Ngā Tohuwhenua Mai Te Rangi: A New Zealand Archeology in Aerial Photographs
Coal was essential to a wide range of secondary industrial processing and domestic usage in the New Zealand domestic and export economy. The earliest coalmining was small in scale. Easily accessible surface deposits in places such as the Whanganui Inlet in Northwest Nelson were worked by hand, and the product taken out by scow to the major cities. Scows in ballast were taken into the harbour on high tide and anchored on tidal flats near the coal source. The ballast was thrown out, the coal loaded over the flats at low tide, and the scow would depart on the next tide. Ballast heaps on the mud flats can still be seen but do not show clearly on the available vertical aerial photographs.
In other areas, such as Brunner on the Grey River, the coal deposits were large and the earliest works were soon destroyed by larger-scale mine development and other works integrated with the coalmining. At Brunner, the works incorporated brick-making and coke production. Later nineteenth-century developments were substantial and dominate the landscape record. 1 Open-cast mining was rare, most mines being underground. Where the coal seams lay close to the surface, the galleries into which the coal seam was worked may have collapsed. The pock-marks of such collapsed areas can still be seen on aerial photographs at Hikurangi, north of Whangarei, or on the Denniston Plateau, north of Greymouth, illustrated here.
Railways or aerial cables with suspended buckets to remove the bulk commodity were common and had considerable landscape impact. Denniston is notable for its 'self-acting incline'—a rail system designed for country too steep for conventional traction engines. The coal was transported down the incline by gravity while the empty coal wagons were pulled back up the incline by a system of cables running through brake drums. The incline had a grade of 15° (one in four). The system at Denniston operated from 1880, while the earliest mining on the plateau had commenced in the 1860s. 2 The field is no longer worked.