Report on the Geology & Gold Fields of Otago
Oil Shale
Oil Shale
Orepuki.
This mineral was forwarded from Orepuki through Mr. Daniel. It was reported on in December, 1873, as follows:—Laminated, very fissile, greyish black, shale flexible in thin layers, densely speckled with mica scales, cuts easily with the knife with unctuous, waxy, section; inflames readily over ignited lucifer match, and maintains after removal of the match a long somewhat smoky flame; the shale shows no trace of woody tissue.
Water | 25 per cent. |
Earthy residue and charcoal | 49.5 per cent. |
Crude oil | 16.8 per cent. |
Dunedin.
This shale was forwarded by Dr. Burns from Burnside, near Blueskin. It is of the same mineral nature as the Orepuki shale, described above. It yields per ton of shale 38 gallons of crude oil. This, when purified by redistillation, after treatment with sulphuric acid and caustic soda in succession, yields per ton of shale about 14 gallons of oil, fit for burning in lamps, and 9 gallons of heavy unctuous oil suitable for lubricating purposes.
If we could produce our own sulphuric acid and soda cheaply, it might be profitable to extract burning and lubricating oils from these shales. As it is, the price of imported acids and alkalis is such as to deter the proprietors of these shales from importing the retorts and other appliances necessary for this purpose.