The Vicksburg Mine
Andrew Hickenlooper, Brevet Brigadier-General U.S.V.
Chief Engineer of the Seventeenth Army Corps

        After the failure of the general assault on May 22d, orders were issued to commence regular siege operations. General J. B. McPherson occupied the center with the seventeenth Army Corps, covering the main Jackson road, on which the Confederates had constructed the most formidable redoubt on the entire line, and intrusted its defense to the 3d Louisiana, a veteran regiment. Because of its strength, commanding position, and heavy armament, this redoubt became the main objective point of the engineering operations of the seventeenth Army Corps.
        It was approachable only over a broad, flat ridge, forming a comparatively level plateau, extending eastwardly from the fort for a distance of almost five hundred yards before descending into one of the numerous ravines or depressions which extended in almost every conceivable direction over the ground lying between the contending armies. The Third Division, commanded by General Logan, occupied the position immediately in front of the fort, and upon these troops-more especially those of the brigade commanded by General M.D. Leggett, working under the direction of the chief engineer of the corps-was imposed the greater part of the labor.
        The "pioneers" of the corps were at once sent to the cane-brakes, swamps, and lowlands in the rear to construct sap-rollers, gabions, and fascines, and details of 150 men for day and the same number for night duty were made for work on the main sap, which was commenced on the Jackson road at a point about 150 feet south-east of a large frame plantation house, known as the White House, which for some unexplained reason had been left standing by the enemy. Up to this point troops could be marched in comparative safety under cover of the intervening hills, supplemented by the construction of parapets at exposed points.
        The line of the first section was selected during the night of the 23d under cover of an attack made upon the enemy's pickets. Upon this line the workmen were placed at intervals of about five feet, each equipped with a gabion, pick, and shovel, with instructions to cover themselves securely and dig a connection through to the adjoining burrow before daylight. The day relief was engaged in deepening and widening the sap thus commenced, and on the following night the second section was laid out and occupied in the same manner.
        On the 25th of May the Confederate commander sent in a flag of truce, for the purpose of tendering permission to bury the Federal dead who had fallen in front of their works during the heroic assault of the 22d, which was gladly accepted. This incident afforded the chief engineer a much needed opportunity of closely inspecting the ground to be passed over, of fixing the salient points in his mind, and of determining upon the general direction of the various sections of the sap. The highest point between the fort and the White House was selected as a spot upon which to locate a battery and "place at arms" (afterward known as Battery Hickenlooper), the guns of which rendered valuable service in covering the extensions of the sap beyond that point. Two 8-inch naval guns located in battery south-east of this point also rendered effective service in silencing the guns of the Confederate fort; thus leaving the Union soldiers exposed only to the ever vigilant sharp-shooters of the enemy. Not even a hand could be safely raised above the parapets ; and heavy rope shields, or aprons, were hung in front of the embrasures for the protection of the gunners while they were sighting their pieces. A favorite amusement of the soldiers was to place a cap on the end of a ramrod and to raise it just above the head-logs betting on the number of bullets which would pass through it within a given time.
        The sap-roller, used to protect the workmen from an enfilading fire during the opening of each section of the sap, was a wicker casing five feet in diameter by ten feet in length compactly filled with cotton. The roller was several times found to be on fire, and on the night of June 9th it was totally consumed ; but through what agency was, at the time, a great mystery. After the capitulation it was ascertained that cotton saturated with turpentine and placed in the hollow of a minnie ball had been fired from a musket into the packing of the roller. It was difficult for the sharp-shooters to reach the Confederates by direct firing, and the artillerymen found it impossible to gauge their shells so as to cause the explosion immediately behind the Confederate parapets. To overcome this latter difficulty, when the sap reached the vicinity of the fort we caused " Coehorn mortars " to be made from short sections of gum-tree logs bored out and hooped with iron bands. These novel engines of warfare, being accurately charged with just sufficient powder to lift six or twelve pound shells over the parapet and drop them down immediately behind, proved exceedingly effective.
        The general plan of conducting the work with flying-sap by night and deepening and widening by day was pushed forward with the utmost energy until June 22d, when the head of the sap reached the outer ditch surrounding the fort. A few days previous an order had been issued for all men in the corps having a practical knowledge of coal-mining to report to the chief engineer. Out of those reporting thirty six of the strongest and most experienced were selected and divided into two shifts for day and night duty, and each shift was divided into three reliefs. On the night of the 22d these men, properly equipped with drills, short-handled picks, shovels, etc., under the immediate command of Lieutenant Russell of the 7th Missouri and Sergeant Morris of the 32d Ohio commenced the , mining operations by driving a gallery, four feet in width by five feet in height, in at right angles to the face of the parapet of the fort. Each relief worked an hour at a time, two picking, two shoveling, and two handing back the grain sacks filled with earth, which were deposited in the ditch until they could be carried back. The main gallery was carried in 45 feet, and then a smaller gallery extended in on the same line 15 feet, while from the end of the main gallery two others were run out on either side at angles of 45 degrees for a distance of 15 feet. The soil through which this gallery was driven was a reddish clay of remarkable tenacity, easily cut and requiring but little bracing. So rapidly was this work executed that on the morning of the 25th the miners commenced depositing the powder, 800 pounds at the extreme end of the main gallery and 700 pounds at the end of each of the lateral galleries, making a total of 2200 pounds. From each of these deposits there were laid two strands of safety fuse,- obtained, as was the powder, from the navy,-this duplication being made to cover the possible contingency of one failing to burn with the desired regularity and speed. These six strands were cut to exactly the same length, and having been carefully laid, the earth, which had been previously removed in grain-sacks, was carried back and deposited in the most compact manner possible, and well braced by heavy timbers, beyond the junction point of the three galleries. From this point out to the entrance it was more loosely packed in.
        The Confederate garrison, surmising the object in view, were active in efforts to thwart the purpose of the Union forces by throwing hand-grenades and rolling shells with lighted fuses over their parapet down into the trench in front of the fort.
        They also countermined in hopes of tapping the gallery. So near were they to the attainment of this object that during the last day the miners could distinctly hear the conversation and orders given in the counter-mine.
        The powder was brought up in barrels and kept in the main sap at a safe distance from the enemy's hand-grenades and shells, and there opened and placed in grain-sacks, each one of which contained about 25 pounds. These were taken up on the backs of the miners, who made the run over the exposed ground during the intervals between the explosion of the enemy's shells ; and so well timed were these movements that, although it required nearly one hundred trips with the dangerous loads, all were landed in the mine without a single accident.
        The commanding general having been advised on the day previous that the work would be completed before 3 P. M. of the 25th, general orders were issued directing each corps commander to order up the reserves and fully man the trenches, and immediately following the explosion to open with both artillery and musketry along the entire twelve miles of investing line; under cover of which the assaulting columns, composed of volunteers from the 31st and 45th Illinois, preceded by ten picked men from the pioneer corps under charge of the chief engineer, were to move forward and take possession of the fort. F`or an hour or two previous to the time of the explosion the scene from "Battery Hickenlooper," where General Grant and his subordinate commanders had taken their positions, was one of the most remarkable ever witnessed. As far as they could reach to the right and left could be seen the long winding columns of blue moving to their assigned positions behind the besiegers' works.
        Gradually as the hour of 3 approached the booming of artillery and incessant rattle of musketry, which had been going on day and night for thirty days, suddenly subsided, and a deathlike and oppressive stillness pervaded the whole command.
        Every eye was riveted upon that huge redoubt standing high above the adjoining works. At the appointed moment it appeared as though the whole fort and connecting outworks commenced an upward movement, gradually breaking into fragments and growing less bulky in appearance, until it looked like an immense fountain of finely pulverized earth, mingled with flashes of fire and clouds of smoke, through which could occasionally be caught a glimpse of some dark objects,-men, gun-carriages, shelters, etc. Fire along the entire line instantly opened with great fury, and amidst the din and roar of 150 cannon and the rattle of 50,000 muskets the charging column moved forward to the assault. But little difficulty was experienced in entering the crater, but the moment the assaulting forces attempted to mount the artificial parapet, which had been formed by the falling debris about midway across the fort, completely commanded by the Confederate artillery and infantry in the rear, they were met by a withering fire so severe that to show a head above the crest was certain death. Two lines were formed on the slope of this parapet, the front line raising their muskets over their heads and firing at random over the crest while the rear rank were engaged in reloading. But soon the Confederates began throwing short-fused shells over the parapet, which, rolling down into the crater crowded with the soldiers of the assaulting column, caused the most fearful destruction of life ever witnessed under like circumstances. The groans of the dying and shrieks of the wounded became fearful, but bravely they stood to their work until the engineers constructed a casemate out of the heavy timbers found in the crater, and upon which the earth was thrown until it was of sufficient depth to resist the destructive effects of the exploding shells. As soon as this work was completed, and a parapet was thrown up across the crater on a line with the face of the casemate, the troops were withdrawn to the new line beyond the range of exploding shells.
        The crater being secured, again the miners were set at work running a new gallery under the left wing of the fort. This mine was exploded on the 1st of July, leaving the fort a total wreck.
        In the meantime the main sap had been widened sufficiently to admit of the convenient movement of troops in " column of fours" during the contemplated assault, the necessity for which was happily avoided by the surrender on the following day.
Source: Battles and Leaders of the Civil War