Numbers 9. Reports of Major General C. Duane, Corps of Engineers, U. S. Army, of operations November 13-December 31.

HDQRS. ARMY OF THE POTOMAC, ENGINEER DEPT.,
November 20, 1864.

GENERAL: I have the honor to submit the following report of the engineering operations in this army for the week ending November 19, 1864:

Captain Harwood was in command of the Battalion of U. S. Engineers. The mining gallery at Fort Stedman, with its lateral branches, was completed on the 18th instant, under the direction of Lieutenant Benyaurd, U. S. Engineers. This officer had also charge of constructing an infantry breast-work between Batteries Nos. 13 and 14, which will be completed, weather permitting, on the 22nd instant. The construction of Fort Conahey has been completed under the immediate direction of Lieutenant Howell; and Lieutenant Phillips, assisted by Lieutenant Benyaurd, made a thorough inspection of the line from Battery Numbers 13 to Fort Stedman.

The following extracts from the weekly report of Lieutenant-Colonel Spaulding, commanding detachment Fiftieth New York Volunteer Engineers, will show the nature and extent of the work performed by the officers and troops of his command:

At the date of my last report, Lieutenant Taylor with one company of this command had completed 130 feet of countermining in front of Fort McGilvery. On Sunday 10 feet additional gallery was driven, making 140 feet in all, and this was deemed sufficient. On the 14th Lieutenant Cameroon, with one company of this command, was sent to build a magazine in the fort in rear of the line near the Avery house and also in the fort near the Friend house. These magazines were completed last evening, except the doors. This morning the doors were hung, locks and staples placed on them, and the keys handed over to the officers commanding the respective forts. The fraise and abatis around Fort Haskell were completed by Lieutenant Van Rensselaer on the night of the 13th, working two companies of this command. On the nights of the 12th and 13th the abatis was examined and thoroughly repaired in front of the rifle-pits from Battery 13 to Fort Stedman. Lieutenant Van Rensselaer reports that on each side of Batteries 11 and 12 portions of the abatis had been removed, evidently had been taken away by the pickets for fire-wood. On Tuesday afternoon Lieutenant Dudley was sent with his company to repair and extend the corduroy roads in the covered ways in the rear of and in the vicinity of Fort Sedgwick. With the aid of teams from the Second Corps, Lieutenant Dudley laid and repaired about 460 yards of corduroy road in these covered ways and completed the work on Thursday afternoon. On the 16th I sent Lieutenant Kenyon with one company of this command to place a wire entanglement in front of the works from Fort Fisher to Fort Welch, to take the place of slashing removed by the troops. This entanglement was commenced on the right of Fort Fisher, and extended along the whole front, to a point about 200 yards to the left of Fort Welch, and was completed on the afternoon of the 17th instant. Captain Van Brocklin reports the condition of Fort Stevenson as follows: "Ready for nine barbette and twenty-two embrasure guns, 850 feet of infantry banquette complete, and the abatis built on the front and right flank. All the essential parts of the work will be complete by the night of the 20th (if the work is continued on Sunday), unless it may be a portion of the abatis.

In the topographical department, the map of the country west of the Weldon railroad is still in course of construction. Additional surveys of that portion of the country were made during the last week and plotted, which are to be added to this map. A map showing the lines occupied by the U. S. forces in the neighborhood of the Wilderness Tavern Scale, four inches to the mile), is also progressing rapidly.