75D301-18-Q-68156_-_Drilling_Scope_of_Work.pdf

Vertical Hole Drilling at the CONSOL Energy Enlow Fork Mine

2041, Pleasant Grove Road, Claysville, PA 15323

Work Scope:

In order to evaluate the effects of longwall-induced subsurface deformations on the mechanical integrity of gas well casings, NIOSH/PMRD/GCB intends to drill an 8-inch vertical hole to 475 feet below the surface at a surface site above the CONSOL Energy Enlow Fork Mine F28 development. Three strings of in-place inclinometer sensors at 10-foot intervals will be installed along a 3.34-inch O.D. plastic casing from 175 to 225 feet, 275 to 375 feet, and 425 to 475 feet below the surface. The plastic casing will be grouted from the bottom of the hole to 150 feet below the surface. In addition to the inclinometer monitoring hole, three 8-inch vertical permeability monitoring holes will be drilled to 135-ft, 235-ft, and

395-ft depths to monitor longwall induced permeability changes. The field work pertaining to the drilling operations, in-place inclinometer casing/sensor installation, and solid/slotted casing installation will consist of several separate tasks. The project will consist of:

Task 1. Drilling an 8” vertical hole down to 475 feet below the surface. Anticipated costs for the completion of this task include:

a. Mobilization of drill rig

b. Drilling 475 feet of 8” vertical hole

Task 2. Installation and stage-grouting of 3.34-inch O.D. inclinometer plastic casing, and installation of three strings of in-place inclinometer sensors. Anticipated costs for the completion of this task include:

a. Standing time of the drill rig

b. Installation and stage grouting the 475-foot long inclinometer casing, which will be purchased separately

c. Installation of three strings of in-place inclinometer sensors, which will be purchased separately

Task 3. Drilling three 8” vertical holes down to 135 feet, 235 feet, and 395 feet, respectively, below the surface and installing solid steel casing down to 20 feet above the bottom of hole and installing slotted casing at the bottom 20 feet of each hole.

The contractor will perform all drilling and installation operations, and will coordinate with

NIOSH/PMRD/GCB and mine personnel.

Safety Compliance

The contractor will comply with all on-site safety policies. The contractor will cooperate with all on-site hazard/safety training and procedures, including making all personnel and equipment available for inspection at any time while entering, leaving, or working at the site.