Encyclopedia of Environmental Science and Engineering, Volume I and II

(Ben Green) #1

POLLUTION FROM MINE DRAINAGE 1019


TABLE 2
Cost and effectiveness of various at-source prevention and corrective techniques

Control techniques Effectiveness % Cost Remarks

Surface mine reclamation 25–90 $300–3000/acre Includes backfilling, regarding, contouring, and water control
structures. Prevents acid formation, erosion control, runoff of
dissolved soils. Cost and effectiveness controlling factors are nature
of surface and overburden, slope of land, and proposed use of land.
Mine sealing (air) 0–50 $1000–5000/seal. Additional
cost of $5000–100,000/seal
may be required to control
entrance of air through
subsidence holes,
boreholes, outcrop, etc.

Sealing of an underground mine to prevent entrance of air. Prevents
acid formation. Cost of effectiveness depend on the ability to locate
and seal all air paths to the mine, type and condition of mine
operating and type of seal. Most mines cannot be airsealed.

Mine sealing (flooding) 75–99 $1000–20,000/seal.
Additional costs of $5000–
20,000 may be required to
control drainage through
bore holes, outcrop, etc.

Sealing of an underground mine to completely and permanently flood
the working. Prevents acid formation and sometimes all discharges.
Cost and effectiveness depend on the ability to seal all discharges,
size of mine, dip of seam, outcrop condition, condition of mine
opening, type of seal, and amount of grouting required. Is not
applicable to all mines.
Drainage diversion 25–75 $200–20,000/acre The prevention of water from entering the mine area. Prevention of
siltation and flushing of pollutants. Cost and effectiveness depend on
ability to divert as much water as possible in properly designed
structures.
Impoundment 50–95 $350–1000/acre-ft Flooding of surface mine pits. Prevents acid production. Cost and
effectiveness depend on complete and permanent flooding of the
material responsible for acid production.
Refuse pile reclamation
(reject material from
mining and processing)

25–75 $1000–3000/acre Stabilizing a refuse pile with soil, chemicals, vegetation, etc. Prevents
acid production and siltation. Cost and effectiveness depend upon
the availability of the land in which the refuse piles can be filled and
also upon the availability of impervious materials such as clay, fly
ash, or limestone for compaction over the surface of the filled area.
Reject tailing pond (reject
material from mining
and processing in slurry
form)

25–95 $300–2000/acre Stabilizing of tailings by flooding, soil covering, chemicals, vegetation,
etc. Prevents air pollution and discharge of suspended and dissolved
solids. Cost and effectiveness depend upon the size, location.

Revegetation 5–25 $70–700/acre Establishment of vegetative cover on reclaimed surface mines, reject
piles, and pond. Prevents erosion. Cost and effectiveness depend on
the type of cover, soil conditioning, and thickness of cover required.
Controlled pumping and
drainage

25–75 $0.190.23/1000 gallon Involves rapid removal of water from a mine before it gets
contaminated or discharge of contaminated water at regulated rate so
that dilution provides minimum contamination effects. Cost and
effectiveness depend upon the characteristics of the material in the
mine, contact time between water and exposed materials, rate of
pumping, pumping head, and amount of dilution water available.
Inert gas blanket Under research and development Filling of an underground mine with an inert gas to prevent acid
production. Control of the bacteria in a mining environment.
Prevents acid production. Technique does not show merit at this
time.

Sterilization Under research

Internal sealing Under research and development Internal sealing of underground mine to prevent acid production and/or
mine drainage discharge.
Longwall mining Under research and development Allows complete removal of the coal in an underground mine. Mine
roof collapses behind the working face, eliminating “breathing” of
the mine.
Daylighting Under research and development Strip mining of a previously mined underground seam. Removes pillars
left before. Surface must be reclaimed.

C016_010_r03.indd 1019C016_010_r03.indd 1019 11/18/2005 11:03:04 AM11/18/2005 11:03:04 AM

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