Laserfiche WebLink
I <br />Section 816. 102 (b) Continued. <br />cut-and-fill terraces may be allowed, if the terraces are compatible <br />with the approved postmining land use and are appropriate substitutes <br />for construction of lower grades on the reclaimed lands. The terraces <br />shall meet the following tequirements: <br />(1) The width of the individual terrace bench shall not exceed 20 feet, <br />unless specifically approved by the regulatory authority as necessary <br />for stability, erosion control, or roads included in the approved post- <br />mining land use plan. <br />(2) The vertical distance between terraces shall be as specified by the <br />regulatory authority, to prevent excessive erosion and to provide long- <br />term stability. <br /> (3) The slope of the terrace outslope shall not exceed lv:2h (50 per- <br /> cent). Outs lopes which exceed lv:2h (50 percent) may be approved, if <br />i they have a minimum static safety factor of more than 1.3, provide <br /> adequate control over erosion, and closely resemble the surface configu- <br /> ration of the land prior to mining. In no case may highwalls be left as <br /> part of terraces. <br /> (4) Culverts and underground rock drains shall be used on the terrace <br /> only when approved by the regulatory authority. <br /> As stated in Section 30 CFR 816.102 (a}, Kerr Coal's plan to re- <br /> store an undulating topography which approximates premining grades <br /> makes the use of cut sad fill terraces unnecessary. <br /> {c) Small depressions may be constructed, if they- <br /> (1) Are approved by the regulatory authority to minimize erosion, <br /> conserve soil moisture, or promote vegetation; <br />• <br /> 816-133 <br />