1. All exploration holes shall be adequately plugged with cement from the bottom of the hole upward to a point three feet below plow depth. The remainder of the hole between the top of the plug and the surface shall be filled with cuttings or nontoxic material.

2. If multiple aquifers alternating usable quality water and salt water zones, or other conditions determined by the Chief to be potentially deleterious to surface or ground water are encountered, the conditions must be isolated immediately by cement plugs. “Usable quality water” is defined as ground water that is used or can be used for a beneficial purpose, including, but not limited to, domestic, livestock, or irrigation uses. Each hole shall be plugged with cement to prevent water from flowing into or out of the hole or mixing within the hole. The length of the plug shall be determined by the Chief based on available data on the specific site.

3. Each exploration hole shall be plugged as soon as reasonably practical after drilling, unless multiple aquifers are encountered.

4. Alternative plugging procedures and materials may be utilized when the applicant has demonstrated to the Chief’s satisfaction that the alternatives will protect ground waters and comply with the provisions of this chapter. In the event that a hole is more suitably plugged with a nonporous material other than cement, the material shall have characteristics at least equal to cement.

5. In the event that an exploration hole is to remain unplugged pursuant to the provisions of § 45.1-278, the procedure contained in subdivision 2, if applicable, shall be applied and the exploration hole shall be plugged to the extent required by that paragraph.