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Confederate engineers schemed to blow a section of Yankee earthworks sky-high.

The Army of the Potomac started it all. About 4:44 a.m. on July 30, 1864, a sputtering Union fuse ignited 8,000 pounds of gunpowder packed in a mine underneath Pegram’s Salient, a section of the Confederate lines at Petersburg, Virginia. A mass of earth, military materiel and men lazily—surreally—lofted 200 feet in the air before it came crashing back down like a “shower from a fountain” according to one Federal witness.

The blast created a massive hole about 30 feet deep that gave the ensuing fight its name: the Battle of the Crater. But while the explosion had given Maj. Gen. Ambrose Burnside’s Union troops the great boon of surprise, a number of blunders by the Federal high command frittered away that advantage. By 1:45 p.m., the savage struggle ended with the Confederates still holding on to their shattered earthworks. Some 5,300 men on both sides became casualties in the battle. Despite their victory, the Confederates were understandably nervous about other potential Union mines, and began a frenzy of countermining operations and developing their own plans to detonate a section of the Yankee earthworks.

The armies hunkering down in the Petersburg trenches were participants in the longest, most complex and perhaps most important campaign of the war. General Robert E. Lee staked the fate of his Army of Northern Virginia on the outcome of this campaign, which ran from June 15, 1864, to April 2, 1865. He had lost the strategic initiative to Lt. Gen. Ulysses S. Grant in the Overland Campaign that had preceded the confrontation at Petersburg and was fighting to save both his army and the Confederate capital.

Even with the important triumphs achieved by Federal troops in the West, the Confederates were still holed up in what a recent historian has called their “last citadel,” the lines that defended Richmond and Petersburg. In fact, Maj. Gen. William T. Sherman’s grand march from Atlanta to the sea and through the Carolinas was primarily a movement to bring 60,000 Western veterans to help Grant reduce that last Rebel stronghold.

Field fortifications played a pivotal role in the Petersburg stalemate. After 292 days of continuous contact, trenches stretched for some 35 miles from a point southeast of Richmond to the area west of Petersburg, crossing two rivers, two rail lines and several major roads.

The explosion of July 30 added a new twist to the campaign. “This was something so new and so terrible that a profound impression was produced,” recalled Confederate engineer officer W.W. Blackford, “and nothing else was talked about. Every man in the trenches was sure there were a hundred kegs of powder right under him. Not a [playing] card could be seen, and everybody was reading his Bible.”

Placed in overall charge of countermining along the Richmond-Petersburg lines, Blackford also expanded countermining efforts to eight sites by adding works where City Point Road, Jerusalem Plank Road and Squirrel Level Road crossed the defenses. Cooke’s Salient, located somewhere between Pegram’s Salient and Jerusalem Plank Road, and Elliott’s Salient, north of the James River, were the other locations.

A large quantity of supplies and specialized equipment began to flow toward these work sites. Hundreds of feet of rope; dozens of sperm, tallow and wax candles; a variety of carpenter’s tools; thousands of sandbags; boxes of matches; 3,300 feet of one-inch plank; and quantities of sheet iron were requisitioned and shipped. The diggers used oil-burning miner’s lamps at the head of the galleries, while candles illuminated the rest of the excavation.

It was difficult to find ventilating equipment. The Engineer Bureau in Richmond tried to purchase “six good second hand blacksmith bellows” to pump air, but none were available. Instead, Colonel Alfred L. Rives suggested that Lee’s engineer troops construct fans “to force in the air through wooden box tubes, connected by canvas covered with pitch.”

The Engineer Bureau found several water pumps and also shipped large amounts of iron, wood and lead pipe. The Confederates hired a civilian plumber to connect the pipes, using the softer lead variety to join sections of wood and iron piping, “thus making a flexible joint.”

The miners needed augers to bore forward through the undisturbed earth at the head of each gallery. Private Thomas Fowler of the 41st Alabama developed an auger for use aboveground, consisting of a hollow iron cylinder 3 inches wide and 10 inches long, “slightly flared at the end,” and attached to a 10-foot wooden pole. It could be rammed into the ground and twisted, then drawn out to bring up dirt that was knocked or pushed out of the cylinder. A man could reportedly dig 10 feet in 15 minutes (although Blackford later claimed a rate of only 20 feet in half a day).

Walter Stevens sent a pattern of the borer to the Tredegar Iron Works in Richmond and ordered 100 for immediate delivery. He then distributed them to the troops, who eagerly dug holes in the trench floors 30 feet apart and later dug more holes at two-foot intervals. After digging some 20 feet (using rope attached to the wooden handle), the men poured water into the holes, knowing the red clay would hold the liquid in place for a long time. If a Federal mine hit it, the water would fall out as a danger signal to the anxious Rebels. Blackford admitted after the war that this really did not make the salients more secure, but it eased the minds of the infantrymen.

The top priority for the Rebel counterminers was Pegram’s Salient; the engineers wanted to find the Union gallery before it could be used for another attack. Captain Hugh T. Douglas, in charge of Confederate mining operations, and Brig. Gen. Henry Wise examined the Crater after 5 p.m. on July 30, but came across too many unburied bodies to be able to discover anything else. They continued the next morning with a crew of 20 men (some of them black Union prisoners), digging three new shafts in the north, south and center of the crater near its rim. Over the next two days, they discovered what seemed to be evidence of the Union branches in the northern shaft, and they stopped work at the other two spots.

Blackford wanted to enter the shaft to examine the evidence, but by then the air inside was foul with the stench of decaying remains. Gases from decomposing corpses were seeping through the underground fissures created by the mine explosion. Blackford tied a rope around his shoulders and went down, but when his head started to swim, subordinates pulled him out. The smell was said to be“villainous beyond description.”

The engineers acquired a fan normally used to blow chaff away when wheat was thrown in front of it, then rigged up a pipe made of grain bags, sticking one end into the shaft and attaching the other end to the fan. A Federal mortar shell soon destroyed the apparatus, but the Confederates replaced it and continued to use the fan to cool off workers in the shaft.

Unable to locate the Union gallery, Blackford, Douglas and Wise shifted their attention to other locations. At Colquitt’s Salient, Company H, 1st Confederate Engineers, extended the gallery more than 83 feet toward the Hare House and carved out three branches before stopping work on August 3.

Lieutenant William Alexander Gordon of Colonel Thomas Talcott’s 1st Confederate Engineers Regiment took charge of the countermining at Cooke’s Salient, employing his Company G and 100 infantrymen. With advice from more experienced miners, Gordon sank shafts at both wings and in the middle of the salient. The shafts were 4 feet square and went to a depth of 26 feet through hard clay. Galleries extended forward from each shaft, 43 feet long on the wings and 50 feet in the center. Then Gordon’s men dug a connecting gallery that was 1,116 yards long at the forward ends to connect all three shafts. The design was exactly like that of Douglas’ countermine at Pegram’s Salient, although it presented a much wider front. Gordon finished the countermine in late September and placed guards in it 24 hours a day to listen for signs of enemy mining.

Rumors of Confederate mining on the XVIII Corps front worried Maj. Gen. Edward Ord. He requested help, and Union engineers soon started digging a listening shaft at the fort.

The Confederates intended to spring a mine on Ord’s front at Gracie’s Salient. Walter Stevens ordered it on July 31, based on apparent evidence that the Federals were mining from the head of the sap they had dug in July. The powder arrived on the evening of July 31, and Douglas supervised its placement that night, with civilian miners named Blunt and Black providing technical assistance.

They placed four barrels of powder, a total of 450 pounds, in two chambers. Douglas had hoped to spring the mine with lanyards, but since they were not available, he used four strands of safety fuse, each one stretched from a powder barrel to a single powder train that reached the mouth of the gallery.

All was ready by 9:15 a.m. on August 1, but Douglas was informed that he could not spring the mine while the burial truce was in effect at Pegram’s Salient 600 yards to the south. When it ended at 11 a.m., Gracie gave the signal and Black lit the powder train.

Douglas and his crew waited 45 minutes, but nothing happened. Black then ventured into the gallery and found that three pieces of the fuse had burned out and a fourth piece was “burning slowly.” He cut off the fourth piece, believing the slow burn would produce a poor detonation, and brought it out for examination. It was found to be “very defective and perfectly valueless,” in Douglas’ words. The frustrated engineer decided to postpone the explosion and extend the mine closer to the Federals.

The Rebels shoveled out mud and pumped water on the night of August 1. The gallery had two branches, both of which had been started before July 31, but the second one seemed to be headed more directly toward the sap. Douglas decided to clear out the debris and leftover sandbags from this second branch and extend it as far as possible. A new shipment of shovels and picks arrived, and Douglas’ men worked around the clock. By August 4 they had gone as far as the captain dared and began to dig a powder chamber to the side and at the head of the branch. It was only 41⁄2 feet long.

That night Douglas directed the placement of eight barrels of powder, totaling 850 pounds. He again used safety fuses and constructed cotton tubing to hold the powder train encased inside a long wooden box.

All was ready by the evening of August 5, and Wise fired the mine at 6:30 p.m. The Federals were taken by surprise as a mass of earth 30 feet in diameter suddenly rose 100 feet into the sky, “the centre portion being elevated considerably above the sides.” Fortunately for the Yankees, however, the mine exploded 40 yards short of the saphead. The main Union line was so far away that no debris fell into it, and Federal sharpshooters in the sap didn’t even deem it necessary to evacuate their positions.

Ord was inspecting his line at a spot fairly near the explosion when he felt the earth jar and saw “a cloud of dust and smoke rising high in the air.” He ordered reserve troops up to the line as a hail of Rebel artillery and musket fire followed the explosion. Union casualties were slight but included one of Ord’s best brigade commanders. Colonel Griffin Stedman and Brig. Gen. Adelbert Ames, his division leader, were leaning against the side of a trench in conversation when a bullet smacked into Stedman’s chest. The brigade leader died the next morning.

The Confederates lost a few men in the exchange of fire, which lasted at least half an hour after the explosion. When everything became quiet again, Union engineers examined the crater from the head of the sap and assumed the Confederates had intended to destroy the position but made a mistake. Army of the Potomac commander Maj. Gen. George G. Meade, however, did not believe that Robert E. Lee’s engineers would miss their target by 40 yards.

Meade suggested they must have intended to use the crater as an advanced infantry position to attack the XVIII Corps at night. Ord did not support this view, asserting that the crater was “not in a place likely to be occupied by them.”

Most of the Confederates defending Petersburg recognized the mine as a failure. Major General Bushrod Johnson groused that the “effect was slight. Not a gabion or sap roller displaced, nor much of a crater formed.” The explosion collapsed the branch and the gallery back to the shaft and dropped debris on the Confederate picket line.

Douglas had been unable to stop the explosion on July 30, and this second failure ruined his military career. Colonel Talcott had ordered him to fire the mine at noon that day, but he had hesitated, saying that he was “not a miner.” Placed under arrest, Douglas offered to resign his commission. He cited his age (somewhat more than 45) and “other reasons, not deemed necessary to mention.” Douglas sent in a letter of resignation that was accepted on September 28. He finished the war as a civilian engineer employed by the Confederate Army.

The Confederates were a step behind the Federals in underground engineering at Petersburg. Douglas made two basic errors in stopping 40 yards short of the saphead and improperly tamping the mine. It is possible that his age, as well as fatigue and perhaps depression over his failure to stop the explosion at the Crater, led to those errors.

The strands of safety fuse Douglas used on August 1 happened to be defective, but those employed on August 5 worked perfectly. The Confederates acquired 458 feet of powder hose in late August, a premanufactured powder train consisting of a “tube of strong linen.” Often called a Gomez fuse, it was intended to be put in a wooden casing and filled with the aid of a tin funnel.

Countermining continued under Blackford’s supervision after August 5, and troops began a new countermine near Jerusalem Plank Road by August 12 that was the most extensive at Petersburg. When finished, the complex totaled 1,088 feet of galleries and branches. The main gallery extended more than 146 feet southwest toward Jerusalem Plank Road, with a network of three branches and two connecting galleries between the branches. The Confederates built two chimneys for ventilation and four short listening chambers at key locations.

The Federals learned of the Rebel countermine at Jerusalem Plank Road from a deserter on August 12 and assumed it was an offensive mine. On more than one occasion, they evacuated Fort Sedgwick for a few hours until warnings about its imminent destruction proved false. Countermining began at Fort Stedman—named for the recently killed Union colonel—sometime in early August as well.

The shaft was sunk in the ditch of the work, its dimensions were 7 by 10 feet, and the hole was 12 feet deep. By the end of the Petersburg Campaign, Stedman was protected by a network of galleries and branches 200 feet in length.

While the Confederate engineers continually tried to beat their Union counterparts at their own game, they never got close to the undermining success the Union had at Pegram’s Salient. Grant, in fact, advised Meade to prepare a secondary line opposite the point of attack, to stop any assault and pin the Rebels in the crater. He assumed Ord’s XVIII Corps front was the most likely place for Rebel mining efforts and believed any assault could be “repulsed with great slaughter.” In the end, however, it was the fighting above ground, not the digging below, that decided the Siege of Petersburg.


This article is excerpted from In the Trenches at Petersburg: Field Fortifications and Confederate Defeat, by Earl J. Hess. Copyright 2009 by the University of North Carolina Press. Used by permission of the publisher,

Originally published in the October 2009 issue of Civil War Times. To subscribe, click here