40 CFR § 147.2555 - Aquifer exemptions since January 1, 1999.

In accordance with § 144.7(b) and § 146.4 of this chapter, the aquifers described in the following table are hereby exempted from the definition of an underground source of drinking water, as defined in 40 CFR 144.3:

Aquifer Exemptions Since January 1, 1999

Formation	Approximate depth (feet below ground surface)	Location
Powder River Basin, only approximately 0.4 square miles of the Lance Formation which is less than 0.005% of the Basin at indicated depths and location.	3,800–6,800	Two cylindrical volumes with centers in the wells COGEMA DW No. 1 and 18–3 Christensen respectively, and radius of 1,320 feet. Both wells are located in the Christensen Ranch, in Johnson County, WY. The COGEMA DW No. 1 well is located at approximately 450 feet West of N/S line and 100 feet North of E/W line of SE/4, NW/4, Section 7, T44N, R76W. The 18–3 Christensen well is located approximately 600 feet West of N/S line and 550 South of E/W line of NE/4, NW/4, Section 18, T44N, R76W.
Lance Formation at indicated depths and locations	3,800–6,500	Two cylindrical volumes with centers in the wells COGEMA DW No. 2 and COGEMA DW No. 3 respectively, and radius of 1320 feet. Both wells are located in the Christensen Ranch, in Johnson County WY. The COGEMA DW No. 2 is located at approximately 2,290 feet from the North line and 1130 feet from the East line SW1/4 SE1/4 NE1/4 of Section 7, Township 44 North, Range 76 West. The COGEMA DW No. 3 is located approximately 3300 feet from the North line and 1340 feet from the West line center of SW1/4 of Section 5, Township 44 North, Range 76 West.

[64 FR 14803, Mar. 26, 1999, as amended at 67 FR 47726, July 22, 2002]