Posted on 29th January 2021
There are many different slate chipping aggregates to choose from when thinking about the decorative chippings for your garden, pathway or driveway. But indigenous slate chippings are probably one of the hardest wearing and environmentally friendly options to consider.
Understanding the geology and origins of the product you choose helps you have a broader appreciation of why slate from the UK is one of the best buys you can make.
Slate is one of the most durable and versatile materials available and is friendly to fish and planting. The Welsh and Cumbrian slate from which plum, blue and grey slate aggregates originate were formed from metamorphosed sedimentary rock 430-500 million years ago in the Cambrian and Silurian periods. The green slate from Coniston in Cumbria is extracted from metamorphosed volcanic ash during the Ordovician period.
Slate chippings are processed from the bi-product produced during the extraction and manufacture of indigenous slate for roofs, walls and floors. These products are highly prised as a roof in Welsh or Cumbrian slate is renowned for being one of the highest quality, and are consequently used on many buildings of significance such as Buckingham Palace, 10 Downing Street and the turrets of London Bridge as well as many buildings of importance across the major towns and cities of the UK.
Therefore, the smaller non-workable stone blocks and offcuts from roof slate manufacture are recycled for use in making decorative aggregates and construction slate aggregates. This is different from most other aggregates which are explicitly quarried, which means that slate is more environmentally friendly by ensuring the maximum use is made of the material extracted from slate quarries necessary to maintain the supply of traditional British roofing slate.
Before processing into aggregates, the rock is carefully selected, ensuring only clean material is loaded into an impact crusher, which has a rotating blade that reduces the rock piece sizes and creates its shape.
The resulting material is then graded by size as it moves through a series of mesh screens, enabling it to be segregated into the different decorative slate aggregate sizes. The walling and rockery products are hand-selected using a picking station that is fed from the weathered material that originates from the original rivings and offcuts from slate craftsmen splitting roof slates.
The geological composition of British slate aggregate means it is stronger and more likely to resist breaking under heavy use than many other decorative slate aggregates, which means it is ideal for a domestic driveway, paths or parking spaces and will require only minimal maintenance and occasional top-up.
Of course, using slate also means you can have a small piece of places in the UK that are also favourite holiday destinations, with the South Lakes and North Wales offering fantastic scenic walks and adventure holidays around the mountainous areas from which slate has been extracted for the past two centuries.