Mine Mapping and Surveying - Coal Waste Impoundments: Risks, Responses, and Alternatives - page 62

acquire or copy mine maps from coal companies. The Federal Abandoned Mine
Lands Fund could be a source of funding for this activity.
Storage Risks
Damage to archived mine maps can result from improper storage, natural
aging of the materials used, water, fire, or other circumstances ( Sidebar 4.4 ).
MSHA requires that underground mine maps be kept in an area on the surface
to minimize the danger of loss by fire or other hazards (30 C.F.R. § 75.1200).
The committee concludes that electronic data storage can reduce the risk of
permanent loss or damage of mine map data and improve the ability to
maintain multiple backup files both on- and off-site. The committee
recommends that upon receipt of a paper copy of a mine map, the state or
federal agency should have it scanned into electronic data files. The original
paper maps should be stored in fire- and flood-proof vaults, while electronic
copies of mine maps should be stored on site with regular backup to an off-site
facility.
Mine Surveying
Accurate mine maps will be critical to future site assessment for coal waste
impoundments, as well as for other land-use decisions. An important
component of an accurate map is the closure of the mine survey. Closure is a
measure of the acceptable error within a closed-loop survey. Closure standards
for surface surveys vary widely by state ( Table 4.1 ) and type of real property
(e.g., urban, suburban, or rural). MSHA regulations (30 C.F.R. § 75.1200-2)
require operators of all underground mines to conduct a closed-loop survey, but
do not specify the standard of closure and the distance between the last closed
loop and the active face.
The committee concludes that the establishment of uniform mine surveying
and mapping standards is essential to ensure that underground coal mines are
accurately located with respect to other mines and surface structures, including
refuse impoundments. Therefore, the committee recommends that MSHA set
standards for minimum closure error for all underground closed-loop
surveys and that a closed-loop survey be maintained within a standard
distance (to be determined by MSHA).
Mine elevations are also an important component of a mine survey. The
mine elevations are posted on the map adjacent to each spad. The spad is the
underground equivalent of an iron pin or steel rod that marks property corners