A stalemate and a miner's idea
By late June 1864 the armies at Petersburg had dug in. According to the American Battlefield Trust, Ulysses S. Grant had been reluctant to order frontal attacks on well-entrenched Confederates since Cold Harbor, and two weeks after Union forces arrived the lines had settled into a stalemate. Petersburg mattered because it sat on the rail lines that supplied the Confederate capital at Richmond.
Part of the Union line was held by Maj. Gen. Ambrose E. Burnside's IX Corps, which included the 48th Pennsylvania Veteran Volunteer Infantry. The National Park Service's historical handbook for Petersburg says a large share of that regiment had been coal miners. Their commander, Lt. Col. Henry Pleasants, was a mining engineer, and the handbook records that he overheard one of his men say, "We could blow that damned fort out of existence if we could run a mine shaft under it."
The target was Elliott's Salient, a Confederate battery position. The plan had three steps: dig a long gallery from a ravine behind the Union picket line to a point under the battery, explode powder at the end of it, and send a strong body of troops through the gap. The men of the 48th, the handbook says, hoped the reward would be the surrender of Petersburg and perhaps the end of the war.
Digging the mine
With approval from Burnside and Grant, the digging began on June 25. The regiment had to improvise. The handbook lists mining picks made from straightened army picks, cracker boxes turned into barrows to carry out the dirt, and timber for shoring sawn from a bridge. Pleasants aimed the tunnel with an old theodolite sent from Washington, and the shaft ended exactly under the salient.
By July 17 the gallery was nearly 511 feet long. The Confederates heard faint digging and sank countermines behind their own lines, two of them close to the Union tunnel, but none struck it. The handbook adds that many on the Confederate side believed a shaft longer than about 400 feet could not be ventilated without air shafts along it.
From July 18 the miners dug two side galleries running parallel to the Confederate works, which added about 75 feet and brought the total to 586 feet. The roof of the tunnel was about 20 feet below the enemy works, and the shaft averaged 5 feet high, 4.5 feet wide at the base and 2 feet at the top. Digging ended on July 23, and on July 27 the men placed 320 kegs of powder, averaging 25 pounds each, in eight magazines: 8,000 pounds in total. They packed sandbags around the powder to drive the blast upward and spliced two fuses into a 98-foot line.
| Date (1864) | Event | Source |
|---|---|---|
| June 25 | The 48th Pennsylvania starts digging the mine shaft | NPS Historical Handbook |
| July 17 | The gallery is nearly 511 feet long and directly under the Confederate battery at Elliott's Salient | NPS Historical Handbook |
| July 18 to 23 | Two side galleries add about 75 feet, for a total of 586 feet; digging finishes July 23 | NPS Historical Handbook |
| July 27 | The mine is charged with 320 kegs of black powder, 8,000 pounds in all | NPS Historical Handbook; American Battlefield Trust |
| July 29 | Burnside learns that his division of Black troops will not lead the attack | NPS Historical Handbook |
| July 30, 3:15 a.m. | Pleasants lights the fuse; it burns out at a splice | NPS Historical Handbook |
| July 30, about 4:45 a.m. | The mine explodes after two volunteers relight the fuse | NPS Historical Handbook (NPS stop page: 4:44 a.m.) |
| July 30, shortly after 1 p.m. | Mahone's final charge reaches the crater's slopes; the fighting ends soon after | NPS Historical Handbook |
A last-minute change of plan
Burnside wanted a fresh division of Black soldiers, about 4,300 men of the United States Colored Troops, to lead the charge. The handbook says Meade opposed this on the grounds that if the attack failed, Union commanders could be accused of wanting to get rid of the only Black troops then with the Army of the Potomac. Burnside was not told until July 29, the day before the battle.
With a day to go, Burnside had the commanders of his three white divisions draw straws to decide who would lead. Gen. James F. Ledlie of the 1st Division drew the assignment. The handbook records that 110 guns and 54 mortars were made ready to shell the Confederate line, and that a Union demonstration near Richmond had drawn troops away, leaving about 18,000 Confederate soldiers to hold Petersburg.
The explosion and the fight in the crater
Pleasants lit the fuse at 3:15 a.m. on July 30 and expected the blast at 3:30. Nothing happened. By 4:15 it was clear something had gone wrong, and two volunteers from the 48th, Lt. Jacob Douty and Sgt. Harry Reese, crawled into the tunnel, found that the fuse had burned out at the splice, relit it and got out. The mine went off at about 4:45 a.m.; the National Park Service's stop page for the site gives 4:44.
The blast threw men, guns and earth into the air. The handbook says at least 278 Confederates were killed or wounded and two of the battery's four guns were destroyed beyond repair. The hole was, by its estimate, at least 170 feet long, 60 to 80 feet wide and 30 feet deep.
Then the attack lost its momentum. The handbook describes a delay while the stunned troops took in the scene and obstructions between the lines were cleared. When the Union soldiers reached the crater, many stopped to take cover on its steep slopes or to look at the damage. Reinforcements followed, but instead of pushing on they joined the men in the crater or spread out to the right and left along the lines. By 8:30 a.m., the handbook says, over 15,000 Union troops filled and surrounded the crater. The Park Service stop page adds that the Federals could not move out of it mainly because of intense Confederate artillery fire.
The Confederates recovered quickly. Lee ordered two brigades of Maj. Gen. William Mahone's division up from the lines south of the city, and mortars were brought within 50 yards of the crater. Shortly after 8 a.m. Mahone's men arrived, gathered in a ravine about 200 yards west of the crater and charged, driving the Union troops who had pushed beyond the rim back into it. A second charge at about 10:30 was repulsed.
Inside the crater, the handbook says, the packed troops had no shade, food or water, and no competent leadership. Meade ordered a withdrawal more than an hour before the second Confederate charge, but Burnside held back the order until after midday. Shortly after 1 p.m. a final charge by Mahone's men reached the slopes of the crater, and after a close-quarters fight with bayonets and rifle butts it was over.
Casualties, and why the numbers differ
Sources agree on the outcome but not on the exact counts, so it helps to see them side by side.
| Figure | What sources report |
|---|---|
| Main tunnel length | About 511 feet (NPS Historical Handbook); 510 feet (American Battlefield Trust) |
| Size of the crater | At least 170 ft long, 60 to 80 ft wide, 30 ft deep (NPS Historical Handbook); 170 ft long, 60 ft wide at either end, 30 ft deep in places, from contemporary accounts (NPS Crater stop page) |
| Confederates hit by the blast | At least 278 killed or wounded (NPS Historical Handbook); about 300 South Carolinians killed (American Battlefield Trust article) |
| Union losses | 3,798 (American Battlefield Trust battle facts); over 4,000 killed, wounded or captured (NPS Historical Handbook); 4,000 (Trust article) |
| Confederate losses | 1,491 (American Battlefield Trust battle facts); about 1,500 (NPS Historical Handbook); 1,800 (Trust article) |
The Trust's battle-facts figures, 3,798 Union and 1,491 Confederate, are the most specific; the handbook's "over 4,000" and "about 1,500" are rounded totals. The blast figures differ in kind as well as size: the handbook counts killed and wounded together, while the Trust article speaks of men killed. For the crater itself, the handbook says plainly that measurements vary considerably.
The toll fell heavily on the Black soldiers of the United States Colored Troops. The American Battlefield Trust says that most of the Black soldiers were badly mauled and that the United States Colored Troops were the target of particularly brutal Confederate retaliation.
What happened next
Grant called the battle "the saddest affair I have witnessed in this war," as quoted by the American Battlefield Trust. Burnside was relieved of his corps command for his role in the defeat. Instead of ending the siege, the battle was followed by eight more months of trench warfare around Petersburg.
The site is now part of the Eastern Front unit of Petersburg National Battlefield, where the crater is Stop 8 on the park tour. For the general who directed the campaign, see our Ulysses S. Grant profile.