Encyclopedia of Environmental Science and Engineering, Volume I and II

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.

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