Agricultural Activity. The cultivation and tillage of the soil, dairying, the production, cultivation, growing and harvesting of any agricultural commodity, the raising of livestock or poultry, and any practices performed by a farmer or on a farm as incident to or in conjunction with those farming operations, including preparation of these products for market.

Angle of Repose. The maximum angle of slope (measured from horizontal plane) at which loose cohesionless material will come to rest on a pile of similar material.

Backfill. Earth, overburden, mine waste or imported material used to replace material removed during mining.

Borrow Pits. Excavations created by the surface mining of rock, unconsolidated geologic deposits or soil to provide material (borrow) for fill elsewhere.

Critical Gradient. The maximum stable inclination of an unsupported slope under the most adverse conditions that it will likely experience, as determined by current engineering technology.

Excavations for On-Site Construction. Earth material moving activities that are required to prepare a site for construction of structures, landscaping, or other land improvements (such as excavation, grading, compaction, and the creation of fills and embankments), or that in and of themselves constitute engineered works (such as dams, road cuts, fills, and catchment basins).

Grading. To bring an existing surface to a designed form by cutting, filling, and/or smoothing operations.

Minerals. Any naturally occurring chemical element or compound, or groups of elements and compounds, formed from inorganic processes and organic substances, including, but not limited to, coal, peat, and bituminous rock, but excluding geothermal resources, natural gas, and petroleum.

Person. Any individual, firm, association, corporation, organization, or partnership, or any city, county, district, or the state or any department or agency thereof.

Reclamation Plan. The applicant's (operator's) completed and approved plan for reclaiming the lands affected by his surface mining operations conducted after January 1, 1976, as called for in Section 2772 of the Act.

Resoiling. The process of artificially building or reconstructing a soil profile.

Stream Bed Skimming. Excavation of sand and gravel from stream bed deposits above the mean summer water level or stream bottom, whichever is higher.

Surface Mining Operations. In addition to the provisions of Section 2735 of the Act, borrow pitting, streambed skimming, segregation and stockpiling of mined materials (and recovery of same) are deemed to be surface mining operations unless specifically excluded under Section 2714 of the Act or Section 3505 of these regulations.

Topsoil. The upper part of the soil profile that is relatively rich in humus, which is technically known as the A-horizon of the soil profile.