[Code of Federal Regulations]
[Title 30, Volume 1]
[Revised as of July 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 30CFR77.217]

[Page 611-612]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 77--MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES--Table of Contents
 
                    Subpart C--Surface Installations
 
Sec. 77.217  Definitions.

    For the purpose of Secs. 77.214 through 77.216-5, the term:

[[Page 612]]

    (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 Manager.
    (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 elevations.
    (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]