Twelve Apostles was one of the smaller mines in the north-western area of Minera. According to the Brunton Symons Map of 1865, Apostles Shaft is located at SJ 2533 5261, and the sett encompasses the stonework remains of a rectangular building at SJ 2522 5265 along with the adjacent shafts. Two large shafts are situated to the north of the rectangular building at SJ 2512 5267 and SJ 2528 5264. The 19th-century returns suggest the mine worked around two large shafts that can be identified at SJ 2509 5253 and SJ 2513 5249, which are shown on the 1871 1st edition OS map. The leat running from Steddfod Pool contours the perimeter of the sett.

Smith (1921) suggests that the shafts in the area lie on north-west strings off the Main Vein, including the Union, Crych, Sand, Llewellyn, and an extension of the Ragman Vein, based on information from an 1865 map by mining engineer Brenton Symons. The direction of these veins is difficult to trace, particularly to the south of the mine buildings, where the earliest workings on the sett are located.

The early workings form an intense area of open-cuts, shallow trials, and spoil tips. Several horseshoe-shaped earthworks, resembling the remains of ore-bins, are visible. These workings certainly pre-date the 19th-century Twelve Apostles mineshafts.

Several shafts, along with small trials, are found on the sett. An 1863 plan by Isaac Shone shows the cottages and land bounded on the north-eastern side by the leat , roughly north of boundary bank, marking the Twelve Apostles Mine sett. The area to the east is shown as Central Minera Mine. Brenton Symons records the Ragman sett working to the west of Twelve Apostles; the shafts beyond the western boundary bank, presumably belong to the Ragman sett. Mining returns for lead and silver were submitted from 1872-1882 for Minera Consols, and it is suggested that the company worked in conjunction with Twelve Apostles during 1883-4, employing two underground and four surface workers in 1883 and only four underground in 1884.

The Twelve Apostles Whim Shaft is fenced off, and the earthwork remains of the horse whim circle, approximately 11.5m in diameter, lie to the south-west. The shaft is recorded as “Apostles Shaft,” the main shaft for Twelve Apostles, sunk to 30 fathoms. It is recorded as a whim shaft on an undated mine plan for Minera Union sett and appears as one of only two shafts on the sett in the 1st edition OS map of 1872.

Two large shafts and spoil tips lie to the north of the main mine buildings. The ladder pit, providing access for miners, is recorded on the undated mine plans.

West of these shafts is a stone-lined shaft located alongside path. Two substantial shafts are located at the eastern end of the sett.

North of the survey area, two shafts named Eddy’s Shaft and Western Shaft are recorded on the undated mine plans and were presumably worked by Eisteddfod Mine on the Crych Vein.