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Bethesda

There are mountains of slate waste in North Wales. In fact according to recent research about 730 million tonnes of it. A considerable percentage of this belongs to Alfred McAlpine Slate Ltd (AMSL) who has regularly supplied some of it to local markets for activities such as road building. It has not, however, been economical to send it further afield, until the introduction of the Aggregates Levy which classified slate as exempt from tax. As the possibility of an increase in tax is highly likely in the future, the market of slate as a secondary aggregate will continue to grow.

There are only three large scale slate quarries currently active in North Wales, two are near Blaenau Ffestiniog and one at Bethesda, producing mainly roofing slate, as well as work surfaces, paving and flooring, tiles and slabs. In total they create nearly six million tonnes of slate waste each year, of which historically only approximately 275,000 tonnes is produced as secondary aggregate.

The largest of the three quarries is Penrhyn at Bethesda, owned, like one of those at Blaenau Ffestiniog, by AMSL, who produce by far the largest quantity of slate, and therefore the majority of the waste.
Slate can make a perfectly good aggregate, but there is limited demand for it in north west Wales, where McAlpine have been selling it for the past thirty years. The cost of transporting it to other markets has always proved prohibitive, but the introduction of the Aggregates Levy is changing that.

Since the introduction of the Levy, and the exemption of slate, AMSL have doubled the amount of slate they are crushing.

The processing of the material is the subject of a ten year contract with AMPL, which is their first contract in the UK for recycling of slate. Penrhyn already crushes slate into a range of products-type one sub-base, drainage stone, fine aggregates to replace sand in concrete (slate has a high silica content), industrial minerals and granules used for making green roofing felt. To reduce the current quantity of waste material and further increase the range of saleable products a decision was made to increase production which would result in more saleable product availability by introducing a washing system into the production cycle. This would provide a more diverse product; a significant growth area has been the use of slate as a decorative aggregate in gardens where it has found favour as a more resilient alternative to tree bark and available in three colours - plum, green and blue. Additionally other complimentary slate walling and paving products are being produced and sold, via distributors, to garden centres and DIY shops.