The History of Well-Drilling in Edinburgh

on  Tuesday, April 12th, 1910.

Mr. J. Morison Inches in the Chair

The following paper was read:—

The History of Well-sinking in Edinburgh for the last Fifty Years.
by Robert Henderson.

The water question must always have been a vital one from the earliest ages; and the actual practice of obtaining a supply by excavations and borings, can be traced back to a very remote period in the world’s history. In the scriptures and other ancient writings, wells are frequently referred to, and the ancient Greeks specialised in rope and bucket wells, often finishing off the tops of these wells with a handsome carved marble curb. In Egypt there are wells probably dating back for 4000 years, lined with brick and wood. The Chinese from time immemorial have practised the art of boring through the earth’s crust. Until comparatively recent times, well-sinking was confined to the very simple practice of sinking a shallow shaft and tapping the first gravel bed.

The Province of the Artois in France may not inaptly be described as the home of modern well boring. Borings are extremely numerous in that province: some of them of great depth. The now common expression “artesian” is derived from Artois, where boring has been practised from ancient times.

The town of Modena in Northern Italy about the period of the beginning of modern history paid the well-sinking profession a great compliment by adopting two boring chisels as its Municipal Coat of Arms.

So far as I can ascertain the first mention of boring in Britain is in connection with the proving of the foundation of St. Paul’s Cathedral, London, by Sir Christopher Wren, its famous architect. To realize fully the extreme importance of the art of well-boring to the world’s progress, one has only to glance at the vast oil fields of America, Asia, and elsewhere; or turn their eyes to the rejuvenating effect it has had on some parts of Australia, where hitherto barren lands are becoming smiling paradises of cultivation; or to come nearer home, note the vast growth of such brewing centres as Burton-on-Trent and Edinburgh, which is directly due to the excellent quality of the brewing liquors obtained by well-sinking operations.

In such a subject as this, too, it is impossible to avoid some reference, however brief, to the geology of the district in which water-finding operations are carried on, but I will only briefly mention that the whole area of the Edinburgh brewing water lies below what is known as the lower carboniferous and the calciferous and Upper Old Bed Sandstone series of rocks. These rocks, or as we professionally call them “metals,” consist chiefly of shales, sandstones, limestones, clays, etc. These deposits are, however, much cut up, upheaved, or depressed, by the intrusion of igneous rock, in the shape of “faults,” dykes, and contortions caused by the terrestrial disturbances that took place during the formation of Arthur’s Seat, Calton Hill, Castle Rock, Braids, Pentlands, etc. The rocks found in these hills or in their immediate vicinity are called trap rocks, and consist of what is known in the geological world as basalts, whinstones, lavas, porphyritcs, etc.

Owing to the terrestrial disturbances already alluded to there exists a series of depressions or geological basins in the strata over which Edinburgh is built, and each of these basins has a supply peculiar to itself; some produce first class pale ale brewing waters; others again yield waters more suitable for heavy mild ales. The greater part of old Edinburgh is built over a basin whose water-carrying beds yield that quality of brewing water which has made the ales produced in that district of world-wide fame. Here calciferous and Upper Old Red Sandstone rocks abound, and the waters percolating through these rocks have become impregnated with beneficial mineral matters.

There is no need for me to enlarge on the chemical constituents of Edinburgh brewing waters, because you gentlemen will have a complete knowledge of that subject; but I cannot help thinking that the abbots who founded the Abbey of Holyrood, or their brewing advisers, must have had some geological knowledge of the strata underlying the “Old Town” when they first began to produce Edinburgh ales. Probably they were first attracted by the crystalline flow from the now historical well of St. Anthony on the slopes of Arthur’s Seat, and may have carried the waters from this well to the sacred precincts of the Abbey for brewing purposes, or they may have observed the fine beverage produced with water taken from shallow wells, sunk for domestic purposes in the immediate neighbourhood. Be that as it may, the abbots of Holyrood and their dependants were sound judges of the quality of a brewing water, as is evidenced by the cluster of prosperous breweries in the district at the present time.

My first acquaintance with Edinburgh wells was in the year 1863, when I commenced, under the direction of my father, what I may term my apprenticeship. At that time the water used by the Edinburgh brewers was, for the most part, drawn from strata at considerably higher levels than the present-day supply comes from. The depth of the wells at that time would range from 25 to 60 feet from the surface. Perhaps one or two reached the then great depth of 100 feet of excavated shaft, and an additional 100 feet or so of a 2¼ or 2½ inch bore-hole. These bores, yielding less or more water, were in many cases the principal supply of the brewery.

During the first half of the last century, it was the custom of the Edinburgh brewers, when their brewing supply gave out, to seek an increased supply by means of mines driven from the sides of the wells into the water-bearing strata, presumably in the hope of piercing some impermeable “dyke ” or fault standing as a barrier, to prevent water finding its way along the fissure and into the well-shaft. Consequently, there are to be found in the wells at the present time many hundreds of feet of these mines, extending in all directions—now high and dry—at about 25 to 40 feet below the surface. In some wells these mines have ramifications, forming quite a network of small, low galleries, whereby we may enter one way, and come back to the shaft again by another.

The ordinary man in the street, at that time, would no doubt have been greatly surprised if he could have penetrated with his vision the causeway and underlying strata underneath the Ganongate, Cowgate, etc., to a depth of about 50 feet, and have seen the miners burrowing, like human moles, in all directions, through small, narrow passages, sometimes too small to allow of turning, in search of the wherewithal from which to brew the sparkling beers for their thirsty throats.

The result of this lateral piercing was sometimes extremely interesting—success would sometimes crown the operations, but the new supply was often completely different from the old, but, nevertheless, a good brewing liquor.

The wells in existence previous to and in 1863 were of an exceedingly crude nature. They seem to have been sunk by men entirely ignorant of even the elementary principles of putting down a vertical shaft. Their plant was primitive, consisting principally of a windlass and rope-winding apparatus, and the shafts appear to have been sunk from the run of the rope as it uncoiled from the windlass drum, always taking the bucket, or “kettle,” as indicating the centre of the shaft. These old windlasses were of a long pattern, and the rope would sometimes travel a few feet across the diameter of the shaft as it descended, so the reason is not far to seek why some of these wells were several feet off the plumb! The mines, too, were curiously crooked in direction. The miners seem to have simply hewed away in an unreasoning manner, trusting largely to chance. That state of matters, I am pleased to say, does not now exist. During the last 40 years I have conducted the deepening of most of the principal wells from their former depth, from time to time, to their present depths, ranging from about 200 to over 250 feet of well-shaft. Almost in every case the wells had to be “stripped down” and straightened before the deepening proper could be commenced. The pumping arrangements of the period were of a very primitive kind, the pumps being driven by a shaft carried to the well-head. As often as not, the position of a well was determined by its proximity to a driving-shaft, so as to secure the motive power, and this led to some of the wells being sunk in most inconvenient corners, for subsequent sinking or boring operations. In other cases the position of the pumps themselves was determined by handiness of getting at a shaft, and a suction, pipe was led there from to the well. With the deepening of these old wells, now pumps of improved pattern were introduced, and new engines specially erected to drive them. Latterly, as fine new wells were sunk to meet the increasing demand for water, pumps of greater pumping capacity were installed and driven by gas-engines, electric motors, etc., or the compressed air system was used when the large supply had to come directly out of a small bore-hole, in a short time.

The pumping capacity of one well alone at the present time is over 55,000 gallons per hour. The amount of water pumped daily for brewing purposes from the strata underlying Edinburgh and Duddingston is approximately two and a quarter million gallons, equaling a supply of about 6 gallons per day per head for the whole population of Edinburgh. The combined pumping power of the Edinburgh and Duddingston breweries’ pumps is equal to lifting the whole of this water in 12 hours.

For raising water in large quantities from artesian wells, the compressed air system, already mentioned, is fast superseding the direct bucket method. An air compressor working at a pressure of 100 1b. per square inch can lift three to four times the quantity that a deep well pump could do in the same time in the same bore. This system has a further advantage—it is possible with it to raise a pure supply from a low level through an impure supply at a higher level. With these remarks on pumping I pass on to shortly consider the advance that has been made in recent years in well-sinking and boring methods and plant.

As the brewing industry of Edinburgh and district increased, the old wells and their supplies were found inadequate to the requirements. This increased demand, as I have said, was met by deepening existing wells and driving mines from the bottom, not by chance as formerly, but in a straight line, with the definite object in view of cutting through a known “dyke,” fault, or impermeable intrusion; or to connect up one well with another, or with an artesian bore. These modern mines are in striking contrast to the old low crooked galleries, they being driven dead straight as a rule to sizes about 5 feet by 5 feet 6 inches and 6 feet by 6 feet, with all the dangerous bits in the sides and roofs neatly buttressed and arched with brick and cement. The modern appliance for driving these mines, which has supplanted the old “hammer and jumper” method in boring blast holes is what is known as a “rock drill.” This is really a small engine with a “cross-mouth” drill attached to the protruding end of the piston rod. Compressed air is the power that works this machine, the air being conducted to the mine “face” through iron pipes led from a compressing engine at work on the well head. This air reaches the machine at about 70—80 lb. per square inch, and is admitted to the cylinder of the “rock drill” by a suitable connection.

The piston, which has a 6-inch stroke, travels out and in, with a rotatory motion, striking some five hundred blows per minute. Two men can work this engine; when mounted on the cross-bar it can easily be raised or depressed and moved about so as to command the whole working “face,” and it is not unlike a little machine gun in general appearance. With it a 2¼ inch hole can be bored in hard whinstone at the rate of 3 to 4 feet in 15 minutes, which would take two men with hammer and “jumper” as many hours. The compressed air serves the double purpose of providing the motive power for the “rock drill” and of ventilating the mine. These machines in conjunction with modern high power nitro-glycerine explosives, which have the advantage of being workable under water, have advanced mining and well-sinking by leaps and bounds. Contracts, that in times gone by would have taken years to complete, can now be brought to a successful close in a few months. Not only have sinking and mining methods improved, but artesian well-boring, too, has advanced remarkably.

The old-fashioned methods of percussion boring by which the rock was pounded into dust, by continually raising and dropping the iron rods with chisel attached, has given place to the newer method of  “core” boring. In the latter kind of boring a tool revolves and cuts out a “core” or pillar of rock which is withdrawn to the surface. There are quite a variety of methods of “core” boring, but two only need be referred to here—”core” boring by diamonds and by “patent steel.” Until lately the diamond as a cutting medium held the field, but the great drawback was the expensiveness of the diamonds and their liability to come to grief—especially in cutting Edinburgh strata.

Quite recently the “patent steel” method of core cutting has come to the front for brewery artesian well-borings. In this method what is known as “patent steel” takes the place of diamonds with great success, as by it great depths can be rapidly reached without the attendant mishaps peculiar to a core cutting “crown” set with diamonds.

The artesian wells of Edinburgh and district breweries vary in depth from 300 to 1600 feet or thereby. The latest “patent steel” artesian well-boring plant, as used by me at the present time, consists of a machine drilling a 6½ inch hole, and adapted to bore holes to a depth of 1200 feet. The engine is a portable one with double 5-inch cylinders, link motion, reversing gear and hoisting drum, with single and double gearing fitted on to iron frame. There is a tripod for withdrawing and lowering rods and drill-tube, and with it 24 feet of rods can be drawn or lowered at one time. The hollow rods, to which the patent steel drill is attached, are rotated by means of a vertical shaft, through which the “boring-bar” (which is also hollow) passes. At the top of the boring-bar is a packing gland connection for joining up bar and rods to a water supply. In the boring-bar there is a slot running the full length of the bar, corresponding to another slot cut in the vertical wheels, where the boring-bar passes through. The bar is fitted sufficiently loose to admit of it passing easily up and down through the hole in the vertical wheel. When boring is in progress a key is dropped into the slots of the bar and vertical wheel This key also is loosely fitted, and while it is tight enough to cause the bar to rotate with the vertical wheel, it is not so tightly fitted as to prevent the bar slipping through as the depth of bore increases. The boring-bar and rods, revolving on ball-bearings, are suspended from the tripod by a chain or rope attached to the drum of the engine. The core-tube is from 15 to 20 feet long, the drilling end of which is fitted with a special “crown” for boring with patent steel instead of diamonds. The drill is rotated by a belt drive from the engine, at the rate of ninety revolutions per minute, and at the same time a stream of water is continuously forced down through the hollow rods. This stream of water keeps the cutting face of drill clear of sand, the lighter particles of which are washed out of bore, while the heavier settles down in sand box, which is the top part of core-tube.

I must now refer to another important part of well-sinking operations, I mean the building and lining between the solid rock and the surface. The building was the best part of some of these old wells, many of the wells being substantially built with neatly hewed and jointed sandstone masonry; some were built with “random rubble,” others with brick. The object in building the mouth of a well is to exclude surface waters and to support the walls of the well. The two modern methods are building with brick and cement and lining with iron cylinders. The iron cylinders are resorted to when gravels or running sands have to be sunk through; although they are occasionally used instead of brick lining.

The most satisfactory way of lining a well with brick is to have a foundation for the brickwork hewed out of the solid rock, and a double wall of circle brick carried to the surface. These walls are about 2½ inches apart, and the intervening space is filled with strong cement “grout” as the building proceeds. This building, when set, proves almost indestructible, and effectually prevents undesirable surface exudations. Sometimes the brickwork is founded upon an iron ring, but the method described is, when possible, always the best.

Within comparatively recent times, a new brewing-water basin has been tapped, which has resulted in a colony of breweries springing up. Needless to say, I refer to the Duddingston supply. Mr. W. Murray may rightly claim to be the pioneer user of this water for brewing purposes, and I myself may safely claim to be the discoverer of this district, because it was as a direct result of various consultations with me that Mr. Murray decided to establish his Craigmillar Brewery in the neighbourhood of Duddingston Station. I obtained my knowledge of the excellence and quantity of this supply through having a general geological knowledge of the strata in that neighbourhood, as well as the practical experience gained in former water-finding operations conducted in and around Duddingston for different purposes.

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