Eighth. The officer will at once send a courier with the information to the officer in charge at headquarters engineer troops.

Ninth. The commanding officer at headquarters will at once communicate with Colonel W. H. Stevens, chief engineer.

Tenth. The officers and miners at the mines will watch attentively in the galleries and notice the approach of the enemy.

Eleventh. It is all important that the gallery at shaft No. 1 [Pegram's salient] be pushed vigorously forward; as No. 2 gallery from shaft No. 2 is intended for a listening gallery the importance of its completion is not so great as that of No. 1. This will be pushed forward as rapidly as possible, but not so as to interfere with No. 1.

Twelfth. As the gallery at Colquitt's salient is the most important one, every effort will be made to extend this work.

Thirteenth. At the bottom of each shaft a well will be dug two feet deep and covered over with plank, to be opened during rains for the purpose of collecting the water that may come through the mouth of the shaft and prevent it from entering the galleries.

Fourteenth. The grade of the gallery must correspond with the grade of the ground.

Fifteenth. Whenever practicable the detachments in going into the salient will carry in with them the frames and sheeting for the gallery.

Sixteenth. Detachments Nos.1 and 2 will operate at mine No. 1; detachments Nos.3 and 4 at mine No. 2, Pegram's salient; detachments No. 5 and 6 at mine No. 3, Colquitt's salient.

HUGH THOS. DOUGLAS,

Captain, Engineer Troops, Charge of Mining, &c.

HEADQUARTERS ENGINEER TROOPS, Blandford, July 15, 1864.

The following organization of the engineer troops engaged in the mining operations before Petersburg has been adopted by the officer in charge:

First. One division consisting of two detachments will be organized for each mine, each detachment under the charge of a non-commissioned officer [sergeant or corporal]. The organization of the detachments will be as follows, viz: 1 non-commissioned officer sergeant or corporal; 2 miners and 2 shoveler at work in the gallery; 2 men at work in the gallery carrying earth to the bottom of the shafts; 2 men at the wind-lass; 2 men dumping earth; 4 men removing earth. Total, 14 men and 1 non-commissioned officer. Six detachments= 84 men, 6 non-commissioned officers, a total of 90 men.

Second. The first detachment will go on duty at the mine at 8 a.m., leaving their camp in time to reach the mines by that hour; they will work until 8 p.m., when they will be relieved by the second detachment; this detachment will leave their camp in time to reach the mine by that hour. It is all important that the officer in charge of the detachments be prompt, and see that their men are ready to move at the proper hour, and that no delay take place in their reaching the mine. Each detachment will be divided into two sections, one the mining section and one the windlass section. The mining section will consist of six men and be divided into two sub-sections of three men each, consisting of one miner, one shoveler, and one assistant; each sub-section will work three hours and rest three hours. The windlass section will consist of eight men, divided into two sub-sections of four men