30 CFR § 77.217
For the purpose of §§77.214
through 77.216-5, the
(a) Abandoned as applied to any refuse pile or impoundment
and impounding structure means that work on such pile or structure has been
completed in accordance with a plan for abandonment approved by the District
(b) Area-capacity curves means graphic curves which readily
show the reservoir water surface area, in acres, at different elevations from
the bottom of the reservoir to the maximum water surface, and the capacity or
volume, in acre-feet, of the water contained in the reservoir at various
(c) Impounding structure means a structure which is used to
impound water, sediment, or slurry, or any combination of such materials.
(d) Probable maximum precipitation means the value for a
particular area which represents an envelopment of depth-duration-area
rainfall relations for all storm types affecting that area adjusted
meteorologically to maximum conditions.
(e) Refuse pile means a deposit of coal mine waste which may
contain a mixture of coal, shale, claystone, siltstone, sandstone, limestone,
and related materials that are excavated during mining operations or
separated from mined coal and disposed of on the surface as waste byproducts
of either coal mining or preparation operations. Refuse pile does not
mean temporary spoil piles of removed overburden material associated with
surface mining operations.
(f) Safety factor means the ratio of the forces tending to
resist the failure of a structure to the forces tending to cause such failure
as determined by accepted engineering practice.
(Secs. 101, 508, Pub. L. 91-173, 83 Stat. 745, 803 (30 U.S.C. 811, 957))
[40 FR 41778, Sept. 9, 1975]
Subpart D--Thermal Dryers