01-2570. Underground Injection Control Program: Substantial Modification to an Existing State-Administered Underground Injection Control Program

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Notice; request for public comment on a substantial modification to the Wyoming 1422 underground injection control program.

SUMMARY:

The Safe Drinking Water Act (SDWA) establishes the Underground Injection Control (UIC) Program, which is designed to protect present and future underground sources of drinking water (USDWs) and to prevent underground injection through wells that may endanger these drinking water sources. The SDWA provides for states to apply for and receive approval from the Environmental Protection Agency (EPA) to administer their own UIC programs, if the State regulations and statutes meet EPA's minimum requirements as specified in 40 CFR parts 144, 145, and 146 or the “protective” standard specified in section 1425 of the SDWA for oil and gas related wells. One of these requirements specified in 40 CFR 144.7 is the identification of USDWs. If an aquifer meets the definition of a USDW as stated in 40 CFR 144.3, injection into it through a Class I, II, or III injection well can occur only if the aquifer is exempted. Exemption from classification as a USDW can take place only if it is exempted from the classification as a USDW according to the criteria in 40 CFR 146.4. Therefore, injection through a Class I, II, or III injection well into any aquifer that meets the classification as a USDW requires a demonstration that the aquifer is not currently serving a drinking water system and is not expected to do so in the future. Certain exemptions are considered substantial program revisions. Once the State program receives final approval, subsequent modifications to the programs can be requested by the State and accomplished through the specifications under 40 CFR 145.32. Upon receiving a request for modification of a State program, EPA determines if the requested modification is “substantial” or “non-substantial.” A request for an Aquifer Exemption is one type of program modification that can be requested by the State. An Aquifer Exemption request often accompanies a Draft Permit for an injection well that will inject into a USDW that can be proven to meet criteria specified in 40 CFR 146.4. If the Aquifer Exemption is considered a “non-substantial” modification to the existing State program, then it can be evaluated and approved or disapproved by the EPA Regional Administrator. However, if the aquifer proposed for exemption contains formation fluids with less than 3,000 mg/l Total Dissolved Solids (TDS) which is related to any Class I well or is not related to action on a permit (except in the case of rule authorized enhanced recovery operations in oil fields), then the Aquifer Exemption represents a “substantial” modification to the State program. In this case, according to 40 CFR 145.32, the proposed program revision shall be published in the Federal Register to provide the public an opportunity to comment for a period of at least 30 days. The authority to approve or disapprove the proposed change lies with the EPA Administrator. The proposed substantial revision to the Wyoming 1422 UIC program for which public comments are being solicited is a request for the exemption of approximately 1 square mile of the Lance Formation at an approximate depth of 3,800 to 6,500 feet below ground surface surrounding two non-hazardous Class I injection wells in the Powder River Basin within Johnson County, Wyoming.

Public comments are encouraged and a public hearing will be held upon request. A request for a public hearing should be made in writing and should state the nature of the issues proposed to be raised at the hearing. A public hearing will be held only if significant interest is shown.

DATES:

EPA must receive public comment, in writing, on the proposed modification of the Wyoming 1422 program by March 1, 2001.

ADDRESSES:

Send written comments to Valois Shea, Ground Water Unit (8P-W-GW), Environmental Protection Agency, Region VIII, 999 18th Street, Suite 300, Denver, Colorado, 80202-2466, by the deadlines provided above. Copies of the application and pertinent materials are available for review by the public between 8:30 a.m. and 4:00 p.m. Monday through Friday at the following locations: Environmental Protection Agency, Region VIII, Ground Water Unit, 4th Floor North Terrace, 999 18th Street, Denver, CO 80202-2466; and Department of Environmental Quality, Herschler Building, 122 West 25th Street, Cheyenne, WY 82002.

FOR FURTHER INFORMATION CONTACT:

Valois Shea, US EPA Region VIII, 8P-W-GW, 999 18th Street, Suite 300, Denver, CO 80202-2466, [phone].

SUPPLEMENTARY INFORMATION:

I. Introduction

On September 25, 2000, COGEMA Mining, Inc., (COGEMA) and the Wyoming Department of Environmental Quality (WDEQ) submitted to EPA a request to grant an Aquifer Exemption for the Lance Formation in the areas contained within Township 44 North, Range 76 West, 6th P.M. , SW1/4 NW1/4 Section 5, SE1/4 NW1/4 Section 5, SW1/4 Section 5, NE1/4 Section 7, NW1/4 SE1/4 Section 7, NE1/4 SE1/4 Section 7, NW1/4 NW1/4 Section 8, NE1/4 NW1/4 Section 8, SW1/4 NW1/4 Section 8, and NW1/4 SW1/4 Section 8, surrounding two Class I Non-Hazardous deep injection wells, the COGEMA DW No. 3 and the COGEMA DW No. 2, in Johnson County, WY. The total area of the Lance Formation included in the proposed exemption is approximately 1 square mile. The proposed injection intervals are approximately 3,800 to 6,500 feet in depth below ground surface for each well. The proposed injection interval is based on the depth of the Lance Formation intersected by adjacent Class I Non-Hazardous deep injection well, COGEMA DW No. 1. A similar exemption of a portion of the Lance Formation was proposed for the COGEMA DW No. 1 in the Federal Register on August 27, 1998 (63 FR 45810). The notice also solicited public comment of the proposed action. No public comments were received, and the final notice of the Aquifer Exemption was included in the Federal Register on March 26, 1999 (64 FR 14799).

The Lance Formation fluids contain less than 3,000 mg/l Total Dissolved Solids (TDS), dictating that this Aquifer Exemption be a substantial revision of the Wyoming Underground Injection Control (UIC) program approved under section 1422 of the Safe Drinking Water Act. Criteria for classification of a program revision as substantial or not, are in UIC Guidance #34, Guidance for Review and Approval of State UIC Programs and Revisions to Approved State Programs. The procedures to follow to approve or disapprove substantial program revisions in the UIC program are in § 145.32 and in UIC guidance #34. The aquifer proposed for exemption has been determined by WDEQ to be too deep to be considered as an economically feasible source of drinking water. EPA has examined the Aquifer Exemption request, the accompanying information, and responses from WDEQ and COGEMA to EPA requests for additional supporting information, and, for reasons described herein, recommends approval of this request to exempt the designated portions of the Lance Formation from classification as a USDW.

II. Background

COGEMA operates the Christensen Ranch in-situ leaching uranium mine within the Wasatch Sandstone Formation in Johnson and Campbell Counties, WY. The Wasatch Formation overlies the Lance Formation by about 2,600 feet at the mine site. The mining operation has comprised five well fields to date. The operation has reached the phase where large scale restoration of the groundwater within all the well fields is required to close the operation. Two Class I Non-Hazardous deep injection wells are currently being used to inject the above-mentioned waste stream into previously exempted portions of the Lance Formation. However, with the current disposal capacity of the two existing wells, the rate of the restoration process is limited. A large portion of the mined aquifer is on “standby” until either (a) the disposal capacity can be increased by the addition of two new wells, or (b) the restoration process is completed in other mined-out areas. The additional disposal rate capacity created by these two proposed wells will increase the rate of the restoration process significantly, restoring the Wasatch Formation water quality to its class of use standards two years sooner than without the two additional wells. The mined areas on “standby” awaiting restoration must require a continuous bleed-off because a negative pressure regime must be maintained in order to keep the underground water flow directed into the mining area to prevent the contamination of adjacent areas of the aquifers (the Wasatch Formation). To maintain the negative pressure, water must continuously be pumped out of the mined areas in standby mode. The additional two years required for complete restoration without the two new wells would result in approximately 31 million additional gallons of waste stream to be disposed of that could be avoided by the construction of two new wells, increasing the disposal capacity.

Groundwater restoration is conducted to return the groundwater affected by mining to its baseline condition or to a condition consistent with its pre-mining or potential use upon completion of mining activities. After the restoration process is completed, the concentrations of contaminants are reduced to levels below drinking water standards. For the successful restoration of the groundwater quality within the mined-out areas of the Wasatch Formation, a wastewater disposal capacity of 300 to 500 gallons per minute (gpm) will be required over the next 6 years.

III. Injectate

The injectate will consist of operational bleed streams from commercial in-situ leaching uranium mining operations as well as fluids from the restoration of the aquifer. The constituents on the injectate include the following process and restoration bleed streams: normal overproduction (well field bleed) streams, yellow cake wash water, laboratory wastewater, reverse osmosis brine, and groundwater sweep solutions. The bleed streams are defined as non-hazardous, and as beneficiation wastes exempt from regulation under the Resource Conservation and Recovery Act as stipulated by the Bevill Amendment (40 CFR 261.4(b)(7)).

IV. Basis for Approval of Proposed Aquifer Exemption

The information provided by COGEMA in the reports included in the docket adequately addresses the requirements of 40 CFR 146.4 supporting approval of the proposed Aquifer Exemption request for the Lance Formation.

146. 4 Criteria for exempted aquifers

An aquifer or a portion thereof which meets the criteria for an “underground source of drinking water” in § 146.3 may be determined under 40 CFR 144.8 to be an “exempted aquifer” if it meets the following criteria:

(a) It does not currently serve as a source for drinking water;

The nearest documented well completed in the Lance is over 24 miles to the west of the site. The exact use of this well is unknown, but appears to be associated with oil or gas development. Approximately 30 miles to the west, the Lance outcrops to the surface and wells developed there are for livestock use. Where the Lance Formation occurs near the surface at the western edge of the Powder River Basin 30 miles southwest of the proposed exemption area, five wells jointly completed in the Lance and Fox Hills formations formerly served as public water supplies to the municipalities of Midwest and Edgerton, WY, until 1997. At that time, the wells were abandoned because of low water productivity (40 gpm sustainable flow) and the expense of treatment that would be required to continue using these wells as a public water supply. The towns of Midwest and Edgerton have determined that piping in pre-treated water 50 miles from Casper is more economically feasible than continuing operation of the wells completed in the Lance/Fox Hills formations, even at the relatively shallow depth of 1,500 to 2,000 feet. Therefore, the Lance is no longer supplying water to a public drinking water system within 30 miles of the proposed Aquifer Exemption area.

(b) It cannot now and will not serve as a source of drinking water because:

. . . (2) It is situated at a depth or location which makes recovery of water for drinking water purposes economically or technologically impractical.

The depth of the Lance Formation within the Aquifer Exemption area ranges from 3,800 to 6,500 feet based on the information from the COGEMA DW No. 1 well. The Powder River Basin consists of a deep syncline. The Aquifer Exemption area occurs very near the deepest occurrence of the Lance Formation within this syncline.

Alternatively, the Wasatch Formation overlies the Lance Formation in the Aquifer Exemption area and provides a more shallow, potential water supply source available for use in the area. According the USGS publications referenced by COGEMA, any water supply wells (aside from water flood wells related to oil production) in the proposed Aquifer Exemption area are completed in the Wasatch Formation. The Wasatch Formation is a high quality, prolific aquifer, located at approximately 1,200 feet in depth or shallower throughout the Powder River Basin, including the proposed Aquifer Exemption area. The Wasatch Formation, alone, contains a volume of water that would supply a population of approximately 1.3 million people for 100 years. Given this abundant, shallow supply of high quality groundwater, it is reasonable to conclude that the deeper Lance Formation will never be required to provide a source of drinking water in the area of the Aquifer Exemption.

COGEMA provided a cost evaluation for the capital costs and estimated operating costs for developing a private (50 gpm) and a public (750 gpm) drinking water well, including treatment costs based on the water quality analysis of samples collected from the Lance Formation as a water supply source within the Aquifer Exemption area. The costs to develop the Lance within the exemption area were compared with estimated costs to develop the Wasatch Formation as an alternative public water supply (at the 750 gpm rate). The incremental cost increase for using the Lance Formation water versus Wasatch Formation water as a drinking water source for the public water supply is approximately $3,691,250. The incremental increase in operations and maintenance cost of using the Lance water over the Wasatch water as a drinking water source would be $2.40/1,000 gallons.

The Midwest-Edgerton public water supply scenario should be noted as the most compelling support for the approval of this Aquifer Exemption request and the feasibility of using the Lance Formation as a public water supply. The five wells were abandoned in favor of piping in an alternative water supply. The decision to abandon these wells was based on the economic impact of the need to treat the water and the low production rates of the wells, even though the costs of development had already been expended. Furthermore, the wells tapped shallower portions of the Lance Formation compared to the depth of the Lance within the proposed Aquifer Exemption area.

In summary, the Lance Formation probably will never be considered to be an economically feasible source of drinking water in the area of the Aquifer Exemption because of the great depth, low water production capacity, and treatment costs that will be necessary based on the Midwest-Edgerton wells. The cost of developing the Lance Formation as a drinking water supply within the proposed Aquifer Exemption area is high compared to that of developing shallow, more prolific, and higher quality sources of drinking water, such as the Wasatch Formation. The Wasatch is better suited for development in this area as a source of drinking water due to higher producing capability, significantly better water quality, and no water treatment costs.

V. Regulatory Impact

There will be no modification of regulations in the Wyoming DEQ Water Quality Rules and Regulations as a result of this proposed program modification. The Code of Federal Regulations 40 CFR part 147, subpart ZZ, which codifies the State of Wyoming UIC 1442 and 1445 program within the Federal regulations, will be modified to include this program modification once approval has been granted by the EPA Administrator.

Dated: January 11, 2001.

D. Edwin Hogle,

Director, Ground Water Program, Office of Partnerships and Regulatory Assistance, Region VIII.