23 Friday 7th May - Extending Trench 3

Today, we had four excavators assisted by Trevor, the farmer, in the morning.  It was yet another cold day at the site, even though it was sunny.  The trailer came in very handy again to shelter out of the wind at lunchtime.
We started by extending trench 3 towards the spoil heaps, doubling it in size. 
Trevor really came into his own and set to with a very efficient shovelling technique to clear a lot of the loose material. 
In profile it was similar to the other half, although there did not appear to be the same loosely packed slag as in the first section.  The higher density slag seemed to be nearer the upper levels with more aerated, less dense slag at deeper levels.
More small pieces of charcoal/burt wood were found at the lower levels and much of the slag contained traces of other metals/minerals -copper, lead etc.  It is not clear whether what we have in the corner is the base of a furnace but there are a number of burnt sandstones set quite firmly in a bed of clay.  The patch of light coloured clay excavated by Mike earlier proved to be a little more extensive with a possible arc of stones and slag circling around it.
These photos indicate the extent of the excavation.  Trenches 1-5 run from the top of the slope down towards the river.  Their homogeneous gradation from stones/fuel/ore at the top to slag/burnt fuel at the bottom but without any clear sign of structures or  furnaces suggest that we might be taking a cross section through a much more extensive site.  Though not yet analysed by an expert, the slag appears to be more like bloomery slag at the bottom of trench 3 and blast furnace slag towards the top, suggesting the smelting occurred over a long period of time and the transition from the earlier method to the later one. 
Thanks to Janet for the text and Alex for the photographs.