If you have heard of jet you probably think of Whitby Jet. This is a semi-precious gemstone formed from the fossilised remains of the monkey puzzle tree. This was traditionally used in jewellery making and due to its ‘jet’ black appearance it was synonymous with mourning jewellery such as that Queen Victoria sported.

If you know a bit more about jet you will know that it is found amid the shale band and was often washed out of the cliffs of the Yorkshire Jurassic coast. This is probably why Jet is so greatly associated with Whitby.

What few less people realise is that Jet was actively mined throughout much of the North York Moors and the Cleveland hills. Very little is actually documented about the jet mining industry and as we have come to realise virtually all that can now be learned of what was assumed to be a cottage industry can be obtained from within the jet mines. As such over the last two years we have been researching and visiting disused jet mines. Our aim is to find and survey as many of these as possible and through this learn as much as possible about this little known industry.

Our first impressions with these mines was that they were all small, they all appeared to be very close to the surface and so subject to widespread collapse. It was theorised that these were all small scale operations undertaken by single families or as side lines by ironstone miners or even farmers. Many mines appeared to fit this depiction and in many areas this appears to have been the case.

However some mines have been found that do not fit this model. We have found mines that appear to have been extensively worked which suggest that this may have been a larger industry than first thought. To date whilst the smallest mine that has been found was around 30 m the largest so far exceeds 5 km and we know we have extensive passage yet to survey and we expect the total length to far exceed this.

We have a lot of work to still do on this project and have no idea when we will complete it. To date we have explored mines throughout much of the north, west and central parts of the North York Moors and surrounding areas.

A small word of warning, jet mines are incredibly unstable, and believe us the passages are seriously complex and getting dangerously lost is a real possibility. Finally we have also recently found out that in some circumstances the air can become bad. So if you’re thinking about going into a jet mine have a chat with us first!