Tuesday, June 3, 2014

Whose idea is it to dig a mine? And how?

Testimony of Brevet Major General Robert B. Potter.
Headquarters Army of the Potomac,
Before Petersburg, Va., December 20, 1864.
Brevet Major General Robert B. Potter sworn and examined.
By Mr. Chandler:
Question. What is your rank and position in the army ?
Answer. I am a brigadier general and a brevet major general of volunteers,
commanding the 2d division of the 9th army corps.
Question. Will you state to the committee, as concisely as possible, what you
know in relation to the springing of the mine and assault upon the enemy's
works on the 30th of July last?
Answer. About the 24th of June, I should think, the idea of mining under
the enemy's works in my immediate front was suggested to me; in fact, I had
thought of it before
, and several others had thought of the same thing. Lieutenant
Colonel Pleasants, commanding the 48th Pennsylvania volunteers, came
to my quarters and suggested to me that he was familiar with mining, and that many
of the men in his regiment were miners, and that they thought they could undermine
one of the enemy's works in my immediate front. After some conversation
with him, I wrote a communication to General Burnside, who was then my corps
commander, suggesting this plan of mining the enemy's works, and giving some
of the details. The general subsequently sent for me to come to his headquarters
and bring Colonel Pleasants with me, which I did, and we had an interview
with him. Subsequently he notified us that he had submitted the plan to
the general commanding the army of the Potomac, who approved of the same,
and that we were authorized to undertake the work.

This is testimony before the Congressional Committee on the Conduct of  the War some months after Petersburg. Aside from the peculiar qualifier "I should think" Potter is sharing an opinion. It's hard to know exactly what was on his mind in late June, but here is his report to IX Corp headquarters six months earlier OR(40)1:220 ...

June 19, 1864.
Assistant Adjutant-General, Ninth Army  Corps :

COLONEL: I inclose a report from Colonel Griffin for the information of the commanding general. We also hold the advanced line of yes­terday as a picket-line, which is pretty well intrenched. I think of making a covered  way to  it.  This  division  occupies  the  entire  line as well as supports it, only a picket of the Third Division being left, whose position rendered it inexpedient to relieve them with the others; but this will be done at the earliest opportunity if possible, but my division is pretty well all in use now.
Very respectfully,  your obedient servant,
Brigadier- General.

P. S.-There is a redoubt not quite 100 yards in front of our line, which I think can be approached by a sap. At any rate, its reduction seems quite practicable with the spade when we get a covered way to the ravine.  I will forward a diagram, showing location of batteries, &c., shortly.

and a few days later OR(40)2:396-7, Burnside forwards the Potter message to Meade.

[General MEADE :]
June 24, 1864 -- 6.10 p. m.

GENERAL : The following dispatch has just been received, and is for­warded for your information and guidance, in case of the success or repulse of the attack.*
Major- General.

June 24, 1864.
Maj. Gen. JOHN  G. PARKE,
Chief  of  Staff, Ninth Army Corps:
GENERAL : Lieutenant-Colonel Pleasants, of the Forty-eighth Pennsylvania Veteran Volunteers, commanding First Brigade, has called upon me to express his opinion of the feasibility of mining the enemy's work  in my front.   Colonel Pleasants is a mining  engineer  and has charge of some of the principal mining works of Schuylkill County, Pa. He has in his command upward of eighty-five enlisted men and fourteen non-commissioned officers, who are professional miners, be­sides four officers. The distance from inside of our work, where the mine would have to be started, to inside of enemy's work, does not exceed 100 yards. He is of the opinion that they could run a mine forward at the rate of from twenty-five to fifty feet per day, including supports, ventilation, and so on. It would be a double mine, for as we cannot ventilate by shafts from the top, we would have to run parallel tunnels and connect them every short distance by lateral ones, to secure a circulation of air, absolutely essential here, as these soils are full of mephitic vapors. A few miner's picks, which I am informed could be made by any blacksmith from the ordinary ones; a few hand­-barrows, easily  constructed ; one or two  mathematical instruments, which could be supplied by the engineer department, and our ordinary intrenching tools, are all that are required. The men themselves have been talking about it for some days, and are quite desirous, seemingly, of trying it. If there is a prospect of our remaining here a few days longer I would like to undertake it. If you desire to see Colonel Pleasants I will ride over  with him or send him up to you. I think, perhaps, we might do something, and in no event could we lose more men than we do every time we feel the enemy.
Yours, very truly,

The finished mine was 510 feet in length (170 yards) and had a single main gallery. Digging began at noon on the 25th of June and by early morning three days later was 130 feet long OR(40)2:484

June  28, 1864-8 p. m.
Maj. J. L. VAN BUREN, Aide-de-Camp :
SIR : Colonel Pleasants reports that the gallery was 130 feet at 12
m. to-day by measurement.   It was reported to me to be 130 feet about
9.30 a. m., which was the distance I stated to General Burnside this morning. That was, however, only estimated. The gallery was run fifty feet the first day and forty feet each day since, which rate of pro­gression Colonel Pleasants thinks he will be able to maintain.
Very respectfully,  your obedient servant,
Brigadier- General.


Perhaps in another post we can look at the cautious way generals used qualifiers in their reports and official correspondence. The "I should think" seems peculiar when the written correspondence must have been found in preparation for testimony by mid-December. The "seemingly" poses the question: Why qualify the men's desire to mine?

The mine was proposed by Pleasants on the 24th. By the end of the 25th the tunnel was already 50 feet long. There had been little time to design/construct a "double" mine. Perhaps Potter didn't understand what Pleasants had said? As to the "mephitic vapors" that might lead to such a design, were these Potter's words? or from Pleasants? Major Duane, Chief Engineer of the Army of the Potomac, had authored a manual for military mining and counter-mining in 1862. But coal mining and Army mining were horses of a different color. Duane's manual recognized the need for ventilation in longer mines, but suggested shafts to the surface (not in these conditions, so close to the Confederate lines) and/or parallel galleries connected by horizontal shafts.Perhaps this influenced Potter? Note the following highlight, though. The "simple" ventilation design from coal mining and the speed with which a single gallery was begun and continued so rapidly points to a clear vision in Pleasants' mind and something different in Potters'.

Oliver Christian Bosbyshell (late Major in the 48th)
The 48th in the War
Avil Printing Co., Philadelphia, PA, 1895.
digitized by Google from a copy in the Harvard College Library

The ventilation was accomplished in a very simple way — after a method quite common in the anthracite coal mines. A perpendicular shaft or hole was made from the mine to the surface at a point inside of the Union rifle pits. A small furnace, or fire-place, was built at the bottom of this hole, or shaft, for the purpose of heating the air, and a fire was kept constantly burning, thus creating a draft. A door made of canvas was placed in the gallery, a little outside of this fire-place, thus shutting it in and shielding it from the outside air at the mouth of the mine. Wooden pipes, extending from the outside of this canvas door, along the gallery to the inner end thereof, conducted the fresh air to the point of operations, which, after supplying the miners with pure air, returned along the gallery towards the entrance of the mine, and, being stopped by the canvas door, the vitiated air moved into the furnace and up the shaft to the surface. By this means a constant current of air circulated through the gallery. As the work advanced, the inside end of the wooden pipe was extended so as to carry good air up to the face of the workings.

Bosbyshell's words echo the report of Pleasants OR(40)1:556-563, part of which mentions ventilation and nowhere uses the word "mephitic", which appears only once in the three parts of OR vol. 40.

The mine was ventilated at first by having the fresh air go in along the main gallery as far as it was excavated, and to return charged with the gases generated by the breathing and exhalation of the workmen, by the burning of the candles, and by those liberated from the ground, along and in a square tube made of boards, and whose area was sixty inches. This tube led to a perpendicular shaft twenty-two feet high, out of which this vitiated air escaped. At the bottom of this shaft was p1aced a grating, in which a large fire was kept burning continually, which, by heating the air, rarefied it, and increased its current. Afterward I caused the fresh air to be let in the above-mentioned wooden tube to the end of the work, and the vitiated air to return by the gallery and out of the shaft, placing a partition with a door in the main gal­lery a little out of the shaft, to prevent its exit by the entrance of the mine. The latter plan was more advantageous, because the gases had to travel a less distance in the mine than before.

Robert Potter was one of those citizen-soldiers whose background could not have prepared him to command a combat division of 5,000 men. He was a 30 year-old attorney at the beginning of the war, with no previous military experience. Intelligent enough to learn how to lead men in battle and brave enough to command from the front, he was still schooled only by his experience with the Army of the Potomac. I'm sure when he looked at the Confederate position on the ridge right in front of his division he might has thought to himself, as did others as well, "yes, we should blow that up", but in fact his first report on the 19th mentions "approached by a sap" .. which would be a trench with perhaps a roller to protect the men with shovels, the most conventional way in siege by "regular approaches". Perhaps he was familiar with Duane's manual, and can that have led him to think this?

or, more likely, was he thinking of this?


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