Drill ground

“ But before we proceed to their detail consideration, we must answer the question how far the drill ground only suffices for the purpose of training. Generally, one can subscribe to General von Schlichting's principle—that forms and principles must be learnt in the drill book, but their application in action only in the open country. Tactical exercises on the drill ground, which have not for sole purposes to bring to expression certain formal principles, are always an evil, and mislead the troops. ”

“ Boring a well involves using a giant drill. Onshore, the drill equipment is housed within an open steel girder tower called a Derrick, which is about 50m high and mounted upon a platform set about 11m above ground. Within the derrick, a system of pulleys and a wire rope, called a Drilling Line, acts like a crane, from the hook of which is suspended the Drill String. ”

“ A drill resembling a dog's hinder leg, never looks well in a garden, and therefore the little gardener must have recourse to his line. This ought to be long enough to stretch quite across his ground, and when he wants to strike a drill, he should stretch it across from path to path, and, taking his hoe in his hand, cut or scrape a little furrow, about three or four inches deep, by the side of his line. In sowing peas and beans, the drills are generally a yard apart, and between them other crops are sometimes sown. ”

“ An old fire drill works best because the wood becomes charred and it is easier to keep a charred drill dry. In working any drill, care must be taken to keep up a steady and rapid motion with a downward pressure. The wood meal which is ground from the hearth by the drill must be allowed to collect in a little heap near which dry tinder is placed. It must be protected from strong drafts, but it may be fanned gently with the hand. As the spindle becomes warm from twirling, the wood meal becomes warm, then it begins to smoke, and at last it is fanned into a flame. ”

“ The starters were a foot long, each succeeding drill five or six inches longer than the preceding one and slightly narrower at the bit, so that it would follow in the hole. Seven or eight drills made a set, the longest four or five feet. Carefully he wrought, and watched with anxious eye as he plunged the hissing points into the water and, holding them up, saw the temper draw steel-blue and white-specked to the edge. For if a piece broke from one of the bits, no more could be done in that hole. The broken particles of steel would be ground into the rock. ”

“ In cases of extreme hardness two drills may with advantage be used intermittently upon the same hole; one of these should have its cutting edges ground at a more acute angle one to the other than is the case with the other drill, thus the cutting edge will be lessened in length while the drill will retain the strength due to [I-445] its diameter, so that a maximum of pressure may be placed upon it. When one drill has cut deep enough to bring its full length of cutting edge into action, it may be removed and the other drill employed, and so on. ”

“ It will be obvious from these considerations that the more correctly the drill is ground, the longer it will last without regrinding, the greater its amount of feed may be to take an equal depth of cut, and the nearer the diameter of the hole drilled to that of the drill—the most correct results being obtained when the drill will closely fit into the hole it has drilled and will not fall through of its own gravity, a result it is somewhat difficult to attain. ”

“ He also keeps the workmen supplied with new drills as they need them, by relaying their requests to the steelman who carries the steel to the men in the swings as it is needed. This steel is used over and over again; as it is dulled it is taken to the blacksmith shop on the ground via the cable car, heated, sharpened, re-heated and tempered and sent back to the mountain again. About 400 of these drills are dulled each day. They drill on an average about four feet before being sharpened. ”

“ No other sort of drill equals in fascination that which the embryo M.F.B. man must go through. Unlike a soldier or sailor, he must undertake many of the actual dangers of warfare during ordinary drill on the parade-ground. The instruction, conducted by superintendents who have gone through the mill themselves and know [Pg 245] every detail of the work, is divided into two parts—theoretical and practical.
The room in which most of the theory is taught is particularly interesting. It contains a half section of every apparatus or device used by or in connection with the brigade. ”

“ When fire is to be lighted by means of this implement, the lower part of the drill pin is daubed over with a little train-oil, one foot holds the light-stock firm against the ground, the bowstring is put round the drill pin, the left hand presses the pin with the drill block against the light-stock, and the bow is carried backwards and forwards, not very rapidly, but evenly, steadily, and uninterruptedly, until fire appears. ”

“ The only drill during the winter was route marching; we also had gymnastics and an occasional lecture from adjutant, sergeant-major or musketry instructor.
The spring drill of 1860 commenced, and every man must have a month's setting up. This means lots of work for the instructors; every regimental parade ground for three hours daily is covered with squads, commencing with section one, doing squad drill till they reach battalion drill, when the companies amalgamate and drill together. ”

“ In the evening the drillers, with their powerful air-drills, bore a series of five or six six-foot 'shot-holes,' four along the roof, and two on each side for the 'rib-shots.' Then a third crew of men, the 'shot-firers,' fill the deep drill-hole with long cartridges of coarse black powder, and blast down the coal, which falls broken and crumbled into the cut prepared by the machine-men. ”

“ A more efficient method of hand-drill work is, however, where one man holds the drill, and another swings the hammer or sledge. Another form of hand drill, called a churn drill, consists of a long, heavy bar of steel, which is alternately raised and dropped by the workman, thus cutting a hole by repeated impacts. ”

“ The boom of the drilling rig as it raises and drops the drill provides the necessary impact. With the core method, as its name implies, a hollow boring drill cuts its way aided by steel shot and a flow of water forced through the pipe that rotates the cutting tool.
With either method the results are the same. Sooner or later the drill will reach an underground water course of sufficient size to give an ample flow. As such drilling is done on a charge of three to five dollars a foot, the owner, of course, hopes for sooner. ”

“ The drills are light enough to be easily erected and dismantled, and compact, so that they can be used in restricted and out-of-the way places, while their simplicity entails little special training on the part of the workman. With pneumatic and other power-drills the cost of piercing holes for explosive charges is reduced to less than one-quarter of that of "jumping" with a crowbar and sledgehammers. With the hand method two men are required, usually more; one man to hold, guide, and turn the drill ”

“ The two drill carriages employed are larger than those at East End, and are intended to carry five drills each—in all, ten drills working at the breast of the heading. Assuming, as we may safely, that the rate of progress is proportional to the number of drills employed, ten drills would advance 100 feet per month; and with full power provided and further experience to be acquired by the workmen, this and even greater average rates of monthly progress can be made and maintained. ”

“ The large charges in deep holes break the walls very irregularly; misfires cause more delay; timbering is more difficult in the face of heavy blasting charges; and the larger amount of spoil broken at one time delays renewed drilling, and altogether the advantages seem to lie with hand-drilling in shafts of large horizontal section.
The rapid development of special drills for particular conditions has eliminated the advantage of hand-work in many situations during the past ten years, and the invention of the hammer type of drill bids fair to render hand-drilling a thing of the past. ”

“ The deeper holes are made only in surface excavation of rock, the shallower, to a maximum depth of say 12 ft., being suitable for tunnelling and mining operations.
Hand Drilling.—The work is either “single-hand” or “double-hand.” In single-hand drilling, the miner wields the hammer with one hand, and with the other holds the drill or “bit,” rotating it slightly after every blow in order to keep the hole round and prevent the drill from sticking fast; in double-hand work, one man strikes, while the other holds and rotates the drill. ”

“ He operated on a piece of hard diorite an inch and three-eighths in thickness, and employed as a drilling agent a wooden wand of ash, or at times, of pine, in conjunction with sharp quartz sand. Attached to the wand was a heavy disc, to act as a fly-wheel, and an alternating rotatory motion was obtained by means of a bow and cord attached at its centre to the apex of the drilling-stock, and giving motion to it after the manner of a "pump-drill," such as is used by the Dacotahs [100] and Iroquois [101] for producing fire by friction, or what is sometimes called the Chinese drill. ”

“ The weight and consequent mobility of a drill, aside from labor questions, have a marked effect on costs, for the lighter the drill the less difficulty and delay in erection, and consequent less loss of time and less tendency to drill holes from one radius, regardless of pointing to take best advantage of breaking planes. Moreover, smaller diameter and shorter holes consume less explosives per foot advanced or per ton broken. ”

“ This isn't a kid's job; it's a man's job down in these mines."
"I am simply pointing it out to you, sir. At the same time I want to ask your permission either to abandon the drift until it can be shored [pg 35] up, or to back-stope until we can get through to solid rock."
"Go on with your drifting. We can't stop for a little thing like that, I tell you," answered the mine captain, turning and starting away.
"Pull out your drills," commanded Rush.
The drill-men began to obey his command. ”

“ For the purpose of illustration, we will take the case of a hole bored vertically downwards, and will suppose the boring to be carried on by double-hand.
Boring the Shot-holes. —The surface of the rock having been prepared to receive the drill, one man sits down, and placing the shortest drill between his knees, holds it vertically, with both hands. The other man, who stands opposite, if possible, then strikes the drill upon the head with the sledge, lightly at first, but more heavily when the tool has fairly entered the rock. ”

“ There's a yard at the back of the building nigh on to a hundred feet square, which is put up in such shape that water can be used the same as you would at a fire, and here drills go on like this, for instance: An alarm is sent out for a certain company when they least expect it, and the men find themselves called into headquarters to show what they can do. All that you're going to see, lad, and talking about getting points, why, you can learn more there in one exhibition drill than you could at forty fires, 'cause you're understanding just how the thing is going to be done. ”

“ The usual duty of a heavy drill per eight-hour shift using two men is from 20 to 40 feet of hole, depending upon the rock, facilities for setting up, etc., etc. [*] The lighter drills have a less average duty, averaging from 15 to 25 feet per shift. ”

“ An iron pipe eight or ten inches in diameter is driven down through the soil until it comes to rock. Now the regular drilling begins. At the top of the derrick is a pulley. Over the pulley passes a stout rope to which the heavy drilling tools—the "string of tools," as they are called—are fastened. The drilling goes on day and night. The drill makes the hole, and the sand pump sucks out the water and loose bits of stone. When the drill has gone to the bottom of the strata which carry water, the sides of the bore are cased to keep the water out ”

“ When his first hole was bored, and his little drill raced wildly through into space, like the screw of a liner on the crest of a wave, he started a second, close beside the first; then a third, and a fourth, and a fifth, slowly honeycombing the thick steel with his minute excavations. Sometimes a drill would snap off short, and he would have to draw a fresh one from his stock. ”

“ I had the good fortune to witness one of these reviews, and the spectacle dwells vividly, still, in my imagination. Drill of the soldiers, singly, and in squads, is the chief labor of the garrison. Skilful drill-sergeants, for the most part young, active, intelligent men, having the port and bearing of gentlemen, are constantly at work, morning and afternoon, breaking in the raw material as it arrives, and rendering it fit to be moulded into the common mass. Company officers move their companies, to and fro, unceasingly, lest the men should forget what the drill-sergeant has taught them. ”

“ By remembering the immense and concentrated weight of the upright drill and stem, the tremendous force of even a short fall may be conceived. The drill will bore many feet in a single day through solid rock, and a few hours sometimes suffices to force it fifty feet through dirt or gravel. When the debris accumulates too thickly around the drill, the latter is drawn up rapidly. ”