Monday, July 21, 2025

Solar Panels, Local Mines and an Adit in Hollywood Glen

© Eugene Brennan
I cycled up to the Glen of Imaal yesterday afternoon. My route took me via Kennycourt to Grangebeg, Lemonstown, Hollywood and then up the steep road from Donard to the glen. I usually go this way because the road is quieter, with very little traffic and then return via the busier but more downhill Knockanarrigan road.

The L8333 road from Hollywood to Donard runs parallel to the N81 and through the picturesque Hollywood Glen. It's is one of my favourite places in west Wicklow, lined on both sides by tall pine trees and rocky crags in places.  A planning application has been lodged recently to Wicklow County Council on behalf of Wicklow Renewables Ltd for a solar PV development  and battery energy storage system (BESS) facility in the area. According to the planning application, the site will cover an area of ca. 65.4 ha and consist of an array of solar panels, 192 BESS units comprising 22 modules, a 38 kV substation and other ancillary works. The location of the proposed solar development is on raised ground behind the treeline in the photo below. The boundary of the proposed development extends southwards and to the west towards the N81.

Hollywood Glen. © Eugene Brennan

Notice about planning application by Wicklow Renewables Ltd. © Eugene Brennan

Mines Local to Kilcullen

Apart from the Modubeagh and Gracefield coal mines near Wolfhill, one of the nearest mines to Kilcullen was the Deerpark Colliery near Castlecomer, which opened in 1924. Anthracite, a high carbon coal, also known as "Kilkenny Coal" and used before coke for ore smelting, was extracted from the  mine. This was  transported on a dedicated branch line that ran through Castlecomer and joined the Waterford & Maryborough branch of the GS&WR, itself a branch of the Dublin to Waterford rail line. The Deerpark colliery closed in 1969.  The region south of Ballylinan, (located 6 km south of Athy) including parts of counties Laois, Carlow and Kilkenny, is riddled with the remnants of now closed coal mines.  These mines tapped into several anthracitic formations that are part of the Leinster Coalfield. Mining has also taken place in Wicklow since ancient times and one of the most well known mining areas is around Avoca, where sulphur, lead and copper were extracted. Lead was mined at Glendalough and also in its sister valley, Glendasan.
A useful resource is the OPALS (Online Prospecting Application Licensing System) interactive webmap, from the Department of the Environment, Climate and Communications, which  provides locations and information on historical and current mineral exploration and mining in Ireland.

OPALS (Online Prospecting Application Licensing System) interactive webmap. Image courtesy and © Tailte Éireann

Hollywood Mine

Halfway between Hollywood and Donard and now overgrown with briars and lady ferns is what appears to be the entrance to an adit. The adit is partially flooded and the echo of water dripping from the roof can be heard. While a mine shaft is a vertical structure, an adit is a horizontal passage that extends sideways into a mine. This is marked on the c. 25" OSI map and is denoted as "Spa Hole" and "Iron Mine Disused". I haven't been able to find any information so far on this working, other than a geological report on the glen that indicates it's a glacial feature, deeply carved by high-energy, water run-off as ice melted. The second map below from Geological Survey Ireland shows audited sites, with links to reports accessible by clicking the link in the pop-up.

Entrance to Spa Hole adit. © Eugene Brennan

"Spa Hole" marked on 25" OSI map. Image © Tailte Éireann

Audited Geological Heritage. Image © Tailte Éireann Geological Survey Ireland