As a follow up on our last post on Raheen Mill in Clonmel, here Billy explains the milling process which was likely followed at the site in a little more detail.

The eighteenth century Mill at Raheen was typical of it’s time, comprising a vertical waterwheel used to grind grain, principally oats or corn. The original wheels were known as “Scud Mills”, where an open stream or river was utilised. Later mill-races were developed at a higher level along the river to guarantee the water flow. From a survey carried out by Shirley Markley in Clonmel, the undershot waterwheel was the most commonly used. These wheels were the only types which could be installed along the banks of large rivers in areas of low relief.

The plate to the left shows a sketch section through a typical mill, featuring a water wheel, wheel pit and wallower on ground floor, grinding stones on first floor and storage area on second floor (source:  www.norfolkmills.co.uk ). Typically the internal working parts of the mill were still made of native hardwoods like apple, oak and crab-tree. Oak in particular was used for making mill-shafts because of its durability. In terms of the vertical waterwheel the power terminated with the wheel shaft inside the mill in a large cogged wheel, known as the trundle wheel. The cogs were pegs mortised into the rim of the trundle wheel in the early examples. As it turned, these meshed with the vertical staves of a lantern pinion   which turned the central vertical shaft. On the floor above was the pair of millstones, the lower “bedstone ” was fixed in position while the upper “runner stone ” rested on top of the vertical shaft and rotated with it. Towards the end of the eighteenth century, the wooden trundle wheel would have been replaced by a large bevel gear – a solid casting five to six feet in diameter, rotated on the inner end of the wheel shaft. Pulley drives were often taken off the spindles to power the sieves, fans and dusters on the meal floor.

In 18th century mills there were approximately four stages in the milling process. The first stage was “shelling” where through grinding the outer casing and kernel of the grains i.e. seeds and hulls respectively, were separated.

Following this the grains were reground with the stones set closer together. This produced a coarse meal, containing a fair proportion of impurities e.g. whole kernels, passed downwards along a wooden spout on to a meal sieve. There then followed the “sieving” process whereby layers of perforated plates set in a wooden frame, one below the other, sorted the fine meal from the heavier grain. Finally, the meal went to the “sacking” stage via a small chute or spout. Meanwhile, the coarser, unground kernels were screened and either rejected or elevated back up for further grinding.

The illustration to the right depicts a profile of typical 18^th century mill showing bin floor, stone floor and meal floor(Source – www.angelfire.com/folk/molinologist/problems.html ).

For further information on mills and milling contact Billy on 091 765640….

Some of the principle finds from the excavation at Raheen Mill can be viewed on the blog here and here.

Author and Director: Billy Quinn

Here’s a summary of excavation work carried out by Billy for Moore Marine at Raheen Mill, Clonmel, Co. Tipperary last year. The work was carried out in advance of the construction for a flood defence wall on the southern side of the River Suir at the site of the former Raheen Mill, Denis Burke Park. Conditions at the time were as bad as they are currently and excavation was difficult and uncomfortable to say the least. The work was carried out under licence No. 09E504, between December 2009 and February 2010 by Moore Marine on behalf of Mott McDonald Ireland Ltd., Consulting Engineers.

Desktop analysis of historical and cartographic sources relating to the proposed development record that there was a mill located on this site since at least 1821 (Killaly’s and Leahys Map 1821 & 1831 respectively). According to the 2nd Edition OS map dated 1904 the mill was later converted into use as a smithy and continued to function as such in the possession of the Whelan family until the 1950’s. Beyond this date the building fell into ruin, the upper floors and interior were demolished and the gable walls were reduced to the height of the adjacent river bank walls. What survived above ground until recently were portions of the north, east and west walls. These enclosed a landscaped space with a section of the east wall incorporated into an entrance feature leading into Denis Burke Park.

The full scale excavation of the site followed a programme of archaeological testing that recorded deposits and structural remains associated with both the earlier mill building and the later smithy. During the test phase three trenches were machine excavated exposing an intact paved surface below a layer of modern infill. Elsewhere to the south, testing along the footpath exposed a number of modern services that truncated the mills entire southern range.

The excavation was carried out over a six week period with a team of four. The excavated area extended 13m E/W by 9.5m N/S from the northern riverside wall to the roadside kerb of the footpath. Internally the mill measured 5.6m E/W by in excess of 10m to the south. Within this area the excavation reduced the ground by approximately 1.8-2m, exposing the underlying natural silt and bedrock.During the removal of the overburden, which contained frequent amounts of heavily corroded iron debris and other modern finds, a mill stone and stone quenching trough were discovered. Both these finds define the buildings use over a period of 200 years. Also re-exposed was the stone pavement found during testing. This floor was cut N/S through the centre by a plastic duct that ran from the road to the south and emptied out into the river via a hole knocked through the northern mill wall. The installation of this service, possibly in the early 1980’s damaged much of interior, including both the wheelhouse wall and wheelpit wall to the north as well as disturbing pre-existing layers.

The stone pavement interpreted as the smithy floor, would originally have covered the southern portion of the mill building with the northern half probably used for storage. The floor slabs were set in a rough mortar bed that overlay a charcoal enriched layer. Below this surface was a thick layer of alluvial sand, probably taken from the river bank and used to raise the internal levels of the building when the mill was re-converted to be used as a forge. The mill floor was recorded 0.75m below the smithy floor and was divided into two working platforms; to the south was the millstone floor where the grain was ground and stored, this level dropped down to a rectangular chamber known as the wheel pit. The waterwheel was separated from the wheel pit by a stone wall that survived in very poor condition. The wheel house was evident by blocked up arches in the eastern and western gables. These arches allowed water to flow in from the weir via the head race to power what was probably an undershot vertically set waterwheel before discharging into the river. The waterwheel powered the trundle wheel in the wheel pit which in turn rotated a wallower that turned the grinding stones via a stone nut. Also found in the wheel pit was a sub rectangular stone feature set into a retaining wall that separated both floor levels. This feature had a gradual batter along its elevation and was interpreted as the base of a meal sieve through which the ground grain was bagged.

To the east of the mill wall excavation took the form of a stepped in trench that exposed the wall foundations at a depth of 2m below the surface level, at which stage the site began to flood. To the west a number of abutting walls were found. These walls do not appear on the 1st or 2nd edition maps and probably date to the early 20th century. As with the structural remains to the south these walls were removed during the installation of the large water main.

Following the excavation of the mill and the recording of the elevations, the mill walls were partially demolished, and were later removed under archaeological supervision to allow the development of the flood defence wall.