[Code of Federal Regulations]
[Title 40, Volume 19]
[Revised as of July 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR146.32]

[Page 711-712]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 146--UNDERGROUND INJECTION CONTROL PROGRAM: CRITERIA AND STANDARDS--Table of Contents
 
     Subpart D--Criteria and Standards Applicable to Class III Wells
 
Sec. 146.32  Construction requirements.

    (a) All new Class III wells shall be cased and cemented to prevent 
the migration of fluids into or between underground sources of drinking 
water. The Director may waive the cementing requirement for new wells in 
existing projects or portions of existing projects where he has 
substantial evidence that no contamination of underground sources of 
drinking water would result. The casing and cement used in the 
construction of each newly drilled well shall be designed for the life 
expectancy of the well. In determining and specifying casing and 
cementing requirements, the following factors shall be considered:
    (1) Depth to the injection zone;
    (2) Injection pressure, external pressure, internal pressure, axial 
loading, etc.;
    (3) Hole size;
    (4) Size and grade of all casing strings (wall thickness, diameter, 
nominal weight, length, joint specification, and construction material);
    (5) Corrosiveness of injected fluids and formation fluids;
    (6) Lithology of injection and confining zones; and
    (7) Type and grade of cement.
    (b) Appropriate logs and other tests shall be conducted during the 
drilling and construction of new Class III wells. A descriptive report 
interpreting the results of such logs and tests shall be prepared by a 
knowledgeable log analyst and submitted to the Director. The logs and 
tests appropriate to each type of Class III well shall be determined 
based on the intended function, depth, construction and other 
characteristics of the well, availability of similar data in the area of 
the drilling site and the need for additional information that may arise 
from time to time as the construction of the well progresses. Deviation 
checks shall be conducted on all holes where pilot holes and reaming are 
used, unless the hole will be cased and cemented by circulating cement 
to the surface. Where deviation checks are necessary they shall be 
conducted at sufficiently frequent intervals to assure that vertical 
avenues for fluid migration in the form of diverging holes are not 
created during drillings.
    (c) Where the injection zone is a formation which is naturally 
water-bearing the following information concerning the injection zone 
shall be determined or calculated for new Class III wells or projects:
    (1) Fluid pressure;
    (2) Fracture pressure; and

[[Page 712]]

    (3) Physical and chemical characteristics of the formation fluids.
    (d) Where the injection formation is not a water-bearing formation, 
the information in paragraph (c)(2) of this section must be submitted.
    (e) Where injection is into a formation which contains water with 
less than 10,000 mg/l TDS monitoring wells shall be completed into the 
injection zone and into any underground sources of drinking water above 
the injection zone which could be affected by the mining operation. 
These wells shall be located in such a fashion as to detect any 
excursion of injection fluids, process by-products, or formation fluids 
outside the mining area or zone. If the operation may be affected by 
subsidence or catastrophic collapse the monitoring wells shall be 
located so that they will not be physically affected.
    (f) Where injection is into a formation which does not contain water 
with less than 10,000 mg/l TDS, no monitoring wells are necessary in the 
injection stratum.
    (g) Where the injection wells penetrate an USDW in an area subject 
to subsidence or catastrophic collapse an adequate number of monitoring 
wells shall be completed into the USDW to detect any movement of 
injected fluids, process by-products or formation fluids into the USDW. 
The monitoring wells shall be located outside the physical influence of 
the subsidence or catastrophic collapse.
    (h) In determining the number, location, construction and frequency 
of monitoring of the monitoring wells the following criteria shall be 
considered:
    (1) The population relying on the USDW affected or potentially 
affected by the injection operation;
    (2) The proximity of the injection operation to points of withdrawal 
of drinking water;
    (3) The local geology and hydrology;
    (4) The operating pressures and whether a negative pressure gradient 
is being maintained;
    (5) The nature and volume of the injected fluid, the formation 
water, and the process by-products; and
    (6) The injection well density.

[45 FR 42500, June 24, 1980, as amended at 46 FR 43163, Aug. 27, 1981; 
47 FR 5000, Feb. 3, 1982]