IRELAND AND PORTLAND CEMENT.
In the last Journal published by the Department of Agriculture and Technical Instruction in Ireland (Note 1), there is an excellent series of articles by Mr. Charles Spackman, dealing with the manufacture of Portland cement. Portions of this series are devoted to the position which Ireland holds with regard to this material. It appears that Ireland is especially favoured in the possession of cement-making ingredients. They are widely distributed, and in many cases close to good markets, and to means of transit by rail or water. One of the best positions is said to be near Cork, where the materials are the lower carboniferous limestone and shale. Similar substances occur in the neighbourhood of the Kilkenny coalfield. The limestone is fairly pure, the carbonate of lime reaching from 97 to 98 per cent. The upper carboniferous and the calp limestones and shales occur in abundance in the neighbourhood of Dublin; and to use Mr. Spackman's words : "Dublin could not only be independent of any outside source of supply, but might also ship Portland cement to other ports, and deliver by rail over a large district" (Note 2). Again, in the neighbourhood of Dundalk suitable materials also occur. To the north of the town there are beds of carboniferous limestone. In some places nearby there are beds of black calcareous shale at present thrown away, but they do not appear to occur in sufficient quantity to render their site independent—as far as cement making goes—of an outside source of clay. Silurian beds and also alluvial clay of good quality are found nearby. Surrounding Armagh are extensive beds of lower carboniferous limestone. The stone is practically pure limestone, and there is no shale, so that suitable clay or shale would have to be obtained elsewhere. Near Benburb, the lower, the middle —or calp—and the upper divisions of the carboniferous limestone occur. The calp division consists largely of shale or of impure or clayey limestones, which are well adapted for use in cement making. Here there are all the necessary materials on the spot, but they are not sufficiently near a railway. A market could, however, be probably reached by the Ulster Canal, which is close by. Near Dungannon and Stewartstown there are beds of carboniferous limestone with calcareous shales in many places, while at Coal Island are the shales from the coal measures (Note 3). Carboniferous limestone and clay occur at Cookstown (Note 4). North of Belfast materials of a different character, but equally suitable, are found. There is chalk, and though suitable clay is not abundant, the lower lias beds, consisting almost entirely of shale, occur in places between Carrickfergus and Larne (Note 5), north of Larne, and on the western coast of Island Magee. This shale, which is in every way suitable, occurs in close proximity to the chalk. Having regard to the fact that there is all this suitable material ready at hand it might be wondered why Ireland is not more forward in cement manufacture. The reason is, of course, largely that fuel is expensive. It is urged by Mr. Spackman, however, that though Ireland has not the advantage of cheap fuel, other conditions may compensate for this, and he adds: "The difficulty so often raised is not really insurmountable." First of all Ireland might start where others have left off and obtain the full benefit of past experience. Engines and boilers of the most economical type might be laid down; and the mills might be designed so that the least possible loss would obtain. Since in dealing with Irish materials the dry process must be employed, the use of open kilns is deprecated, since it would result in considerable waste of fuel, no profitable use of the waste gases being possible. Shaft kilns are recommended (Note 6). In these the process of burning is continuous, the clinker being withdrawn at the bottom, while coke and raw material are fed in at the top. In them it is stated that 4 cwt. of good clean coke are required to burn one ton of clinker (Note 7). Attention is drawn to the fact that the bulk of the cement imported into Ireland goes from the London district, where coal has to be taken either from the North of England or from South Wales. It is urged that with modern, well maintained plants, cement manufactories on the north, east, and south coasts of Ireland would be at little disadvantage as regards cost of coal per ton cement produced when compared with the works in the London district. Could a cement industry be started on a firm basis in Ireland, there is no doubt that that country would benefit. It not only possesses abundance of suitable materials conveniently placed, but materials of such a nature as to admit of manufacture by some of the most economical methods as regards consumption. Ireland uses a great deal of cement. Belfast alone requires some 80,000 tons per annum. One of the brands best liked in Ireland comes from the Isle of Wight (Note 8), where all fuel has to be imported. If the Isle of Wight can import fuel and yet profitably ship its product to Ireland, why cannot Ireland make its own cement cheaper than this sea-borne material? Many suggestions are thrown out as to the choice of sites. For instance, a factory on Belfast Lough could be situated on the chalk. Coal and clay could be brought by vessel. Such a factory would not be in very different state to some of the works on the Thames (Note 9). It is not anticipated that a large export trade could be carried on, but a plant placed at a port—or on Belfast Lough—might conduct a coasting trade with other Irish ports, or even with Scotland. The home manufacture of cement, which could be sold at a reasonable price, would, it is pointed out, result in an increased demand for cement, and also for crushed stone for concrete construction. Of stone suitable for this purpose the country possesses an abundant supply. Mr. Spackman, and the Department of Agriculture and Technical Education, merit the thanks of all Irishmen for bringing this subject so prominently forward, and we can only hope that their efforts will meet with the success they deserve.