Faro supplies 3D model scans of Irish mine

Successful scanning of Tankardstown mine in Ireland to build digital 3D models

Following the work Geospatial Survey Solutions Ltd and Deri Jones & Associates Ltd (GSS/DJA) had done on recording abandoned lead mines in Mid Wales for the RCAHMW, they succeeded in bidding for a survey project in Ireland. Tankardstown mine in Bunmahon, Co. Waterford is part of the Copper Coast Geopark (www.coppercoastgeopark.com). Sited on the sea cliffs to the east of the village, the impressive engine house and chimney stack are still in relatively good repair.

Underneath the workings, there lies a veritable rabbit warren of tunnels and shafts, extending some 300m under the shaft head and 12.5km in extent, judging by the late 19th Century mines plan. The majority of the workings are now inaccessible due to flooding and cave-ins, but some 500m of the tunnels can still be entered by experienced mine explorers.

“A project of this nature requires detailed paperwork to ensure access to the site, insurance cover for the kit and people and detailed risk and equipment assessments to ensure we could handle anything the mine could put in our way” states Deri Jones, director of Deri Jones & Associates Ltd.

GSS/ DJA assembled a pretty unique team consisting of an experienced mine explorer, an ace photographer and then worked with a local group to get the kit (and them) down and back out the mine and provide safety cover. Opti-Cal Survey Equipment provided a Faro Laser Scanner

Focus3D and all of the survey work was tied together finally by a total station. The plan was to do the surface works within one full day of scanning and pano photography and then three days to complete the underground workings.

The access to the mine was achieved via an adit tunnel located some 8m above the beach, at the bottom of a steep and loose gully in the seacliff, or via a 45m shaft from the roadside. Inside the mine it was generally dry after a short thigh deep wade, but typically muddy. Another adit ran

out of the cliff face further to the west, allowing a traverse loop to locate the bottom of the shaft and resection to survey points on the cliff-top. Even at low tide, this meant carrying out total station work in knee deep seawater to be able to see the survey points at the top of the cliff.

Scanning

For the surface works, GSS/DJA carried out 26 scans, giving a good coverage of the buildings and

allowing getting close enough to counteract the effect of the fog lying on the site, essential for the colour overlay data and panoramic photography. Underground, they recorded 56 scans using the FARO Laser Scanner Focus3D, referenced to the total station traverse using spherical targets, which was tied in to the OSI grid using the RTK GPS.

Photography

Due to the nature of the project and prior experience with getting good images underground, GSS/DJA built a LED powered light rig for their camera and made use of exposure bracketing and HDR imaging to capture as much of the fantastic colour and detail as possible. Over a thousand images were taken for the panoramic aspect of the project and cooked down to create the panoramic tours of the surface works and underground.

Deliverables

“In addition to the scan data and photos, we also received a set of mine plans from the team at Copper Coast. These were modelled up in 3D and tied in to the survey data to give a true 3D representation of the site and the workings below it. Two short animated flythroughs were created by using the scanned data from the surface and the underground working.

The created panoramic tours of the site are made available online.” concluded Mr. Jones.