12. The Granite Industry.
Aberdeen has long been known as “The Granite City.” It is built of granite, chiefly from its great quarries at Rubislaw. The granite is a light grey, somewhat different in texture and grain from another grey granite much in vogue, that of Kemnay on Donside. There are many quarries in the county, and each has its distinctive colouring. The Peterhead stone is red; Corrennie is also red but of a lighter hue. The granite industry has made great strides of recent years. The modern appliances for boring the rock by steam drills, the use of dynamite and other explosives for blasting, as well as the devices for hoisting and conveying stones from the well of the quarry to the upper levels by means of Blondins have all revolutionised the art of quarrying.
Granite Quarry, Kemnay
Granite Quarry, Kemnay
It was long before Aberdeen people realised the value of the local rocks for building purposes. The stone used in the early ecclesiastical buildings was sandstone, which was imported by sea from Morayshire and the Firth of Forth. The beginnings of St Machar Cathedral and the old church of St Nicholas as well as the church of Greyfriars, built early in the sixteenth century and recentlydemolished, were all of sandstone. Not till the seventeenth century was granite utilised. At first the surface stoneswere taken, then quarrying began about 1604, but little was done till 1725. Between 1780 and 1790 as many as 600 men were employed in the Aberdeen quarries. Great engineering works such as the Bell Rock Lighthouse, the Thames Embankment, the foundations of Waterloo Bridge, the Forth Bridge and London Bridge, where great durability and solidity are necessary, were made possible by the use of huge blocks from Aberdeenshire. The polishing of the stone made a beginning in 1820, and now a great export trade in polished work for staircases, house fronts, façades, fountains and other ornamental purposes is carried on between the county and America as well as the British Colonies.
Apart from building purposes, granite slabs are largely used for headstones in graveyards. This monumental department employs a great number of skilled workmen. There are over 80 granite-polishing yards in Aberdeen. Here too the modern methods of cutting and polishing the stones by machinery and pneumatic tools have greatly reduced the manual labour as well as improved the character of the work. Unfortunately the export trade in these monumental stones has somewhat declined owing to prohibitive tariffs. In 1896 America took £55,452 worth of finished stones; in 1909 the value had fallen to £38,000. The tariffs in France have also been against the trade, but an average of nearly 10,000 tons is sent to continental countries. Strangely enough, granite in the raw state is itself imported to Aberdeen. Swedish, Norwegian and German granites are brought to Aberdeen, to
Granite Works, Aberdeen
Granite Works, Aberdeen
be shaped and polished. These have a grain and colouring absolutely different from what is characteristic of the native stone, and the taste for novelty and variety has prompted their importation. In 1909 as much as 27,308 tons were imported in this way. Celtic and Runic crosses, recumbent tombs, and statuary are common as exports.
The stone is also used for the humbler purpose of street paving and is shipped to London and other ports in blocks of regular and recognised sizes. These are called “setts,” and of them 30,000 tons are annually transmitted to the south. Stones of a larger size are also exported for use as pavement kerbs.
The presence of quarries is not so detrimental to the atmosphere and the landscape as coal mines, and yet the heaps ofdébris, of waste and useless stone piled up in great sloping ridges near the granite quarries, are undoubtedly an eyesore. To-day a means has been found whereby this blot on the landscape is partially removed. The wastedébrisis now crushed by special machinery into granite meal and gravel, and used as a surface dressing for walks and garden paths—a purpose it serves admirably, being both cleanly and easily dried. Not only so but great quantities of the waste are ground to fine powder, and after being mixed with cement and treated to great pressure become adamant blocks for pavements. These adamant blocks have now superseded the ordinary concrete pavement just as it superseded the use of solid granite blocks and Caithness flags. This ingenious utilisation of the waste has solved the problem which was beginning to face many of the larger quarries, namely, how they coulddispose of their waste without burying valuable agricultural land under its mass.
Granite is the only mineral worthy of mention found in the county. Limestone exists in considerable quantities here and there, but as a rule it is too far from the railway routes to be profitably worked. It is, however, burned locally and applied to arable land as a manure. In the upper reaches of Strathdon, lime-kilns are numerous. By means of peat from the adjoining mosses the limestone was regularly burned half a century ago. To-day the practice is dwindling. A unique mineral deposit called Kieselguhr is found in considerable quantity in the peat-mosses of Dinnet, on Deeside. It is really the fossil remains of diatoms, and consists almost entirely of silica with a trace of lime and iron. When dried it is used as a polishing powder for steel, silver and other metals; but its chief use is in the manufacture of dynamite, of which it is the absorbent basis. It absorbs from three to four times its own weight of nitro-glycerine, which is the active property in dynamite. As found in the moss it is a layer two feet thick of cheesy light coloured matter, which is cut out into oblong pieces like peats. When these are dried, they become lighter in colour and ash-like in character. The Dinnet deposits are the only deposits of the kind in the country. Inferior beds are found in Skye. The industry employs 50 hands during the summer months, and has been in operation for 28 years. The beds show no sign of exhaustion as yet, and the demand for the substance is on the increase.