B01 Attachment 8 Well Abandonment.pdf

Pamunkey Indian Tribe Construction of Sanitation Facilities February 2022 Well Abandonment

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SECTION 02528

WELL ABANDONMENT

PART 1 - GENERAL

1.01 SUMMARY

A. This section includes the proper abandonment of wells including well holes, submersible pumps, drop pipe, and submersible cable.

1.02 RELATED WORK

A. Section 02512 – Individual Household Water Systems B. Section 02525 – Individual Well Drilling

1.03 REFERENCES

A. Applicable state codes for Commonwealth of Virginia.

1.04 SUBMITTALS

A. Method of abandonment.

PART 2 – PRODUCTS

2.01 MATERIALS FOR WELL ABANDONMENT

A. Conform to applicable state and local regulations.

B. See table at the end of the section for acceptable materials for the type of well being abandoned.

PART 3 - EXECUTION

3.01 EXISTING CASED WELLS

A. Pull pump and drop pipe from existing wells prior to abandonment.

1. Well pump and drop pipe is the property of the homeowner. Contractor to dispose of well pump and drop pipe offsite if directed by the homeowner.

B. Disconnect interior pressure tank from water system if new community water service line is being installed.

C. Cut driven casing off 2 feet below ground surface.

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D. Fill hole with appropriate material.

3.02 METHODS OF ABANDONMENT

Well Type Method

Unconsolidated Formation Wells

Driven-Point Sand-Point 2 1/2” dia.*

Material may be poured without using a conductor # pipe.

Wells & Drillholes 2 1/2” dia.

Conductor # pipe required except when bentonite chips or pea gravel is used.

Dug Wells Conductor # pipe not required unless well is 18” diameter.

Bedrock Wells

Bedrock wells not extending through Maquoketa Shale

Conductor # pipe required except when bentonite chips or pea gravel is used.

Bedrock wells extending through Maquoketa Shale

Conductor # pipe required except when bentonite chips or pea gravel is used.

Dug Wells Conductor # pipe required only for placement of grout or concrete; or if well is 18” diameter.

Well Pits Must perforate floor & knock out 1 wall of pit.

# The terms conductor pipe and tremie pipes are synonymous. The bottom of the pipe must remain submerged in the grout throughout the filling process. Conductor pipe must be metal pipe, thermoplastic pipe rated for at least 100 psi or rubber-covered hose reinforced with braided fiber or steel and rated for at least 300 psi.

3.03 RECORDS

A. File abandonment reports with designated state agency and provide a copy to the Engineer within 30 days.

END OF SECTION

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Table: Acceptable Materials for Well Abandonment

Well Type

MATERIALS

Clean Clay or Silt or Clean Native Soil

Approved Bentonite Chips ^

Neat Cement Grout

Concrete@ Sand-

Cement Grout

Bentonite-Sand Slurry w/ min. mud wt 11 lb./gal

Chlorinated, Sand Free Pea Gravel

Unconsolidated Formation Wells

Driven-Point Sand- Point 2 1/2” dia.*

No No Yes No No No No

Wells & Drillholes 2 1/2” dia.

No

Yes, if well is 4” min. dia. &

500’ max.

depth

Yes Yes Yes

Yes, Provided top 5’ filled with neat cement grout, sand-cement grout or concrete

Yes, but in depths below

250’

Dug Wells

Yes (top 5’ of curbing must be removed following filling)

Yes Yes Yes Yes No No

Bedrock Wells

Bedrock wells not extending through Maquoketa Shale

No

Yes, if well is 4” min. dia. &

500’ max.

depth

Yes Yes Yes No Yes, but in depths below 250’

Bedrock wells extending through Maquoketa Shale

No

Yes, in top 500’ & for 40’ plugs at top 7 bottom Maq. Shale contact surfaces

Yes Yes Yes No

Yes, in depths below 250’, but not in M. Shale contact surfaces

Dug Wells Yes, but only in unconsolidated portion of well

Yes Yes Yes Yes No No

Well Pits Yes Yes Yes Yes Yes No No

* Driven-Point, Sand-Point wells may be pulled prior to filling the hole if the well is 25’ deep or less.

The top 5 feet of dug well curbing must be knocked out to provide soil contact with the filling material.

@ When concrete is used, the gravel size may not exceed 1/3 the inside diameter of the conductor pipe.

40’ impermeable plugs shall be provided at each bedrock formation change. [See s. NR 112.26(7)(a)] ^ Bentonite chips may only be used for wells not deeper than 500 feet and having not more than 350 feet of standing water in them. The ships must be poured across a coarse mesh screen such that excess dust does not enter well. Pour rate should not be faster than 3 min.

per 50 lb. Bag to prevent bridging

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