1018 POLLUTION FROM MINE DRAINAGE
Separating surface and underground mines is not feasible
as they frequently occur together and interact to add to the
problem.
Presently operating mines have certain characteristics
which differentiate mines them from other mines. Primarily
because they are now in operation a responsible owner or
operator can be located and people, equipment, machinery
and power are available at the mine site. This allows con-
sideration of procedures to treat the mine drainage as well
as procedures to reduce or minimize the amount of pollut-
ants discharged both during the remainder of the mine’s
life and after mining has been terminated. Procedures pres-
ently available may be employed to minimize the amount
of mine drainage pollution which issues from an operat-
ing mine, but no procedures are now available which can
totally eliminate it.
Non-operating, or abandoned mines, generally do not
have any responsible person readily available, or any other
resources such as personnel and machinery, which makes
abatement techniques more expensive for this type of mine
than for one which is operating.
When a mine is still in the planning stage, it is easier
to plan for future prevention of pollution and thereby reduce
it. For instance, provisions can be pre-planned for a mine to
have rapid and complete drainage during the mining opera-
tion, thereby reducing the pollutional discharges which other-
wise may need to be treated. Additionally, improved miningmethods can provide for minimum void spaces after mining;
also water level control after mining ceases can be provided
only during the mine pre-planning stages.
The methods for alleviating mine drainage may be
divided into the two basic categories of treatment of mine
drainage, and prevention of the formation of discharge of
pollutants.
Treatment removes pollutants by physical/chemical
means and generally results in only specific pollutants being
removed or reduced. The process must continue for as long
as the source produces pollution and usually in the case of
mine damage this is tantamount to “treatment in perpetuity.”
Disposal of wastes and constant usage of power or chemicals
made such treatment unduly consumptive of both human and
physical resources. Treatment methods for coal mine drain-
age are summarized in Table 1 and many of the methods are
applicable to other types of mine drainage pollution.
Prevention is the total cessation or massive reduction of
the formation or discharge of pollutants during and after the
operating life of the mine. Prevention of all forms of pollution,
including dissolved and suspended materials, is obviously more
desirable than simple treatment of pollution with its attendant
problems. Provisions for prevention of the formation of pollu-
tion cab be planned into a mine while it is still on the drawing
board. Specific techniques for prevention and correction of
pollution from mines, both operating and non-operating, are
shown in Table 2.TABLE 1
Summary of treatment techniquesPollutants removedaNeutralization and
aerationMicrobial iron
oxidationReverse
osmosis Ion exchange Flash distillationd Electro-dialysisProduct
recovery Silt basinsAcidity XXX NA XX Xc XX Xe Xf NAIron XX XX XXX Xc XXX? Xf NA
Aluminum XXX NA XXX Xc XXX Xe Xf NA
Manganese Xb NA XXX Xc XXX Xe Xf NA
Copper XX NA XXX Xc XXX Xe Xf NA
Zinc Xb NA XXX Xc XXX Xe Xf NA
Hardness — NA XXX Xc XXX Xe Xf NA
Suspended solids X NA NA NA NA NA Xf X
Dissolved solids — NA XXX Xc XXX Xe Xf NA
State of artg CU PP PP R, PP, FSOc FSD Re R R, CU
Cost, $/1000h 0.05–4.55 UK 0.30–2.57 0.30–2.53 0.33–3.25 0.52–2.52 UK 0.02–1.0
Waste productj S S B B, R B B S,B,R S
a NA—Not applicable,? Questionable, X-degree to which removed, the greater number of “X”s the higher the removal.
b Must be raised to very high pH.
c Various ion exchange techniques are under evaluation. Their effectiveness and which pollutant is removed depends on the technique.
d 5 mgd plant is under construction in Pennsylvania. Techniques has only a limited potential.
e Technique will not operate where iron is present in water.
f Various product recovery schemes are under consideration; however, all are still in research stage.
g R—Research, PP—Pilot Plant, FSD—Full Scale Demonstration, CU—Common Usage.
h Cost depends on the degree of pollution, size of plant, pre- and post-treatment requirements. UK—Unknown.
j Each treatment process has a waste product that must be disposed of and creates additional problem. S—insert sludge, B—highly mineralized brine,
R—regenerate.C016_010_r03.indd 1018C016_010_r03.indd 1018 11/18/2005 11:03:04 AM11/18/2005 11:03:04 AM