

.MINKS. MILITARY. 



MINES, MILITARY. 



within thr town, the assailants were enabled to enter the Utt.-r by 

 surprise. The other kind was executed in a similar manner, and was 

 intended to lay the rampart of the place in ruin*; for this purpose, the 

 gallery, having been driven at far as the walls, was carried on to the 

 right am! left under the Utter, which were supported by props of 

 timber till the time appointed for the assault was come ; then, the 

 prop* being drawn away or consumed by fire, a portion of the rampart 

 fell into the ditch ; and the troops, who were kept in readiness, passed 

 over the ruins into the town. Mines of this kind are described in a 

 relation of the siege of the castle of Boves near Amiens, at which siege 

 Philip Augustus attended in person. At the siege of Melun, which 

 was carried on by Henry V., king of England, and the Duke of 

 Burgundy, in the year 1420, the besiegers having driven their mine 

 almost up to the walls, and the besieged having executed a mine in 

 opposition, a barrier was erected where the two galleries met, and there 

 the king and duke fought with lances against two Dauphinois. 



As the parties engaged two abreast, it is evident that the galleries 

 must have been a considerable breadth. The old French writers occa- 

 sionally applied the term mines to what were also then, and are now, 

 called trenches. Thus, at the siege of Harfleur, in 1449, mention u 

 made of broad and deep trenches by which the approach to the wall is 

 smid to have been rendered secure; and the same works are immediately 

 afterwards called mines. 



Gunpowder was, in 1487, used in military mining by the Genoese 

 at the siege of Serezanella, a town belonging to the Florentines ; but 

 on this occasion without success. It is stated, however, in the life of 

 Gonsalvo de Cordova, that Peter of Navarre, a Spanish engineer, formed 

 mines with gunpowder at the siege of Cephalonia, near the end of the 

 15th century, when the Venetians and Spaniards took the island from 

 the Turks. And in 1503 the same engineer, or, according to Vallicre, 

 an Italian called Francis George, succeeded in taking by such a mine 

 the Cattle del' Ovo at Naples. This fortress was situated on a rock 

 nearly surrounded by the sea, and had during three years resisted the 

 united arms of the Spaniards and Neapolitans. From that time the prac- 

 tice of forming mines with gunpowder was almost constantly followed in 

 the attack, and after a short time gradually in the defence of fortresses. 

 So powerful was the effect of mines in the attack, that it was not an 

 unusual occurrence for the besiegers after forming their mine to 

 invite the besieged to see it, in order to bring about a surrender with- 

 out further bloodshed. The besieged from very early times had a 

 gallery placed a short way in advance of the foot of the wall, termed 

 an envelope gallery, to warn them of the operations of the besiegers. 

 From this gallery branches were run out, and used to what was termed 

 " give the camoufet to the enemy's miners ; " that is, a small charge was 

 exploded, which, though insufficient to produce any surface effect, 

 destroyed the besieger's gallery and suffocated his miners. From this 

 to the adoption of ordinary mines was a small step. By means of 

 1173 mines, great and small, the Venetians defended Candia during 

 mure than two years (1666 to 1669) against the whole power of the 

 Turks. By mines also, in 1762, the town of Schweidnitz was defended 

 during 63 days by the Austrian* against the Prussians. In the course 

 of this last siege two of the mines fired by the besiegers had charges of 

 powder amounting to 5000 Iba. each ; and the depth of the charge 

 below the surface of the ground was from 18 to 20 feet. 



In the siege of any place the mining operations of the besiegers are 

 directed to the discovery and destruction of the galleries of counter- 

 mines ; to the blowing up of any advanced works belonging to the 

 garrison ; to the demolition of the wall of the counterscarp, in order 

 that the descent into the ditches may be facilitated ; and, occasionally, 

 to the formation of breaches in the principal ramparts. On the other 

 hand, the countermines are employed by the defenders to destroy the 

 trenches and batteries of the besiegers beyond the foot of and upon 

 the glacis, the galleries made by the besiegers, and also the lodgments 

 which may be made on the breaches or within the works. It is easy 

 to perceive, therefore, that a system of countermines must add greatly 

 to the strength of a place, by obliging the besieger to proceed with 

 circumspection in bis approaches above ground, in order to avoid the 

 risk of being blown up at every step; and, according to Bousmard 

 ( Kami general de Fortification '), if the glacis of a fortress be counter- 

 mined, the duration of the siege, which otherwise would have extended 

 to onn month only, may be prolonged to six weeks. 



By means of mines in the attack of a fortress, the besieger has a sure 

 and certain method of gradually, it may be slowly or it may be rapidly, 

 according to the ground, appliances, and activity of the enemy, but 

 till a certain and irresistible means of reaching and destroying the 

 defences of the besieged. And this with the lost of comparatively few 

 men. The successful explosion of a mine by the enemy may destroy 

 a few miners, while an assault costs hundreds or thousands of men. 

 But yet almost every exploded mine is stop in advance for the 

 besieger. Being superior in the field he seizes the crater formed by 

 the explosion, incorporates it in his works, and pushes on from it by 

 frseh galleries, The galleries of both besieger and besieged have been 

 destroyed in the neighbourhood of the crater by the explosion of the 

 mine, whether these were exploded by besieger or besieged. The 

 besieged then pushing on again from his nearest undertroyed gallery, 

 meet* the besieger half way, unices, ss occasionally happens by skill 

 he circumvent- bin., but this half way has been a clear loss to the 

 lueleged and gain to the besieger. Hence no system of countermines 



can render a work impregnable ; but as a means of delaying the fall of 

 a work, in fact of restoring as far as science can the equilibrium of 

 attack and defence, it exceeds all the other means at the disposal of the 

 besieged: it to a great extent renders the possession of sn: 

 numbers, position and material, on the part of the besieger, iiu^ 

 The onward and irresistible advance of the besieger, rapid above ground, 

 from the nature of the work is, though certain, slow in these under- 

 ground operations. And he cannot neglect them. If the besieged have 

 countermines the besieger cannot refuse to meet him with the same 

 weapons. As the French engineers Gumpertz and Le Brun say, with 

 respect to this, " The loss of a great number of men, and the dis- 

 couragement of the' whole besieging force/perhaps even their defection, 

 would inevitably follow such a resolution. When, therefore, the front 

 of attack is countermined, the besieger must call the miners of his 

 army to his aid." 



The great difference between civil and military mining is this. In 

 civil milling the operations generally carried on at a great depth are in 

 solid rock, whereas in military mining they are near the surface in 

 soft ground, which requires supporting to prevent its falling in and 

 crushing or stifling the miner. The principal portion of the art of 

 the military miner consists thus in the management of these supports 

 or linings. In permanent systems of countermines, that is, in 

 fortresses furnished with defensive mines as a portion of their defence, 

 the galleries, being made to last for years, are lined with masonry. 

 Many different systems or plans for the arrangement of countermines 

 have been suggested by the different engineers who have written on 

 the subject. These, though varying much in many details having the 

 same object in view, ore to a great extent similar. They are disposed 

 over the exposed portions of the front of fortification, and where an 

 enemy would be likely to form his trenches, lodgments, and breaching 

 batteries, that is, round the ravelins under the glacis, and in front of 

 the bastions in the main ditch and also in the rampart The object to 

 be kept in view is to expose as little as possible of the galleries to the 

 destructive effect of the enemy's mines ; hence they should ne\vr, if 

 possible, present their sides to the enemy, as the effect of a mine we ml. I 

 be not only to destroy the gallery in its neighbourhood, but perhaps 

 to cut off a large portion of uninjured gallery and render it useless for 

 further defence. The galleries must therefore be disposed so as to 

 present their ends to and lie in the direction of the enemy's approach. 

 At the same time they should not be so far apart that the enemy 

 might pass between them without being heard. As the sound of a 

 pickaxe cannot be heard beyond 60 feet underground, from 100 to 120 

 feet is the greatest distance they should be asunder. And on the other 

 hand they should be close enough for the mines fired in them to cover 

 the intermediate space with their destructive effects without injuring 

 one another. Assuming then that the galleries ore 15 feet under 

 ground, which is considered the best depth for defensive purposes, they 

 should for reasons which will appear from the action of the explosion 

 explained further on, be at central intervals of 48 feet 



Space does not permit of our entering further on this subject : the 

 reader is therefore referred to the article ' Mining, Military,' in the 

 'Royal Engineer Aide Memoire.' It may be stated, however, that 

 the main gallery which, passing along the counterscarp, serves na the 

 base of the system of mines, is termed the magistral gallery ; tin- 

 advanced galleries are termed littcnin;/ galleries. If there be an inter- 

 mediate gallery, parallel to the magistral, it is called the enrdope ; and 

 those giving access from one to the other, galleries of communication, 



In offensive mining, the earth is supported by wood-work. There 

 are two different systems of mining, one with what are termed mining 

 frames and sheeting, the other with cases. Mining frames for shafts 

 consist of four pieces, two 44 feet long, and two 3 feet long, about 

 4 4 inches by 3 inches thick. The long pieces are made with tenons, 

 which fit into mortices cut in the short pieces, which are further notched 

 to one-third of their thickness ; these being fitted together form the 

 frames, which are placed horizontally in the shaft at intervals of 4 feet, 

 and retain the sheeting plonks, (which, ore outside them and prevent 

 the earth falling in,) in their places. 



Gallery frames differ from shaft frames in being composed of only 

 three pieces, two uprights called stanchions, and a top piece called the 

 capsilll 



The system of mining with coses is more expeditious than with 

 frames and sheeting; they have long been known as Dutch coses, 

 and were introduced into the British service by General Sir Charles 

 I'asley. They consist of four pieces about 1 foot wide, namely, two 

 stanchions, a capsill, and a groundsill ; and for ordinary work are cut 

 out of 2 inch deal. The stanchions have tenons, 2" long by 3" >-. i,l,-. 

 which fit into mortices of corresponding dimensions cut in the t-n<l ..f 

 the capsill and groundsill. These form rectangular cases, which ore 

 placed touching one another if the soil is light, no sheeting being 

 employed. 



The dimensions of the different galleries and branches employed in 

 mining are in the clear 



Helglil. Width. 



Great Gallery . 66 



1. 

 2. 

 3. 

 4. 

 5. 



Principal Gallery 

 Common Gallery 

 Great Branch . 



.Small Branch 



