Minnesota Administrative Rules

6132.2300 OVERBURDEN PORTION OF PITWALLS.

Subpart 1.

Goals.

The overburden portion of pitwalls shall be designed, developed, and reclaimed to be structurally sound and promote progressive reclamation.

Subp. 2.

Requirements.

Surface overburden portions of pitwalls shall be designed and constructed to the following standards in items A and B.

A.

The final slopes shall consist of benches and lifts as follows:

(1)

the toe of the surface overburden portion shall be set back at least 20 feet from the crest of the rock portion of the pitwall;

(2)

lift heights shall be no higher than 60 feet and shall be selected based on the need to protect public safety, the location of the pitwall in relation to the surrounding land uses, the soil types and their erosion characteristics, the variability of overburden thickness, and the potential uses of the pit following mining;

(3)

the sloped area between benches shall be no steeper than 2.5:1; and

(4)

runoff water shall either be temporarily stored on benches or removed by drainage control structures.

B.

When acceptable research demonstrates that the goals are satisfied, the commissioner shall approve other measures that satisfy subpart 1.

Statutory Authority:

MS s 93.44 to 93.51; 103G.222

History:

17 SR 2207

Published Electronically:

June 11, 2008