The Garreg Vein was worked within the woodland of Coed y Garreg and the surrounding farmland to the east. Shafts are located both north and south of the road from the Maes Achwyfan Crossroads to Whitford. In the woodland south of the road, shafts can be found at SJ 1340 7870 and SJ 1335 7863, while to the north, another lies at SJ 1338 7875. Further north, near Garreg Farm, two additional shafts are situated at SJ 1370 7820 and SJ 1400 7780.

In the 1720s, the Quaker Company was raising ore from the Garreg site using a whimsey. Although the ore was of good quality, mining operations were limited to the summer months due to persistent flooding. The company referred to the site as Windmillfield,. A Newcomen Engine shaft was introduced in the 1730s, but historical accounts indicate it remained flooded during winter (Bevan-Evans).