" This work resulted in the discovery that torbanites are much more common than had been previously supposed, while the various qualities of gas, splint and cannel coals, as well as other valuable materials known by local names such as batts," jacks,' ' gees,' rattle-jacks,' rums,' etc., were recognized, classified and their potential yields of oil determined. It was recognized from the first that great central retorting stations would be required dealing with at least 1,000 tons per day, but as a war emergency measure, at the request of the production department, small stations at the collieries, capable of dealing with 100 tons per day, were suggested. For the larger stations, of which twelve or thirteen could be established, approximate sites were considered, with reference to facilities for transport and the minimum expense in assembling sufficient material of approximately the same grade. It wAs soon made clear that each difft-rent material would require slightly different treatment.' The average production of oil from the material selected for treatment was from 33 to 35 gallons of crude distillate per ton, and from this distillate at least 10 per cent of petrol can be obtained by refining.
The Committee of the Institution of Petroleum Te•chnologists took up the research where the depart ment left off, and concentrated chiefly upon the treat ment of canneloid material and colliery waste, including " smalls," but excluding domestic and industrial coal. These latter were not considered, since it did not appear that the country was prepared to give up the uneconomic open coal fire.
The discovery of hitherto unknown supplies of retortable material continued, and the examination and preliminary testing proceeded. It was soon evident that a compromise between the recovery of a maximum quantity of oil and the utilization otherwise of the raw material would give the best commercial results. Thus it does not pay to attempt to obtain and• one product at the expense of all others. Complete extraction of oil-content leaves the solid residue too low in volatile matter to give the best results either in a gas-producer or a briquette works. The attempt to obtain a maximum yield of gas results in a useless residue and a poorer quantity of oil.
Material high in ash (such as torbanite) yields the best oil at the lowest temperature, and probably also the largest quantity of oil a ton.
The results obtained on the distillation of various descriptions of minerals quoted by the same authority, may be given as indicating, not only the possibility of securing valuable oil products, hut the great loss which is entailed in burning coal in its natural state.
The residual solid fuel in the low temperature process is generally of such a character that, though it has been deprived of the products which are given off in the form of smoke, etc., under present methods of burning, its calorific value is higher and its rate of consumption less than the original coal. That is to say, this residual fuel is far superior to gasworks' coke, and can be readily lighted and burned in an open grate.
It is clear, therefore, that we possess in this country extensive mineral deposits from which can be readily secured large supplies of fuel oil and motor virit. Coal doe' not, however, exhaust these, for there are in different parts of the country practically unlimited deposits of shales which could be made to yield, by a similar process, even larger supplies of oil, provided these were deprived of their sulphur. Many attempts have been made to discover a means of desulphurizing the2..e oils, and although it has been claimed that a satisfactory process has been found, it has not yet been carried out satisfactorily on a commercial scale.
The principal deposits of oil shale in England occur in the Kimmeridge clay of Dorsetshire. These measures pass in a north-easterly direction into Norfolk, and extend to the cast into Sussex and Kent. A consider able amount of exploratory and experimental work has been done in connection with this material, but so far with no commercial success, since the oil obtained is characterized by a high sulphur content. The nitrogen percentage is also very high.
The outcrop of the Kimmeridge shales in Norfolk provide an almost unlimited deposit of mineral. The upper series of shales form a close-grained rock, dark brown in colour, with distinct planes of fracture. The underlying shale is a greyish-blue rock. These shales differ from Boghead and Torbanites, and more closely resemble the Scotch shales. Bulk tests show a yield of 40 gallons of oil per ton of shale and 66lb. of sulphate of ammonia ; the sulphur content is 64.
The oil-shales of Jurassic age discovered in the Island of Skye and Ramsay resemble the Norfolk Kimmeridge shales very closely.
It is, therefore, from this point of view that the issue between coal and natural liquid petroleum is joined, and I see no reason why this country should not soon become an oil producer on a large scale.