Mining, and its associated impacts have been around for centuries. Katina De Sousa (Astron’s Rehabilitation Principal Scientist) recently took the opportunity to consider whether we have anything to learn from historic mines while visiting three heritage sites in Wales:
- Great Orme copper mine
- Dolacouthi gold mine
- Blaenavon World Heritage Site.
In this article, Katina discusses her observations from the Great Orme copper mine located in north Wales. At Great Orme there is evidence of mining occurring in the Bronze Age using simple tools made from rock and animal bones.
Aside from general amazement that mining was occurring at this site over 4,000 years ago, the overwhelming impression at Great Orme is how minimal the impact is from the mining activities compared to modern day large-scale mining operations. At Great Orme the ore was mined very selectively as it was done by hand using very rudimentary tools and the malachite ore was very high grade. In some areas the tunnels are so narrow an adult can’t crawl through them (archaeologists think that some of these were probably mined by young children).
This targeted mining limited the area of disturbance of the pit and underground workings as well as the storage of waste rock at the surface. Additionally, due to the effort involved in moving the waste rock from the underground by hand it was generally backfilled into completed tunnels. This further reduced the amount of waste rock at the surface and the impact of the mining activities.
So what can we learn from the Bronze Age miners…
The mining by hand of high grade ore in the Bronze Age is obviously very different to the mechanised mining of relatively low grade ore deposits that occurs today. However, seeing the limited impact of the targeted mining at Great Orme on the surrounding landscape made me wonder whether the cost of conducting rehabilitation will ever become high enough for backfilling of pits to become more common due to economic viability. Many mining companies continue to report increasing costs for rehabilitating and closing sites – so maybe this could be a reality in the not so distant future?
A further stretch would be whether improvements in technology could lead to more selective mining once again being possible even for low grade deposits. The Bronze Age miners using their antler tools (which were probably considered cutting edge at the time) couldn’t have envisaged the scale and capacity of machinery we use for mining today. So who knows what technological advances the future holds?
For those of us involved in planning for closure of a mine site, it is worth remembering that it is easier (and potentially cheaper) to try to minimise disturbance areas at the planning stage than have to deal with them at the rehabilitation stage. Targeted mining and backfilling of mine voids are two ways of doing this. But can we accomplish this outcome in other ways to achieve benefits for the environment and the bottom line?
Stay tuned for the next article to find out if we have anything to learn from the only known Roman gold mine in the United Kingdom, Dolaucothi.
Animal bone tools used at Great Orme copper mine
Underground tunnels at the Great Orme copper mine
Surface mining at Great Orme copper mine