Ruthin & District U3A

EVERY month, the Berwyn & District and Ruthin & District U3A geology groups have a monthly event.

On July 26 they met up with Jason Parry, the Cefn Mawr quarry manager for a guided tour around the busy working quarry.

Jason began by explaining the workings of the quarry.

How all workers carry a walkie-talkie and know exactly what is taking place from minute to minute, lorries approaching, blasting etc. Health and safety rules apply at all times and everything is monitored.

Once kitted in hi-vis jackets, hard hats and goggles, the tour began by passing four enormous silos that are filled twice daily with limestone aggregate.

After a climb of many steps, group members were level with the top of the quarry and could see the whole of the action.

They were even allowed to watch some blasting, which was a bonus. Jason spoke about the different types of limestone the quarry produces and their uses.

Conservation of the site is of paramount importance and the top few layers of the quarry no longer mined are now covered in grass and trees where appropriate.

On the way to an area of SSSI (Special Site of Scientific Interest), group members passed a limestone cliff face full of brachiopod and crinoid fossils and they could see the layers of mudstone.

There are even layers of volcanic ash in some areas of the quarry.

Moving on, they came to Jason's SSSI site.

A meadow is a project of Jason's.

No machinery is allowed on this site.

There's special meadow plants only, attracting butterflies, bees etc. It is an ongoing project.

Sheep are allowed into this precious area once all the plants have set seed and they eat the grass.

It is a splendid site.

This tour was amazing and and the group thought it was one of their best trips, with Jason being an excellent guide.

Remarkably, the whole event was free.

Groups can arrange a visit and they won't be disappointed.

The limestone was formed 350 million years ago in warm, tropical seas.

Wales at that time was by the equator.

Plate tectonics have gradually moved us to where we are now, but we are still moving.

It can be made up from the body skeletons of algae, shellfish and sponges etc, lying on the ocean floor building up in depth over the millions of years.