ENFORCE20572

• Permit No: C1987072
• IBM Index Class Name: Enforcement
• Doc Date: 8/6/1987
• Doc Name: LA PLATA 1 MINE STIPULATION 4 FN C-87-072
• From: MLRD
• To: LA PLATA COAL CORP
• Violation No.: CV0000000
• Media Type: D
• Archive: No

STATE OF COLORADO
Roy Romer, Govei
DEPARTMENT OF NATURALRESOURCES
MINED LAND RECLAMATION DIVISION
DAVID C. SHELTON, Dlreetor
DATE: August 5, 1987
T0: peter O'Connor
FROM: John T. Doerfer ~~
RE: ACID DRAINAGE TREATMENT PLAN - LA PLATA MINE - FILE N0. C-87-072
I have reviewed the plan received July 17, 1987 from La Plata Coal Corporation
for treating acidic drainage on the La Plata Mine site. This plan was
submitted in response to Stipulation No. 4 of the permit.
The plan identifies lime or limestone as the neutralizing agent, a system of
two ponds as the reactant vessel, and a limit of pH 6 as the criterion for
treated water discharge. These are the major elements which need to be
identified in any treatment plan. However, in order to provide further
clarification on how the treatment system will operate, the permittee should
submit the following information to the Division to satisfy the stipulation.
1. The plan states lime or limestone will be used. A finely ground limestone
(median size - 10 microns) is preferable to an agricultural type lime for
use in the system. The limestone will reduce the pH slower than lime but
act longer. Lime should be used only if fine limestone is not available.
2. The plan should describe why two (2) ponds will be used. If the second in
the series acts as a backup to the first this should be stated. The plan
should state at what level the iron precipitate will be removed from the
first pond and where this material will be placed on the site.
If limestone addition is planned to take place in the second pond as well,
the level or frequency at which the second pond will be cleaned should
also be stated in the plan. If the outflow from the first pond following
treatment does not meet the pH discharge criterion, additional treatment
could take place in the second pond.
3. The sizing and location of the treatment system should be described in the
plan. The following information should be included:
A. Identify the location of the acidic seep on a revised map of
hydrology (Exhibit 7) or on a new figure,
B. Show the location and extent of each pond on the map or figure,
C. Estimate the excavated volume of each pond,
D. Show the location and direction of flow into and out of the ponds,
423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-2273 Tel. [phone]