Minn. R. agency 144, ch. 4725, MONITORING WELLS, pt. 4725.7250

Current through Register Vol. 49, No. 24, December 9, 2024

Part 4725.7250 - ELEVATOR BORINGS

Subpart 1.General.

An elevator boring must be constructed according to the general construction standards in parts 4725.2010 to 4725.3875 and cased, sealed, and maintained according to this chapter to prevent the vertical movement of water.

Subp. 2.Casing.

The boring must be cased to the bottom of the excavation.

Subp. 3.Exception.

The boring is exempt from the requirements in parts 4725.2150; 4725.2175; 4725.2185; 4725.2250, subpart 8, concerning extension of the casing 12 inches above the established ground surface; and 4725.2250, subpart 11.

Subp. 4.Hydraulic fluid leakage protection.

Hydraulic fluid must be protected from leakage by:

A. attaching a watertight cap or plate to the bottom of the casing and surrounding the casing with neat-cement or cement-sand grout. The grout must extend at least three inches above and three inches below the bottom of the casing. The grout must be inserted according to part 4725.3050, subpart 2;

B. grouting the inside of the casing with cement-sand grout or neat-cement grout. The grout must extend at least two feet above the bottom of the casing and be inserted according to part 4725.3050, subpart 2; or

C. encasing the hydraulic cylinder in a Schedule 30 plastic outer pipe or sleeve with the bottom of the pipe or sleeve capped and the top extending above the pit floor.

Subp. 5.Repair.

In addition to the requirements of part 4725.3750, when a hydraulic cylinder is removed from an elevator boring for repair or replacement, the boring must be protected from hydraulic fluid leakage according to subpart 4.

Subp. 6.Sealing.

An elevator boring which is unsuccessful or no longer in use must be sealed according to part 4725.3850. The hydraulic cylinder, debris or obstructions, and sand placed around the hydraulic cylinder must be removed prior to sealing.

Minn. R. agency 144, ch. 4725, MONITORING WELLS, pt. 4725.7250

17 SR 2773; 33 SR 211

Statutory Authority: MS s 103I.101; 103I.111; 103I.205; 103I.221; 103I.301; 103I.401; 103I.451; 103I.501; 103I.525; 103I.531; 103I.535; 103I.541; 103I.621; 144.05; 144.12; 144.383; 157.04; 157.08; 157.09; 157.13