The start of Thursday 14th March marked the beginning of the 4th day of fieldwork on the Black Mountain. Menna and Sarah from DAT were joined by three volunteers – Tony, Joe and Brian – all of whom were wrapped up and raring to get on with more archaeological investigations on site.
The plan was to continue the plane table surveying that was successfully started on Day 3. The weather was again bright and less windy which bode well for carrying on the good work! All that could be recorded from Wedsnesday’s survey point had been, therefore it was necessary to move the survey equipment to a different location. Due to the difficulties encountered when using plane table survey equipment when it’s set up on a concrete base it was decided that it would make sense to move the survey point to location that wasn’t floored in concrete. Whilst this would make the plane table station more stable and harder to accidentally kick out of place, it meant that the new survey point would have to be linked in with yesterday’s; easier said than done, it seems!
Difficulties ensued, and I’m not entirely sure that I understand exactly what had to be done in order to callibrate the new survey point with the old one… But according to Menna in involves measurements, alignment with fixed points and a certain amount of moving the table ‘a little bit to the left, no, right again, no, this way’.
Once this was sorted it was possible to carry on the previous day’s good work – by the end of the day over half of the office block building had been surveyed and recorded on a plan!
On another area of the site it was noticed that overnight there had been some collapse. Exposed areas of stonework are susceptible to freeze-thaw damage; this happens when water gets into cracks in the stonework and freezes. The freezing water expands causing stress on the cracks and when the water thaws the crack relaxes. This stress eventually causes irreparable damage to a monument. What you can see in the image below is an area of newly collapsed stonework from the front face of one of the kilns.