These 2 volumes published for The South African Tunnelling Conference 1970. See photos of title page for various organisations and people involved. The books measure approx. 30 by 22 cm. Vol 1 has 246 pages and Vol 2 has 104 pages. Maroon cloth boards with gilt lettering on the front and spine. The pages are glossy, illustrated with numerous graphs and with small black and white photos. No dust jackets. The boards have some staining and wear at the edges but otherwise in good order. There is some staining on the pastedowns and endpapers and a small tear across one of the pastedowns of a bit of the paper stuck down, but internally the pages are clean and the binding in good order. There is also a label half torn out which was stuck on the front paste down.