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Petersburg • East • Southeast • West • Monuments • Markers • Facts • Timeline

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The ‘Ventilation Shaft’ wayside marker is on the walking trail leading from the entrance to the mine up to The Crater at Stop Eight on the Petersburg National Battlefield Eastern Front Auto Tour.

From the marker:

Ventilation Shaft

“Regular Army wiseacres said it was not feasible – that I could not carry the ventilation that distance without digging a hole to the surface… But I have succeeded.”

– Lt. Col. Henry Pleasants, 48th Pennsylvania
July 23, 1864

The most serious problem that faced Lt. Col. Pleasants was getting fresh air to the men working in the tunnel. He came up with a solution commonly used in the Pennsylvania coal mines.

One hundred feet into the mine, Pleasants’s men dug a vertical ventilation shaft – the remains of which are in front of you. They then placed an airtight canvas door across the mine opening and ran a wooden duct the length of the mine to the forward end of the chamber. The fire that burned continuously at the ventilation shaft drew stale air out of the mine; fresh air was drawn through the duct to the men working at the head of the tunnel.

The upper left of the marker shows a cutaway drawing of how the ventilation shaft worked, along with the captions:

The air-tight partition (1) ensured that the fire (2) would draw air from the interior of the tunnel (3), thus drawing the stale air away from the workers.

Fresh air drawn through the wooden duct (4) replaced the stale drawn out of the mine by the fire at the ventilation shaft.

From the caption for the drawing on the right:

Once beneath the Confederate works, the Federals dug lateral magazines, which they packed with 8,000 pound of gunpowder.

From the caption to the bottom drawing:

This is a scale drawing of the 511-foot-long tunnel.