On Saturday 26th May, our Quarry & Asphalt Division hosted a visit by the Belfast Geologists' Society to our Croaghan and Carmean quarries.
The visit was facilitated through the good offices of Laverne Bell, Bio/Geodiversity Officer for QPANI. Angus Kennedy, our Deputy Quality Manager, and Gavin Ramsey, our Environmental Officer, were the Northstone guides for the day.
The visit kicked-off at Croaghan in, of all places, the new Head Office car park, where a 1946 Broadbent double-toggle jaw crusher, resplendent in the old red and grey Maxwell colours, was viewed close-up. Its design and operating principles are exactly the same as the first ever mechanical crusher patented by Eli Whitney Blake of New Haven, Connecticut, in 1858. After viewing the whole quarry from a good vantage point, the group visited the asphalt plant. Its operation, including how asphalt plannings are recycled, was explained. The Croaghan visit was rounded-off with a look at a volcanic pyroclastic deposit exposed in the side of a lagoon recently cut through the floor of the quarry.
The excursionists then travelled, through heavy rain and hail, to our Carmean Limeworks, where, through a surprisingly sunny afternoon, the exceptional "textbook" geology exposed in the quarry workings was examined. Numbers were boosted by the arrival of additional members for this part of the tour. The party was able to view the large Carmean fault which cuts through sandstone, chalk and basalt. Of special interest to our visiting rock hounds was the possibility of finding fossils – ammonites, echinoids (sea urchins), belemnites, bivalves, brachiopods and sponges. The afternoon closed with a look at the junction between the chalk and the basalt, where there is a layer of shattered and jasperised (reddened) flints in a white crumbly matrix. This may represent another pyroclastic deposit from the very start of the outpouring of the lavas that covered the chalk.
At the close of the visit, Mr Philip Doughty, representing the Society, gave a vote of thanks to our two guides, noting that their visit had been like no other visit that they had ever been on. This was the first time that they had seen the actual workings of a quarry, and they had been particularly impressed with the new asphalt plant at Croaghan and the how well the quarry was laid out.
