Gretna, Hm Factory, Eastriggs Explosives Factory, Acids Section, Mannheim Oleum Plant

Canmore ID 374119

Site Number NY26SW 38.2

NGR NY 24720 64947

What remains of the Mannheim Oleum Plant building is situated within a fenced enclosure in deciduous scrub woodland about 80m ESE of the Grillo Oleum Plant (NY26SW 38.1) and 9m NNE of the road that passes to the SSW. It is rectangular on plan and measures 91m from ESE to WNW by 56m transversely, but is now reduced to little more than a concrete floor and square concrete footings that supported the steel stanchions for the building’s frame. The building plan comprised broad twin central bays, each measuring c.19m wide with side-aisles each measuring c.9.5m wide. The whole structure was symmetrically divided by a row of sixteen concrete footings running down the length of the building. The on-site remains also demonstrate that a broad central entrance was located at the ESE end of the building, but evidence for similar at the opposite end has been destroyed by a later Narrow-Gauge Railway (NY26NW 46.27). The interior of the main building contains sixteen rectangular stone- and brick-lined furnace pits, each measuring 10.5m from NNE to SSW by 5m transversely and 1.65m in depth. These are laid out in two rows either side of the building’s central axis and are evenly divided into four groups by another aisle crossing the centre at right angles. These pits represent eight furnace double units. Some pits are recently? infilled with brick and concrete debris derived from the demolition of the last surviving Drying Houses (NY26NE 14.6). The remainder are open and frequently flood. All are interlinked by a network of tunnels running under the concrete floor, which were provided for the small hand-pushed trolleys that ran throughout the basement collecting ashes and clinker from the furnaces suspended over the pits. It is not completely certain where these trolleys emerged, but it seems likely that they were lifted from rectangular openings that are situated immediately outside the four corners of the main building. Three solid raised brick and concrete platforms, situated between the four most westerly pits on the N side of the building, supported the three coolers linking the double units of the two Herreschoff furnaces which burnt pyrites ‘fines’. These platforms were accessed from the central aisle by twin flights of steps situated at their WNW and ESE corners respectively, although the most westerly pair are now missing. The other twelve pits are all that remain of six double unit lump burner furnaces which were fuelled with ‘lump pyrites’. These furnaces were connected to associated tanks, gas coolers and absorption towers that were located on the far sides of the pits . The only remaining trace of this part of the plant seems to be an isolated rectangular plinth situated SSW of the more westerly pits in the southern row, which may possibly have supported a settling tank. The side aisles are heavily overgrown, but that running along the NNE side of the building includes sixteen paired semi-circular plinths sitting alongside a vegetation-filled gutter. These once supported Acid Reservoirs. By contrast, only six pairs were noted in the SSW aisle, located at its ESE end.

The building is identified as a Mannheim Oleum Plant in the description of the works (MMW 1919, plan, 51-60; see also MMW et al 1921, 2-45) given in a Ministry of Munition Works report (MMW 1919, plan) held in the National Archives, Kew, outlining the processes involved in the manufacture of the cordite propellant during the First World War at H.M. Factory, Gretna (Site 3, Eastriggs)). The report confirms that it was a steel framed building comprising four spans. A photographic panorama and a diagram (S.No.250) in the report, together with descriptions of blueprints (SUPP 10-16 Index; SUPP 10-17 3171; SUPP 10-18 3394-5; Supp 10-19, 3656; SUPP 10-21, 3901A; SUPP 10-23, 10603, 10692), blueprints (SUPP 10-24, 3170-1, 3175; SUPP 10-25 3290-1; SUPP 10-26, 3505; SUPP 10-27 3656) and ground-based contemporary official photographs taken during and after construction (MUN 5-297 pt1 143, 171-2, 184-5, 204, 242, 250-1; MUN 5-297 pt2 278-9, 305-6; MUN 5-297 pt3 349-51, 369, 390, 426-7, 437-9, 472; MUN 5-297 pt 5 710F) held by the National Archives at Kew, provide additional information. These sources indicate that the building was a brick-panelled and corrugated-iron sheet clad structure, with weatherboarded gables. The central bays measured 10.5m in height, while the side aisles measured only 4m in height. The wood-framed, rubberoid covered ridged roofs were capped by chimney pipes and ventilators running almost the full length of the building, while the interior was lit by natural light. Ten broad, steel-framed windows were situated in an upper row at both gable ends of the central section of the building, with the six in a row below allowing space for a pair of broad, sliding doors at their centre. The side aisles had two similar windows at both gable ends. The NNE and SSW elevations had a continuous strip of windows with corrugated iron sheet cladding below at clerestorey level above the side aisle roofs. The same side aisle elevations were brick panelled with small rectangular windows spaced at regular intervals below their eaves, and a double door located at their centre.

The building was offered for sale by auction as part of lot 506 on 22-5 July 1924 (HM Treasury 1924, 100 ,item 4); Carlisle City Archives DX 170/38) and it was purchased by Messrs. J. Jackson & Co. Ltd of St Vincent Street, Glasgow (Carlisle City Archives DX 2040/3). After its removal only the foundations were left in place and these are readily visible on an aerial photograph (M124/13 04127) flown on 19 August 1940.

Visited by HES Heritage Recording (MMD and ATW), 4 April 2022