_GENERAL DOCUMENTS - C1981017 ‎(283)‎

• Permit No: C1981017
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Name: Bid Documents ‎(IMP)‎
• Media Type: D
• Archive: No

-35-
The ,effect of increasing soluble salts is short-termed over the
life-of-mine. Upon completion of mining, there will be no discharge from
the mines and upon successful rev tion, the preparations plant ponds
will be removed. Thus, upon nit n, the soluble salt content of the
surface water should return t .
The mine discharge has not had an effect on the ion balance in the
stream. The baseline information indicates that the surface and ground
water is dominated by calcium bicarbonate. The mine discharge water and
the receivin Creams are likewise dominated by calcium bicarbonate.
On
impacts of the Coal Basin mining activities on surface
water is an increase in the sediment load carried in the stream from the
road s tem. Mid-Continent has monitored two streams, Bear Creek and
Braderic'C, Creek which have drainages that are not affecte by the mini
operations he Division used the average total suspended solids co nt
as the base 'ne val,ue for determining increased sediment yields fr the
roads. All t roads are within the Coal Creek and-Dutch Cre k
drainages. a ore, ona sediment above the aver a for Bear
r`ad ich Cre ks was attributed to the roads. Using th' method of
comparison of the to for Bear and Braderich Creeks as Tent levels
with data for Coal a d Dutch Creeks as disturbed sampl and the water
quality data submitte by the applicant, the Divisio determined that
the road to Mine No. 5 ontributes a roximatel 6 tons of sediment pex4
r)c� year to Coal reek an the Mines 1 , 2, 3, and 4 hdul roads contribute r,d
2.778 tons of sediment per�yrear to Dutcn rYoa� There are 154 acres of
roads within the permit area; thus, the average sediment yield from the r V9
road system would be approxima ly 18 tons o This figure is
most likely higher than the sedi n actually generated from the roads. vtF� '
b ;Dutcn
e Bear and Braderich Creek water eds'are smaller than the Coal and
` Creek watersheds. Likewise,
t e flows in Coal and Outch Creeks are
gher than in Braderich and Bear,,Cre s and sediment loads are greater
r unit volume. As flows increase in treams, the velocity alsocreases, thus, the capacity ,of the wate to carry sediment is increased.
agricultural areas, an.,erosion rate of 22 ons/acre/year would be
excessive. However, iry teep mountain terrain ith�lfrge amount of
Mancos shale, this er6sion rate is of excessive. A rosion rates in
excess of 200 tons ,per acre are quite common see ater Quality Data in
Volume 5) . Therefore, the sediment yield from the ads is not excessive
and should not -significantly affect water quality.
The applicant submitted a plan to monitor runoff from tj road system to
refine the estimate of sediment generated by the road sys em. This plan
should be adaptable in determining the effects of downgrade g the roads
from haul roads to access roads «pon completion of the rock nnel
project. I,-.�11