Dorothea Quarry
At the start of April, we went to Dorothea quarry along with Project Dorothea and Bangor University. Those of us in attendance were curious about the drone’s capabilities in such an environment and how well it would perform using the infrared function for archaeological purposes. The brief of the operation was simple, to fly the drone over sites of interest and take aerial photographs, switching to IR imaging to detect features and layouts of the archaeological structures hidden under the extensive branches of trees on the site without causing any damage to the trees or the structures, made possible by the time of year and the white hot function on the drone.
​
The tour began at the entrance to the site where Project Dorothea have cleared the former bridge from extensive vegetation and completed an archaeological survey on the listed structure. The bridge formed part of the original road into Tal Y Sarn, before a significant civil engineering project rerouting the river. We began with some apprehension and took some aerial shots of the bridge, following its path from above the treeline to discern which direction it takes into the area now lost to the extraction industry.
We continued onwards, just beyond the known end of the bridge to the biggest point of mystery and intrigue, the extraction made island located in the middle of the quarry lake. A location where only a drone with advanced capabilities such as the thermal imaging would be able to provide a true glimpse of what was waiting to be discovered under the trees on the island. With some apprehension of what may be there, the drone was launched and flown over to the island to reveal some of its hidden secrets. With a series of photographs using the White Hot function of the Thermal Imaging drone revealed a clear pattern, perhaps a wall to a road or a building once located on the island, there is most certainly an archaeological feature on the island, which may warrant further investigation by ariel imagining. The site is too dangerous to reach in person.
Following our success on the island, the tour continued along the footpath towards the flooded Dorothea pit, the focus for this second flight was an enormous slate cutting shed or mill and its associated buildings: a smith’s workshop and mill offices for which extensive archaeological investigation is planned this summer. The images gathered by the drone will be invaluable in planning this work, particularly given the clarity of the layout of these structures produced when using the IR imaging function of the drone to pick out features under the branches of the trees. The footage below which transitions from the wide-angle camera into the white hot function demonstrates how effective this technique is to determine what remains of the old mill in greater detail.
We look forward to returning to Dorothea Quarry to record the progress of the project in the future and to utilise the features of the thermal drone in other projects to help understand, map and record heritage sites and items of interest to heritage, archaeology and other related fields.
​
A big thank you to Leona, Matt and Callum for showing us around this incredible site.