The investigation of iron metalworking remains from both Tell Dhiban and the Armenian Garden began with the selection of appropriate material from the collections held at the University of Liverpool and Manchester Museum respectively.
The selection process focused upon locating and selecting any possible ferruginous slags fragments and cakes from each of the collections that were within the desired date range. Written records of the materials within the collections were initially examined and any specimens specifically identified as slag were duly noted. Whilst searching the material collections for these specimens, any additional specimens visually identified as potential slags were also taken for further examination.
Once a suitable quantity of slag material had been selected from each of the collections they were all subjected to an initial cursory examination, this was done by eye, with the aid of a loupe and magnet to assist in the correct identification of ferruginous slags. A number of iron oxide pseudomorphs, fuel ash slags, ceramic rich slags, and heavily corroded iron objects were identified and rejected during this process, eliminating all of the non-slag specimens from the assemblages.
Along with the selected slags a single ceramic rich furnace lining slag specimen was retained from
the Tell Dhiban collection, this specimen was also prepared for analysis to determine composition, this sample will not be counted with the general slag samples.
The Tell Dhiban collection yielded a total of twenty-six ferruginous slag specimens with a overall mass of 7.2kg, whilst the Armenian Garden collection yielded eleven specimens with a total mass of 14.1kg.
The material assemblage selected from the Tell Dhiban collection consisted of both large, mostly intact slag cake specimens, and small, mostly fragmentary specimens. This observation led to the assemblage being divided into two sets; set one encompassed all of the largest specimens, which includes the planoconvex smithing hearth bottoms / furnace bottoms and largest fragments thereof;
whilst set two includes all of the remaining smaller nodules and fragmentary slag specimens. This arrangement resulted in an almost even divide in the number of specimens between the two sets, with set one containing eleven specimens and set two containing fifteen specimens. The sets to which each of the specimens have been allocated is given in the final column of Table.1.
All of specimens selected from the Armenian Garden collection were larger, mostly planoconvex slag cakes, with very little fragmentary slag material being present in the collection within the required date range.
After completing the initial cursory examinations to determine if the specimens were actual ferruginous slags, a more thorough examination was undertaken to record the physical aspects of all of the remaining selected specimens. Firstly, all of the material present in every sample bag was subjected to a mild cleaning regime using a soft brush, to remove any loose material, surface debris and dust; subsequently each specimen was examined, both macroscopically and with the aid of a loupe, then photographed and weighed. The largest specimens that exhibited a planoconvex
appearance were also subject to dimension measurements. This information was recorded for each specimen along with the appropriate identification reference code.
Some of the slag specimens were selected for further investigative cleaning to reveal potential underlying surface inclusions, textures, imprints and colourations, that would otherwise be obscured by surface encrustations. These specimens were thereafter re-examined and re-photographed. The investigative cleaning procedure involved rinsing the selected specimen with a continuous stream of plain tap water whilst scrubbing the specimens surface using a small nylon brush, this scrubbing and rinsing action was continued until the entire exposed surface had been cleaned and until no further material was being removed from the surface by the process, this end point was denoted by the water run-off being clear and free from particles. The specimen was then thoroughly rinsed with deionised water and patted dry with paper towels. An air duster was used to expel any remaining water from cracks and vesicles, and then the specimen was immediately transferred to a drying oven set to 100˚C for at least twenty-four hours. At no point during this procedure were the specimens left wet for more than one hour before being transferred to the drying oven.
Fig.13. Example of exploratory cleaning of Tell Dhiban set one specimen BR41.19.95. Top images are pre-cleaning, bottom images are post-cleaning. The post-cleaning images also show the white surface concretion, visible in a number of places over the slag cakes surface.
During the aforementioned initial examination it was noted that some of the specimen bags contained a number of objects, this was due to either associated objects being grouped together, or the original material being to some degree friable and falling apart. In these circumstances the largest actual slag fragment or nodule, or most representative slag fragment was selected for further sampling and analysis.
Fig.14. Associated artefacts which were all grouped into a single sample bag under the sample number CE27.7.73. The four objects in the top-right are all iron pseudomorphs, the three objects bottom-right are all fragments of slag that have broken away from the larger slag nodule shown on the left of the image. Sampling was conducted on the largest slag nodule.
Fig.15. An example of a fragmented slag cake, which has most likely been broken apart by the action of oxidation, many of the specimens exhibit some degree of friability and cracking (Jerusalem SA235).