencoe Massacre of 1692. Ballachulish produced the slates that roofed Scotland, until cheaper substitutes from overseas heralded the decline of the quarry in the early twentieth century through to its closure in 1955.
Ballachulish slate was originally mud on the seabed about 550 million years ago at a time when the configuration of continents and oceans would have looked very different from today. The continents have subsequently moved about the surface of the globe and major oceans have opened and closed. Ballachulish slate records the former existence of such an ocean.
Slate is a very fine-grained, metamorphic rock that splits readily into thin slabs having great tensile strength and durability. A true slate does not as a rule split along the bedding plane but along planes of cleavage, which may intersect the bedding plane at high angles. Slate is formed under low-grade metamorphic conditions (low temperature and pressure). Mud particles carried by rivers to the sea gradually accumulated on the sea-bed to form layers of fine grained sediment. The original material was a fine clay, usually in the form of a sedimentary rock (e.g., a mudstone or shale). The parent rock may be only partially altered so that some of the original mineralogy and sedimentary bedding are preserved; the bedding of the sediment as originally laid down may be indicated by alternating bands, sometimes seen on the cleavage faces. Cleavage is an inherited structure, the result of pressure acting on the rock when it was deeply buried beneath the Earth's surface. The direction of cleavage depends upon the direction of the stresses applied during metamorphism.
Slate may be black, blue, purple, red, green, or grey. Dark slates usually owe their colour to carbonaceous material or to finely divided iron sulphide. Reddish and purple varieties owe their colour to the presence of hematite (iron oxide), and green varieties owe theirs to the presence of much chlorite, a green micaceous clay mineral. The principal minerals in slate are muscovite and biotite (in small, irregular scales), chlorite (in flakes), and quartz (in lens-shaped grains).
Ballachulish Visitor Centre has lots more interesting information on display and they are very helpful too. You can visit the slate arch that was built by the quarry workers to get the slate from the top level of the quarry down to the ships waiting at the harbour. You can also see the old slate boathouses on the shore of Loch Leven.
The above information was compiled from the following sources:
• Wikipedia, the free encyclopedia
• Barbara Fairweather, MBE The 300 -Year Story of Ballachulish Slate.
• Ballachulish… Undiscovered Scotland: The Ultimate Online Guide
In order to log this cache please email your answers to these questions via our profile.
1. The slate here has a distinctive blue vein running through it, why is this?
2. Facing North at the Question co-ordinates, describe what you see in front of you and what you think the line near the top is.
3. How many slates were produced in 1845?
4. Please add a photo of yourself and or gps in the quarry if possible, although this is not a requirement for logging the cache.
Please feel free to log this cache without our confirmation; we will contact you if your answers are wrong.
Many thanks to the Ballachulish Visitor Centre, to the Community Council and to the Highland Council for their help assistance and approval in enabling this Earthcache. They have asked us to request that visitors to the site do not park at the gateway, but use the large car park nearby; take their litter home, and clean up after their dogs.
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