REP21401

• Permit No: C1981025
• IBM Index Class Name: Report
• Doc Name: PASSIVE MINE DRAINAGE TREATMENT
• Media Type: D
• Archive: No

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f luctust iom and long term changes in tlw),
groundrster recharge systems, and the 6eologit
formations rhith discharge [he mine rater.
Surface hydrology evaluations re re performed to
date rmine peak flora expected during ma for prec-
ipitation event/ so that treat went structures
could be aired appropriate ly, and [o establish
the overall hydrologic balance in the project
area.
Sail end vegetation types rithin [he raterahed
re re cherac[e tized in order [o Dreditt runoff
volumes end to Lacili[ate rat lame[ion of the
site folloring installation of the treatment
system. Large scale topographic naps of [he
mine drainage vic ini[v re re preps red or ob-
tained. Climata[it Factors such ee rioter con-
ditions, type of precipitation, end elevation
re re considered in Che design. Pe rmiaaion for
the feasibility study frov the landorne rs and
[he amen of the rater rights ras obtained.
N.P.D.E.S. and 404 Permit requirements verc
eddrea sad.
The second stage of the design process involved
an eveluat ion o[ the mining activities rhich
resulted in the acid mine discharge. Thia
effort consisted of reviering existing mine yaps
and/or talking rich individuals knwledgeable
about [he mining activities and the layout of
the mine. The potential for future mining roe
evaluated [o asses [he probability that revered
mining activities could provide for the ab-
atement of the acid mine drainage problems. The
mineral reserves and the mineral rights
ownership ps [tern in the mine areas verc also
determined.
The third stage of the PMDT design process vss
aimed a[ properly siting treatment facilities.
This stage of the process vas heavily dependent
on the data gathered during the raterahed
evaluation. Deviled stream channel
x asurementa of the mine dra inege verc done.
Both longitudinal and crou-sec bond profiles
re re -prepared fraa actual surveys or large ate le
topograph it yaps. This information roe
necessary to evaluate alternate locations [or
the component/ of Che trntment systems.
The final stage in the design process ras aimed
et the specific facilities to be included in the
PHDT systems. Paciif ty designs included
drarings of treet••en[ component/ and coot actor
bid spec i[ita[ions. Reclasu (ion pl sns verc
developed Co revege[a[e the peat ri [h
etidophillic and equephillic planes and ~~to
ravage v [e [he other disturbed areas rich
appropriate spat ies (eg. accen roads, staging
areas, horror and exervated srns).
Design Con sideretione The siting requirexnts
for PMD7 pest, bogs are bs sad on lsborstery
obse rva[ions for u[ion exchange upacit ies of
different va rietiea of peat (eg. ]0- Y00 vstq/100
gm dry peat )~ end observed perneability
factors for peat (eg. 100-200 [t3 peat/rpm
drainage).g•q The ern snilable end sui able
for use as an art{[{s iel bog is another major
airing consideration.
t
A weans for providing uniform inflor o[ mine
rater into Che entire cross-sectional area of
nth bog ws net<uary. This ru ¢complished
rich • cork liner or exfilt u[ion gallery a[ [he
upstream end of both bogs.
The boltm of the Thompson bog ras sealed rich
ben[oni[e (ley. Since peat is relatively
imps rmeah le and racer seeks the Ilor path of
lean[ re eistance, the bottom o[ the bog must nor
have • greater permeability than the Deal. The
Marshall a5 bog vas excavated in a tighc ea ndy
clay subetra[e rh ile the Thompson •2 bog vss
l orated pa rtially in fill macar is 1.
The bogs re re placed in valet ively flat
I oesCiona. The Nershell bog bottom originally
a loped 15:1 (f[) horis ontal to verc is al. Ac
Chet elope, peat fended to ra eh down-grad ienc,
and mine drainage infl ws [ended to channelize
thrwgh the bog. The bog ras reexcavated [o
final grade of i0:1 (f[).' Thia is similar to
the slope in the Thompson bog. At flora of
8,500 gpd the movement of rater through [he
Marshall bog is barely perteptsble. As in-(love
increa ae to 14,L00 gpd channeliza[ion and sheet
flws are observed.
Loose rock (heck dame, as described by Heeds
30 verc designed for retaining the peat and
alloying rater rithin [he bogs [o drain freely
into [he receiving stream channel. Highly
faceted quarry rock vas utilized. Such rack
remains stable at higher ang lea of repose than
rounded river rock. Loose rock (heck dams
should not exceed 6 Eeet in height in any case.
Loose rock check dens ere preferred aver single
fence shack dams. A tingle fence dam ras
conatruet ed belor the Thompson bog using river
rock and plastic coated the inlink fence
materials. The single fence failed and • loose
rock dam ru crated by default. Filter fabric
at the dorttstream end of both bogs prevents peas
from rash ing through or clogging the loose roc4
drain.
It is de si cable co place the ion exchange mad ivm
(eg. peat) upstream of the neutralize[ ion medium
(eg. limestone). Thia gre stly reduces armoring
of [he limestone surfaces by mecal ox idea.
Hwever, since many draining mine portals are
located on steep mountain elopes, it vat/ be
deeivble to louts ascot ion devices each u
drop structure e, ups( re+v of artificial Doge er
vet land e. Thia could Dromo[e ne ul o: id etioe
end prat ipi[etion prior to vac al sdeorbtion eed
filtretien in the bog, end neat nliatioo Dv [M
limestone.
Limestone tren<Me end dro9 s[rvctures ere Wet
looted in steep tern io. grif tlv flerieg otvr
[code co sever tM lineaceee prevvet{sig tY
buildup of octal oxide pncipicatee wad Rvpee-
suling (cQeiw• sulphate prat iplunsl.
Sceurimg cnetes dear net tin aerfarva. AI w,
turbulent' Hers iv lisrsteae !{Ilya efsv.els
provide good savories sec tarfae dlsvlM
e:solutfee which sm6avcvs eM vwtnliutiar of
vinerel ecidiry.il Li~sta~i~l d
se lectvd ter Lt'a pvrieya
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